I have because my Bobcat dealer said "they're designed to run wide open and that's how you should run it. It keeps everything working like it should". What do you all think?
We had a similar discussion a while ago about how wide open to run skidsteers, and I'm of the opinion that you don't usually need full throttle with a skidder. Not so with a mini-ex. I can't imagine feeling like I was getting anything done if it wasn't at full throttle.
Well, this has got me thinking... Years ago when I was running loader/backhoes I don't think I dug wide open. More like, enough throttle so that the engine didn't bog down when I put a good load on it. Maybe 3/4 throttle or so depending on the machine...
Our mini spends days idling when we are laying blocks, so soon as we start earthworks the throttle gets jammed open wide.
My machines are run at the lowest possible engine speed that i can without labouring the engine or making the hydraulics groan . Most machines have load sensing hydraulics that supply adequate oil and pressure throughout the rev range . The only time i run WOT is when i'm running a mower/mulcher . Wasting fuel and wearing out machines is not proffitable , when 1/2 the revs will do most jobs adequately .
Under no conditions do you want to run a piece of equipment or even a diesel mower for that fact WOT. Like any diesel engine they produce maximum torque at lower RPM's. Running the engine wide open only serves to waste fuel and there's is little power difference if any.
By mower/mulcher i meant the hydraulic powered excavator mounted kind which require all the oil and pressure the machine can supply .
I run between 3/4 and full. I find between 1/2 and 3/4 to be a bit too weak and slow even with the load sensing thingy. I'll change the rpm a bit every 1/2 hr of so if I'm steady on the machine and not getting on and off. I also shut the auto idle off if I'm working around people.
jammed WOT, how could you stand to work so slow?
Always wide open....The boss looks at you like "whats wrong with it" when you slow down. Out in the Heavy industry field where I've been for 25 years its hammer down or take a hike!
IMO it's a total waste of fuel to run wide open unless you're having trouble digging or lifting. I usually run at 1/2 or a little over that.
I suppose there are two ways of digging , run at full noise and feather the joysticks to control the beast or run at half noise and pull them back a poofteenth more to get the same speed .
That's the difference between someone owning the machine and an owner operator, there's no advantage to running it wide open, if you want to go fast, go jump in your truck. The world of machinery evolves around torque which occurs at lower rpm - look at the specs, and you'll see the only difference is the fan noise when you're WOT. It only sounds like you're working harder.
Yes I have heard several operators say the salesman said it run wide open. I started in 1964. This was right before I went in business I was working with 2 new International Harvester TD 20 dozers grading houses and pushing scrapers. The Man that owned the business had marked a line on the throttle to were the setting was like 4 notches from the top. He said that the machine would burn 20 gallons less diesel a day and do the same amount of work. If you don't need full power back off on RPM's a little. Just give it a try if it works you, along with saving fuel there is less wear on components as the rpm's decrease in most cases. 98% of the time you don't need full power. 44 years later I am still only using the power I need to get the work done and look at the thousands of gallons of fuel I have saved. The same thing applies to moving dirt speed is what wears out undercarrages. I am not saying never run full power only use what you need to get the work done.
Good point, you're only hitting the pile or dropping the blade for maybe 5-10% of the time, the rest o the time the engine is doing nothing. The same theory holds true for boat diesels (8.3liter) run them in the torque curve (40-50%) and you only burn around 12 gal per hour - at wide open throttle they burn 38 gal per hour and only increase the speed another 4 knots.
I run most stuff at 3/4 throttle. A little less noise and I get the same work done. Only time I'll run full wide open is if I'm in a scraper, cutting without a dozer behind me & when I have a farm tractor on a blower pushing silage up a pipe. Not having to unclog a pipe is worth the extra fuel and noise.
Id say the torque at lower rpms is correct, but the engine isnt doing the digging the pump is. I think your straining the pump at lower rpms because your not pushing the fluid fast enough. If the pump is straining what are you really saving?
My dealers master mechanic said that running closer to full was better because it kept the hydraulics cooler than running slower. I'm still a bit green so I'll take his word on it for the Kubota. So maybe there's the cooling thing to consider as well, specific to the different brands and age of machines. All you folks have way more hours than me so you would know better. Anyways after about 200 hours on the new machine I found about 85-95% was a good match for speed and my skill on this machine and I had more than enough power for digging.
Huh - The engine isn't do the digging???? The pumps on those engines are both geared and designed to operate at the torque rpm/level of the engine.
If I am grading or doing something critical I keep it around 1/2 throttle. I dont usually go above 3/4 throttle, I dont see the advantages of full throttle, you get the same amount of work done, and all that happens is the hydraulics move faster when you push the joysticks more, and the machine is a whole h#ll of a lot louder to. The only time I've ever put it at full throttle is when I was pulling some fallen tree's out of a pond and I needed every bit of the power I could get out of the machine..
I thought that the control was more of a speed RPM control as opposed to a throttle. The high/fast the setting thet faster things moved, not nessisarily more power just more speed.
I completely understand owner-operators looking at fuel savings, chain wear exc... But lets say you work on a deep cut sewer crew running a 375 cat. Ok run that beast at half throttle and try and get a loaded bucket of blue clay out of a 25 foot cut and get cycle time and feet per day. It aint gonna happen! If you can only get 400 foot of sewer in in a day cause you need to save fuel, when you would get 700 feet at full throttle, it's a no-brainer.Understood thats an extreme case, but what about the speed and cycle time on a mini-case excavator? I have operated both. The mini cycles twice as fast at full throtttle. Have any operators here tried running a concrete breaker on an excavator at half throttle? On a mini or a large backhoe, 590 case for instance. The breaker speed and the amount of concrete broken increases with RPM's!
