Contour Enthusiasts Group Archives Forums Modifications Forced Induction My new turbo

Well, from looking at the figures I'm thinking that unless this turbo is running 1.5 bar or more boost, then it wouldn't be worth your time. This is assuming the turbo is sized efficiently to the tractor engines size and desired rpm range.

So lets think it through:
It maxes out at 2200 rpm with max torque attained at 1400 rpm. It is a four stroke engine so you take displacement times half the rpm range and find out that the engine moves around 240 cfm of air at normal atmospheric pressure. It is hard to determine how much of the torque curve sloping off is due to the engine design and the massive rotating assembly and how much is from turbo efficiency range. I'd guess the former.
But anyway, back to the calculations.

240 cfm at 0psi boost. Lets assume the tractor is running 20psi boost, that is a pressure ratio of 2.36 or 1.36 bar above atmospheric.
2.36x240cfm = 566cfm

This is about the cfm I was using to push about 320 wHP on my car.

So until you get the boost pressure the turbo is run at, you won't know. You don't have a map so what I am doing here is a qualitative comparison of exhaust and intake flow volume of two different engines.....because the turbo doesn't car how many cylinders or the rpm range, it only is relevant based upon how much exhaust is flowing through the turbine, and the compressor is only concerned with the pressure and volume flow of the intake.
Or look at it this way:
A 6 liter diesel engine (2x larger than the 3L engine) operating at 2200 rpm max(1/3 the rpm range of the 3L engine) will move about 2/3 the airflow that a normal 3L engine would at max rpm, comparatively speaking. So unless the turbo is sized with for significantly higher pressures on the diesel than those that you will use on the 3L, or the 5.7L, then you are wasting your time.
Incidentally, your 5.7L engine will push about 450 cfm at max rpm and 80% VE. The 3L will push about 300 cfm at about 90%VE.
So when you find out the boost level of the CAT engine, then use this explanation and the math to see if the turbo would support one of the above engines....and if the boost is it used at is high enough then you have a good shot of it working fine.