Whooopasss

Ok.. we have all the parts in, custom log type turbo manifold for the K20 (Ep3) all electronics, guage smc+ 450 injectors, intercooler, boost controller everything!!

We have 2 turbos in our hands

first one is a t3 with 60 ar comp and 48 ar turbine
second is a t3 with 42 ar comp and 48 ar turbine

the 42 ar comp fits nice and all, lots of space between the turbine and the valve cover, but the 60 ar would hit the valve cover due to the size.

question, our EP has a redline of 6800 RPM.. now with that said, will we notice a big difference in performance between the 2 turbos.. if enough argument is subtanciated (spelling) then we will re-do the turbo manifold to fit the 60 ar turbo intead of the 42 ar.

Opinions please..

sivik2nr

IMO, ( this is coming from a turbo NewB) I would redo the manifold for the t3 with the 60 ar comp. Both turbos have 48 ar turbines. The turbine powers the compressor, and it also decides what speed the compressor will spool up ( how fast the boost threshold is acheived ). A small turbine will spin faster than a larger one, given the same exhaust gas energy to work with.
Since both turbines are the same, both turbos should spool up the same, but the 60 ar should show greater results..

Am i correct in thinking this? Or am i confusing two different things?

Sonny

Pics, Jay, pics!

The .42 a/r is likely a Saab or Volvo turbo with a 45 or 50 trim compressor wheel.

The .60 a/r is likely a Ford Thunderbird turbo with a 60 trim compressor wheel. It is substantially bigger and will perform a lot better.

Sonny

Whooopasss

Here yah go sonny

AR 60



ar 42



when all fits.. then we will have the shaft balanced.. we are only swaping the comp side.. but we are using the same turbine.

E-Rok

go with the 60, id steer for the larger side of turbos that are used on the smaller b series turbos.

BTW what are you doing for fuel? just curious, I want to turbo my friends RSX

Whooopasss

we are going with the SMC+ and 450cc dsm injectors

BTW.. with 6800 rpm redline, is the 42 ar comp not enough for 7Psi??

So we are only planning on running 7 PSi intercooled (since we still have no way to retard timing) will we get better results with the 60 ar at 7psi than the 42 ar at 7psi??


[Modified by Whooopasss, 8:29 PM 2/1/2003]

Sonny

Jay,

Can you take off the compressor housing (it's only 6 bolts...easy) from each turbo and measure the wheels? The outer diameter of the wheels should be the same. The inner diameter is most likely larger on the .60 a/r turbo.

The a/r of the compressor housing is only one factor in the turbo's performance. Of more importance is the "trim" of the compressor wheel inside the housing. You should know what you're using. The difference between a 45, 50, and 60 trim wheel is substantial.

Sonny

Whooopasss

Hi Sonny

Here you go..

the smaller compressor wheel is exactly 1.5 inch from tip to tip (blade)
the bigger compressor wheel is between 1.8 inch and 1.9 inch tip to tip (blade)

given that my measurment is not exact, but that is what it looks like.. let me know what you think..

again, my redline is still set at stock 6,800 rpm.. please take that into consideration..

cheers..

Sonny

Jay,

The smaller wheel sounds like a 40 or 45 trim compressor wheel. Those wheels are very small.

The bigger wheel sounds like a 60 trim wheel. I would definitely use that one.

Your redline of 6800 is more a function of the a/r of the turbine housing than anything else. A .48 a/r turbine is a good match for a 6800 redline. Matched to a 60 trim T3 compressor, that setup will spool fast and hit pretty hard.

Sonny

Whooopasss

and.. as usual.. sonny is very helpful... thanks man.. ok, we will start to re-do the manifold to fit the t3 with the 60 ar and 60 trim.. BTW looks like the husing will clear the valve cover but not the internal wastegate.. hmmm time to do some brain storming to clear this.. thanks a bunch sonny..

all I have to do now is to have the shaft balanced somewhere...


[Modified by Whooopasss, 9:53 PM 2/2/2003]