I don't know maybe all the equipment I've run is different, but there is almost no difference in speed operation between 60-70% open verses WOT. Every job is different, if I'm trying to wrap a job to get the machine loaded and on another job then I'll run it faster than normal. It's sort of like driving a truck, we can all do 80 mph but we know sooner or later it will cost us our job or a ticket.
our mini ( kub. kx121 ) gets run wide open , unless your doing delicate work, same way with our pc 150 and pc 200 and d6 and kom. d65 we have, our 850 case dozer and cat 257b skidsteer have throttle pedals and for those I absolutley love it. the boss is a two position guy in a machine w.f.o and idle
I just don't get the connection of driving a truck fast VS running equipment wide open and risking your job. Making deadlines and making the company money requires production at peak efficency. Thats what all the Bridge, underground and Pile Driving companies I have worked for all these years have stressed. I do know the value of slow digging around utilities, fine grading in tight areas,Exc... Today I idled down my crane cause in a snow storm the signal man was not in perfect view, I get all that but the bottom line in fixed bid work is that the boss DEMANDS the job get done in peak performance at the quickest and safest pace. I here you IdelUp, it's just my viewpoint is different than yours.
I tend to run my micro excavator at full throttle due to it only having two gear pumps - so I find anything less than fully open is just too slow especially when slewing and raisng the boom and dipper simultaneously. I have asked myself this question before and thought about trying to measure the fuel consumption on my 1.6 ton mini which has variable displacement pumps and a hydraulic oil cooler when running at 75-80% and 100% rpm but I find that no two jobs are really the same as far as ground conditions or the actions/motions being asked of the machine to fairly compare. Then again should I be really concerned about fuel consumption on such small machines anyway as the differences are likely to be quite small?? (The engines in question have a maximum speed of 2200-2300 rpm anyway)
Most cowboys run'em wide open but it really depends on what your doing, like on real technical stuff , say digging around electrical lines you may only use 1/4 throttle.
I agree with the above totally. With excavators the large ones. They are made to run wide open. You have different work modes that allow for type of work your doing. Some do that automatically. Mini's are different and not that sophisticated. Unless I am working in a delicate situation I run WOT. The cycle times much better and others stated the machine needs to cool and it cant do that at 50% throttle. You cant run a hoe pac on a mini at anything less than WOT. It needs to make the GPM to run the hoe pac. If there is any doubt, check your owners manual, or contact your service department for the specific machine. There are like some brands or types of equipment that demand or allow for different operating styles. While it is true diesel engines make their torque at lower rpms, excavators need to turn pumps at certain rpms also to flow fluid to make cycle times and create hydraulic hp which is a function of gpm and hp. They also need to cool the engine and hyd oil.
I run WOT, very rarely do I bump the throttle down on any machine even when finishing. If you are a skilled enough Operator to Operate a machine safe and smooth to it's maximum potential then any less than WOT and your dogging it. The only times I bump the throttle down is if I am working in a really tight area and don't want the machine moving as fast as it can because it's dangerous. Or if I'm on a wheeled or tracked machine and WOT will spin them. In that case I give it as much throttle as possible without spinning the wheels/tracks. I can see wanting to save fuel but a mini x burns so little fuel anyways that I can't see it being worth cutting production down....xx% :beatsme to save a couple dollars worth of diesel. The loss of production would likely cost more than the savings in fuel. As mentioned by others, machines are designed to run at WOT. It gives the pumps maximum flow which directly affects the power and speed of the hydraulics and keeps everything running cooler. If it were true that a machine could have just as much power and the hydraulics were just as fast (making it just as productive) at less than WOT and save a bunch of fuel then I would think manufacturers would build them that way and market that like crazy.
I don't think this thread was meant to only apply to mini machines, it's all heavy equipment in general. In addition, it really has nothing to do with the users skill level or being able to handle the equipment as it does the fact that most all diesels reach their max torque power at considerable lower rpm that WOT. Therefore running the engine wide open just serves to add wear & tear on the engine and pumps and burn extra fuel - this is a proven fact.
I guess I must have somehow miss understood the title of the thread and where it was posted then. Compact Equipment > Compact Excavators > Do you run your mini-x at full throttle? That is absolutely true that diesel engines produce more torque at a lower rpm. And it is also true that engine rpm determines how much hydraulic flow there is. How much hydraulic flow there is determines how fast the hydraulics move. Therefore if you are not running at WOT the machine can not move as fast as it is capable of moving. Torque is not the only factor to take into consideration here. If it were then you could set your excavator at half or 3/4 throttle and be able to lift or pull just as much as you can at WOT. But you can't because the pump is not producing enough flow to the hydraulics to give them the power they need.
You should be able to "lift and pull" the same amount at lower revs , your machine will have full pressure at lower revs it just wont have flow . Flow equals speed . Using a hammer etc. obviously requires lots of flow so full engine revs are needed . My 23 tonne digger will pull itself towards the job , skidding the tracks if the object wont move , even at low revs . I think what IdleUp meant is that many people have given input to this thread , even people with larger gear . And it has morphed into a general discussion regardless of it's title .
No I don't see it that way Iron Horse. With all due respect to you and Idel Up There is no possible way to think a machine at half throttle can get IT DONE! I have seen since my Tonka days how this works, and in my fields of vision...i see it first hand. You cannot I repeat cannot get a job done at deadline efficency on a mini or a 375 at half speed performance and meet deadline. This is a physical impossibility!!! I will challenge anyone on a neutral site...or at my place to prove me wrong!I work 6 days a week so this meeting will have to be at my and yer best timing!!!
Of course a machine will rotate faster , dig faster and move faster at full engine revs , that's what flow does . Flow fills the cylinders faster and spins hydraulic motors faster . But if an operator is at full throttle and is pulling the sticks all the way back and not feathering them and sending most of the oil back to tank unused . The machine would be working dangerously fast . So what i'm saying is why feather the sticks and only use a portion of all that oil screaming through the sytem ? Working around people , buildings , trucks utilities etc at those speeds would be dangerous so they only feather the sticks , so why do it .
