Starting my Turbo build, need some help please!

[hotrodstu77]

ok so my build is going to consist of:

RB20 Stock engine with a 3 inch turbo back exhuast
Walbro 255 lph pump
HKS SSQ
Stock RB25 Turbo
Apexi SAFC 2
Wideband Unit
SS oiling lines for the turbo

i'm hoping to run a little more boost (lets say 11 psi, my stock RB20 is running 11 right now but tapers off to 10)
as for power goals, i'm not looking for something crazy but just 250-280 WHP

if there is a way to safe to make 280 whp without buying a new turbo then please let me know.

i know the connecting rod bolts are the weak spots on the RB20 when your running more boost so i was thinking about ARP con rod bolts, head studs and a Gizzmo head gasket. only thing is i'm running my RB20 in a 240sx and would have to totally pull the motor to do the conn rod bolts.

i just want a bit more power as my buddy with a slightly modified 1.8T jetta stayed right on my ass last night with me running a bit rich and going full out! i need to be faster then a jetta lol
if there is an easier way to make more power without breaking anything, taking the motor apart, or changing turbos let me know. this set up was gonna cost me about 4 hundred bucks so if i can get the same kinda power in that price range it would help alot.
what are your thoughts guys?

[markavelli]

gtr injectors would be another thing that can help you reach your power goal.
but I think it would be pretty hard to reach 280 whp with an RB25DET turbo.
the RB25 turbo can safetly handle up to 11 psi of boost.

- M.A.T.

[BrianV8]

ya your going to need at least gtr injectors and definalty more than 11 pounds of boost to make that kind of power out of a rb20. I put an r33 turbo on my car i run it at 15 pounds all day works great. The 12 pound limit is mostly for the series 2 turbo's with the plastic compressor wheel. The good series 1 turbos with the steel compressor wheel can handle much more. Either way it will still tip off to about 12-13 pounds on the top end. I'd be looking for something a bit bigger like at least a gt2530. The r33 turbo is a very minor upgrade. I expected a lot more out of it and am overall unimpressed

[spank110]

gtr injectors would be another thing that can help you reach your power goal.
but I think it would be pretty hard to reach 280 whp with an RB25DET turbo.
the RB25 turbo can safetly handle up to 11 psi of boost.

- M.A.T.

Actually, the r33 rb25 turbo can handle 16 psi with tuning. The ceramic turbine is the weak point but its because folks turn up the boost past 11 psi without properly adjusting the AFR. This leans them out thereby raising the EGT's and causing them to self destruct and blow out the exhaust. Proper tuning is everything.

[Chris_RB]

You should PM Eightball_84 as he runs a RB25 turbo, GTR injectors, and a big FMIC. His car is pretty quick. :-)

[Skym]

With current configuration, ECU retune with Nistune would make the biggest difference to driveability, hp, etc. There can be as much as 22.5kw (30rwhp) gain in hp from a retune. Alot of people try to skimp with ECU retune, but it's the difference between engine being alive, responsive and fun to drive or slow, sluggish when untuned.

From what I understand the ceramic exhaust wheel on stock turbo is glued onto the shaft, as there is no other way to attach ceramics to metal. The glue breaks down with high exhaust temps, which can be from lean A/F ratio or hard use on a racetrack. The exhaust wheel goes off balance and could end up in middle of exhaust. Ceramic exhaust wheel is good for spoolup if that is what your after. Also Ceramic exhaust wheel is one of the reasons the factory runs engine rich.

RB25 turbo can produce around 255rwhp at 14.1psi with supporting mods, but no tuning tricks that I know of. Stock turbo with some tuning tricks can produce around 241rwhp at 9psi with a ECU retune and some supporting mods.

The biggest hp gains are -

ECU retune
Exhaust
Cams (Tomei Poncams if using stock valve springs)
Turbo
Intercooler

Larger injectors, bigger lph fuelpump, Z32AFM are what is called supporting mods. Also engine oilcooler is a must have mod, especially when turning boost levels up. The RB20DET doesn't have a stock water to oil oilcooler behind oilfilter, like RB25, RB26.

