Chrysler 3.5 HO V6 swap (Page 6/33)
diabloroadster NOV 16, 09:35 PM

quote
Originally posted by seajai:

I was looking into using the megasquirt and megashift to control everything. The 41TE is pretty much the same electrically as the 42LE so it would be an easy deal. The problem with the megasquirt is controlling coil-on-plug ignition. There was supposed to be a sequencer in development for that but it didn't look like it was going to come to fruition. Also, I have read somewhere that the megasquirt fuel injector MOSFET's can overheat and burn out.

In 2002 Chrysler combined the TCM and the PCM so I only have 1 computer to deal with on mine. The great thing about having a complete running donor car was I could do some experimenting and determine that, even with all of the other modules disconnected from the CAN BUS, the engine ran fine and the cluster still worked and I didn't get the dreaded "NO BUS" error message. So in the end, I have decided to use the factory computer, it should work fine for me, and there are a few places that can remove the immobilizer programming as well as remove traction control, etc for less than what a stand-alone system would cost me.

My main drive on the project was just to do something that has never been done before. Although, with 253HP and 250 ft lbs of torque, the Chrysler engine should make the Fiero scoot pretty well.




If you cant get the factory PCM working let me know, I can help you get a megasquirt /msd6010 together that should work with the coil on plug setup. Im currently working with a Microsquirt2 only running both the fuel and spark on a LS1 off the stock crank trigger & waste spark. But my experience (very little) is only with LS engines, although I know some folks that are genius's with this stuff.
Good luck with your project!
engine man NOV 17, 05:01 AM
seajai great project way to think outside the box I will be keeping my eye on your progress
seajai NOV 21, 07:22 PM
Making a little more progress in the fabrication of new crossmembers and engine mounts. Here is a pic of the new front crossmember tacked in place, it comes off of the angled front part of the cradle at a 90deg angle and has two 15deg angles to get around the front of the oil pan. It is made using 1/8" wall 2x4 square tubing.



The engine mount plates are cut from 1/4" thick plate and have a lap joint on the crossmember and are butt welded to the cradle. I will be adding gussets when I remove the cradle for final welding.



The transmission mount is about 8" back from the end of the cradle. I felt that it was too far back and I didn't want to cantilever a crossmember back and around to pick up the load of the transmission thinking that it may sag over time. So my solution was to make a separate trans crossmember and attach it to the rear frame rails. The bottom of the rail was plated as well as the crossmember and the two are bolted together. This will allow me to remove the transmission if needed without removing the engine or the cradle.





I'm open to suggestions on this part, I want to tie the rear portion of the cradle into my new crossmember. I was thinking about a couple pieces of 2x2 square tubing set in at a 45deg angle from the lower end of the cradle to the transmission crossmember. These would be plated as well so the crossmember can be removed. Do you think that would pick up the cornering loads on the cradle properly? I would like to avoid having to make an arch over the top of the transmission. I have the room but am concerned about having enough room for mufflers and exhaust, but ultimately want to do whatever is best.



[This message has been edited by seajai (edited 09-28-2023).]

Fierofreak00 NOV 21, 09:52 PM
I like it! -Jason
Hardpact NOV 22, 07:43 AM
Very interesting !! Just one question ... Looks like your welding the cross member in are you welding that to the bolt in cradle ?? Cause the back looks like your welding it to the car if you are how are you going to remove the motor ? This looks like a great swap hope this works good !!

~Tom

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BLUE BY YOU!
NYFOC

seajai NOV 22, 09:25 AM

quote
Originally posted by Hardpact:

Very interesting !! Just one question ... Looks like your welding the cross member in are you welding that to the bolt in cradle ?? Cause the back looks like your welding it to the car if you are how are you going to remove the motor ? This looks like a great swap hope this works good !!

~Tom




The transmission cross member is bolted to the body so it is removable. I made two 1/4" thick plates, drilled and bolted them together and welded the nut to the top plate, I then unbolted the plates. After the lower plate was welded to the car, I reinstalled the top plate to the cross member to align it. The cross member was positioned in the car and the top plates were tacked to the rails. I pulled out the bolts and removed the cross member, and the top plates were finish welded to the body. There are four 10 x 1.5MM bolts holding it in place.



I gotta give a huge thanks to my brother for helping me on this phase of the project. His equipment and welding experience was the only way it was going to happen. I'm a woodworker, so I have design and fab skills, just not with metal. And my welding skills, well, let's just say I need a little more practice.

[This message has been edited by seajai (edited 09-28-2023).]

VF1Skullangel NOV 22, 10:21 AM
I wonder if the 3.3 out of the dodge intrepid will work. I had one and those were bullet proof engines. To bad the Transmissions where weak on those cars. No matter how much you take care of them they where junk.
seajai NOV 25, 07:36 PM
Got the last of the cradle fabrication done this weekend. The final weight of the cradle with the extra transmission cross member attached is 95 pounds, I think I may have overbuilt things a bit but I didn't want any problems. I don't have a hanging scale to weigh both engines but I think the all aluminum 3.5 is probably less than the all cast iron 2.8 so the extra 30 lbs of cradle weight isn't a big deal.

Finished cradle



The Chrysler transmission is quite large with a deep sump so the only way I could see to tie the back of the cradle together was to triangulate a couple mounts into the transmission cross member.







A couple shots from the back and underneath showing the mounts and brackets.





So this is what the engine looks like in it's final position bolted to the modified cradle.



Next up: The alternator and A/C compressor won't fit in their factory positions because of interference with the hinge boxes and firewall so I am looking at moving them down and in. I may end up making some custom "ZZP power log" style tubular exhaust manifolds to make that happen though. I need to lay under the car and stare at things for a while to assess my options first.

I'm pretty excited to have this first step done, it was my first time doing metal fabrication and I was surprised at how time consuming it was.

[This message has been edited by seajai (edited 09-28-2023).]

engine man NOV 25, 07:59 PM
nice job and i under stand about laying there and staring at it you have to get a mental picture of how it will all go together
Hardpact NOV 25, 09:42 PM
Sorry was hard to see the bolt !! Great job in the design !!

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BLUE BY YOU!
NYFOC