Who is feathering??? Yer the one talking about scaling back, and why?What I am saying is...these Hi powered machines are put together to be used to the maximum, excuse me (dangerously fast) is that a operator-is -scared type phrase? If it is...thats bad. If yer in the seat and that wide open throttle is making you nervous......GET OUT! This business has been run by go-getters that believe as I do that anyone who does not run his machine to the max is a man who will not make good money in the field.Operators that get laid off in this area are the guys that :"dont hustle" "dont care".....exc.....
My machine puts out 300litres per minute between the two pumps . I am not tracking while i am digging so i only need 150-200 litres per minute to work the boom , dipper and bucket . I could either run full thorttle and open the valves in the control bank 1/2 way or a bit better to give me the 150-200 litres or i could run half throttle or a bit better and open the valves fully to give me 150-200 litres per minute . It's a no brainer for me . You seem to be getting quite cranky that my opinion does not coincide with yours . I have said nothing derogatory to you but you have to me . Have you ever been on a machine or are you a schoolboy posting here ?
I like to get everything I can out of a machine, every machine. I want the fastest cycle times, the most breakout, the most tractive effort that the machine has. You don't get that at half throttle, but to each his own, if you feel that running an excavator at less the 100% buys a return somewhere, more power to you. I think at the end of the day, productivity pays the bills.
Torque = tractive effort on a machine with direct drive, I think that's where everyone is getting hung up on this thread. We're talking about excavators, let's leave dozers and loaders and everything else out of the equation. RPM's = pump output and on an excavator the pumps are doing the work. If you're not running WOT on an excavator, you're aren't getting the most out of it, simply put. Not to say you couldn't get the job done at 3/4 throttle, that is simply a matter of situation, but for the most production, excavators need to be run full tilt.
I think that mini excavators with variable displacement pumps are designed to run at less than full throttle as the pump compensates for the lack of engine speed by increasing the oil flow - that doesn't mean to say that it shouldn't be run at max rpm though. If we take into account the different operating modes used on modern larger machines which effectively tailor the engine speed and pump output to the specific task at hand then we could say that this is proof that different engine speeds are adequate for certain tasks - so therefore as stated earlier there is not always a need to run the engines on mini's fast all the time. However when finishing/grading with a mini excavator I prefer to run the machine fast because it generally speeds up the process (cycle times) although I know for a fact that I am requiring very little of the power that the machine is capable of producing at that speed. So whats best? speed? (especially if you can operate smoothly and efficently at speed) or running the engine at a speed relevant to the power requirements of the task in hand? Brilliant forum by the way guys.
I'm not sure how 1/2 throttle got mixed in the blend here, but most of the guys that tend to agree not to run wide open, are not talking about running a machine at 1/2 throttle. While the thread is posted on the mini forum, I can tell you this, I've run some small Kubota backhoes (L-35 B21) and those machines are actually dangerous at full throttle. I would never work with someone in the hole at WOT. The overshoot and backlash makes the machine dangerous at full throttle -while on the other hand, larger machines which have more mass are un-affected by this problem. The fact still remains that we're not talking only pump volume here, the pump is worthless without the engine behind it. If the engine develope's it's max torque or *** at 60-70% throttle, then that's where the pump behind the engine is designed to operate at max efficiency. Remember just like a automatic transmission in your truck, you have to match the transmission to the engine. Such is the case on all hydraulic and direct drive applications. I don't think anyone is saying you shouldn't run equipment wide open, each to their own.
Look at it this way. You need to walk excavator or loader what ever several miles on rough ground. I cut the power back and use a high gear or high speed setting for huydrostatic. I will get there the same time as the guy wot in a slower speed setting. The guy with the engine wot is doing wear and tear that is not needed. I can load end dumps at 7/8 trottle as fast as full trottle I just save fuel and wear & tear. As for heat clean your radiator and oil cooler that will stop the heat. If there was a pole as to repairs from wot operator vers as much power as needed you would be see the light. Cowboys cost money, cool hands save money. It's steady continues work that gets the job done with a well thought out plan. Keep the money in your pocket not the repair shop.
I realize this thread has turned into a discussion on all machines. Although my focus was on mini machines in my first post, I voiced my opinion on all machines as well. I disagree with the statement that you can have full pressure at lower rpm's. Pressure and flow are both increased with rpm. Try lifting something really heavy at part throttle, heavy enough to be close to the machines maximum lifting capacity and you will see. As well I have paid attention when mechanics have tested the pressures on machines I have operated...many different types and sizes. Max pressure is at full throttle. Now this one I am not 100% sure on, could be wrong. But the different work modes on a modern excavator do not effect the engine rpm do they? Don't they just determine which circuits get the most flow and pressure? Depending on what your doing you may want more break out force, lifting power, swing speed or whatever. But no mater where you want the power focused the most you still want all the power and speed you can get in order to be as productive as possible. I don't think the different work modes slow the machine down, which we all seem to agree reducing engine rpm does. Slow one circuit down and speed another up, yes. But dropping engine rpm would slow all circuits down and render the feature useless no?
A cowboy operator is one who runs wide open barely in control and beats on the machine. A productive operator is one who works a machine to it's full potential without beating it up. Cowboys cost money productive operators make money....in my humble opinion. I agree walking you don't need full throttle, I walk machines the same way. But walking and working are a two different things.
One thing that we all seem to agree on is that it is best to slow down the throttle when working near underground services and property!! As far as i'm concerned safety is more important than productivity.
