Need some opinions on turbo selection

**cschepp** · 10-13-2010, 05:35 PM

Ok here's the thing I have a rb25 with stock Internals and want to make some good hp with it still being fairly reliable to drive. I have done all the supporting mods for big hp but I am wondering what turbo I should go with for 500ish hp? I was looking at the gt35 or even the gt47. Or even possibly going 2 bigger size top mounts. Anyways please provide some feedback as I would like to start sourcing my turbo selections .

**Zacho** · 10-13-2010, 06:47 PM

500 wheel? Pump gas? max boost? cams? headwork done? Many things contribute.

If your rb25 is 100% stock internals it won't be reliable at that power level. Gt47xx is WAY too big. Gt35r is an appropriately sized turbo but personally I'd either look into a precision billet or wait for the new EFR Borg warner turbos. A good choice now is a borg warner S300sx.

**cschepp** · 10-13-2010, 07:07 PM

Well I wouldn't mind buying a built rb25 head either. Guy in the states managed to make 550 and ran solid numbers all day.

**Super_Dude** · 10-13-2010, 07:29 PM

Wait till sema. This is going to be a big year for turbos

**MaxGTST** · 10-13-2010, 07:55 PM

Go holset .. cheap, reliable and make plenty of power !

**cschepp** · 10-13-2010, 08:18 PM

Ya I know, but I don't want to limit myself. I can run a gt47 and just run low boost. I will try and find a built head that I can buy and if I can't find one I will just start building one myself. Bottom end should be good for 500 hp right? And does anyone have a built head for sale?

**Zacho** · 10-13-2010, 08:29 PM

Bottom end stock is very questionable at that power level. Particularly ringlands.

Run a gt47 and you will need a very robust manifold that is forward mounted to clear everything($$$$). And a bigger wastegate($$$$). And deal with more lag. That is a massive turbo you would never need. I've held a gt42 and its over 50 pounds.

**Super_Dude** · 10-13-2010, 08:43 PM

You know a gt47 is a 1500lb turbo right? If you mean gt40r (the step up from the 35r) you can pm me. I might be selling mine right away. It made 485whp @ 14psi

**cschepp** · 10-13-2010, 08:46 PM

Ok maybe that's a better option. Here is what I have done to the engine, feel free to make suggestions and like I said guy I do want to make some serious power so please advise me where I need to make any changes:
Greddy intake manifold
Q45 throttle body
Aeromotive fpr
750cc injectors
Aftermarket fuel rail
Tomei fuel pump
N1 waterpump
N1 oil pump
Yellow jacket coil packs
External waste gate 38mm
Z32 maf
Power fc
Fmic

The only thing I think I haven't touched that will need some attention is the internals. But once again this is just my opinion, please provide all the input you can

**DRIFT4LIFE** · 10-13-2010, 11:45 PM

go with a brand new gt3076 as the hx35 is like 4-5 sec lag on 420whp on an all stock internal rb25. cams and such will help but not a hole lot.
i witnessed 500whp on a all stock rb25 with a hx35 but ian is now gunning for a 3076 and going to run higher boost for better low end torque and less lag. what is the output of your tomei fuel pump?
my opinion is 3" intercooler piping and intercooler in and out size also bigger gate and MAF-less management...like vipec... again this is opinion. sounds like your on the right track tho.

i would leave the engine how it is and fix it when it breaks. i would value this opinion cause i had a ok rb25 and i went over 6000$ in parts and labour it still on a stand. had i fixed it to stock it wold be in and running. i seen ian run 420-450whp on his stock rb25 and i keep kicking myself.