i was just wondering if someone could point me to a page, or explain the differences in compressor trims. i've looked but cant find much info anywhere, maybe i'm looking in the wrong place. thanks.

 

Much like automobile names, there isn't a whole lot of meaning in compressor names. These links will show statistics on some of the more common aftermarket turbochargers:

http://www.turboneticsinc.com/index01.html
http://www.ihi-turbo.com/
http://www.majesticturbo.com/
http://www.egarrett.com/products/orig_equip.jsp

 

I dont know but maybe he meant the letter trims? As in p-trim, q-trim and so on. If he didn't, I would like to know

 

err whoops i guess those trims are for the hot side not the compressor

 

yeah, i meant the letter trims on the hot side, just trying to figure it out. thanks though.

 

Guess no one can help us out....

 

huh, guess not. maybe we ought to go buy some books??

 

The single turbo Supra guys and DSM guys I know are always debating trims. You might try posting this question on one of their boards. It may be because more are available to them?

Alan

 

I'm assuming you need more information on turbine trims.

There aren't many maps for turbines (any I can think about). Trimming the turbine wheel and having it flow more (theoretically) should enable more potential for your power band.

A/R ratio of the turbine section (or hot side) has a more direct and weighted affect on spool time. If you increase the efficiency of the turbine wheel (trimming it to flow more), then it should help the spool since the wheel should spin better. My guess is that the affect is minimal.

As for efficiency, you're still limited by your compressor.

J

 

We are asking about the LETTER trims such as p-trim, q-trim and so on. Everyone knows what a/r ratio does.

I think when you say trimming the turbine you mean clipping it, which actually DECREASES the efficiency, but increases the maximum flow.

 

All things being equal a P-trim will spool quicker but have a little less top end than the Q.

Check out the new GT-Q and GT-R turbines.

HoustonT over at Supra forums has a dyno of identical runs (boost 27 psi, fuel 11.5, timing, etc.) with a 74 GT-Q and 74 GT-R (both .81 A/Rs)... the GT-R made 50 more rwhp with zero additional lag... amazing.

Here are the two dyno's overlayed...

 

damn, must be nice to have resources like that

 

so judging by the graph, theoretically the P trim should have spooled quicker, but the Q achieved 50 additional horsepower. i know that there are 3 main trims that are in use: V, P, and Q. i know that Q trim flows more than P trim, which flows more than V trim. which will in turn make higher horsepower, and just the opposite for spool time, i'm guessing. my intention for this post was to find the best trim for a gt35/40. my goal is mainly a street car, with a few yearly trips to the drags. i'd like a quick spool with over 400 @ 15psi daily, and the ability to turn it up to 20psi on those "special occasions" i dont think i'll have a problem with the 35/40, .70 front, and 1.06 rear. but since i'm doing it, i like to get the best i can for my goal. thanks for the help.

 

Those plots compare the GT-Q and the GT-R trims... they are brand new Garrett wheels.

I did not show anything with a P or Q trim.