Please take this as a help not a critic, profit by what has worked. You are tripping over dollars and picking up pennies. Yes if you need full throttle for a function OK. I am talking about the operator that always runs wot. The other day I watched as an obstruction was investigated. 710 backs in slams the throttle wot and starts taking off material to find out what was burried. The same could be done at 3/4 or 7/8. To get full power out of a Turbo Diesel Engine does not happen the second you need it, it takes maby 10- 15-20 seconds for the boost to come up. We used to check dozers for correct power and that is the way, check the boost. Put an engine on dino same deal. You are not going to get full power the second you need it. You will find that the modes of operation on excavators, relate to fuel delivered to the engine, and the amount the hydraulic pump strokes. I have spent a lot of time playing with different setting, and usually use normal work and power keep the throttle 2 clicks from the top. Even if you try 1 click you are going to see a savings. If you read some post the guys that feel they need to run wot, complain about fuel usage, motor replacements to name a few. I think there are a lot of different types of cowboys. When the operator automatic goes wot for each task, there is no way that he needs it. He may not be a cowboy but he should be thinking more about what he is doing. Blow and show. I will take a steady pace over that any day.
Regardless of what throttle setting you use; 3/4 or full, or how hard you pull the controls, the when the breakout force reaches it's pre-determined level, the bypass opens so all the throttle in the world won't change this setting. . . .
BrianHay , in regards to your comment on oil pressure not being at max untill engine speed is high . When the pressures on my 23 tonner were set as a warranty claim because they were incorrect from new , they were set at the second click from idle . Which is 1450 revs , it was then cracking the reliefs at 320BAR (4800psi) , the only reason that they did not do it at idle is because it stalled the engine . You should have full pressure at these revs , oil is incompressable . If you try it you will find that you can crack the relief valves at a little above idle , if you hook onto a stump etc. if not your pump is shot . I'm not having a go at anyone , drive as you feel . I'm just saying how i opperate mine . The work i do is different to all you guys , i pull trees out with a vertical tree extraction grab . I work on the third or fourth click out of a ten click dial . This gives me between 1650 revs and 1850 revs , which is plenty to pull these trees and walk to the next in high range . When i'm digging around big trees and tearing large roots i crank it up to click 8 = 80% which is where i would run while digging hard soil . I can keep up with my machines fuel usage daily with the 3 Jerry cans i carry in my car . The engine is a 172hp Cummins 6BTA which comes standard in many generator sets . It is working no harder than if that same engine was in fact in a generator so you would not expect it to use any more fuel than this . So it costs me around $90 per day in fuel , thats the saving i work towards . My machine has a swing speed of 13 revolutions per minute at WOT , that's a bucket speed of about 50 mph while swinging . I would hate to see a machine on a construction site , with people , buildings , vehicles and other machines working nearby with an excavator working at those kinds of speeds . (Just my opinion .)
Pressure and flow are 2 different variables. If I ran a hoe at 4 clicks and tried to dig anything, I'd be buried sitting next to a guy running wide open. You can have pressure to the lines all day, typically full pressure is built at fairly low RPMS but max flow is not. Flow is getting the work done, which also correlates to engine/pump RPM. The lower the RPM, the lesser amount of flow you're going to have. I agree that most of the time, running 80-90% throttle will probably get the job done, but if you're loading trucks or doing anything that requires serious production, I guarantee the boss is going to be on your ass to speed it up if you're not running full tilt. If running at 80% throttle is costing 10-15 seconds per truck, and that's very conservative. Do the math over an entire day and see what costs more, fuel or production. Now, with minis, I think they're worse. I can't get anything done with a mini at less than WOT, seriously, there just isn't enough juice. I think they're half as productive if you reduce RPM's by 25%, so again, what costs you more at the end of the day?
In general I find I can participate in discussions on this board without having to wear my Moderator hat at the same time. However, whilst this thread is very interesting I strongly object to several inferences here that basically insinuate that many here (and myself) are some sort of a poor operator (the word cowboy is used) because, in my case, I run my mini-ex at WOT whenever I can. As an O/O I can tell you that machine is my lifeline. So here's your first at last warning. Keep the personal insults, derogatory references and the like out of it and stay on topic. The topic is "mini" excavators at WOT....not excavators above 8 tonnes. Back to the thread. I run WOT for two reasons: 1.) my machines runs at a barely fast idle for 4 days out 5, so when we get to the digging, backfilling or loading of the truck I want to clear the cobwebs so to speak and make sure the engine is not getting carboned up. 2.) its plain and simple, the WOT setting is a lot faster than 75% (on my machine) and thats how I operate when its safe to do so. You can pretty much call me what you like, but please don't insult members here, that you don't know personally, because they have a different operating practice to your own.
^^well said - but i'm sure no offence was intended by anyone who used the said term^^ I feel that there is more than just engine/throttle speed in determining a 'good' operator such as excavating style, machine maintenance and general performance. The other thing to bear in mind with mini excavators, is that each manufacturer design's their machines to work in different ways with different pumps, engines and hydraulic systems so there may not be a general 'rule of thumb' when operating these unlike larger machines which all tend to offer various operating modes. If we all owned the same mini then this would be an easier discussion!!
I'm going to ask what might be a silly question... Is "full throttle" actually the highest speed at which a given engine is able to run without damaging itself? In other words, have the designers limited the engine output by limiting just how fast the "throttle" alone is able to make the engine run? Because if that's the case, then maybe peak operating efficiency is reached at (or very close to), that "WOT" speed, and any throttle setting lower than that will be less efficient. As a design feature, that would certainly make sense to me. Does anybody know for sure, one way or the other?
My 3.5 tonne Yuchai that i traded on the 23 tonner had in the opperating manual "it is recomended that the machine should not be worked below 1800rpm's" . It had a WOT speed of 2650 rpm's .
WOT = Full Throttle = the high engine RPM allowed for that engine design. You can get this usually from the shop manual, it's not always in the operator manual. I have tractor manuals that also refer to this as high idle (highest RPM allowed). That did not mean that the engine had to be operated at that RPM only that it should not exceed that GOVERNED RPM. Again it does not mean that the engine has to be run at FULL THROTTLE unless it was required.
I have not had mine long, but I have been running full throttle so far. Once I get used to it, I may try it at less to see how it works.
