Xerxes

I know that for the compressor wheel size and housing size and a/r, you can use compressor maps, but what's the best way to choose a turbine? How do you know what a/r and what size wheel to get?
Also, is there a correspondence between Garrett and Turbonetics wheel sizes?

-Xerxes

cyan1de

displacement, rev limit (redline), top end / low end power, whether the turbine will fall off on the top end, etc. http://www.turbofast.com.au may have some good info for you.

Xerxes

they've got some cool calculators there, but they don't exactly explain how to pick a turbine.

i understand that those attributes are all important issues for picking a turbine, but i haven't seen anything like a "turbine efficiency map" etc. From what i've seen it seems like everyone picks their turbines based on experience and guesswork

cyan1de

that's how it's mostly done. most people just want a turbo for the street and therefore don't want a 'laggy' turbine. a .63a/r is good for most 1.8L & up with high rev limits. plus it all depends on when you want spool up time. do you want spool up at 2500rpms? 4500rpm but have more power? it all comes down to what you want and what suits your motor best.

immortal

GO BIG OR GO HOME.

BlueShadow

From what I've read selecting the Turbine is more a a trial-and-error method rather than an exact science. However insted of making your own "trial-and-error" test you can ask around for people with similar setups and ask what their turbine characteristics are.

If you want to be precise and use numbers, you will need to know and measure a few things . Here is a quote fomr Maximum Boost by Corky Bell.

"Judging by the numbers requires measurement of exhaust manifold pressure, or turbine inlet pressure, and comparison with boost pressure"

In the book there is a chart that shows boost pressure (Y-axis) and turbine inlet pressure (X-axis). you find out what PSI you are running and what your turbine inlet pressure is, and see where the lines intersect. the lines intersect within the chart and it tells you what the best A/R size to use.

for those of you with the book, its on page 34 fig. 3-13

BlueShadow

I think the A/R's are pretty much the same thing, but their labeling system is **way** different.

GT2835 blah blah = Garrett
T4/T3 = Turbonetics almost everyone else
TD04/5 -18G/20G etc.= Mitsubishi Heavy Industries (Greddy)
RH6/RH9 = IHI turbo's ???

and everything else in between. why cant they just all use the same labelling system? the turbo's I dont know how to read yet are the SP56?, SP57, T66, T78, and T88's. what are those? are those just straight T4's?

X2BOARD

Doesn't the Garrett have a different blade design/ number of blades than the Turbonetics ?