jmc1986mj Posted March 12, 2009 Share Posted March 12, 2009 Hey all! I'm a new Comanche owner :doh: and new to the forums. I've been browsing through all the threads searching for performance upgrades for the 1986 2.5L I-4 (if there are such things). Intakes, throttle body spacers, exhaust, ignition, and gearing (with 30x9.5x15 tires). Thanks for any input! *J Link to comment Share on other sites More sharing options...
WyoCherokee Posted March 12, 2009 Share Posted March 12, 2009 well sadly there are no real performance upgrades. since the manifolds are one piece about the best you can do is grind down the ports to help flow, i do believe there is a cam you can buy that helps out but I'm not positive. exhaust...a good flowing muffler and pipe withminimal bends in it. go ahead and cut out the cats unless you need them for smog. for intake you can go with either a hiflow stock filter such as k&n or you can get rid of the air box and run an inverted cone filter off of the tube. I'm not sure about the throttle body, probably a new injector would help out. The reccomended gears for the 2.5 is the 4.10's from what i have gathered...anything over the stock 3.55's will help allot. especially with your tires Link to comment Share on other sites More sharing options...
Eagle Posted March 12, 2009 Share Posted March 12, 2009 There are camshafts. The factory used to offer three levels of performance cam kits through the Mopar Performance Catalog. A friend of mine in NAXJA bought one of the Stage 3 cam kits for his 2.5L MJ. I believe he later sold the truck without ever installing the cam. If anyone is interested, I can ask if he still has the cam kit and, if so, if he's interested in selling it. I believe Clifford Performance & Research offers cams for the 2.5L, as well. Link to comment Share on other sites More sharing options...
Pete M Posted March 12, 2009 Share Posted March 12, 2009 Step 1: Tune up (and I mean a full one including a new fuel injector, timing belt and tensioner). Step 2: Dump the stock mech fan in lieu of an electric fan. Step 3: upgrade the gearing in the axles (what you do here really depends on the tires you have). That's all I'd ever do to a 2.5L. :thumbsup: Link to comment Share on other sites More sharing options...
jeepcoma Posted March 12, 2009 Share Posted March 12, 2009 From this post I'm pretty sure they make headers. Actually, I think I've seen quite a few 4cyl headers for sale. http://nwct.craigslist.org/pts/1060817859.html Link to comment Share on other sites More sharing options...
bigd44889 Posted March 12, 2009 Share Posted March 12, 2009 thay do make a tb spacer to hav't tryed it yet $80 at advanced auto Link to comment Share on other sites More sharing options...
jaekl Posted March 12, 2009 Share Posted March 12, 2009 Through the production run the 2.5L made some significant improvements. You should be glad you don't have a 84 or 85 set up. (XJ) Compared to a 86 throttle bottle the carb versions is terrible. Then in 87 they squeezed a bit more out and my 88 is noticeably different than my 86. Perhaps as a minimum you might be able to retro yours using a later model donor. Renix era probably fairly easily but MOPAR era would require a total swap. Does anybody have a list of the changes required to turn a 86 2.5L into a later one? Link to comment Share on other sites More sharing options...
wolfpackjeeper Posted March 12, 2009 Share Posted March 12, 2009 I would get a high flow cat, not remove it. Taking it completely out will take the bottom end power right out of the equation, which would suck. Look into upgrading to the better cam. (interested in that Mopar stage 3, your friend has Pete) Header's are available, they are still made for 4cyl wranglers and should work fine. You can open up the head with some work, and it would improve. Look into swapping to the MPI setup, found in 1995 wranglers I think. A guy on NAXJA has done it, think he is on here too. Took the entire engine harness and computer for an MPI setup and grafted it into the MJ. I am slowly planning my 4cyl build out. I could switch to a 6cyl, but why. This truck is a DD/project truck, and the 6cyl is heavy. Looking to end up with a rebuilt 4cyl with a turbo, probably going to try to control it with a megasquirt computer system. Link to comment Share on other sites More sharing options...
Pete M Posted March 12, 2009 Share Posted March 12, 2009 Eagle has the friend with the cam, not me. :D And using the mpi setup from an XJ would likely be easier than one from a wrangler. Gearing is still your best bang for the buck. Link to comment Share on other sites More sharing options...
Red 1989 MJ Posted March 12, 2009 Share Posted March 12, 2009 Welcome to the club. :clapping: You will surely find some help here. :smart: Link to comment Share on other sites More sharing options...
TNT Posted March 12, 2009 Share Posted March 12, 2009 Rebuild it and turn it into a turbo engine. Build it for about 15-20psi with an intercooler and meth injection. It would be about 400hp. Use an AMS stand alone computer and hang on. Link to comment Share on other sites More sharing options...
wolfpackjeeper Posted March 13, 2009 Share Posted March 13, 2009 Rebuild it and turn it into a turbo engine. Build it for about 15-20psi with an intercooler and meth injection. It would be about 400hp. Use an AMS stand alone computer and hang on. read my mind Link to comment Share on other sites More sharing options...
mjeff87 Posted March 13, 2009 Share Posted March 13, 2009 A guy on NAXJA has done it, think he is on here too. Took the entire engine harness and computer for an MPI setup and grafted it into the MJ. I know Glenn (aka Ghost) did the MPI swap on his 2.5 XJ. It's doable, but you need to swap ALL of the electricals, including the interior harness, to make it work. For that amount of effort, might as well swap in a 4.0 (JMHO.....I've done the 4.0 swap on my MJ) Jeff Link to comment Share on other sites More sharing options...
