1998-2002 chrysler LH platform drivetrain

so, it looks like the 914 will be showing up in a couple of weeks. which means i have a new challenge car.....

anyway, im looking at the 1998-2002 chrysler LH platform cars to donate the 3.5HO and 42le trans for the porsche.

info on this stuff, outside of normal repair, is pretty thin on the ground. ive beel looking for months, and only found a couple of swaps. one in a locost, one in a vanagon, and one in a fiero. apparently not many guys think like i do.

anyway, vigo came up in a discussion from way back on another fourm about beefing up the 42le, which made me think of him being the all knowing, all powerful late model mopar guy here. which made me think that THIS would be the place to do my research and ask my assinine questions.

at this point, im looking into feasability of this swap, electronically speaking. want it to run and drive just like it would in the donor LH platform car. i know i can make it fit in the porsche, as i have a sawzall/welder/torch/no regard for purists. i just dont kow how to make it run and drive.

from my research, it appears that SOME cars have what is called SKIM, which appears to be much the same as the old GM VATS system. it also appears that there is a PCM and TCM and BCM that ALL must talk to each other for the drivetrain to operate. all the completed swaps utalize the donor cars instrument cluster as well, which is apparentlky required for the atio-stick to function.

what i havent found out is what all is actually necessary to run one of thse things, what can be deleted, what cannot be deleted, and what electrical issues i need to deal with. id like to use paddle shifters instead of the factory shifter setup, and retain the porsche style gauges instead of the donor gauges. lastly, id like to delet as much of the emmisions and complexity as possible.

im thinking about megasquirt, but cant tune worth a crap and dont have the patience to learn. also, i doubt that i could get the drivability out of it that the factory pcm gives.

so i guess, what im looking for, is a bone here. what all do i need to have to make this drivetrain run by itself, in a car that it aint supposed to be in? and how can i do it for the absolute least amount of money, with the fewest parts?

the idea of a mid enngined 1800lb car with 275 horse makes me smile.

michael

The Vanagon guy is on here. At least he was. I haven't seen anything posted in a long time. Maybe over in the build threads now. I believe he was using the earlier LH 3.5L and trans.

I had an Intrepid R/T for about a decade. Sold it to a buddy last year. It has the 3.5 HO. Great car. I probably should have kept it.

The factory Autostick setup is just two momentary contact switches. It's easy to wire up something like a paddle shifter instead of those two buttons.

There isn't really any aftermarket support for the platform. As far as I know nobody has hacked the factory system on them. I don't know of anyone running them on Megasquirt, but I wouldn't be surprised if somebody did by now. In theory a Megasquirt and a Megashift combo should operate the drivetrain.

For least amount of money, I'd find a 300M that was rear ended and pull everything out of it. I'd also grab the factory service manuals and start studying the systems. A savvy dealer tech might be able to disable some of the functions with a factory DRBIII, but I don't know how much can be disabled or ignored.

If an automatic is what you want, I'd go for an Audi/VW with the longitudinal engine and transaxle setup just like the LH platform. You will probably spend more on the initial purchase, parts down the road.... but you can get performance parts and there is a lot of info on them.

Can't you get the 1.8T with the longitudinal transaxle and just front wheel drive? Or the 2.7TT would be a riot.

ik thought about it with the VW swap as i may be closer to somewhat legal for SCCA after the challenge. but i have a pathological hatred of VW late models after an ex girlfriends jetta.

Hmm. Some of this stuff i am only 80% certain on, but here goes:

You shouldnt need the bcm or the instrument cluster for a running car with autostick. You do need the BCM if you want to use the stock instrument cluster. Autostick doesn't need the cluster, that i know of, it just sends a signal to let the cluster display the current gear.

Autostick on one of those is plugging in an autostick TCM and running two wires to a switch or switches. Basically your '3' position will become autostick and then the switches will be active. 'L' position will cease to do anything special.. I think it will still be autostick in L.

You CAN run the motor itself on megasquirt, and it's technically possible to run the trans on megashift, but i wouldn't do either. Megashift will do a half-ass job running that trans unless you spend dozens of hours tuning it in, i think. I would run the stock pcm and tcm to start with and see if you feel the need to change it later. The TCM is kind of annoying in that even an autostick TCM forces a 3-4 upshift at 5500 rpm. This won't be an issue unless you're racing on venues over ~110 mph. 4th gear may live for a while in such a light car but it is a very weak clutch pack and there's nothing you can really do to fix that other than getting the TCM to let you go higher in 3rd. If you have a complete LH to start with you can TRY to get a chrysler dealership to flash your TCM to a Prowler cal which has no forced upshifts. Or you can buy a prowler TCM and plug it in. With big-ol' LH stock tire sizes, 3rd gear will go 135-140mph @ 6500 rpm. Just gotta get the TCM to let you.

Also, why 98-02? For the power ratings? If running a 96-97 would make the security issues easier i wouldnt hesitate to run the older motor. One thing that's not obvious from the power ratings is that if you put a decent intake and exhaust on a 96-97 motor you will gain most of the power difference between that and a 98. Not many people realize this because you have to remove the plenum to get the stock intake pipe out on an early 3.5 and most people just aren't that serious. Same on the exhaust side.. you have to replace the stock downpipes and most LH enthusiasts dont go that far with their exhausts. Also if you do a 96-97 i have a 'no speed limiter' PCM i can send you. Otherwise they have a limiter at like 108, super aggravating.

So I guess the question is, WOULD running a 96-97 make thigs easier? Bigger ttb, headers, and porting were already in the plans. 98-02 was for the powedr, and they are prevalent in my area. If I can get the power out of almost any of them, what year would make this the easiest and still be able to use the prowler tcm?

I really dont know that. Although there were changes to the drivetrain, they are basically interchangeable as far as dimensions and hardpoints and all that. I would think the deciding factor would have to be the electronics associated with them.