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[4]

86 Jeep Cherokee with blower

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pdentrem

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#1
I did a bunch of work on a buddy's 86 Jeep Cherokee. He bought it new and wanted more power out of the 2.8 V6 Chevy. Factory is had 110hp.
Started by installing a Edelbrock headers and going dual exhaust later. That was the start and the engine did improve a bunch. The next step I told him was improve the intake side. So he shows up with Offenhauser Dual plane 4 bbl manifold and a Holley 390cfm carb. Now we are talking!

Time moves on and he says "I need more power". My response was EFI. We begin a quest on what was available in the OEM and aftermarket. Ended up getting a complete engine and EFI system and wiring from a 85 Camero 2.8V6. I opened the harness and removed all the stuff that was not needed for the EFI and we then installed it on his original 2.8. With the EFI installed on the 2.8 the Jeep was a completely different animal. Power was beautiful and pulled from idle all the way up to the rev limit, ECM controlled.

The engine from the Camero I sent the block out to be checked and rebored to 30 over. He meanwhile talked to GM St Catharines plant dyno guys and got main bearing caps and rods from the 3.4V6 (OHC). I supplied a 3.1 crankshaft and we ended up with a 3.2 V6. Over the winter I built up the engine from the Camera and he says he got a Paxton Supercharger. Just the unit, no brackets etc.:cool:

We install the new engine and start measuring up for brackets and clearance. First thing was the alternator was in the way. OK we put it below the blower, about where the AIR pump was. Made up a bracket that mounted on the frt of the block and used other OEM brackets to allow adjustments for the belt. Meantime he had some government work done on the blower brackets. Need a belt tensioner for the blower belt as well.

We install and run the new engine with the blower. WOW!

Ok we need better injectors. Since I was working at a GM shop I was able to get and try different injectors. 2.8, 3.1, 3.4, 5L and 5.7L injectors. 2.8s had not top end, too lean. 3.1 pretty good, 3.4 just no good, 5L top end fantastic but too rich from idle to mid range. the 5.7L way too big everywhere. We settled on the 3.1 injectors as this was the closest and would not require a custom fuel map.
Also used a 454 bb starter to turn the engine over. The blower is a load that the original starter was not designed for. Moved the aircleaner to the firewall and use the high pressure air from there as we cut into the cowl area.

The final outcome was a very powerful Jeep Cherokee that no ones knows what is under the hood until you step on it. Blower whine and see ya! Very danderous, as you can hit 100 in no time when you are passing someone and can surprise the passee!!

The pictures are scans as this was pre digital camera days for me.
First picture is stock and wheres the engine?
Second picture is the Camera donor engine with the components ready to install.
Third shows the first stage where we installed the Camero MPFI.
Forth is the installed blower belt and tensioner.
Fifth shows the installed Paxton and temporary duct work. ABS pipe can be your best friend. We could not really make a duct until everything was in place.
The last picture is the completed install with the new blower duct to the throttle body.

running-need-tube.jpg wheres-the-engine.jpg belt-layout.jpg stage1complete.jpg completed.jpg 31v6.jpg
 

Tony Wells

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#2
I had an 84 JGC, and I agree.....that is one weak engine. I bought all the hard parts to rebuild it, but ended up selling the thing before I did the job.

Looks like you did very well!
 

pdentrem

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#3
The only thing that was not put back was the AIR pump. Since it has MPFI from the Camero, it did not need the pump etc. Going with an electric pusher fan also gave us more room for the belt drive. Actually one has more room with the straight 6 vs the V6.

Also since it is pre88 no emission test to worry about but it is cleaner than before with the carb. MPG increased from 24 to 30 plus if driven right even better. Best he saw was 34 by babying it with the new motor still being broken in.

Next topic will be a header build for my old Beretta GT.
 
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