I'm doing a rebuild on my S4 tII, and would like to get 220-240 rwhp out of it. I've searched and read a ton of threads, but still haven't found the answers I'm looking for. My turbo has a chipped blade and a little shaft play. I've been looking into BNR, but can't decide whether to just get mine rebuilt, or go for a stage 1. I've also been looking into RTek, but can't decide which model to get. Basically if someone could give me a basic list of what I need, or what setup would make between 220-240 rwhp while still being reliable I would really appreciate it, I'm pretty confused so far. Money isn't a huge concern. Also, I would like to keep the tmic, and not have to mess with tuning too much. Thanks to whoever lends a hand.

 

You can get close to the lower number by installing a decent intake/filter and a non-cat exhaust system. However, if you need to pass emissions, you will need to go a different route.

 

"not have to mess with tuning too much"

learn how to tune.

 

Upgrade injectors (I think 720 secondaries, but don't quote me on that) and fuel pump, get a S-AFC or more preferably and rtek, get a BNR hybrid (probably stage 1) and have someone tune it properly. Also, more open exhaust if that isn't already done.

The numbers you want are maybe attainable on the stock turbo, but it is on the high end of what it will do and won't be as reliable. You should just get the stage 1 hybrid and be done with it.

 

I would say 720x4 injectors, an rtek1.7 (requires no tuning at all, unless you want to fine tune with a safc), larger fuel pump, a more none restrictive exhaust, and someway to up the boost to atleast 10psi if you want (though not really necessary)

You can get around 220 easy on a stock turbo, but if you need a rebuild on the stock unit, you might as well get a stage 1 from bnr.

If you are going to rebuild the stock unit make sure to get the wastegate in the exhaust housing ported or you will have boost creep in 3rd+ gear. You set it for 10 psi, but as you mash the gas the boost will steadily increase to 15psi even, and thats bad when you want it to stay at a comfortable 10psi. If you are getting a bnr stage 1, it will be ported for you

 

rtek 1.8 actualy (using 4x720cc injectors)

get a good stock turbo, port turbo waste gate,remove emitions, 3" exhaust, remove rats nest, etc....

i feel 220-240 is very posible on stock turbo and stock intercooler

 

woops, yea rtek 1.8 is the one

 

the only mods i've done are intake, exhaust, and microtech. admittedly, i do run a front mount, but got 233 atw. although, i'm in australia, not sure if altitude comes into it. dunno much about the states!! hope that helps, and good luck!!

 

Alright, so it sounds like RTek 1.8, 4-720cc's, BNR stage 1, fuel pump, emissions delete, and exhaust. Would I need a s-afc if I get RTek? I have no experience with safc.

Does that sound like a decent list?

Also, when I rebuild it should I port it out?

 

Back when I was running a stock S5 Jspec engine I made 240whp with the following:

Stock S5 Jspec (right off the boat) and stock S5 Turbo
RB 2.5" Downpipe, and custom 2.5" single exhaust
Rtek 1.5 Stock fuel system (injectors, pump, rails) again, everything was just off the boat
Stock electronics, AFM, boost sensor (obviously the ECU was chipped)
Stock Intercooler in the stock location
HKS intake with Home Depot TID

That was at 11psi. here is the dyno sheet:



video is here:



I ran it that way for 2 more years daily driving it in the summer putting on over 50k Km's per summer, it was a touch lean, so be careful. You would be better off getting a 1.8 I think it is now, some 720's, and a higher volume fuel pump, the one you are using is likely 20 years old anyways.

I am doing things a lot differently now, but I was in college and I surprised many a expensive high hp cars it was truly a Jap ratrod as we called it, rusty chassis and all.

It can be done decently cheap just do it right.

 

Do a catalytic converter delete. I bought some flanges and tube from mazdatrix and made my own cat delete pipe. I live in Texas in an emmissions county so I just bolt the cat back on once a year, do smog test, take it off again.

 

What do you guys recommend for injectors, and how do I know if I need low imp. injectors. I heard that all 1987 t2s used low imp, but I've also heard that it's only the real early ones.

 

Check the faq for injector specs and 720 secondaries would be fine for your goals.

 

you need low impedance (i have an 87 aswell)

the stock turbo should do 220-240 with no problems, so dont drop the extra cash on the BNR unless ya have to.

 

My turbo has more shaft play than I would like to run, and it has a chipped blade. I would love to keep the stock turbo so I can save some cash, but a rebuild is almost as expensive as getting a stage 1. Are there other options? Also, could I run an S5 turbo instead?

 

You could run an s5 turbo instead and it is actually a slightly better option than the s4 turbo.

 

Not necessarily. The second half of the 87 model year uses high impedance injectors. You can look to see if there is a resistor pack on the passenger wheel well. If you have one, its low imp, if not its high imp. Also, look at the inejctors and check with with the FAQ.

 

truth, mine was made in NOV of 86 so i knew it was low.

you should be able to get a good condition turbo from some one on here for around 150-200 bucks.

 

Get the Rtek 2.1 + Racing Beat turboback. This is the best bang for your buck. You can hook up an inexpensive wideband and use it to do some basic tuning. If you find out you arn't geting enough fuel, you can upgrade to either 720 secondarys or 720 all around.
The racing beat exhaust will ad 59 hp which will get you 220-240 flywheel hp. Some good tuning should get you a couple for hp. That should get you pretty close to what you goal is. Say 220ish whp.

As far as the turbo, either get one here(I have one that burns oil $100 ) or send it off to BNR. He does great work. I have the stage 2 and have been very happy with it. The only cons of the stage 2 are, you have to make a TID, you can't slip the air pump on it.

GL

 

dude, do your homework...

i have reached 260rwhp @ 14psi on stock turbo and stock ports, and it is reliable!
have run this setup for alsmost 2 years without any issues.
now i have a BNR stage 4 ready for installation

note. this is an S5, if that should make any difference...

 

+1

My car is tuned to 296 to the wheels on the stock turbo. Granted, this is with a agressively *TUNED* standalone, FMIC, huge streetport, full exhaust, ect.... (probably a favorable dyno) but the point is 240 WHP is EASY on the stock turbo.

All you need is Rtek, 720s, full exhaust, fuel pump, intake, boost controller, turbo wastegate porting. Set the boost controller to 13-14 psi. Done - 240 to the wheels.

 

BNR stage 1, RB exhaust, rtek 2.1, and whatever injector it needs (i'd expect 550/720 and an FD or better fuel pump).

be a fun car!

 

very nice results! the port and tune make all the difference..

but to show how SAFE mine is tuned:
i was tracking the car and the fuelpump picked up ari in a hard left corner, it ran A/F of 18 under full boost for 1-2 seconds, without any issues.

with a more agressive tune, specially timing, it would most definately be dead...

so if i would have i tuned more agressive, i would get even more power to the wheels, but you lose in terms of safety