Twin Turbos

Does anyone know how the twin turbos work on a '92 GTO. Is one of them for low revs and the other one for high revs, or do they both boost at the same time? I wanna learn something guys. PLEASE TEACH...

they are the same turbo front and back, the reason there are 2 is because its easyer to twin turbo a V engine car than single turbo it. There is one turbo for each exhaust manifold.

yes they are 2 TD04 9b turbos. they are not sequential (aka they boost at the same time) they put out ~9psi for 91 - 93 and ~11psi for 94 - 99 (or until 00 or 01 if you count europe and japan). you can easily ($18) up the boost with a MBC to 14.5psi safely (aka stock guage is crap) and get 355 hp with any model. you can go as high as about 18psi peak to about 10psi at 7k rpm on the stock turbos. they are small so they drop off at high rpm (start dropping about 4.5k rpm i think).

chris

An excellen article can be read here http://www.team3s.com/FAQturbobasics.htm

Wat does this mean?

"you can go as high as about 18psi peak to about 10psi at 7k rpm on the stock turbos."

I thought 7k rpm...was your PEAK ???

Wat does this mean?

"you can go as high as about 18psi peak to about 10psi at 7k rpm on the stock turbos."

I thought 7k rpm...was your PEAK ???

the stock rev limiter on a VR-4 is at about 7.5k rpm i believe so that is you stock peak rpm. what i ment was peak psi of boost. you can go as high in boost as 18 maybe 20 after the turbos are fully spooled up (which happens very quickly) but when you get to higher rpms, you boost level drops.

oh ok, thanx bud. But you wouldn't want that psi on a stock turbo right?

oh ok, thanx bud. But you wouldn't want that psi on a stock turbo right?

i have heard both ways, i would suggest going to www.steal316.com and reading the stuff about flow maps on there. basically, if you are pushing 18psi out of the stock turbos you are operating out of the turbos peak efficiency range and thus you are blowing a lot of really hot air in (which is bad, we want cooler air). i have heard that this is pointless but i have also heard people say that they gained power from it. i am sure that if you go to www.3si.org and do a search you will get more info than i can provide here.

it should be noted also that the stock fuel setup will not work at pressures above 14.5 psi or so on the stock turbos so you should make sure you have the fuel to back up the boost.

DON'T RUN 18 PSI on stock turbos.