Hey, can someone explain to me exactly what the A/R or aspect ratio refers to? Is there an A/R for the turbine and the compressor or is the A/R some sort of overall number? I'm looking at a single turbo supra with "GTQ67" turbo, which he says is a 67mm compressor with an A/R of .68. He said its bigger than the T61 which used to be on it. Here's the dyno for the T61 turbo. http://www.booost.com/movies/supra_dyno.jpg

He said he thinks the new turbo is making about 670rwhp instead of 620. I seem to recall most of the A/R's for most the t-78's, t-88's t-66's gt3540's on rx7's being around .85-1.05 Can someone just explain how it all works for me? Thanks.



-Rob

There is the turbine and compressor wheel a/r. All you have to worry about is the turbine a/r, which will effect spool time and power. A/Rs are only important in comparing the same turbo. Bigger a/r moves more air(compressor housing) or more exhaust(turbine housing). bigger = more power/lag...

so when going from one turbo to another, A/R has no meaning? an A/R of .7 on one turbo may spool slower than an A/R of .9 on a totally different turbo?



I just saw the topic pinned on the top of the single turbo forum, i imagine that will answer my questions - but maybe not...

Yeah if you read that pinned topic it will explain it for you.



Supra's run totally different a/r's then rotaries do. Much smaller usually. 670 or so sounds about right for a GTQ67. Thats a bad ass turbo. Its basically a ball bearing T66 with a Q trim exhaust wheel,I believe