TTA Stock Turbo Question

[Epitome]

I have a customer with an old, original ad for the TTA. Not only does it say that the car will be produced with a roller cam (never happened), but it also says that the turbo's center section was water cooled. He believes he had seen one of the hardtop Indy cars with a water cooled center section (which could be true I guess). I told him that my understanding is that the TTAs were produced with a non-water cooled center section. We are both just curious about the truth from someone here that knows. Thanks

 

[1BADDAM]

Magazine rumors. I have an article that states they have S.S. headers as well. Some have claimed adjustable wastegates......... I imagine the list will go on.

 

[TT/Ameasap]

No water cooled. SS headers yes. The TTA turbo is the same as a gn but the wastegate hole is bigger for controlled boost. Part number is different too.

HTH
Bo

 

[Epitome]

Just as I thought....thanks

 

[skturbo]

Early in the planing stages of the TTA they wanted to have a roller cam but was droped due to cost. The TTA never came with a water cooled turbo. The TTA did however come with a different turbo but it had the same size waste gate hole. The difference was the better flowing compressor housing. As for the adjustable waste gates I have seen the cars with and without. Most with. A lot of these cars would go to the dealer for service and the so-called mechanic would see oil in the inlet bell and condem the turbo. The oil would be coming from the vent on the valve cover. To make maters worse they would order a replacement and it would be a GN turbo and not be the correct turbo.

Steve K.

 

[TT/Ameasap]

Steve,
I think your talking about the replacement turbo for the GN. That turbo has the bigger housing.

The TTA had a wastgate hole dia. of .912-933" vs GN .820

Some of the cars had adj. WG that could move .015 of movement for .5+ PSI gain.

Just from my sources...Although could be skewed a bit.

 

[skturbo]

Your right. You are skewed a bit.:smile:

The TTA came with a compressor housing that had raised "Garrett" letters not stamped into the casting. It also had a square with a "L" in it. It had a wider grove cut into the inside of the housing for improved flow. The grove on the GN was .210 and the TTA was .236 .026 wider. It had the same size compressor & turbine wheels as the GN. The housing on the left is a original TTA housing the right is a GN.

Steve K.

 

[phillyturbosix]

All the TTA info you ever needed....

20th Anniversary Turbo Trans Am

 

[RatFink]

My car came with a non adjustable wastegate actuator. The chip was to control the boost. I don't think GM would want to "encourage" anyone to "try" the adjustability of something that could easily void the warranty.

 

[2QUIK6]

My car came with a non adjustable wastegate actuator. The chip was to control the boost. I don't think GM would want to "encourage" anyone to "try" the adjustability of something that could easily void the warranty.

Just to point out that the GNX came with an adjustable wastegate rod. Never seen one factory on a TTA, but I guess anything is possible if the supplier had some left over from the GNX run 2 years ealier but I'd think that would be highly unlikely..maybe on one of the 5 pilot cars.

 

[hiballin]

The TTA came with a compressor housing that had raised "Garrett" letters not stamped into the casting. It also had a square with a "L" in it. It had a wider grove cut into the inside of the housing for improved flow. The grove on the GN was .210 and the TTA was .236 .026 wider. It had the same size compressor & turbine wheels as the GN. The housing on the left is a original TTA housing the right is a GN.

Steve K.

Good info, thanks for posting the side by side pics. As far as wastegate rods go, I've never seen an adjustable one on an unmolested car. #486 and #1048 both have fixed length rods.

Maybe some cars built earlier than mine had an adj rod?

 

[Razor]

The Y on the rubber hose to the WG was different as well I believes :redface: