Apparently John Deere has come up with a new engine that complies with the new it4 regulations. it passed all it4, eu and carb emissions tests. hopefully it still has as much power as it would have otherwise, but personally I think its awesome that they are one of the front runners in helping out the environment a little bit. here is the link to the article that has more detail than this hick can provide y'all http://blog.machinefinder.com/3983/john-deere-engine-achieves-certification
Power doesn´t seem to be what suffers in the emissions control game. It´s the fuel consumption that goes through the roof as more filters and after burners are added. It will be interesting to see what progress occurs once manufacturers have mastered the emissions requirements and can then return to engineering for efficiency.
In California they are beating us to death with the new regulations. It seems that with any new advancement there is a learning curve. Hopefully they (manufactors) will be able to provide us with both power and fuel economy. Hats off to Deere for being ahead of the curve.
Deere is not a front runner in this respect. The company is no doubt doing some great engineering, but T4i is a legal requirement for engines 175 hp and larger as of Jan. 1 2011. Every manufacturer that sells a diesel engine rated 175 hp and up had to, by law, certify those engines to EPA Tier 4 Interim standards before they could sell them as of the start of this year. I don't know exactly how T4i technologies affected power density, although I suspect it did not generally diminish horsepower per displacement. What we're seeing across the board from machines, including those from Deere, is that the newest-generation machines with T4i engines are mostly seeing at least a slight increase in power, with manufacturers promising an increase in fuel efficiency as well. Aftertreatment devices -- exhaust filters and/or catalysts -- are allowing the engine makers to tune the engines for improved fuel efficiency. Here's a roundup of some products introduced at CONEXPO in March that expands on this point somewhat. Many of the machines detailed here were selected specifically because the manufacturers increased power and promised improved fuel efficiency because of T4i engines. Diesel engines rated from 75 to 174 hp will have to satisfy T4i emissions requirements as of Jan 1 2012. And engines rated up to 74 hp have been required to meet T4i emissions limits since Jan 1 2008. Phase-in dates for EPA emissions Tiers and horsepowers