4.0L HO Jeep Engine Build

Jeep runs great and has tons of torque right off idle. I just had the Jeep emissions checked and it passed with flying colors. This is tested on the dyno, not an idle test. The emissions guys couldn't believe it and three of them came over to talk to me. I wonder if they get a hp reading off those dynos?

Limit________________As Tested

HC 2.5000_________.2254
CO 25.000_________5.5722
NOx 4.5000________1.5838

Yes, the HC is really POINT 2254. Even if emissions are not a consideration where you live, this gives an indication of how efficient this build is. At this time I have approximately 10k on this buld and it runs great, burns no oil and gets over 20 mpg on the highway.

Even though it pulls nicely off the line (at sea level I really have to watch my throttle input to avoid squealing the tires) and pulls hard as the revs climb to about 4500, it is cam limited to about 4800 rpm. With the Lunati cam, I think I could still pass emissions and have it pull nicely to 5200+ rpm while giving up a bit of off idle response. Right now it's almost jerky off idle. Great for off road use though.

Don't bother with the 4 hole mustang injectors. It's just runs too rich on start up and it's really not needed, even with the mods I made. The stock pintle style injectors are made to whack the backside of the intake valve and the engineers knew exactly what they were doing when they designed this engine.

BTW, welcome to the forum!