Jump to content
SAU Community

Recommended Posts

Background info:

S2 R33 GTST RB25DET (unopened bottom)

HKS GTRS Kit (brand new)

Bellmouth Dump pipe 3" exhaust

JJR FMIC with enclosed POD intake

PowerFC

eBoost2

I have had some really annoying issues with controlling boost on my GT-RS. I cannot for the life of me (or my tuner) get any less than 1.3bar (~19psi) of boost once you are above 5000rpm.

Our troubleshooting started at thinking it was the eBoost2 causing issues so we isolated any boost control and ran the feed from the intercooler to the wastegate directly. This caused a 0.9bar boost from low revs to 1.3bar for anything above 5000rpm. So this eliminated the eboost as a suspect.

Then we figured if it was still overboosting on 'wastegate pressure' then it is something to do with the wastegate itself. We thought, perhaps it was the JJR Split Dump I had installed, causing the wastegate flap to get stuck and not fully open. We have changed this to a bellmouth dump (HKS dump) and looking at the JJR Split dump, there was definetly SOME restriction (with all the carbon build up). We took it for another run and we still hit 1.3bar (a little less about 1.25 - 1.3) instead of 0.9bar.

So we are now at an end, we cannot think why it is boosting so high. The boost gauge is fed of a T-Piece from the Fuel Regulator and the eBoosts feed runs off the standard boost gauge in the dash (but the eboost is currently bypassed till we can get wastegate pressure).

Has anyone else come across this or does anyone else have any troubleshooting options? Its an unopened bottom end and whilst I have no worries running 1.2bar, I am very very susceptible to cold day boost spikes to 1.4 bar etc..

Thanks in advance for any advice you can give, and if you need more information, i'll be keeping track of this topic to respond.

Cheers

Sam

Link to comment
https://www.sau.com.au/forums/topic/231339-hks-gt-rs-wastegate-issue/
Share on other sites

Mine used to do this when the GTRS was running off the stock ecu, would just keep making a shit load of boost no matter what we did. Once the microtech was tuned the problem was gone...

Mine is set up to about 19psi at the moment, and holds it fine. However i can run in it as low as 14psi with the profec setup for it.

When it hits 5000rpm, does it just violently spike, or does it slowly keep climbing in boost?

It just climbs at a steady rate, not a quick shoot up but not overly slow either.

I wonder how the Standard ECU affected yours PM-R33?

We have also since tried to play with the wastegate actuator itself and it appears to only really change how fast the boost will build but not dramatically affect final boost.

Just from your post in the other thread PM-R33. This is the dyno sheet.

What I cannot understand is that this is from about a month and a half ago and the boost looked perfect. No issues at all. Yet once I got behind the wheel, I had nothing but trouble with it. Absolutely nothing has changed in the setup since this dyno (apart from a new bellmouth dump today).

r33dynopsiforumwk1.jpg

I have a similar issue with my car, exact same combo as the OP, but greddy profec boost control. Rev too high and the boost alarm goes off. It's limited to 1.2, but goes up to 1.6 (not spiking, goes up and stays up). My engine check light also flickers (possibly just showing knock? I dunno). It was also perfectly fine for one month after the GTRS was installed (just recently), and now I'm getting this 5h1t. I hate not being able to put my foot down :P

My car goes in for looking at (Trojan too!) very soon, I'll keep you up to date. John already had a fiddle with the boost, but it made no difference. Strangely, he says he has no issues with it on the dyno, yet I can make it happen whenever I want (ie rolling in 4th doing 60kph, then put your foot down - BAM, warnings/alarms). I'm sure he'll see it this time around. I'll be watching this thread.

It is VERY odd Ben. As the Dyno sheets show, the dyno is having no issues, but once moving, it overboosts, and like you say not a spike and back down, it does in fact stay up high.

evil weevil, i was thinking a busted vacuum hose and they have been replaced once, but I am happy to replace them again just to make sure.

Hmmm very strange....

Bit off topic, Sl33py on your profec when it goes over the maximum boost and the screen turns red, does yours actually make like a warning sound? Because mine never did but i swear its ment too...

It just climbs at a steady rate, not a quick shoot up but not overly slow either.

I wonder how the Standard ECU affected yours PM-R33?

We have also since tried to play with the wastegate actuator itself and it appears to only really change how fast the boost will build but not dramatically affect final boost.

i found that my hks gtrs wastegate/actuator setup did exactly what your talking about when i had no boost controller inline

unplug your boost controller and put it straight on your wastegate actuator and see if its any different, if it doesn't change then maybe your boost cotroller is the problem

maybe rig up a simple bleed valve and see if you can control the boost with that to eliminate your boost controller

My profec makes the warnings noises when it goes red and the stock check engine flickers on and off at the same time. Very unnerving, as mine's been specifically tuned to run very safely, but I'm getting all the bells and whistles in my face when I just blat it a bit in traffic to get around someone!

My profec makes the warnings noises when it goes red and the stock check engine flickers on and off at the same time. Very unnerving, as mine's been specifically tuned to run very safely, but I'm getting all the bells and whistles in my face when I just blat it a bit in traffic to get around someone!

