Hello, searched but its hard to search a/r and such. I was just wondering (day dreaming about stuff) what the stock turbo's (s4) A/R is?

Thanks
~Tweak

 

just read your post and realized no one replied, i dont know what it is but someone should, i would like to know myself considering i have an s4 and never really thought about it until i looked at your thread. sorry man

 

I always thought it was something like 1.0. I'm pretty sure its stamped inside, for some reason I thought s4/s5 were different too. Keep in mind that all depends on the size of the turbine wheel. A 1.0 P trim is HUGE compared to a 1.0 stock turbine..

 

inside the housing ?

 

Ohhh kk. Nevermind than. I forgot that the different trims and such matter.
Thanks.

 

If it's the hotside a/r's you are inquiring about, the S4 is a 0.86 a/r and the S5 is 1.00 a/r (or close there abouts for the two).

 

it is my understanding that the s4 and s5 turbos are the same hotside except for the design of the twin scroll system (equal runner on s5 manifold/turbine vs unequal runner with flapper on s4). I've never physically compared them however.

 

The s4 has a smaller scroll on one side therefore it has a smaller a/r.