Rb26 Gt-ss Turbos - When Should Boost Kick In?

[DAN00H]

again - it is the cam timing being out - the boost controller is a red herring in this one... the tuner has not put the belt on correctly, or has the timing set wrong.

[Roy]

Im with pnblight and DAN00H, its not your boost controller....it could be. But i would be checking things like cat or muffler having failed?? A restriction somewhere…

As this has now affected your car with the 2530s and now the GT-SS. Its possible even after the turbo swap he still has the cam belt off or cams way out. That would explain the lazy power and lazy response far better then the AVCR

Anyway, speak to the ppl that have a track record with these sorts of cars, be it CRD, BD4s, Unique Autosports etc...they will have a better idea having looked at the car then any of us

[saliya]

It's not often that I agree with R32Nismoid, but he's right on this one. I was never able to get stable boost on my large internally gated terbs (GT-RS) with the old AVCR fitted.

By going to a dual solenoid unit I was able to get a much steeper boost raise without spiking (i.e. wastegates are kept absolutely closed until desired boost is hit and then controlled to give a very stable boost).

As previously recommended, try a manual boost controller or even direct off the actuator springs. I think the HKS kits come with 1 bar actuators from memory?

Could this be due to the way that the boost controller was operating? Was the single-solenoid config

operating as a bleed or inline? Is the dual-solenoid config operating as a bleed or inline?

I can fit my head around 'one solenoid cannot bleed off enough air' - which could be rectified with:

* adding another solenoid

* replacing solenoid with bigger solenoid

* changing the solenoid operating configuration so it is not a bleed

I'm really interested in this one! As you may have guessed, I can't wrap my head around

"You MUST have 2 solenoids" - it doesn't make any sense (but waiting to be educated

Thanks,

Saliya

[Topaz]

in regard to profec B spec II, how good is it? what kind of boost can it run?? it is still a single solenoid unit, isnt it?

I run R34 GTR turbos at 0.9-1bar with a PRfec B Spec II all day everyday (my GTR is a daily, although I'd prefer it not to be really), but I never rev it hard enough to get that high on the roads very much. All my dyno graphs display a well held peak boost and it feels really smooth as the boost/rpm increases. Recently went to Drag Warz with SAUWA and had a boost spike of 20.2psi . Everything seemed normal so I don't know if it was a boost spike or some sort of glitch.

I just didn't want the 'look at fkn me, yeah, thats right!' AVCR

Whats the peak power expected with GT-SS's?

[rev210]

As people have pointed out the areas of possible improvement may come from a tweak of the cam timing along with adjustment to the fuel & ign maps to suit. The boost controller can be a problem if not set correctly.

Always worth doing the basics too like a compression test. Do those sorts of tests when you go home after wringing it's neck at the track or dyno every time you go. Takes only a little time to do.

The group A turbo's I had were on full boost a little over 4k. They are much bigger though. So it says there is some hope.

[R31Nismoid]

Whats the peak power expected with GT-SS's?

300-330rwkw

depends how far you push it.

Hopefully Jan/Feb i'll be in the "push" category and we'll see what happens when you lean on them hard

[Topaz]

300-330rwkw. Hopefully Jan/Feb i'll be in the "push" category and we'll see what happens when you lean on them hard

Sweet!, I'd be happy with 400hp (305rwkw). The GT-SS's are pretty much my preferred option for a turbo upgrade. My current turbos are at full boost at 3700rpm, with a good tune could the GT-SS's come on full sooner? Not that 3700 is too high....

....Sorry for the lo-jill....

[R31Nismoid]

Turbos virtually come on like stock, so depending on what you class as "fullboost" be that 14psi or 25psi is what matters.

But yeah, for 400rwhp, they are what you want without a doubt.

Have a read of the FI guide, there is a link to "first set of turbos" or something like that for the RB26 parts.

Lots of info in that one

[GeeTR]

Hopefully Jan/Feb i'll be in the "push" category and we'll see what happens when you lean on them hard

Thems fiiightin words!

[justinfox]

Just an UPDATE everyone.

It was the boost controller! Wasn't set up right. Wheeeee!!! Much more response, a whole lot smoother on boost too. Now to take it to the track again! Shame it's so damn hot at the moment.

[RellikZephyr]

Cool glad to hear shes all good again

so that could mean that the lag in my car (stock turbos, 1 Bar @ 4200) could also be the controller

will have to look at that

RellikZephyr

EDIT: Amazing!! Guess what the problem with mine was DUN DUN DUNN!! The Boost Controller as well

All is good

Yay for me!!

Edited November 29, 2006 by RellikZephyr

[ferni]

Good to hear, what was actually wrong with it?

[Beer Baron]

good stuff, very glad to hear it's sorted now. Is it making more power too? I'd love to see a graph of it now. I was a bit shocked with the initial graph, as my GTR makes the same power, with 32 turbos, stock cams, stock dump, stock front pipes, stock IC etc and has full boost around 3500 rpm (1bar) and makes 270rwkw. it also runs a little richer at around 11.5:1 for some added piece of mind at the track (i'm not keen on 12:1 and above for RB on track).

your thing should be an animal now

[justinfox]

Dyno run soon!

[Beer Baron]

good stuff! fingers crossed we see a massive improvement. I do still think 12:1 is just a whisker too lean up top (rpm wise) for a moderate power GTR that is bound to see some spanking at the track. if it were my car I'd be looking for something in the 11.5-11.8 range to give a bit more margin for kaboom. a little bit extra fuel does have a small cooling benefit too (just dont go too far).

[Beer Baron]

how's it going? I finally got around to scanning my last dyno runs and since I said I would post them up, I will. It should at least give you a baseline.

one graph is power and boost, the other is power and AFR.

[Bass Junky]

Can you say "Stable Boost"

[Beer Baron]

yeah, lol. it comes on fast and early and stays there. profec B II and HKS wastegate actuators to thank for that i guess. I think it's quite a good graph. it's taken me a while to get there. very meaty, and lots of area under the curve. all through optimising stock gear. the only question mark is turbos as I'm not 100% sure they are stock, but power output would suggest they are, or maybe 32N1s.

[sewid]

Maybe standard R34 GTR turbos ... there's another idea about your car I had the other day...

[Beer Baron]

wow. I just looked back at the fist page to compare graphs again and the difference is crazy. two cars with peak power figures almost the same, but at 100kmh for instance justins making around 80kw, mine is making around 160kw! at 120kmh justin is making 130kw vs 190kw... There has to be something further wrong with the set-up I think. or tuning perhaps?