I've done some searching, but nobody, including A-spec seems to have in depth information about the differences in these two turbos. From the limited info I've seen it all seems to be the same?

The GT35r t4 has a t4 turbine cover (.68 A/R), 61mm compressor wheel with a TO4S comp cover (.70 A/R)



The GT35r basically has a 56 trim , the turbine housings or covers are t3 and the A/Rs avaiable are .63 , .82 and 1.06







of course both are ball bearing not cermaic and oil and water cooled





hope I could help ya a little https://www.nopistons.com/forums/pub...#>/biggrin.png

Yep exactly what i was looking for, thanks.

so you mean to say that the gt35r/t4 doesnt have the anti compressor surge compressor housing?

T4's come in .84, 1.0, 1.06, 1.12 for Turbine A/r









-S-

There is the boss man right there! Thanks mang, with any luck I'll be contacting you in about a month, once i get outta the desert, for the T4.

I have the GT35RS-T4 and i'm sure it's way overkill for 14lbs. I should have it by this weekend.

Let me know what you think. https://www.nopistons.com/forums/pub...#>/BURNOUT.gif

I've tried to understand it myself but i'm still confused. This is my take but ovcourse it may be wrong.



T4 changes the boost curve. It starts higher then the T3 but drops off later as well. The RS allows for more boost and still being effiecient. I didn't care about more then 1bar of boost, so I prolly should of stuck with the R instead of the RS but I did not want power to drop off before redline. Boost does not drop off but from looking at dyno charts, it seams most peoples power goes lower over 7krpm even though full boost holds. If i'm lucky I can eventually have a track map done as well.

Keep in mind that where power falls off is also directly related to turbine housing size & porting. A lager turbine housing with aggressive porting will move the power curve up. The result is more top end HP @ the cost of slightly decreased response.



The "T4" at the end represents that the turbo has a T4 turbine.