ok so here is my situation. i have an s5 n/a engine. i am in the process of turboing it now. i am going to be rebuilding the engine, all seals all rotor seal etc. all stock porting (except the exhaust sleeves in the N/A housings)

here is what i am going to be using for sure.
s5 n/a housing
s5 n/a rotors
turbo irons
s5 turbo LIM
s5 turbo UIM
N370 ECU
N370 MAF
walbro 255
turbo ii primary fuel rail
turbo ii secondary fuel rail

i know i need to run larger primary and secondary injectors, and i know those depend on tuning and turbo etc. the thing is im not sure what turbo i should run. i have been told the gt35r is a great turbo for the 13bs. i was thinking of running rtek, im not sure which one though 1.5 1.7 2.1 etc i think i have to use the 1.7
or higher right because of the larger injectors. i was considering running the 2.1 but wasnt sure if it would be overkill. im not wanting to run too high of boost because i want my engine to last. i was thinking somewhere around 8 lbs of boost.

would you guys still suggest the gt35r turbo for such low boost applications?
and with the setup i have listed what primary and what secondary injectors would you guys suggest?

thanks in advance

 

why are you using N/A rotors and housings?

a 35R will require at least rtek 2.1

 

the reason im running na rotors is because i started with a complete n/a engine and was going to turbo it. i diassembled it and discovered the rear iron was bad,a small chunk was missing from the coolant seal lip. so i just ordered all turbo irons to make matching the turbo LIM and UIM easier.

do you have any idea about the injectors??

 

wow i was hoping that people would know more on this topic...

 

can someone at least tell me if it would be a waste to run a gt35r turbo at such a low boost application. or can someone chime in injector sizes for this settup

 

If you are going to run 8psi you could just keep it cheap and run a stock turbo. That being said though it wouldnt make you any harm running the gt35r even at 8psi so if you have the money/time then just do it.

Injectors...at 8psi I would say at least run the 1.7rtek which you will have to put 720cc secondaries and leave the 550cc primaries. With the 1.7 and the 255lb pump you should be fine at 8psi. Now the only problem I have with the 1.7rtek is that you are kind of stuck there with the same map unless you run an ASFC or something like that (I have a 1.7).

I hope this helps you.

 

a 35r is too big for that boost level, you want a 30r or even just a medium size garret t3.

na rotors are excellent for low boost, but if using na housings make sure to remove the exhaust diffusers as these will be bad for spool time and power.

 

i have already ported the exhause sleeves. and i was thinking about a bnr stage 1 turbo. and maybe an rtek 2.1

 

i waas told by someone on the forum to avoid stock turbo at all costs...not sure why.....what do you think about a bnr stage 1? still 720cc secondaries and 550cc primatys

 

The stock turbo's just old, and you can't do much with the stock A/R size at certain points, you either clip the wheel to allow more flow but hurt spool, or you overrun it. It's not so bad if you're never going to leave 8psi, you probably wouldn't gain much from any turbo replacement being that low as the stocker will still be relatively close to it's efficiency range still.