Tuning Gurus step inside

[slimtastic]

Slimtastic,this turbo was on the car when I bought it from the original owner and from talking to him about what he did to the car he said it was completely original(stock).Everything from the air box to the chip was stock,the turbo even had the stock inlet bell with a hose going to the pass side valve cover.He also said that "these cars are fast enough and there was no need to modify anything",I had to tell him I was just going to restore the car in order to purchase the car from him,so I think it is an original stock turbo.Is there anything on the turbo that will confirm it is indeed a stock turbo?Thanks for your reply,ikle.

....the guy wouldnt sell if you were gonna modify it? so why the hell did he sell it lol

as far as the turbo is concerned, i think the only way to check is to get a dial calaper and measure the diameter of the turbo compressors inducer side. but off the top of my head i dont have any idea what the stock measurement should be.

did you ever measure the wastegate hole size?

 

[ikle]

On the exhaust and compressor housing "Garrett" is stamped into the casting.The hole where the exhaust turbine sits is 53mm wide from edge to edge and the wastegate port is 20mm wide from edge to edge.The only thing I did to this turbo is I removed the compressor housing and ported and polished the outlet a little and I Bell Mouthed and polished the inlet to match the Kirban machined inlet bell.

 

[slimtastic]

On the exhaust and compressor housing "Garrett" is stamped into the casting.The hole where the exhaust turbine sits is 53mm wide from edge to edge and the wastegate port is 20mm wide from edge to edge.The only thing I did to this turbo is I removed the compressor housing and ported and polished the outlet a little and I Bell Mouthed and polished the inlet to match the Kirban machined inlet bell.

the "garrett" is normal for all stock turbos and just about all TA turbos with a stock a/r

well with that information on the turbine. id make another post asking what a stock turbo's turbine diameter is (its besides the point, but still good to know anyways).

whats the diameter of your wastegate puck? if you look at the iron exhaust housing you should see a "soot line" where the wastegate puck covers the wastegate hole. this line is gonna tell you how much you can port out your wastegate hole (in the hopes of more boost control).

 

[ikle]

Thanks again for all of the replies its been very helpful.Correct me if I am wrong, by installing the Dutt neck stock intercooler it changed the velocity inside the turbine of the turbo making it harder for the exhaust gases to exit through the wastegate port?So in order to be able to lower and control the boost I need to enlarger the wastegate port to allow more exhaust gases to exit the wastegate port,which in turn will lower the boost.If I enlarge the wastegate port will it affect on how the turbo spools up?If so would it be better to buy one of Razors "Alky" kits and tune for the lowest boost my actuator will control? Thanks,again ikle.

 

[BEATAV8]

It's not that the velocity changed, what really changed with the dutt neck is pressure drop. Reduced restriction.....

think of it like this...
before the dutt neck the turbo was generating 20psi of pressure at the compressor outlet (compressor cover). The restriction through the intercooler was high, so the engine and boost gauge saw 16psi. (just an arbitrary example here...)

After the dutt neck install, the turbo is still making 20psi of pressure at the compressor outlet, but now the engine and boost gauge are seeing 18psi. Less restriction, less pressure drop, slightly more flow....

Since the wastegate is connected via a small hose to the compressor outlet, not much has really changed as far as the turbo is concerned.

Regardless, post some pics of your turbine housing and your wastegate puck. It would help us to diagnose....

 

[slimtastic]

If I enlarge the wastegate port will it affect on how the turbo spools up?If so would it be better to buy one of Razors "Alky" kits and tune for the lowest boost my actuator will control? Thanks,again ikle.

enjarging the wastegate hole wont hurt spoolup. and putting alky on the car is really just a bandaid. your really better off fixing the boost creap issue rather than covering it up

 

[TurboBuRick]

regardless, post some pics of your turbine housing and your wastegate puck. It would help us to diagnose....

x2

 

[Rich Gio]

Tagging along...got a Dutt neck IC going in this weekend!

 

[AlaskaGN]

I am having the same problems. I run a RJC boost controller though, it was the same w or w/out it.. I was told to look for vacuum leaks or exhaust leaks. im really interested in what the cause if of yours.