N/T Transmission in a Turbo Application

[aspekt9]

So here's the deal, I'm getting ready to start working on the N/T. It's a 92 GS with 66,000 original miles on everything (minus timing belt and all that jazz). So my question is, if I'm going to turbo it many people suggest the turbo transmission swap. Is what I'd like to know is if I have the transmission rebuilt to even better spec than the turbo transmission, will that be sufficient enough to run higher boost on? Also the N/T Flywheel and NT clutch I would be forced to use since the bell housing on the N/T transmission is smaller than the Turbo transmission by about an inch or so, so will the N/T flywheel and say an ACT 2600 hold enough power?

 

[dsm-onster]

It's cheaper and the same amount of work just to swap to a turbo tranny.

 

[spoonman]

The N/T transmission has a higher axle and final drive ratio giving you better off the line power, but the differential is likely to break with a strong clutch and higher horsepower (300-ish). But I have also broken turbo differentials also. I suggest that you talk to shep transmissions on putting in a limited slip, then the tranny will have great acceleration and you do not have to worry about the differential going out. You need to use the N/T flywheel and a N/T clutch because like you said the bellhousing is shorter. One problem with the turbo transmission is the cars had mounts that moved the engine and tranny closer to the front of the car, so if you put in a turbo tranny the diff will touch and slightly rub on the k-member.

 

[dsm-onster]

Are the internals as strong? Is it really just the differential that is weaker?

 

[spoonman]

The internals are visibly smaller and said to be weaker but I have not seen or hear of actual proof. The differentials do break easier thought because of the higher axle ratio which just puts through much more torque. The higher ratio does help out alot at the track though and can lower 60 foot times, but not as much as AWD tranny.

 

[cruisintalonawd]

I' was forced to put a N/T tranny in my car when I couldn't find a turbo tranny and I beat the living piss out of it and I boke the rear motor mount and the left axle twice and the tranny still held up.

To spoonman: What do you mean higher axle????

 

[dsm-onster]

He means the same thing as the "rear motor".

 

[spoonman]

He means the same thing as the "rear motor".

The axle ratio is the ratio of how many times the pinion gear rotates compared to how many times the ring gear on the differential rotates. The ratio is more widely discussed in RWD cars because the gears are more interchangeable. The higher the axle ratio the more turns of the pinion gear are need to rotate the ring gear, and with a higher ratio you have higher rpms going to the tires resulting in faster acceleration with more torque. The higher ratio also puts more stress on the axles and diff and the car will have a harder time maintaining traction off the line, this is why my sister's 4.33 rear end mustang does wheelies.

 

[aspekt9]

And what about a Flywheel and clutch that can withstand up to 400 HP? Assuming I retain the NT transmission and have it rebuilt.

 

[spoonman]

I believe the N/T flywheel is lighter by a few pounds but still just as strong, finding a good N/T clutch will be difficult but I believe Clutch Masters and Center Force makes one for the N/T.

 

[aspekt9]

It seems ACT makes a N/T clutch: Products for your Vehicle | Products ~ Advanced Clutch Technology®

I'm not sure how numbers are translated. Do you think the ACT 2600 would hold up to 400 HP? Also which model number corresponds to the ACT 2600?

 

[dirisec]

This is what happens to n/t transmissions, at least to mine.

 

[spoonman]

This is what happens to n/t transmissions, at least to mine.

Did something internal break and cause the crack? What type of set up were you running with that transmission and how did you drive on it?

 

[dsm-onster]

The casing is made from the same thickness aluminum. My brother has a crack in his AWD bellhousing. I've seen more than 2 turbo transmission bellhousings crack.

 

[dirisec]

Did something internal break and cause the crack? What type of set up were you running with that transmission and how did you drive on it?

Well, hard would be the correct adjective to describe the way I was driving it, it was at the drag strip looking for a nice launch( wich I got ) but when i went for second it was already broken . Only the bellhousing suffered my wrath. I'm running a 2100 ACT pressure plate and 4 puck disc with springs.

 

[dirisec]

The casing is made from the same thickness aluminum. My brother has a crack in his AWD bellhousing. I've seen more than 2 turbo transmission bellhousings crack.

Today I bought a turbo tranny, the guys at Jack Transmissions told me the housing of the turbos are stronger, no disrespect, but I hope youre wrong on this one. If it breaks I'll let you know.

 

[dsm-onster]

Jack knows WAY more than me about transmissions.

 

[dirisec]

I'm pretty sure you both know more about transmissions than me, but I'd be really pissed if I was investing in a new trans wich I had to change the pressure plate and clutch also and didnt have to.