JeepcoMJ Posted March 13, 2009 Share Posted March 13, 2009 2.5 + performance? lol :rotf: :rotfl2: now I've heard it all! :clapping: p.s. TB spacers are COMPLETELY WORTHLESS never buy one they don't do jack squat Link to comment Share on other sites More sharing options...
bigd44889 Posted March 13, 2009 Share Posted March 13, 2009 tb spacers do exactly what thay are made to do taller the spacer low torqe range no more power(as i think pat means ) just changes were u make most power Link to comment Share on other sites More sharing options...
JeepcoMJ Posted March 13, 2009 Share Posted March 13, 2009 tb spacers do exactly what thay are made to do taller the spacer low torqe range no more power(as i think pat means ) just changes were u make most power ...adding .1 liter of air volume is NOT going to change your power OR torque by much, if any. the difference would be negligable and not noticable. throttle body spacers are a scam. Link to comment Share on other sites More sharing options...
bigd44889 Posted March 13, 2009 Share Posted March 13, 2009 like i said it DON'T give u more just move what rpm u get best torqe Link to comment Share on other sites More sharing options...
JeepcoMJ Posted March 13, 2009 Share Posted March 13, 2009 like i said it DON'T give u more just move what rpm u get best torqe I respectfully disagree, and push the statement to further say that .1 liters of intake volume is hardly capable of effecting ANY performance changes on any vehicle. Link to comment Share on other sites More sharing options...
bigd44889 Posted March 13, 2009 Share Posted March 13, 2009 i agree we will leave it at that have a good evening :cheers: Link to comment Share on other sites More sharing options...
wolfpackjeeper Posted March 13, 2009 Share Posted March 13, 2009 tb spacers do exactly what thay are made to do taller the spacer low torqe range no more power(as i think pat means ) just changes were u make most power they are another holdover from the carb era that do not work as intended in the fuel injection era. Carbs benefited from spacers and high rise manifolds, to some extent throttle body injected motors do too. However MPI setups get virtually no gain. Some throttle response to make you feel more powerful is about it. Link to comment Share on other sites More sharing options...
dasbulliwagen Posted March 13, 2009 Share Posted March 13, 2009 I looked for the Mopar cam kit for the 2.5, found a part number, took it to the parts dept at my dealer, they stopped making the cam kit in 2003. No dealer in the country has one in stock, and searching has found few if any other companies offering one. I didnt find the one on Clifford, but did find a 4bbl intake and headers for the 2.5. Combine that with a cam, high flow cat, a 390 cfm holley 4bbl carb, MSD ignition and Id bet there would be a considerable improvement......yeah yeah yeah... for what you would pay you could have a 4.0, or a V8, but sometime you have to work with what you have, little by little over time as I'm sure most of us know. A few hundred here and there is doable.... a 2000-3000 dollar one time outlay is a lot harder to do for most of us here, not that it would cost quite that much, or for many of us to have the space or workshop to have a donor vehicle. Its just easier a little at a time, one small project at a time for 95% of us in our driveway or whatever... Just my opinion..... Link to comment Share on other sites More sharing options...
Eagle Posted March 14, 2009 Share Posted March 14, 2009 My friend does still have his factory Stage 3 cam kit, new-in-box. He confirmed that he now has no use for it and he's willing to sell it to a Comanche Club member, but he doesn't know what to ask for it because he can't find any listings for that kit or any comparable kit from any of the cam companies. I do not wish to become a middle man in terms of negotiating, but I don't think he wants to join another forum at this point so he's not putting out a way to contavt him directly. If anyone is interested, send me a PM with an idea what you think is a fair price, and your e-mail address. If he thinks you price is in the ballpark, he can contact you and I'm out of the loop. Link to comment Share on other sites More sharing options...
project88mj Posted March 14, 2009 Share Posted March 14, 2009 the best performance upgrade for a 2.5 is to do nothing to that motor go out and buy a 4.0 block and put all your money in to bulding a 4.6-4.7 stroker and then one day swap that in once it is all done :clapping: Link to comment Share on other sites More sharing options...
Geonovast Posted March 14, 2009 Share Posted March 14, 2009 the best performance upgrade for a 2.5 is to do nothing to that motor go out and buy a 4.0 block and put all your money in to bulding a 4.6-4.7 stroker and then one day swap that in once it is all done :clapping: :agree: :agree: :agree: Link to comment Share on other sites More sharing options...
bigd44889 Posted March 14, 2009 Share Posted March 14, 2009 not everybody has time,cash or place to do that Link to comment Share on other sites More sharing options...
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