Yeah, I get emotional sometimes speaking about equipment at highest possible output IronHorse, nothing personal. I was just raised at high output hi reward. Sorry I missed your post , I was out of town...
Boss tells us run it wide open thats what the governor is for
I started this thread. A lot of good posts on each side of the fence, but at the end, I still don't know what's best for the machine. Guess I'll try running it at 3/4 and see how she does. This is just a personal/weekend thing for me. I'm not trying to meet any deadlines or high production quotas. I just want to do a job in a timely manor and be good to my machine. I am working it hard. Clearing hardwoods with it. Digging out roots and stumps. Walking timber and laps to piles and the burn pit. Generally over working the machine, but it's mine, it's all I have and I'm careful with it. Wish I could afford a 20 ton machine, but it would be overkill in the long run. Thanks for all the great posts!
Our pleasure Country. We all have different opinions, and work practices but in the end we all try to help each other out, minus me and my over-the-top attitude sometimes!!!
Could try running at 75-80% for general duties, if the machine struggles then raise it up until their is no engine hesitation. Use 100% for tracking, as speed is helpfull when travelling otherwise you will be there all day!!!! As you say its your machine so run it how you feel is best for your tasks.
when it's all said and done...answer this.If you are running a mini excavator at half speed...can you get from the front of a building just traveling to the back in 10 seconds, no it takes 20. Ok . If you are digging a trench 100 foot long by 4 feet deep at half throttle....it takes , say 1 hour. At full throttle......one half hour. Tell me how to justify that !!!
The function of a hydraulic motor is nothing like the way a hydraulic ram functions .
Sort of like the truck driver saying if I go 95 mph I could get there sooner . . .
That adds to the entertainment factor though.. I spent a little time on the machine this weekend. Ran it at 3/4 throttle. Everything of course was slower and it was weak. I ran it like that for an hour or so. Just to try and get used to it. I was doing my normal, digging out smaller trees, piling and then walking them to the burn pile. After an hour I pushed it up to full throttle and it was like a new machine, fast and strong again. Maybe it just me or my particular machine, but 3/4 throttle is just too weak and slow. At most, I'm only putting 30 hours a month on the machine. So if full throttle does put more wear on it, I still should be ok with my limited use.... I was more worried about fuel consumption though. Mine just seems to burn a lot of fuel compared to what others have said.... I'll try running it at 3/4 again when I have some fine grading to do and see how that works.
Experimentation is the key and as you say no one speed is adequate for every task so you have just got to play around a bit!!
The thread is in the mini excavator forum. So, i figured that was what the question was about too. Mine are wot for digging. If not, they tend to heat up a little. I do slow them down for diggin in tight areas. But, without wot, the speed of the stick, bucket digging, boom, and slew, are all noticeably slower at 70%. At least on a mini
full throttle all the time, doesnt matter if im stripping some topsoil or searching for other utilities or fine grading. i'll controll the speed with my joysticks, cause after the 3 seconds of delicate work i want to be WOT to dump my spoils and returning for another pass. like others have said i want the most i can get from a machine and 60-70% throttle is no where near as fast as 100%
Yeah, that's pretty much what I'm finding. Anything less than 95-100% WOT is too slow and under powered. As the OP on this thread, it was meant only for mini-x's. It would be dumb to lump all equipment together and ask the same question.
Most of the time I run the mini-ex at about 70% throttle. But occasioannly when you need more power like getting out of a ditch or moving from on eplace to another, I go 100%. So it's really up to the job you are doing.
Hi all, New memeber from Adelaide, South Australia. I run a Cat 301.8C and run the throttle to suit the conditions. Around pipes or areas where pipes could be I back it off for more "feel" but when the going gets tough I crank it up to full for max. power. Bruce
Welcome to Heavy Equipment Forums Croweater. You croweaters will soon out number the Sandgropers here.
Then we will send some of this weather back to you, at full throttle!!!! Welcome croweater, it's good to see another one on the forum. Rn'R.
Thanks for the welcome!! I am making small talk now to lose my probationary members status.
WTO, is the way to go, imo, until you get to the stuff you want to "feel" before you rip it up... I usually back off the throttle a little. Nothing can ruin your day faster than sending out the utlity company to charge you for repair on a marked line.
I say giver her you know what! Burn up the machine, make money, and when one machine is stuffed, throw it out and buy a brand spanking new one. No one I know pays me to go slow. And I'm an owner operator. Pete
Straight from a manufacturers mouth . http://www.youtube.com/watch?v=NI_2us0bG4k&feature=PlayList&p=ADEFE42B7EADB9BB&index=7
Like a lot of others here I vary the rpm's to suit the job. I do not see the point of revving the guts out of the machine if I am doing 'fiddly' work and by the same token when I need extra working speed and a bit more digging power the throttle is flat out. I guess it depends, if an ex is working at maximum capacity it should have max rpm and if you are gently uncovering pipes or something the machine should be backed off. On my machine (Kobelco SK005) I do find that it's speed and power output varies with engine rpm. However mostly I run the baby ex at just under WOT. I also think that this poll should have a C answer of sometimes. On a related note, out on the farm harvesters are ALWAYS run flat out because that is how they are designed to operate, whilst usually a farmer will buy a tractor that is slightly bigger than the job it needs to do and then backs off the revs a bit. We used to run the tractors at about 1800-1900 rpm, whilst WOT is 2200-2400 rpm. This reduces engine wear, cabin noise and fuel consumption. Doing the maths this means the engine turns 24000 times an hour more at WOT and every stroke is wear and uses Diesel. In a 24 hour day that is 576000 revs. This also has the advantage of when you need a bit of extra power to get through a tough spot or up a hill, you have reserve. However these days with torque rise engines that is not such a drama. This will also apply to OTR trucks, which are geared so that at the highway speed limit (100kmh in Oz unless it is a road train) the engine ticks over at about 1800-1900 rpm. I reckon if someone brought out a truck that needs to be at WOT to maintain 100kmh, no one would buy it. Sorry for going slightly off topic.
