TheDice951

i have a pretty good idea about turbos and i just need some clarification on some things....

an .87 a/r exhaust side
V.S.
a .50 a/r ehaust side

i always thought the smaller the exhaust side the faster it will spool, but my friend has been arguing with me and saying the bigger one would spool faster.

i have been thinking about it and what i thought makse more sense. my issue is, im looking for a new turbo for my 951 and cant seem to decide what to get....

i want something that spools quick and can hold boost until redline and am shooting for 350-400hp.....

Rogue_Ant

If the turbine housing & wheel is the same family, then you are correct in thinking that the smaller turbine should spool up quicker.
However, if your comparing a T3 .87 a/r to a T4 .50 a/r then it gets more complicated...

TheDice951

ahh...its all t3.... so i was right then.. cool

thanks for verification

gt37vgt

I smaller turbine can get out of its own way quicker / has less inertia but if you have put to much compressor wheel on the other end it will struggle as it will generate less shaft torque than a bigger turbine .

TurboTommy

You're talking about the wheel size.
But, there's also the actual housing size. Each has its' own characteristics when playing around with different sizes.
The hotside of a turbocharger is much more complicated than the coldside, and I'm still trying to get a handle on understanding it.

gt37vgt

yeh i was just talking turbine/wheels and yeh the hot side is not completely strait forward you may find when you go 1.05 to 0.82 it gets more response i but then you go to 0.48 and the restriction is too much and it in fact gets laggy again as it chocks up...
that turbo calculator on the ray hall page is pretty good .. for that stuff

TheDice951

it would be much easier if i could find the I.D. plate on the upgrade that to PO did.... then i would just get one the same size..... mine is leaking oil into the exhaust..... its my daily so i need one i can slap on as soon as i remove this one....