Rb20 Boost Pressure

[stilettoman]

I have a 1992 RB20DET from a 1992 R-32, no mods that could effect boost - we made a custom intake manifold, but that was strictly for cosmetic reasons. The wastegate controller does not appear to have been tampered with. It goes right up to 11 pounds boost, but never over that.

1. What is the normal max boost pressure on this engine when completely stock?

2. What is the rated horsepower, and at what boost pressure is it measured?

I have done quite a bit of searching, can't find the answer these seemingly simple questions. Anyone here know the answers?

[brentos_mentos]

I'm not 100% sure, but from what I know, and I'm sure someone else can confirm for me, the stock RB20 wastegate actuator is 10psi and the power an rb20det makes from factory is about 165kw at the flywheel I think?

[Ben C34]

stock exhaust? They effects boost.

[GTSBoy]

10 psi actuator. Can easily see 11 psi, especially with an exhaust or a bigger TB, bigger intercooler (and surely this has a FMIC otherwise what is the point of a modified plenum?).

Standard power was 160kW at the fly, give or take one or two.

[Missileman]

My stock HCR32 (auto) was on the dyno recently, 117Kw atw, 10psi tapering down to7.5

[GTSBoy]

 

My stock HCR32 (auto) was on the dyno recently, 117Kw atw, 10psi tapering down to7.5

 

Wow. That's awful. When I tuned mine, it was an auto ECU but had been converted to a manual box years before. Running 14 psi on the factory tune it did ~150 rwkW (and the dyno is a pretty good one, certainly comparable to most other DDs). Boost would hold up pretty well at high revs. After the ECU was tuned and with boost turned down a little (12-13 psi) because we were at max in a few areas, it was more like 170rwkW.

The only other mods on the car were full exhaust, FMIC and metal turbo inlet.

[Missileman]

awful????? going by this converter http://www.mk5cortinaestate.co.uk/calculator4.php and wiki I'm down 12 HP from new

anyways 3" turbo back goes on this weekend weather permitting and the following weekend new EV14 injectors then I'm off to the drags

[GTSBoy]

Yuh, awful. Even before I put a boost controller onto my RB20 it would pretty much hold 10 psi up to high revs, and that is where most of your low reading is coming from (assuming no low reading dyno). 7.5 psi boost is soft compared to 10. And as you can see from my report above....14psi makes it a completely different thing. 150rwkW feels drastically different to 117.

[Missileman]

Still think you're being a little harsh, 12hp below new running stock everything accept a fuel pump, the only possible issue is a slight exhaust gasket leak which will get confirmed when I put my 3" exhaust in. You don't know your compression test readings for those dyno figures? When I put my injectors in I'll do a compression test.

[stilettoman]

Thanks for the replies - that takes away the mystery somewhat. I have owned a lot of cars, but this is my first experience with a turbo. As I stated before, the purpose of the custom intake was purely cosmetic - to get rid of all the clutter on top of the motor. I already described this here:

http://www.skylinesaustralia.com/forums/topic/428272-not-living-in-oz-but-one-of-the-other-colonies/

Edited July 10, 2013 by stilettoman

[Frosty]

i believe stock boost on rb20 was 7psi from factory

[GTSBoy]

Nup. 10.

[sneakey pete]

R33's and 34's were 7.

Yuh, awful. Even before I put a boost controller onto my RB20 it would pretty much hold 10 psi up to high revs, and that is where most of your low reading is coming from (assuming no low reading dyno). 7.5 psi boost is soft compared to 10. And as you can see from my report above....14psi makes it a completely different thing. 150rwkW feels drastically different to 117.

Stock exhaust will probably be the culprit of this. Almost everyone makes 10-11 PSI for the full range with their R32 because almost everyone has a aftermarket exhaust. The dyno wasn't particularly low reading as far as i know, 3 r33's on the day all made within 1-2kw's of 180 with only an exhaust and a front mount, and my tuned r32 with 33 turbo mad 170kw's.

Dam 33's.

[GTSBoy]

RB25 is actually only 7psi because of the bleeder solenoid. The wastegate actuator itself is only 5psi.