3800 Turbocharged @ 500-600whp/wtq - Which Manual Transmission?

[hi0npsi]

I've finally decided upon a powerplant for my project because after coming from a Mitsubishi small motor/big turbo background I just can't stay N/A. I do plan to remove the supercharger from my donor engine and run a turbo in the 67-74mm range with a goal of at least 500whp/wtq. Between the 5-speed Getrag and G6 6-speed does anyone here have experience or know someone with experience with either being capable of handling that kind of power either in stock form or built?

My driving style is not hard on transmissions, and I was able to run my stock '05 EVO clutch at 599whp/465wtq without any signs of slipping from the time the car was new until about 10,000 miles when it was sold. Most people can blow up the stock EVO clutch on stock power (240whp/240wtq), but I'm more of a roll into the power and shift relatively nicely as opposed to the rev-limiter launches and no-lift slam shifts type of driver.

Another concern is bang for the buck as a G6 swap will definitely be spendy to accomplish, but I want to do this once and do it right so if that's the ticket then that will be what I run.

Your thoughts and opinions are much appreciated!

Tom

[DarrelK]

Have you been to any of the Fiero forums yet? I've got a stock 3800SCII with the 4T65EHD E auto tranny. I can't really imagine running a Getrag 5 speed with even this stock motor. The problem I've even always heard with that newer 6 speed is that the ratios just don't work well with this motor and I would think that a turbo version would be worse as far as staying on the boost. These motors just pile on the torque and horsepower when boosted. There never was an OEM tranny that was desgined to handle them in the first. The 4T65EHD on the other hand has no problems (some mods needed) handling huge horsepower and torque.

[hi0npsi]

Have you been to any of the Fiero forums yet? I've got a stock 3800SCII with the 4T65EHD E auto tranny. I can't really imagine running a Getrag 5 speed with even this stock motor. The problem I've even always heard with that newer 6 speed is that the ratios just don't work well with this motor and I would think that a turbo version would be worse as far as staying on the boost. These motors just pile on the torque and horsepower when boosted. There never was an OEM tranny that was desgined to handle them in the first. The 4T65EHD on the other hand has no problems (some mods needed) handling huge horsepower and torque.

Darrel,
I've read all over and searched www.fiero.nl about potential manual transmission options with no conclusive information posted by anyone but lots of hearsay. I am against using any automatic transmission as I feel they take the fun out of spirited driving. If that auto is the only "bolt-on" option that will handle the power maybe I'll just have to adapt a DSM 4G63T FWD transmission. Those have been proven for almost 20 years now to handle brutal power in stock form with just a clutch upgrade. Stock EVO transmissions have been into the 8s, so perhaps that's another option by elminating the viscous coupling as many do to run on 2WD dynos. I want to avoid "custom" as much as possible and stick to the beaten path because high cost and problems arrive the second one strays from it, but if that's the only choice then maybe so be it, just looking for input and appreciate the help!

Tom

[funexec]

Are there any paddle shifter applications developed for that motor/auto tran set up?

[DarrelK]

Hmmm... okay, I get where you're coming from on this. I think there are a couple of people you might want to contact on this. First, I'd go here and shoot an e-mail to Ryan at Sinister Performance... http://www.gmtuners.com/ Ryan knows these 3800/Fiero applications inside/out. Next, if you go over to Pennock's again do a search for posts by FieroX. He's already built 3800 motors in the power range you want (although I am farily sure he's always used the 4T65EHD in his cars as well). There's also another forum you might want to check out... www.realfierotech.com
Those guys come across as a little "extreme" on that forum but their is a lot of solid information on 3800 swaps along with transmissions these guys have tried. Oh, and the 4T65EHD is available as a paddle shift in the later cars. Ryan at Sinister did one for an LS4 v8 swap.

[MERCenary]

Murci-Me is the ONLY one that makes the Paddle Shifters for the Auto tranny that looks OEM... You pay top dollar for a top product from a top engineer.

[jdinner]

Have you been to any of the Fiero forums yet? I've got a stock 3800SCII with the 4T65EHD E auto tranny. I can't really imagine running a Getrag 5 speed with even this stock motor. The problem I've even always heard with that newer 6 speed is that the ratios just don't work well with this motor and I would think that a turbo version would be worse as far as staying on the boost. These motors just pile on the torque and horsepower when boosted. There never was an OEM tranny that was desgined to handle them in the first. The 4T65EHD on the other hand has no problems (some mods needed) handling huge horsepower and torque.

Darrel,
I've read all over and searched www.fiero.nl about potential manual transmission options with no conclusive information posted by anyone but lots of hearsay. I am against using any automatic transmission as I feel they take the fun out of spirited driving. If that auto is the only "bolt-on" option that will handle the power maybe I'll just have to adapt a DSM 4G63T FWD transmission. Those have been proven for almost 20 years now to handle brutal power in stock form with just a clutch upgrade. Stock EVO transmissions have been into the 8s, so perhaps that's another option by elminating the viscous coupling as many do to run on 2WD dynos. I want to avoid "custom" as much as possible and stick to the beaten path because high cost and problems arrive the second one strays from it, but if that's the only choice then maybe so be it, just looking for input and appreciate the help!

Tom

Once you stick the motor into the rear of a car you are asking for transmission problems with high HP. You do not get wheel spin like you would with a FWD or AWD. All the weight is transferred to the rear on acceleration, along with wide tires you are asking for trouble.
If you never 'pop' the clutch and never try to 'get rubber' between gears a 915 will work. If you want more strength go with the G50.
Do you plan on installing 500 HP into the rear of a 25 years old tin frame?

[DarrelK]

Yeah, I agree with Jdinner concerning the 25 year old Fiero thing. Facts are (and you do see this in the Fiero forums over and over) when you get into any of these high h.p. applications the stress just goes somewhere else. Guy has strong motor, breaks tranny, guy has strong tranny, breaks CV joints, guy has strong CVs and breaks axles, strong axles= cracked cradle, and finally everything gets a little "twist and tear" thing going on. These now, "older" cars were built around a 4 cylinder 100 h.p. motor originally. Putting 5 to 6 times the power to the ground is gonna do some nasty things. Doesn't mean you can't, just get your wallet and wrenches ready.

[jdinner]

I recommend a frame like the one I made if you want to run big HP.

http://www.youtube.com/watch?v=wBNsFCQhXH0

Jim
www.kwikercars.com