I guess i swing both ways. When i ran the bosses equipment, we had to control the speed with the controls. Even fiddle work. One day i was idled down looking for a utility. The boss comes over and says: "You see that man over there" Yes "He is paying to hear this machine run". Ok boss. Now i own my own equipment, doing mostly what I want to do. Most of the time i control speed with the throttle. It just seems easier on me and the machine. But i guess the Boss was right. Because when you open the owner’s manual of about any Backhoe first thing it says. "Operate Machine at full throttle". So I guess if you are making good money and keeping customers happy. Full throttle! Buy a new machine every few years and live large. When you have what you have, and want it to last as long as possible. Maybe turn it down a notch or two and try to go the distance?
That's why we don't hire rednecks! :drinkup
I will make no bones about it, I agree with redneck pete!!!!
The throttle should be like on my combine. Just a toggle switch. Its all or nothing
There is a difference between running a machine hard and abusing it. If you are talking about working it hard to get the job done quicker to get onto another job I agree but if you mean cutting corners like not greasing it regularly or doing the servicing and thus cutting the life expectancy of the machine in half then I do not agree. Remember when you trade a machine you do not make money, the dealer makes money.
My experience is...Run it hard....full throttle ALL the time. Service as needed...grease exc...when would you slow it down except to look for utilities???
http://www.youtube.com/watch?v=3hWPei84YLs&feature=PlayList&p=ADEFE42B7EADB9BB&index=5 Another one from the Volvo factory , showing the operator working between 1200 and 1400 revs . And they go on to say that the only time the revs would need to be increased is if high volumes need to be shifted and fuel usage is of no concern . When is fuel usage of no concern ??? And yes , i agree if the pressure is on , wind it up , but for everyday excavations i will stick to what the manufacturers recommended . They may know a bit more than I . I admit I have strayed a little as the thread was about mini's but i can't find any info on them , ya or nay .
Before gettting into skidders I was a diesel mechanic. I have also built lots of engines over the years particularly aircooled vw engines for off road racing. The basic physics of engines is the faster something is moving (piston) the higher the force when it changes direction. So the more revs the more force on bearings, rods, gudgeons etc the faster the wear. As an owner operator I only use as much throttle as is required to get the job done. Saves fuel, saves wear, saves your ears. There is no documented evidence (that I am aware of) that running a diesel at full revs makes it last longer. I think its an old wives tale me self.
Sorry, where I was going with the mechanic bit was that we would rebuild the engines on our machines and there was never a discernable difference between the engines of those who we know run them hard and those that used only the power they needed. Provided they were serviced properly and not damaged by overheating etc they were about the same at rebuild time. So the only difference would be in fuel consumption and productivity. So if there is no requirement to run it full throttle and part throttle gets the job done at the same speed then there is no benefit running full throttle all the time.
This is the last time I will post on this topic so here it is. Find me a bid on a project that ask's the contractor for bids on digging up a footing in a tight alley that stipulates a mini excavator must be deployed. Time restraintes and budget are key here. Does the bidee put in clause for mini run at full power or half power? I think not....Thank you for your time
No the bidee would ask for bids and accept the best one in thier view.
Very well said!! :drinkup
I use the the throttle according to what the conditions are and the machine I am running. My bobcat 331 works the best and the smoothest at full throttle. It has gear pumps. My 435 with will cycle the work group fine at 75% but to run the tracks or swing at a decent rate ,it works best at full throttle.When I'm placing rock foe a wall it's lower rpms so I don't bang things up.Variable piston pumps are amazing for being efficient at different rpms. Minis don't seem to have the room for big engines so you have to run wide open. If someone has the skill to master a machines controls running wide open is no big deal. But I've see guys beat a mini to death acting as if speed is the only way to go. Put a big bucket , full throttle and a guy that can't feather his swing and you will have a workgroup wore out in no time. Scott
This has been covered and the general consensus is that if it's advantageous to run flat out, do it. If you wanna sit there and have the mini rev at full rpm while you are trying to gently uncover a sewer line then do it. All I am saying I don't because I don't see the need for it, I sit on top of the motor and do not have a cab and lowering the rpm gives me more control. However if I am doing basic digging I do run it at full rpm because I get more done and truck drivers are not going to be happy having to wait for Mr Gentle to slowly fill up the truck.
I run my excavator to suit the conditions, Most of the time it is maxed. When walking or doin finiky work she is toned down .:deadhorse
I'm the oppisite... I want full control when doing finicky or technical work. With my machine the only way to have that precise control is to have her turned up. Other wise she's unresponsive and slow with input from the controls... And as far as walking, if I want to get where I'm going before my cloths go out of style, she's gotta be pull'n some R's....
I take it you are referring to the 7.5 tonne 442? Does that have electric assist controls? http://www.bobcat.com/excavators/why_bobcat/advanced_hydraulics Which may well mean the machine is designed to work best at full rpm, whilst more primitive machines (like mine) have direct control (the control levers are attached direct to the valves) and work more precisely at lower revs.
I run my 331 at 3/4 throttle most times. Drop it back if I am working close to helpers or am in and out of machine doing ground work. Seems to be only a small speed or lift difference between half and 3/4. Definitely no point in running wide open.
Yeah, the 442 is the only machine I have now. Not sure, but I think it does have electric assist controls....
Are electric assist controls and servo controls the same??
Not sure how they work exactly but I am guessing it is a control by wire system, as found in some airplanes and accelerators in cars (although Mercedes-Benz is developing a brake by wire system ).
