LS1 with chevy transaxle

[Morales Esseista]

I will be puting a turbocharged LS1 into my Ultima and though the G50 might be enough for a 550hp N/A engine it probably won't live long with 700hp and heaps of torque. Still I do not want to pay some mad ammounts of money for a Hewland or similar tranny so now I am wondering whether the stock Chevy C5 transmission will fit. I have found a rather old but interesting topic www.sallee-chevrolet.com/wwwboard/archives/messages/228.html
Does anybody have any experience with fitting this particular gearbox or any other FR transaxle?

[k wright]

Call up Roger Brown at Powerhaus II. Save yourself lots of time buying a transaxle from him that is rated for the power you will have and that already fits the car. Bonus: you can pick every single gear ratio. Less than 16K USD.

ken

[Steve_D]

Sounds like the answer is in the message. The drive shafts are to far back.
Steve

[mkoch1]

my canam is going to be powered by single turbo ls1 motor. I had my g50/50 build by roger at power house. He rebuilt a used box with the following:

heavy duty shift forks (1st/2nd + 3rd/4th)
heavy duty side plates
Replacing the brass synchros with steel (2nd,3rd,4th)
taped the trans case to add an oil pump for cooling
replacing first gear with a 2.6154 gear

On the stock internal motor I hope to put about 500hp to the rear wheels so the trans will probably see over 600. Won't know if it holds till I get it running.

Roger is a great guy to deal with and has built 7+ boxes for ultimas.

Mark

[Morales Esseista]

So how much did it cost you? My drivetrain budget is quite limited for now so I don't want tho shell out 16k for a transmission that won't last. Still the G50 might be a good option as spare ones are cheap as dirt here in Poland. Some medium to high mileage ones can be found for as little as 200 pounds... and still be useable.. for a couple of days at least

Alex

and BTW I contacted Mr Symons and he said the C5 transaxle has a large distance between the mounting surface of the transmission and the axle half-shafts. They should be around 12 to 14 inches further back than in the G50. So it looks as though either the wheels would end up half way behind the rear bumper or the engine would sit behind the steering wheel. Not an optimistic vision.

>> Edited by Morales Esseista on Tuesday 20th January 23:22

[mkoch1]

Here is a break down of the cost.

used g50/50 with LSD (out of 89 turbo) (PHII) - 5500

rebuild labor + parts (PHII) - 1621.10

stage II clutch (600ft/lbs torque) (kep) - 1050

porche / chevy trans adapter kit kep adapter (later than '86 Chevy) - 595

hi torque starter (PHII) - 225

clutch slave (PHII) - 170.00

hd shift fork (1-4) + HD side plate + steel synchros (2-4) + oil pump (PHII) -1615.00

Regear first to 2.6154 (gear + labor) (PHII) - 925.00

speedo sender (PHII) + trans shipping - 390

Total Trans Cost - 12011.10

mark

[RUFAZZ]

Morales Esseista said:

.... the G50 might be a good option as spare ones are cheap as dirt here in Poland. Some medium to high mileage ones can be found for as little as 200 pounds...

Alex,

I might need to speak to you about some of those 200 pound g50's

[Morales Esseista]

You definately wouldn't want to put a 200 pound worth G50 in any car... now in an Ultima it might last for some time.. if you have under 150hp and gently shift gears
If I decide to stick with the G50 I'll be probably looking for a slightly used one and that should cost around 800 quid. So with all those UK taxes I'm not shure whether importing a used gearbox from Poland will in the end be any cheaper than buying one in the UK.

[jschwartz]

Don't forget about broken stub shafts, I've broken one so far, but it was at a sticky drag strip. On the street I doubt your 700 hp will get enough traction to break too much. Remember these cars are a bunch lighter than a Porsche, doesn't put much load on things on the street.
jeff
www.worksstand.com/jeffs.htm