Exhaust Question

[hole]

This weekend I plan to swap a 4.0 head onto my 83 CJ8 AMC 258 i6 / 4.2l engine. I already have the Hesco/Mopar MPI, and have tried many things to cure the "ping", and I'm close, but it still pings ever so slightly on a steep grade loaded with gear. So the head swap should be my once and for all cure. I figured while I'm at it I would have the entire exhaust replaced, but I want to make sure I have the right size pipe, the right cat and muffler. I'd hate to go to the trouble and expense of the swap only to hurt the outcome with the wrong exhaust system. In a perfect world I would like something that's on the quiet side , I'm getting older and loud and obnoxious is no longer necessary Any advice would be greatly appreciated !

 

[Torxhead]

I had an ignition ping like yours, but I have the Howell kit,and was solved by adjusting the vacumn distributor advance, but I believe that with your f.i. conversion there is a factory 4.0 distributor included and it does require premium gas. Other than that it might require a chip modification if the head swap doesn't help. Post up on the results, I have often heard that the head swap provides quite an improvement performance wise.

 

[rufus1138]

if you want to play with it since you are going fi you could put a megasquirt ecu in the system to control fuel mix and have live data, laptop tune the ping out of it, unless you go solid state ignition you wont have that function in the ms tuning program but still, im thinking about this in the future, did any of the compatible heads have full solid state ignition and direct port injection?

 

[Old Dog]

There use to be a guy in my 4x4 club with a 4.0 tj that ran a Banks muffler that sounded good and was pretty quiet.

 

[hole]

if you want to play with it since you are going fi you could put a megasquirt ecu in the system to control fuel mix and have live data, laptop tune the ping out of it, unless you go solid state ignition you wont have that function in the ms tuning program but still, im thinking about this in the future, did any of the compatible heads have full solid state ignition and direct port injection?

I already have the Mopar MPI that uses the 4.0 distributor (non-adjustable)
All of the 4.0 heads are MPI, but the early years up to 1990 are low port and dont flow as well as the later years. 91-95 are the best fit as they have the temp sensor port at the rear of the head like the AMC 258 i6 / 4.2l head does. 96-99 are the same but no sensor port. 00-01 heads have a smaller exhaust valve then earlier years and are prone to cracking.

Old Dog, I'll check into Banks. I have their 4" turbo back exhaust on my CC F250 and have been very pleased with it. I forgot they made stuff for Jeeps too.

 

[hole]

After some more research I found a shop near me that will do it from the collector to the bumper in 2.5" with a Magnaflow muffler for $250 if my cat is good. Seems fair enough All the Banks stuff I'd have to piece meal together since they dont make a kit for CJ's

 

[RM77CJ5]

After some more research I found a shop near me that will do it from the collector to the bumper in 2.5" with a Magnaflow muffler for $250 if my cat is good. Seems fair enough All the Banks stuff I'd have to piece meal together since they dont make a kit for CJ's

Sounds like a great price!

 

[rufus1138]

Cool stuff man

 

[hole]

Got the head swapped yesterday, so off to the exhaust shop later this week! Cant wait to drive it to feel and hear the results :bounce:

 

[hole]

Got the old girl back from the exhaust shop last night and had the chance to drive her. At low speeds (just putting along in traffic) no real difference in power noticed, just a nice subtle exhaust note can be heard, but when the road opened up and I could hammer it I was blown away at the difference the head makes. Mid-range to higher RPM's is a night and day difference! Best thing I've done for my 8 yet Next up is to finally get around to installing the Lomax 4-1 gears that have been on the work bench for a year and I can be done for a while

 

[cj7inthetwigs]

Glad your happy with your new exhaust. Keep us posted on the lomax install ,just learned of this awesome kit and am looking forward to learning more. Thanks

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