Thread: Gt30-76r
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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269

Good point. On a max build it would probably put this turbo out of its peak efficiency island. Such a build would require cams, increased fueling and probably larger ports and all the other tricks. Thus, a GT 35 or such is probably a better match.

This is more for the CIS build that is not after that last 50hp. As such this might make gains in response and efficiency over a larger turbo. I had an HF with its small turbine and large compressor. It is a good upgrade and comes in like a V8 in a very controlled way. I more preferred the fast and hard spool of a smaller turbo but that was me. I suspect for most CIS 930's this turbo will get both the low end kick and carry full boost to red line.

Again, I think of it more like a better K27-7006 than steeping up to a K29, HF, or GT35. Some of the gain is probably going to be from a more efficient hot side on the GT30-76R.

Add to that the lower mass, ball bearing construction and it should be a much quicker spool turbo.

Another plus is we can play with the turbine's AR sizes to tailor one's goals. With the K27 turbos that is not as easy to do.

I believe drmatera found access to being able to tune the hot side very valuable with his turbo.

As a point of reference, the 7200 and 7006 have very, very close to the same size compressor wheels, it seems it is the 7006's larger turbine that lets it make more power. I have often heard there is great opportunity on the hot side.

I truly suspect the 7200's turbine was designed intentionally to choke off the turbo so air flow would not exceed the 3.3 turbo's fueling limits to a large degree. It is never allowed to reach the higher air flow parts of its compressor map. I could be wrong but that is what the information suggests to me. The 7006 keeps making boost with basically the same size compressor wheel.

Last edited by 911st; 10-13-2010 at 09:39 AM..
Old 10-13-2010, 09:37 AM
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