My 435 has hydraulic servos or pilot controls, I'm not sure about the 442 but I did not realize that were" wire only"controls. It's been a week since I last posted and I made a effort to analyze how I run my machine. Picking and placing rock and moving the machine . rotating the tracks, most of the stuff I do is 3/4 throttle. Half throttle next to someone or utilities is fine, and if I'm in a hurry, traveling or digging full throttle. I use a 36" bucket with an extra long smooth cutting edge.I use it most of the time. It extends past the teeth by about four inches. Along with the thumb there is a lot of weight at the end of the stick. This is a newer machine with variable piston pumps while my older (1996) 331 needs to be wound out to have smooth hydraulics with Its gear pumps. If your new on a excavator take the time to run it at differnt speeds to see how it reacts . Not all brands or models act the same. Also as a owner operator and small businees, all my profit is made by being efficient while maintaining as little wear and overhead while I'm doing the job.Sometimes you have to highball to get things done and we do try to be as quick as possiable.I'm always under time constraints being we can only dig part of the year. When I bid on a job ,I know how much I can dig and move and what it will take to accomplish the task so I allow a little extra in case something unforseen happens. I never bid low enough to make make it risky for me. If you have to run balls to wall to maintain a normal bid than you are going to crash. If not on the job it will be when the bills come in for the repairs or loss of income that machine would have made if it wasnt a basket case and beat to death. You don't notice the wear until two or three years down the line and I need five just to pay it off.And I do work in a very competitive market with it being realitivley easy to get into the small machines But being smart about how I do things has always payed better in the long run ,than speed.
I was wrong, I have to butt in here. Half throttle, 3 quarter throttle please. I try and bend the throttle to get more!!! If you save 4 dollars on fuel doing a job at 3quarter power you will not stay in business very long. These small machines are designed to go forever. Grease em, fuel em then run the hell out of em and move on to the next job.
I think we agreed on using the revs to suit the job a few pages ago (or in other words using the machine to it's maximum potential), however apart from fuel there is wear to consider, every time the pistons go up and down it is wear, same thing with the hydraulic pump. If you get an extra 1000 hours out of the motor and pump that is money in YOUR pocket. Sure if you change your gear more often than your underpants this does not matter but trading a machine with a motor that is starting to smoke and a hydraulic pump that puts out less than it should is not going to get you top dollar at trade in time. It could also be argued that wearing out a machine unnecessarily will not help you in your business much either.
I don't know what you run and most mini's are under powered in someway.You seem to feel that a excavator has to be run a full throttle all the time across the board and that make me wonder. . I can only go from my experience we will just have to disagree. It can be a disservice to someone new to these machines, that the only way they will work efficiently is at full throttle. I don't have to run full throttle on the 435 period . I run a friends Case which is the same way. I do a lot of different things other than just dig and this particular model sucks fuel.It has a 18 gal tank that I can go go through in eight hrs but the fuel consumption is only part of the overhead. And If I'm working close to operator going full bore , he better be good and can control the thing and I can trust him, or I'm on his butt in a minute. The older machines I do what ever it takes to run smooth.I have over 6000 hrs between the 435 and 331 and time on many others and full bore all the time has never been the rule just part of the game.
If an ex can lift itself when the blade is out the back it is not underpowered. This is a good test for someone looking to buy a mini/micro. My Kobelco SK005 can just do that at full bore and using the dipper arm ram as well but it is a series 1 with a single piston engine. Series 2 an 3 have a 2 piston Yanmar engine for more grunt.
I am sure you can save a little fuel when you back off a little and some times it is necessary like when you are on slick rock or on a steep hillside cutting a slope but, Insletboy you are my kind of operator. If you want to have hydraulic pump problems with a Tampo or Bomag vibro just let the operator idle it around instead of using the speed control. Also idle around half throttle and call for a compaction test.
all variable displacement hyd. pumps require high rpm's to run within factory specs.
Full throttle...... :usaall variable displacement hyd. pumps require high rpm's to run within factory specs. Controls are set up for feather features.
See, that's pretty much the opposite from what I keep being told. Two different independent mechanics (that work on all types of equipment) and the shop Foreman at my dealer have all told me to run at WOT. They all say that's where it was designed to run. You get the most life out of components by running them at their designed RPM and pressures. If you don't you put unnecessary stress on these components. Lug the engine, lug the pumps ect... Plus in my experience, the machine is slow and not very responsive. When you mow grass do you run your lawn tractor or walk behind mower at 1/2 or 3/4 throttle? No, it doesn't cut the grass "clean". The deck is designed to run at a set RPM. Makes sense to me the Mini-x's or any equipment that the manufacture says to run at WOT would be the same. You just don't see the results of under RPM like the mower with a crappy cut. Or do you.... With sluggish controls and poor cycle times......:beatsme
Well i guess i'm just used to Komatsu's Avance Hydralics.....Variable Displacement pumps are designed to work at rated engine speeds..... If this does not apply to your application then please do as your dealer suggests.... I don't know every brand of machinery...and surley do not want to tell anyone the wrong info...please forgive me...
I agree 1,000%! Do what your dealer suggests. If in dought, ask another dealer and compaire....
Ive got an idea , instead of us all just stating our opinions , how about everyone with an owners manual post what it says about the revs to be used . The manufactures would be correct in what they say as they have designed their particular machines to run at their chosen speeds . Please state the make and model that the manual pertains too .
I think we are reading from different pages, I am trying to say why rev the guts out of a machine whilst you are gently trying to uncover a sewer line. Modern machines may well have to run at 100% to work properly but my old school Kobelco works well with varying the revs depending on the job. For example last week I was clearing some tree branches I cut, basically picking them up with the ex and then cutting them up with the chainsaw. Did I need to run WOT for that job? I also dug out a little tree and needed full power to break the root system. I agree that you should not run a machine at lower revs just to save a bit of fuel and have the machine groaning away and you are probably going to use more fuel. I also am a little weary of advice given by mechanics as they make a living out of fixing worn out machines, I like Iron Horses idea as manufacturers know their machines best. Unfortunately my operators manual is written in Japanese and my Japanese is a little rusty.
If there were no opinions and factory facts only, I would think this here forum would become dead in the water. I think it's great that we can agree to disagree. That's what makes the running wide open vs half throttle a thread that may never go away!!!
