EpitrochoidMan

I posted this in the general automotive (since it's not rotary related, although my next project is a similar sequential system for the 7) but I didn't get any response, I thought ppl who browse this forum would have better info.

Okay, I've finally decided on what turbos to use with the sequential system I'm building for an RB25. The primary-Garrett GT20 (compressor .53a/r turbine .46a/r) The secondary-Garrett GT28RS (compressor .6a/r turbine .64a/r) The stock RB25 turbo is a T25 (compressor .6a/r turbine .5a/r). I'm positive both will spool, and that the primary will spool quick, but if anyone here has any knowledge about the RB25 Hit me with some criticism.

Also, I realize this is like $1500 worth of turbos, I may end up just going with the GT20 and the stocker for the secondary, if I end up spending too much in the build process.

jeremyb

if you're really stuck... i suggest you look a the chart that shows peak power/hp for each turbo at wut psi. it tells you how quick each turbo spools/peak power/AR/etc. So first set a HP goal and take a look at the chart. There IS a chart... i'm just very vyer sorry i dont know the link. I'm sure someone viewing will post a link or something. sorry =/

RETed

Why are you messing with different turbos on the same engine?
You realize the thermal load from the two different turbos might present a problem?


-Ted

EpitrochoidMan

I didn't think that the thermal load from 2 slightly different sized turbos would be that much different than two identical turbos. Especially if I just just use the T25 for the secondary, plus if I don't get the results I want with the T25, then I'll go with another GT20, but not be out the money for 2 turbos initially.

But the main reason, I'm messing around with 2 turbos on the same engine is that

1) 3 turbos won't fit :-)

2) At any given pressure (say 8psi) 2 turbos will flow way more CFM than 1. And in this case, there is less spool up time.