More power for the Iron Duke???

[Draugr]

Have my first Jeep with the Iron Duke dont want to put in a a bigger engine But im looking to find ways to squeeze everything out of her
Electric fuel pump
Electric fan
sure fire plugs???
and anyone give some advice?? thank you

 

[Hedgehog]

This is the same engine found in a Fiero car, some thought it was a sports car. You might find performance accessories in a search on the car.

 

[1930u]

hedgehog is correct...in 1983-1/2 the 84 the Pontiac, Fiero was introduced and there were many performance parts available from the general. I think most of the the stuff was for all out racing but I would think you should be able to find a cam, header and intake. good luck.

 

[Draugr]

thanks 1930u in trying to get as much info for it !!!

 

[1930u]

The iron duke is really a pretty good little engine...if you freshen one up they have good durability and longevity. Be sure to replace the cam gear as they wear pretty quickly and will cause a knocking noise like a main or rod bearing type noise. Many many good engines have been scraped because of the cam gear knocking sound.

 

[Draugr]

the last owner stated he just did a compression test and it was at 125 per cyl how big of a cam can i get with out a rod / spring change?? any advice??? I though about going out and getting a electric fan and fuel pump and maybe high milage oil or royal purple oil???

 

[Torxhead]

My advice would be to try a different axle gear/tire combo, like a bit lower on the gears and a little larger on the tires, I believe you have 4.10s now. I have wheeled with guys with the 4 bangars and they seem to do just fine. Especially looking at that little engine after doing a great 4wd trail. The major complaint is little power on the road as they pass the gas stations.

 

[1930u]

I agree with torx- they are good little engines...and the right set of gears would really help. If I were you...I'd just freshen it up with good a exhaust system and tune...
here's a link for some camshttp://www.compcams.com/catalog/COMP2012/pdf/COMP_Catalog_2012_240-247.pdf
but you need to really think it out. If I remember correctly the duke has a non adjustable valve train which can be a pain when changing the lift. So be sure to talk to cam expert. I also don't know for sure if the engine you have is exactly what Pontiac used in the Fiero. good luck

 

[HackFabrication]

Have my first Jeep with the Iron Duke dont want to put in a a bigger engine But im looking to find ways to squeeze everything out of her... ...anyone give some advice?? thank you

What year CJ and what Transmission ? Your profile just shows the 75 with the I6.

From: Jeep Engine: GM 151

The GM 151 (2.5L) inline 4 engine was used in '80-'83 CJs including the CJ8 , CJ7 , and CJ5 . The GM 151 is often called the "Iron Duke", but is actually a Pontiac engine designed to replace the Chevy "Iron Duke" I4 engine. The engine does have the Chevy bell housing bolt pattern though. The engine is manufactured by GM and uses a cast iron block and cylinder head with hydraulic lifters and 5 main bearings. The GM 151 cetainly is not a screamer, the AMC I4 has much better HP and torque ratings.


Daily Driver Performance??

Run stock size tires, 235R75/15 with either a highway tread or an all terrain tread.

Get the engine tuned properly. Ideally, that would be getting it dyno'd so you have a baseline, and can see what your A/F ratios are doing across the RPM band.

Keep the weight down. A CJ has all the aerodynamic qualities of a brick. Experiment and find you 'sweet spot' as far as speed goes for MPG.

Off Road Performance??

Gearing. Plain and simple. Most GM 151 engines had either the SR4 , T-4 , or T-5 Transmission . All light duty gear boxes. IMHO, if you are going to even think about a bigger tire, you need to address the axle gearing first. The stock 30/20 combo is 'generally' good for up to 35" tires, with some minor upgrades (1-pc rear axles). But if I was thinking about slapping a set of 33-35's on it, I'd also be considering an engine/Transmission upgrade.

Screaming Street Performance???

Full race treatment. But the Transmission will probably grenade. The GM 151 is used in a number of racing categories. I think I even saw one with a Cosworth head on it. Your checkbook is your limiting factor

 

[Draugr]

it is a GM 151 and do run stock tires on it the guy i got it from was a mechanic and new-battery, exhaust, spark plugs, fuel filters, and fender flares. It has a remanufactured carb on it. did a compression test on the motor and it has 125psi per cylinder