Jump to content
SAU Community

Recommended Posts

everything points towards this being your wastegate not able to flow enough, but this isn't likely with a std turbo, unless theres a problem.

You said that the wastegate flap used to catch on the dump but you ground it out and now it doesn't. Are you sure it opens fully. What is the design of the dump like? Do the gases have a clear path to escape or is it opening and forcing the gases to flow against the wall of the dump pipe??

the wierd thing is when i set a  bleeders on say 10 psi the car will run 10npsi down below but will have creeped to say 14up top. playn with the boost was how i originally discovered the prob.

Boost creep, especially on hot days is quite common I think, this is why they invented electroniclly controled valves. RBVS, I must agree with you too.

Have you checked the hose that connects to the wastegate for something like a split. A split hose is likely to act like a bleed-off valve, and the higher the boost you put in, the wider the split becomes, and the more boost it bleeds off.

all the hoses have been checked and r new. im beginin to think and ebc might be the way to go aswell i just dont wanna fork out the dosh for the thing just yet only to discover ive still got the same prob.

black33, the w/g opens till the little arm on the outsde of turbo runs parallel with the front to back of car im assuming this is fully open. the dump is the same shape as the standard flange and on the inside i have ground out any weld, dags, and irregularities so i guess its flowin pretty good i think the gasses would hit the gate before they hit the wall of the pipe. is it possible that the waste passage could be a little fouled with carbon or sumthing the car has done 80000kms.

ebc will not fix the problem. if you have tied the wast gate back so it is always fully open how is a ebc going to help. if you realy want to run less boost put the standard dump back on.(restrict the flow) or you could go to the effort of removing the turbo, dine grinding the wast gate out 1 or 2 mm but not to big so the gate doesnt cover the hole, also grind away the angle the exhaust flows though the gate. I wouldnt bother, 10psi is fine you just need to be able to keep it their.

the other thing coul be like you said somthing obstructing the flow though the gate, but 10psi seems normal to me.

rbvs, i would be happy to run 10psi if i could get it to come on and stay there right through the revs, i actually wanna run 12 but i cant do that at the moment without it creepin another3-4 psi up top will the ebc be able to hold 10+ as bleeders and regs cant seem to do it.

i tried to add an external spring today. it ran 11 psi but still managed to creep to 14+ psi up top (done the same thing as when i tried a bleeder or reg)

Man - it's the wastegate getting stuck. A bleeder, EBC, or extra springs ain't gunna fix it. Rip the actuator out and test it along with the movement range of the wastegate flap. That's the only way your gunna find out what it is.

J

jay95r33, finally got around to runin some compressed air through it, the actuator and wastegate operate really smoothly although the actuator gets to full travel way before the w/g. ie, the w/g itself can rotate around over90 deg whereas the actuator at full trave only rotates it around 40deg. does this sound about right, does anyone know how much travel i should be gettin from my standard actuator?

with the compressed air i didnt have it hooked up to a guage or anything (didnt have one) but being really carful on the button once it cracked its movement was very smooth no binding anywhere.

i am having the exact same problem with my skyline atm, its on stock boost and as revs go up the boost goes to nearly 10psi by the time it gets to the redline, just like ottos, otto when you find out what the problem is please tell me what it is as i have checked everything =]

Otto - that's the problem. If the wastegate isn't opening right up (ie. only 40 degrees), then as the exhaust gasses increase and speed up, it won't be able to flow/bypass enough ehaust gasses to control boost.

Does it look like the actuator or rod has been modified (bent/shortened etc)??

Maybe it's not a stock R33 GTS-t actuator ??

jay95r33, im pretty sure its the stock actuator what i dont get is if the actuator can hold/waste enough for 10psi when its normal why does it creep higher than 10 when the bleeders there.

anyhow picked up a rb20 actuator today and gave that a go (still gotta check if it has the same travel as the rb25 actuator). in second gear it was pretty good-held 10 psi crept to a little over 12 by 6000 and had dropped back to a little over 11 by 7000. 3rd gear it held 10 then for everywhere else was about 1psi higher than 2nd gear. this is a improvment over th rb25 actuator but does it sound acceptable/normal??

it seems no matter what happens down low im always gonna run a couple of psi higher up top.

do you guys think an ebc would clean things up from hear or is my problems still elsewhere considering i wanna run a pretty acurate 12psi??

i would have the biggest cry if i forked out the money for one and it didnt help, this problems already come close to reducing me to tears as it is(he he eh)

The EBC should be able to hold a dead accurate 12psi, because, as you say, the wastegate flows enough to hold as low as 10psi at redline. Any normal boost controller can increase boost above what the wastegate actuator is set to, you just can't run less boost than that.

I'd still be getting the original problem fixed though, the last thing you need is for whatever the problem is to suddenly get worse while you're out in the car.

That's what I'm worried about too.

If it's a mechanical problem, (ie. wastegate flap not opening far enough) then I would be fixing it rather than buying a EBC to get it to work.

Seems like a strange problem, and it could be a combination of things that is causing it.

J

my car is doing this now... full exhaust (split dump) with screamer...just had intercooler fitted, dump pipe and bov fitted couple days ago.. these are the only engine mods, still running stock boost setup. ok we all know stock boost has 2 stages, mine is sitting at 0.5bar before 5000rpm, then just jumps up and keeps increasing, has hit 1bar over 5000rpm, but i backed off, im guessing it will just keep rising. im guessing possibilities are hole in vacuum hoses, or wastegate flap isn't opening enough maybe its hitting dump flange, but i can sure hear it opens. how far does the wastegate flap open on a stock turbo? going to change some of the vacuum hose tomorrow since it could be dodgy.

Yahoooo, success at last!

i ground the wastegate port out a fair bit (so there was less than an 1mm perimiter for the w/g and went for a drive this arvo and bam boots sat pretty dead on 10psi right through the revs, got full boost abit before 3000 (high side of 9psi pretty close to 10) crept to the low side of 10psi by 5000 then sat dead on 10 psi for the rest till redline. more than good enough for me. this was with the rb20 actuator havent tried it with a bleeder or the diy controller yet but im guessin it ill be sweet

so im off to get the safc tuned finally, thanks to everyone that had an imput.

otto good stuff

changed my hoses today, that pretty much rules out the hose leak possibility.

went for a drive tonight, in 3rd and 4th once the stock second stage boost kicks in (over 5000rpm), boost still jumps from 0.5bar to 1bar, hmm this is not gonna be fun fixing this. i only want to run about 0.75bar or 10-11psi. not running any form of aftermarket boost control.

in 2nd gear reached 0.75 bar tops, only in 3rd and 4th it rises to 1bar.

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

    • Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
    • You don't have an R34 service manual for the body do you? Have found plenty for the engine and drivetrain but nothing else
    • If they can dyno them, get them dyno'd, make sure they're not leaking, and if they look okay on the dyno and are performing relatively well, put them in the car.   If they're leaking oil etc, and you feel so inclined, open them up yourself and see what you can do to fix it. The main thing you're trying to do is replace the parts that perish, like seals. You're not attempting to change the valving. You might even be able to find somewhere that has the Tein parts/rebuild kit if you dig hard.
×
×
  • Create New...