t56 or turbo 400?

[tshoey33]

building a 347 turbo motor for my 89 gt. trying to decide if i should put a t56 tranny behind it or a turbo 400 with manual valve body. any thoughts?

 

[Gearbanger 101]

Ummm....pretty big variation there. What do you want...a stick, or an auto?

 

[fiveohwblow]

What are your intentions? Drag racing or street/auto x?

 

[jdb3rd]

Unless you plan on drag racing alot I strongly suggest the t-56

 

[tshoey33]

It will be mostly a street car.

 

[Boosted92LX]

I have a friend with a T56 and 76mm LS2 turbo camaro and it's vicious. Sometimes I think it would do better if he didn't have such a close ratio trans and the turbo was able to spool more between shifts.. By the time he's at full boost (which is a split second), he's shifting already, and that's with 3.55 gears. I plan on going the same route, only I got the wide ratio 5 speed TKO to allow more spool time. Turbos make more torque than any other power adder, close ratio gearboxes are not as necessary, imo...

 

[srtthis]

I have a friend with a T56 and 76mm LS2 turbo camaro and it's vicious. Sometimes I think it would do better if he didn't have such a close ratio trans and the turbo was able to spool more between shifts.. By the time he's at full boost (which is a split second), he's shifting already, and that's with 3.55 gears. I plan on going the same route, only I got the wide ratio 5 sped TKO to allow more spool time. Turbos make more torque than any other power adder, close ratio gearboxes are not as necessary, imo...

correct... thats why you see them running such high gearing.
but im nor sure if a turbo makes more torque then a nitrous car. that would be a close one.

 

[Boosted92LX]

correct... thats why you see them running such high gearing.
but im nor sure if a turbo makes more torque then a nitrous car. that would be a close one.

By power adder I meant snail, centri blower, or screw/roots... didn't factor in nitrous, although seeing specs on that would be interesting.

 

[jdb3rd]

I agree about gearing with the t-56. I have 3:73's and would love to have a set of 3:55's in there. But I've been thinking of a 331 or 347 with maybe 8psi of boost or so and that has me even thinking 3:27's.

 

[bentley429isBAC]

Had a stick and ended up with a th400 running a turbo. Was night and day.

 

[Incon]

I know from my experience that I kept the car in control and off the rev limiter much better with an auto when street driving. Something to consider especially if you have a stock block.

 

[FastDriver]

I've gone back and forth on this so often. I've always had a manual in my cars and its hard for me to think of going with an auto. But its also hard for me to imagine giving up so much performance, consistency, and stability. I cannot keep up with my car using the TKO, though it is notch as hell and needs a rebuild. Anyway, at the moment I'm really thinking about a lentech with a locking converter. That might be the best compromise on a street car.

 

[Gearbanger 101]

Even if the auto was the prefference....what's the matter with a built C4?

 

[Mr. Rustypwnz]

^they suck thats why. Nobody wants to rebuild a trans every year.

 

[Mr. Rustypwnz]

I've gone back and forth on this so often. I've always had a manual in my cars and its hard for me to think of going with an auto. But its also hard for me to imagine giving up so much performance, consistency, and stability. I cannot keep up with my car using the TKO, though it is notch as hell and needs a rebuild. Anyway, at the moment I'm really thinking about a lentech with a locking converter. That might be the best compromise on a street car.

you would love a built 4r70.

 

[hoopty5.0]

I've gone back and forth on this so often. I've always had a manual in my cars and its hard for me to think of going with an auto. But its also hard for me to imagine giving up so much performance, consistency, and stability. I cannot keep up with my car using the TKO, though it is notch as hell and needs a rebuild. Anyway, at the moment I'm really thinking about a lentech with a locking converter. That might be the best compromise on a street car.

The Lentech has a full manual valve body, right? I read their site the other day, but can't remember. A couple of them just sold in the classy-fides

 

[Bullitt347]

^they suck thats why. Nobody wants to rebuild a trans every year.

Only if you do not build it right, there are just as good of parts available for the C-4 as there are for any other 3 speed trans. It is not cheap to build, unless you build it on the cheap. But they are quite capable of taking 1,000 HP. and without rebuilding every year. The big upside is small size and weight, the down side is only 3 gears and that sucks for a street car.

 

[Mr. Rustypwnz]

Only if you do not build it right, there are just as good of parts available for the C-4 as there are for any other 3 speed trans. It is not cheap to build, unless you build it on the cheap. But they are quite capable of taking 1,000 HP. and without rebuilding every year. The big upside is small size and weight, the down side is only 3 gears and that sucks for a street car.

I have SEEN a couple at 1000hp, but they never lasted very long. I have HEARD of them lasting for a good while though at 1000hp, given one was a nitrous car on upwards of 300hp hit of nitrous, so that might be a factor on destroying one.

For his car though I think he would love a 4r70

 

[Gearbanger 101]

I'm going to take a shot in the dark here and say the OP isn't shooting for 1,000hp with a turbo 347.

400-600hp is more likely...which will keep a decently built C4 together just fine. Or a 4R70W for that matter.

 

[srtthis]

I'm going to take a shot in the dark here and say the OP isn't shooting for 1,000hp with a turbo 347.

400-600hp is more likely...which will keep a decently built C4 together just fine. Or a 4R70W for that matter.

depends on the C4 the converter and how well he cools it. turbos are hard as on autos.