Build Thread 1974 CJ5/1.8L 4FB1 Isuzu Diesel
DieselJeep
Jeeper
So my IP is screwy from storage, so overhauling the spare.
In the mean time, thought I'd share my latest score:
a very low mileage, saab sourced, Garrett TB2531 "60" trim, .48/.49 AR, absurd cheap on CL.
TINY lil thing. But, ball bearing, full floating center, water cooled(NO coking!!!), and did I mention TINY?
Capable of supposedly supporting near 200HP.
The inlet on the turbine side isn't even a full T25 style rectangle. It's a circle @ 1 1/2".
It came with a LOT of aluminum tubing, silicon elbows, ect.
The saab intercooler if mounted correctly, might help catch oil and avoid run-on in the event of a turbo seal leak, as both the inlet and outlet are on one side of a narrow unit.
Will bring piece of mind for the full floating center oil seals.
If I understand all the principals, this map illustrates
that I should be 72% turbo efficiency at 14.7 psi boost @ 190 CFM @ 4,000 rpm.
My two goals are @ 2-3psi boost at cruise, somewhere between 1,500RPM and 2,000RPM.
The lower the better, as long as it is above say 1,250.
This will coincide perfectly with the dyno proven torque curve of the N/A 4FB1 cam here in the US, and increase efficiency at cruise.
Plus, get the 4FB1 back up to @ 100-120hp, where it was originally designed to be.
That tiny turbine inlet should be freakin PERFECT for low RPM boost!
I plan to never really wind the motor beyond 4,000RPM(like a "normal" diesel), and hope that I am getting 15psi OR LESS at that point.
The factory governed redline is the highest I have heard of for a factory diesel, at an insane, screaming 5,400 RPM's.
Depends on where real life testing shows @ 15psi, which is the very max I will allow it to push. Been proven the 4FB1 will handle that and more factory. But longevity is a consideration as well.
A factory IDI diesel will NEVER make big power without huge mods. EVER. The combustion flame is deflected from the piston crown, so power is lost. The head restricts the flame front. Top end power is not much of a consideration for me.
My goals are $15 for a full 15gal tank, and @30MPG, and enough power to be able to navigate traffic safely, and I think I might just do it.
Plus, dropping it in 4 high or low, and idling up hills barely burning any fuel will be rather kewl, too...
I have this bad habit of reading books, doing all the complex arithmetic, and keeping magazines and internet gleaned "info" to a distant, subjective suspicion.
HAHAHA. I love this project.
In the mean time, thought I'd share my latest score:
a very low mileage, saab sourced, Garrett TB2531 "60" trim, .48/.49 AR, absurd cheap on CL.
TINY lil thing. But, ball bearing, full floating center, water cooled(NO coking!!!), and did I mention TINY?
Capable of supposedly supporting near 200HP.
The inlet on the turbine side isn't even a full T25 style rectangle. It's a circle @ 1 1/2".
It came with a LOT of aluminum tubing, silicon elbows, ect.
The saab intercooler if mounted correctly, might help catch oil and avoid run-on in the event of a turbo seal leak, as both the inlet and outlet are on one side of a narrow unit.
Will bring piece of mind for the full floating center oil seals.
If I understand all the principals, this map illustrates
that I should be 72% turbo efficiency at 14.7 psi boost @ 190 CFM @ 4,000 rpm.
My two goals are @ 2-3psi boost at cruise, somewhere between 1,500RPM and 2,000RPM.
The lower the better, as long as it is above say 1,250.
This will coincide perfectly with the dyno proven torque curve of the N/A 4FB1 cam here in the US, and increase efficiency at cruise.
Plus, get the 4FB1 back up to @ 100-120hp, where it was originally designed to be.
That tiny turbine inlet should be freakin PERFECT for low RPM boost!
I plan to never really wind the motor beyond 4,000RPM(like a "normal" diesel), and hope that I am getting 15psi OR LESS at that point.
The factory governed redline is the highest I have heard of for a factory diesel, at an insane, screaming 5,400 RPM's.
Depends on where real life testing shows @ 15psi, which is the very max I will allow it to push. Been proven the 4FB1 will handle that and more factory. But longevity is a consideration as well.
A factory IDI diesel will NEVER make big power without huge mods. EVER. The combustion flame is deflected from the piston crown, so power is lost. The head restricts the flame front. Top end power is not much of a consideration for me.
My goals are $15 for a full 15gal tank, and @30MPG, and enough power to be able to navigate traffic safely, and I think I might just do it.
Plus, dropping it in 4 high or low, and idling up hills barely burning any fuel will be rather kewl, too...
I have this bad habit of reading books, doing all the complex arithmetic, and keeping magazines and internet gleaned "info" to a distant, subjective suspicion.
HAHAHA. I love this project.
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