My new Drivetrain... Kinda

[tonypaul]

I have made a change for my drivetrain plans. I have been working on this reverse rotation twin turbo ls1/th425 setup for too long. One day I said "F-it", there is just too much fab work, too many custom pieces to make. And there is no guarantee its even going to work like I want it to.

So next day I got on the phone and made some calls to some contacts I know. I found a complete LS4/4t65ehd from a 2007 Monte Carlo SS with 37,000 miles about an hour away from my house. That afternoon it was in my shop, the harness was hacked pretty bad and it was missing the waterpump (not the housing-just the pump itself) and the starter.

So now Im going with the LS4, I had to do a little soul searching about the drivetrain. I wanted a 600-700hp monster crammed in the back, but in reality I dont need 600-700hp. What I need is A/C, decent gas mileage, something dependabe that I can drive anywhere. And the main thing for me- an automatic trans. I drive in alot of traffic, and the constant shifting of that POS fiero 5 speed was getting old.

 Im keeping the sbc/5speed in the Diablo until everything is finished on the LS4 so I can still drive it. I have made alot of progress on the LS4 so far, but still alot to go.... I swapped the intake/injectors/(throttle body is bored/new)  on the LS4 for one off a LQ4 truck engine.
Fits great, no modding nessary like the LS6 intake. Relocated the alternator to the cabin side of the car, and made a shifter bracket/thingy so a Fiero auto-shifter will work.

Im using Microsquirt for the engine mangement and Magnashift TCM806 for the trans. Im setting it up for Paddle shift, I got a pretty cool set off ebay coming. Im done with the Microsquirt harness, as far as I can tell Im the first person to use the Microsquirt on a LS4. I have had some really good help developing a tune for the 58x crank, I couldnt have done it without the help of these guys. I have a test tune ready to load but I have still have a little more work to do on it.

For now Im just going to run the LS4 stock, leaving in the DOD for now. I want to get it installed and running, then perhaps in the fall remove all the DOD stuff, change the cam/lifters, head studs, ect.
I still gotta get and wire the trans controller- If anyone is needing a trans controller- check out these guys- http://www.magnashift.com/magnashift_controllers.html they are good peoples~ I still got a long list of stuff I need to get but should have everything within 2-3 weeks. I planning doing the swap in the first week of march so I will update when more progress is made.
The first pic is where I left off with the ls1/th425, I may finish it some day.

[rodrieguz]

That black fiero in the pic is what inspired me years ago, I did end up switching out that drivetrain for the reason stated above.  Too much weight behind the rear wheels. 

Tony have you given any thought to a v12 backwards with a  v-drive set-up? 

[tonypaul]

The problem with that setup is its in a standard rotation, it has alot of weight behind the rear wheels. I will have all the weight in front of the rear tires.

 I have done a reverse rotation th425 with a sbc in a Fiero drag car about 7 years ago but I used the factory differential. I did a couple different designs on that one also, 1st was making a gear drive to replace the chain drive but it was really noisey. I then had a standard cut custom ring / pinion made to replace the factory revese cut ring pinion. That worked well, rolled it off the trailer and it went 10.98 on the 3rd shake down run though a full exhaust.
 
As far as my research, no one has done what Im doing as far as using a completly different differential to reverse the rotation for better weight distrubition. It hasnt be easy but Im making alot more progress now that I have a solid excution plan.

[01Lambiero]

TP, Check out Rod's Roadster on KC.  You might gain a few pointers from him as he has been down your road already it seems.  Jim

http://www.kitcentral.com/index.php?set_albumName=Rod-s-roadster-build&id=ebay_pics_405&name=gallery&include=view_photo.php

[01Lambiero]

This concept is not new but if it works...it will work.  Cadillac has the similar setup in their AWD car.  (I can't keep up on the srx, cts, ctx whatever)  All that would be required is to cover the output shaft that goes to the rear end and, of course, recode the ECM.  Hope that your setup clicks.

Jim

[usmc_butler]

Definatly following this thread  I like this idea! 

[tonypaul]

Why would go to all the trouble of reverse rotation on the engine (different cams, different starter, relocating crank and cam sensors) when all you need to do is flip the differential.

For few but important reasons, 1st is drivetrain placement. This will get the engine all the way up against the firewall, making it truely midengine. Just flipping the stock final drive leaves alot of the weight behind the axle center line. 2nd- Flipping the final drive isnt that easy, it places the c/v axle really high and would require major work to the oilpan and making the adapter to flip it would be a major task. 3rd- Im stuck with 3.07 gear ratio, there are aftermarket gears for the final drive but they are big money. With the 4x4 final drive I have many options to choose from, but the 3.42's that are in there now is right where I want to be.

I dont have to change anything on the motor, no cams, no senors, no different starter, nothing... The TH425 runs backwards, the stock final drive is what makes the wheels go the proper way. By using a front 4x4 diff it puts it in the correct direction to be installed backwards....
Hope this clears it up for you!!!

[jdinner]

Why would go to all the trouble of reverse rotation on the engine (different cams, different starter, relocating crank and cam sensors) when all you need to do is flip the differential.

[SchulzeA]

Looks great. I'm working on a similar set up. I'd suggest beefing up the typhoon diff though. It will be puking out axles and gears with that much TQ and HP. At least that's what I found from my research

[batbuilder]

Hey Tonypaul love that engine and the idea of twin turbo that are functional on both sides of the replica engine cover is  going to look great. Very nice.

[tonypaul]

Maybe you can avoid the transmission problems I've had by using the th425.  I've dumped a load of money into mine.  you might want to reconsider the twin turbo concept.  Back in the day they used twin turbos to deal with turbo lag.  With today's ball bearing turbos turbo lag isn't an issue.  At least I don't notice it with my turbonetics t66 on my ls4.  Twin turbos are a "wow" factor though.

Im will be using 2 GT35 turbos, pretty small on the a/r side with no more than 8-10 psi. I could go with just one and get the power I want but I think the twins will look better. It will have twin intercoolers on each side of the car mounted down in the lower side vents and the upper side vents will feed the turbos fresh air. I want to be able to use my Lambo engine cover and having the 2 turbos on each side will look much better than just having one hanging off the side. 

[dratts]

Maybe you can avoid the transmission problems I've had by using the th425.  I've dumped a load of money into mine.  you might want to reconsider the twin turbo concept.  Back in the day they used twin turbos to deal with turbo lag.  With today's ball bearing turbos turbo lag isn't an issue.  At least I don't notice it with my turbonetics t66 on my ls4.  Twin turbos are a "wow" factor though.

[tonypaul]

Just though I would share my drivetrain concept.  The motor in the pic is 5.3l truck engine and the actual motor that Im using is a all aluminum LS2, Im just using the 5.3l for mockup. The final drivetrain will be a reverse rotation twin turbocharged LS2 with the TH425 trans. The TH425 has the final drive removed and I made a adapter plate and a custom shft that mounts to a front differential from a 4x4 chevy truck. However I just found a front differential from a GMC Typhoon that looks like it will work better, I should be getting it on monday or tuesday. Plus it looks like I will be able to use the Typhoon's c/v alxes without too much work.

By removing the factory TH425 final drive and using the 4x4 front differential Im able to run the drivetrain in a reverse roation and get the motor/trans way up in the middle of the car. I still have alot of work ahead of me but I have a solid plan of attack. Im shooting for a easy 625ish hp hopefully on 93 gas, I may end up on E85 but I will cross that hurdle when it gets here.

I will try to update this project as progress is made but my business is very busy this time of year so it maybe awhile.