Rb20 boost?

[krystalized_jdm]

Buying a Boost Controller for my rb20, this car/engine is still COMPLETELY stock. I was wondering, besides the neccesity of getting a fmic, and the obvious boost controller. I was wondering if I can safely boost this up to say, 10-12 psi of boost without re-tuning or doing anything to my engine/ecu?

If it does need to be retuned/edited. Leme know what you guys suggest. Thanks!

[Ghost]

You can run 11-12 psi safely with no tune. Any more than that and you run risk of shredding the amazingly reliable ceramic turbine wheels out of your turbo. Most likely the exhaust wheel. You don't NEED a FMIC but it definetly helps. If you have exhaust, intake front mount, Atmospheric BoV and running a little higher boost a tune does help but isn't a nessecity... You just wont be getting the full ,efficent power of those mods.

[beacher1B0]

If u upgrade exhaust(cat back and downpipe) and also upgrade your intake and maybe get a FMIC u should get around 10 to 12 Psi without a boost controller.

[Ghost]

But that's the expensive way of doing it, lol!

[krystalized_jdm]

Doesn't the ecu restrict the turbo? I swear I heard someone say something about the govern not only restricting speed, but boost, rev limiter, etc. Idc bout rev limiter, I already found my sweet spot for shifting. Thats off the point, anyways. Lol Can the exhaust system/intake serious up the boost that high?

[Ghost]

No to the first question. The ECU regulates the amount of fuel to be injected in correlation to the amount of air being inducted or compressed into the cylinders via the turbo. The turbo itself is a completely mechanical device propelled by the velocity and heat of exhaust gases being expelled from the engine under load. The more efficiently (faster) the gasses flow, the hotter they become (downpipe, exhaust kit, intake, FMIC, etc) and the sooner, faster and more efficiently the turbo spins creating more boost, so yes to that question except for one thing. A wastegate. This keeps your turbo from boosting over a preset psi level. Once the preset pressure is reached, it opens and bypasses the excess pressure and gasses around the turbo to help maintain "stock" psi. This is where your boost controller comes in. The boost controller inhibits the exhaust pressure gasses to the wastegate actuator keeping it closed longer, and resulting in higher maintained boost level... In a nut shell... Sorry on night shift right now so very watered down Explination...

[Skym]

Podfilter, 3" exhaust from dumppipe, modified stock BOV, hybrid RB20 turbo at 12psi, stock ECU tune made the entire powerband from peak boost at lower rpm to close to peak hp lean with my car on dyno. ECU was pulling timing (ECU detecting knock) as A/F ratio hit 13.5:1 on dyno at peak boost at lower rpm (3500rpm+) and then second run I think was 12.8:1 (I assume it was running on knock fuel map). When you want it under 12 for A/F ratio at peak boost, it's a bit of a worry. At peak hp (7500rpm, 12psi) it had a 11:8.1 A/F ratio.

My understanding from a dynochart I've seen for RB20DET with full 3" exhaust from dumppipe, split dumppipe, FMIC, podfilter, is it suffers the same problem my cars engine encountered with running lean and ECU pulls ignition timing, dumps more fuel in, etc. That's when running 13.5psi.

I would say at least 10psi and under to keep A/F ratio safe (under 12.0:1 A/F ratio) and hopefully stop ECU from pulling ignition timing. But stock RB20DET internal wastegate actuator spring pressure is around 12psi (edit: on my car) which is as low as boost controller probably will allow you to go.

An option is finding a auto R33 RB25DET internal wastegate actuator that's rated at a lower psi than manual internal wastegate actuator from a R33 RB25DET. It should allow you to lower boost level to under 10psi.

If tuning ECU, fit Nistune for stock ECU which allows tune to be changed anytime you need to or want to. Also I would upgrade fuel pump, injectors and fit a Z32 AFM with Z32 AFM plug / pigtail wired in to take full advantage of the tune.

[Ghost]

I'm running 11 psi with a 14 ish spike via manual B/C, 3" turboback, podfilter, no FMIC and no leaning or boost or powerband issues. Pulls good and hard, odd backfire cause of BoV, but my last pull was around 190 ish whp. No tune... Yet.

[Skym]

The internal wastegate actuators do vary with spring pressure from car to car (I guess explains the hp difference with factory cars when they test a few cars on dyno).

For example, R32 RB20DET internal wastegate actuator (auto, manual) is meant to be around 11.36psi-12.78psi when tested on bench.

The R32 RB20DET internal wastegate actuators tested on bench for my car were both at around 12psi. So I don't think I could run it below 12psi.

[quadracer111]

My gts-t had a full turbo-back exhaust, intake, 255lph walbro pump, fmic, synapse recirculating bov, and a hallman boost controller set at 13psi.
Man did that thing rip. Don't go above 13psi... Or **** will shatter.

[Ghost]

The internal wastegate actuators do vary with spring pressure from car to car (I guess explains the hp difference with factory cars when they test a few cars on dyno).

For example, R32 RB20DET internal wastegate actuator (auto, manual) is meant to be around 11.36psi-12.78psi when tested on bench.

The R32 RB20DET internal wastegate actuators tested on bench for my car were both at around 12psi. So I don't think I could run it below 12psi.

Im assuming your a GTR? reference to 2 actuators..?

[beacher1B0]

Im almost 100% sure Skym is a RB20 lover and driver. Im sure most of us look up to him because of his general Rb20 knowledge.

[Ghost]

Just wondering cause he pointed out 2 actuators is all.

[Skym]

Thank you for your kind words. RB lover and driver sounds about right. Just picked up a few things over the 12 or so years I've owned a Skyline.

It's a RB20DET engine. One internal wastegate actuator had stuffed spring which caused rattle on back of turbo at idle (wastegate flap rattling around) yet it still reached 12psi when tested on bench (I was told by turbo specialist that it should drop in boost level when internal wastegate actuator is faulty) and the other internal wastegate actuator was a good internal wastegate actuator which reached around 12psi.

About 10psi, it's a guess at best. It's going by boost level, A/F ratio on my car, etc via dyno chart and what I see on fuel map in tuning software for ECU.

Best way (proper way to set it up) is to start from lower boost level (below 10psi with R33 auto internal wastegate actuator) with boost controller and monitor A/F ratio, knock, etc on dyno as you increase boost level in small increments. With dyno you can hold at different rpm, load to check A/F ratio, knock, etc in real time.