On my eBoost i get audible alarms saying i'm overboosting, but that is only because my eBoost is very very VERY inaccurate. It says i'm running 21psi when i'm only running 17psi. I am starting to think that it is because the standard boost gauge line off the back of the manifold is just too small and isn't giving its true reading to the eBoost.

I got my car back last night supposedly all fixed, but I am yet to be able to confirm or deny if it is due to the wet roads. It definetly feels better and stronger.

We changed the dumppipe and took the cat converter out and took some preload off the actuator, the lowest setting we could achieve was 15psi. 17psi low boost and 19psi high boost, supposedly no longer climbing any more. Will update the thread when the raining stops.

On a side note, is there anywhere else to plumb a boost gauge? I have one boost gauge (accurate) running off the FPR line, and the eBoost running off the standard boost gauges line but its quite small, is there anywhere else to move it to?

when I was at WSID the other week thats when mine went apparantly.

Allof a sudden around 3rd gear the profecII flashed red and beeped also.

The highest knock I got on that run as low 30's

I got mine back the other day, given it a drive to mum n dads today and watched the boost gauge and just wastegate sat flat on 14psi, low boost on 16psi so, so far so good with mine.

Hope everyone elses is a simple fix too,

Cheers,

Chris

  • 2 weeks later...

Turns out my boost controller was completely dead and doing nothing to control the coost - simply displaying current boost. Mechanic said it's usually caused by giving/receiving a jump start, which can short out the controller if you don't turn the parking lights on (to get shorted out first), but I'm pretty darn certain I didn't do either.... But with a new controller, it drivers perfectly again :( Funny thing is, as I was about to leave, one of the guys at the workshop on the phone was asked the person on the other end "... did u recently jump start it??" and nodded to me "yep... same issue" hahah. Weird... gonna keep an eye on it!

Thats crazy Ben! Glad to hear that you have it sorted though. Uncontrollable boost is such a worrying thought, mine has settled on 15psi wastegate 17psi low and 19psi high.

Just getting a Metal Cat delivered tonight as at the moment, its a little empty inside. Hopefully it won't make a huge difference to the tune or the boost!

When I got my highflow I was having problems with boost spiking despite having an AVCR working properly. My tuner immediately thought it was the actuator so in went an HKS heavy duty actuator and I have had no problems since.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • You are selling this? I have never bought something from marketplace...i dont know if i trust that enough. And the price is little bit "too" good...
    • https://www.facebook.com/share/19kSVAc4tc/?mibextid=wwXIfr
    • It would be well worth deciding where you want to go and what you care about. Reliability of everything in a 34 drops MASSIVELY above the 300kw mark. Keeping everything going great at beyond that value will cost ten times the $. Clutches become shit, gearboxes (and engines/bottom ends) become consumable, traction becomes crap. The good news is looking legalish/actually being legal is slighly under the 300kw mark. I would make the assumption you want to ditch the stock plenum too and want to go a front facing unit of some description due to the cross flow. Do the bends on a return flow hurt? Not really. A couple of bends do make a difference but not nearly as much in a forced induction situation. Add 1psi of boost to overcome it. Nobody has ever gone and done a track session monitoring IAT then done a different session on a different intercooler and monitored IAT to see the difference here. All of the benefits here are likely in the "My engine is a forged consumable that I drive once a year because it needs a rebuild every year which takes 9 months of the year to complete" territory. It would be well worth deciding where you want to go and what you care about with this car.
    • By "reverse flow", do you mean "return flow"? Being the IC having a return pipe back behind the bumper reo, or similar? If so... I am currently making ~250 rwkW on a Neo at ~17-18 psi. With a return flow. There's nothing to indicate that it is costing me a lot of power at this level, and I would be surprised if I could not push it harder. True, I have not measured pressure drop across it or IAT changes, but the car does not seem upset about it in any way. I won't be bothering to look into it unless it starts giving trouble or doesn't respond to boost increases when I next put it on the dyno. FWIW, it was tuned with the boost controller off, so achieving ~15-16 psi on the wastegate spring alone, and it is noticeably quicker with the boost controller on and yielding a couple of extra pounds. Hence why I think it is doing OK. So, no, I would not arbitrarily say that return flows are restrictive. Yes, they are certainly restrictive if you're aiming for higher power levels. But I also think that the happy place for a street car is <300 rwkW anyway, so I'm not going to be aiming for power levels that would require me to change the inlet pipework. My car looks very stock, even though everything is different. The turbo and inlet pipes all look stock and run in the stock locations, The airbox looks stock (apart from the inlet being opened up). The turbo looks stock, because it's in the stock location, is the stock housings and can't really be seen anyway. It makes enough power to be good to drive, but won't raise eyebrows if I ever f**k up enough for the cops to lift the bonnet.
    • There is a guy who said he can weld me piping without having to cut chassis, maybe I do that ? Or do I just go reverse flow but isn’t reverse flow very limited once again? 
×
×
  • Create New...