I am thinking about getting a turbo but Im just doing my research now to find a good match. Im planning to run around 12-15 psi. The turbo I am set on for now is a Garrett GT40, 82mm with .81 A/R turbine -compressor map . I chose the bigger A/R because I also may be spraying nitrous. What do you think about this turbo? If anyone has any other suggestions, that would be helpful.

Does anyone have volumetric efficencies for the DE-K engine?
I found the efficencies that IceY2K1 used but they are for a stock 4th gen. I guessed a little higher efficencies on the top end since I have a DE-K engine. The stock 4th gen numbers will be close enough but the numbers for the DE-K engine will help some. Thanks!

stock 4th gen by IceY2K1:
2500 81.3%
3000 78.04%
3500 86.26%
4000 84.41%
4500 87.63%
5000 83.79%
5500 78.42%
6000 67.77%
6500 55.84%

 

Anyone?

I have another question. Im going to go with a 38mm wastegate, should I go any bigger if I will be spraying nitrous also?

 

bigger wastegates are supposedly better for low boost setups.

as for the ve, I haven't had much experience with it.
steve

 

the ve will be close to the same for low end but will not drop off till much later in the rpms

a ballpark guess close enought for turbo calculation would be

2500 81.3%
3000 78.04%
3500 86.26%
4000 84.41%
4500 87.63%
5000 90.79%
5500 85.42%
6000 80.77%
6500 75.84%

38mm should be able to keep up fine

 

Thanks for the replies. A buddy of mine is suggesting to go with a larger wastegate then 38mm, he thinks that with the spray and extra exhaust created will make the turbo spike too high.

Also, I have a question about the wastegate, once it opens, and the exhaust goes through it, then where does it go? Many of the kits I have seen, the exhaust does not look like it goes into the downpipe or anywhere. Do most people just have it dump from the wastegate?

 

you can atmosphere dump it or I've seen it routed into the downpipe.

 

well there are severall people on here that have a turbo+spray and ALL of them use a 38mm wastegate so you could get a bigger one but it would be a waste of money

and it is correct that the lower the boost the more exhaust you "waste" through the wastegate because it takes less exhaust to spin the turbo so the bigger the gate you need but a 38mm gate is plenty big enough for a 3l i dont care how much you spray it