I posted here a while back that i had a single grand national stock turbo and want to put it on my 97 formula. Everyone told me it wouldnt work i would 2...so now i have 2 and want to make a twin turbo setup.

Questions. what all need to be done to make this work? besides the tubbing ( that is one thing i wont have a problem with)
is an inercooler a must?

what is the max lengeth of tubing i can use from the turbo to the intake?

what kind of HP will i be getting?

How safe will this set up be?

 

1. A bunch of free time and free money

2.yes....you need an intercooler

3.the less the better

4.what size are the turbos and whats done to the engine..Ie heads?..cam? cr ratio? exhaust..........kinda need to Know that stuff

5.if done right it CAN be safe... but the same can be said about C4 ...

....

 

97formula- I will throw my 2 cents in, which might not even be worth 2 cents.

I dont know that much about stock grand national turbos but I would think they have an intergral waste gate. Personally I would rather have a turbo without that and use something like a deltagate waste gate. You could make a plate to plug the holes for the integral waste gate and use deltagates (or something else).

I would say an intercooler is a must depending on the amount of boost. I would want one with anything 10psi or more.

Even though I don't know anything about the stock grand national turbos I would say they would be good for 350-400HP each. Put twins on a motor, loose a little efficiency, I would say its very possible to make 650-700HP on a nice flowing LT-1.

 

the car is totaly stock

 

Seems to me the GN turbos are a little smaller than the ones I have, so they should work fine. I highly recommend intercooler(s). I am running a pair off a Saab, one for each turbo.
So far as wastegates, the internal ones work fine, as long as they work off boost and are not controlled by vacuum, and by the GN computer. If you need more boost, a simple bleed valve works fine.
My motor is stock, other than a LT4 Hot Cam and rockers. I see 9 psi at 1/4 throttle, and no traction in 1st gear, with more tire than you will ever fit! I still have a slight bog when the throttle is floored at idle, but that is fuel map related more than the turbos.

Get to work putting it together!

 

Turbos are like a pair of shoes. A pair may look and more importantly fit great on one person, but are virtually worthless for another person.