If you want reliablity, Tomei 80.5mm bore, 1.2mm metal headgasket, ARP headstuds, Nissan repair gasket kit (has all the intake, exhaust gaskets, valve seals, etc).

Gizzmo make a stronger intake gasket.

Stock bottomend can handle 400hp+ short burst's, like with a dyno run.

[hotrodstu77]

ok thanks for all the advice. i've heard alot about nisstune and think it would be a good idea cause my car kinda runs like ass right now, its running all rich. i've been reading around still. i like the sound of the 241 hp on stock turbo. how can i accomplish that exactly? i'm not to worried about seals and stuff untill they break lol so what are those tuning tips and how can i get them? who retunes ecu's?

[Skym]

As far as I know -

Podfilter (Apexi)
3" Exhaust from turbo
GTR Front mount intercooler
ECU retune (Nistune)
98 octane fuel (can't remember what the equivalent octane rating is in Canada)

It's roughly 305hp at engine. 2x RB20DET's I know of have had the same 241rwhp result with stock turbo. But there are sometimes good engines off the production line that produce more hp than others. Engine condition (km travelled) or if it was thrashed (worn out), fuel octane (how far you can push ignition timing with high octane fuel before engine knocks), etc can affect the final hp output.

Ztune (Nistune dealer) can supply Nistune and tune Nistune -

http://www.ztune.ca/

[hotrodstu77]

ok well i have a turbo back 3 inch exhuast. i just picked up my apexi SAFC II and my AEM wideband kit. so will i still need that stuff with nisstune?

[tokes]

If you can, take back the SAFC. I think they're garbage, they're a bad bandaid fuel modifier that isn't that great. All you can do is trim fuel levels across a broad RPM band, and have no way of adjusting timing. You can dial back some timing on your CAS but then you're pulling timing everywhere, hurting drivability and low end power when you're out of boost.

Nistune is an add-on to the stock ECU that lets you compensate for larger injectors, different MAF's, different turbos, AND it actually gives you the ability to properly edit your fuel and timing curves, not just hack with the fuel delivery. Get the AEM wideband, throw the SAFC in the trash, and run nistune.

[Skym]

SAFC was designed to be used with intake, exhaust mods. When fitting intercooler, injectors, etc, PowerFC is used.

[hotrodstu77]

well i dont have enough money for the nisstune, thats the thing. i picked up the SAFC from my buddy for 50 bucks so i gotta use what i can. plus i'm basically bone stock. i need to use the SAFC unfortunatly, its all i got money for. and i gotta bring down my fuel levels, i'm running 10.0:1 or richer, thats as far as my AEM goes and it sits there for a while. i knew i was rich but not that rich! so does anyone know how to properly tune the SAFC II to stop my rich problem?

[Skym]

Proper way is on a dyno with wideband plumbed into exhaust. Can do it without dyno, but can't see the hp, torque results after changing settings on SAFC.

[hotrodstu77]

ya im not worried about hp lvls right now i just want it to be running where it should be fuel wise. i've got an aem wideband plumbed in and im running 11-12:1 at idle and 10:1 or lower at boost.

[Skym]

From what I understand on a A/F ratio graph at idle, should be around 14.6:1-14.7:1 (stock engine) and when transistioning to boost, engine should run richer until it hits 11.6:1 at peak boost at lower rpm's, which probably would be around 2500rpm with stock turbo and stay at 11.6:1 throughout until peak power. You'll notice the power graph rises above what it was, if boost graph keeps steady at peak boost until peak power. That's when there is no leaks from BOV, etc and not touching stock ignition maps. 11.6:1 is safe A/F ratio.

Also disconnect stock o2 sensor (puts ECU into open loop where it ignores stock 02 sensor) before making any adjustments to fuel. With stock o2 sensor connected, ECU is constantly adjusting amount of fuel being injected at idle and cruise.