I may be wrong but I thought variable piston pumps give you the ability to run strong hydraulic power at lower rpms. This was the reason to go to these things, the difference is night and day between the two machines I have. My skids are the same way. The Gehl has lots of power just idling without any groaning or stalling that I have with the machines that have gear pumps.Of course they have the most power at full throttle but I find that I just don't need to With gear pumps I have always kept them wound out to keep them smooth. I've also looked through all my manuals and the only one that recommends to run at full throttle is the Mustang skid with gear pumpsTo me thats why you have a throttle so that you can vary the engine speed to the task at hand. The two excavator manuals don't even mention anything but the hp and torque values at certain rpm. I also may be comparing apples and oranges when it comes to to how you operate different sized machines. The 435 acts and feels like a bigger machine and it does come with " load sensing Hydraulics" and that might be a game changer compared to other machines,:beatsme and again thats my own opinion.The smaller machine may take all the power they have to run up to par, and the ones I have run that were smaller did need the full throttle. Now i have clearly worn everbody out on the subject and will go back to work and think about it some more.Scott
Well like i said before i don't knoww all.....i do know Komatsu....So you should check your local Dealer and let them advise........Sorry for the mix up.....
Just pulled out the Yanmar mini-ex operation manual: According to the book the throttle has 2 positions, Idle - Push the lever forward fully, & Run - Push the lever back fully (more rabbit, less turtle ). It goes on to advise the operation of the machine with the throttle in the "run" position and the only time it advises reducing the throttle is warming up from cold start and descending steep hills. Everywhere else it is saying WOT.
Squizzy246b, Does your machine have gear pumps? Scott
No, it has three variable displacement pumps I might add that we have had a very similar conversation on this topic before
For starters I think that the throttle requirments will depend on the configuration of the mini excavator e.g type of quick hitch and bucket e.t.c For example take 2 kubota KX41-3 mini excavators, one has a 'martin' quick hitch while the other has a 'miller' quick hitch, the martin quick hitch and grading bucket on the excavator weighs 105-110KG combined, while the miller hitch and grading bucket weighs 50-55KG combined. when running these excavators together both at say 3/4 throttle the excavator with the martin hitch is slower than the machine with the miller hitch especially when boom lifting. When running both machines wide open there is still a difference in speed not to mention the fact that the pump on the machine with the martin hitch is noiser when operating. What I am trying to say is that I could run the machine with the heavier martin hitch at 100% throttle but would only need to run the machine with the lighter miller hitch at say 80-85% throttle to get the same amount of work done. So the operator of each machine could require different rpm's to do a set task although the make and model of the machines they are operating are the same - so it is not even easy to say that there is a set 'ideal' engine speed for one make and model of machine let alone mini excavators in general.
I have found this to be a very interesting thread. For what it is worth, Caterpillar Service Information System states that engine performance testing be performed at maximum rated speed with the hydraulics in a stall condition. Cycle time testing is also performed at maximum rated speed. Can we not assume that most force or work will be performed with the engine at WOT? Just my thoughts. The testing information is current and is actually for a 320C. I know we are talking about mini's here, but I thought that could be food for thought.
No, it has three variable displacement pumps I might add that we have had a very similar conversation on this topic before Squizzy246b, sorry to take so long to respond but I've been fortunate to be very busy and have had problems connecting to the net. I don't want to infer that running your machine at full throttle will damage it and will always inhance the cooling in high temps.I have a lot of respect for Yanmars and you being the operator with the the experience on the machine knows where it runs best, but intil they put an idle/full throttle switch instead of an variable throttle I will run mine accordingly to the situation and I don't feel it will hurt my machine. Performance testing should be done at at whatever rpms needed to to get the highest values, but machines differ in in how they respond in different situations. See Strott's post. And the question of how you run your throttle will never be be resolved because there are so many models with different system setups.It would probably be better to ask each model owner how they run their specific machine.then there could be some actual info that is relative to model comparisions.Some simply don't perform as well as others and thats the info I want. Scott
G,day Scott. Good to hear you are busy. We are likewise. I think the point being with these modern machines with variable displacement pumps is that running at WOT is in no way going to hurt the machine, they are well capable of running in that position all day everyday. Its a long way from "Revving the guts" out of the machine. Its simply the way the machines are designed these days. Likewise, running at a lesser setting is not going to harm the machine, just that it will be slower, and this is often desirable. My situation is somewhat different as our machine runs at such low Rpm for long periods that when it gets to digging or backfilling we run at WOT to make sure the engine gets a decent run. We used to lay blocks at idle but in summer the hydraulic oil gets too hot. Bumping the revs to a fast idle sees the temp gauge drop to normal. I was watching my nephew run our little mini yesterday and he fought with a huge stump for three hours at WOT, then dropped a revs a little for cleaning up around the hole, then dropped again for prepping the footing. I was very happy to see him operate in that manner (but I gave the property owner some grief about the bloody stump:cool2). Our machine definetly uses more fuel going from 80% to WOT...but lets face it..its a 19hp 3 cyl engine...it aint using gallons an hour.
we bought a brand new 442 in 08'. i ran it at 10,000 ' wide open. in the first 100 hours it burned a liter and a half of 15-40. in the 2 nd 150 hours it burned 3 liters. the air never ran cold with that vent next to the right handed stick, and it always ran in the upper end of the heat gauge. not overheated but hot. so we gave it back because we figured it did not do twice the work as the 435 for twice the price. but , YES wide open for digging. other lesser applications maybe a bit over half or 2/3 rds. that's my opinion on this subject.
550 hrs on the new KX121 and I'm running full throtle all the time except in tight places or when lifting over peoples heads. I always turn the auto-idle off for lifting around people. A couple days ago I was moving some 6' x 6' fancy $2500 windows around a friends yard and was not running full out for that I can tell you! Yikes.