R34 Gtt Stock Boost?

[Nero_Tigre]

Hey, i was hoping someone new what the stock boost for the r34 GTT is once youve removed your boost controller. I'm putting it back in but it wont be for a few weeks so i was just wondering what kind of boost id be running until i put it back in.

[R31Nismoid]

7-9psi id imagine, just like most others

[pottsy]

pritty sure its 7psi bud.

[Daz305]

i got a stock r34 apart from just the cannon at the back is trust/greddy. i got it dyno'd n it said 7-8psi for most of it...

[cankas]

stock boost for r34 gtt is 4psi to 4500rpm then 7psi till red line.

[Skyline1989]

OK.. from my understanding the ER34 holds boost up to 5 psi until 3,500rpm (this is due to the inlet and exhaust Camshafts) the camshafts are somewhat "Variable Valve" and NO.... not like a HONDA

After 3,500 rpm the car should hold boost to approx. 7-9 psi all the way to redline

The car will creep more towards 9 psi if you have a Frount Mount Intercooler

[Howie]

OK.. from my understanding the ER34 holds boost up to 5 psi until 3,500rpm (this is due to the inlet and exhaust Camshafts) the camshafts are somewhat "Variable Valve" and NO.... not like a HONDA

It's not directly related to timing changes... it's the dual stage solenoid. if you ground it, it'll run 7psi constantly.

[cheez]

agree with howie on this 1.

r34 runs dual stage solenoid with 5psi to 4500rpm then goes up to 7psi til redline.

ground the solenoid and u get 7psi til redline or change the actuator to a r32 actuator and get 10psi to red line if the solenoid is grounded or a 7psi-10psi dual stage.

[jay1]

around 7psi i think

[R34~neo6~turbo]

7psi is the stock boost.. but u need to check what boost u running on it b4 u take ur ebc off might be running on too much boost. happend to me lol.

[Alex_r33s2gts25t]

Once youve removed your boost controller youll blow your turbo ...

[Nero_Tigre]

Once youve removed your boost controller youll blow your turbo ...

Lol why will i blow my turbo, i just need to take off the boost controller for like a week until I've got it passed at the cop shop. I dont see why removing the boost controller will blow my turbo, according to what everyones said on the forum itl be running around 5 to 7 psi which is 4 psi less than what ive got it running on now (which btw its dyno tuned at so its not unsafe for my turbos)

[silviaz]

Is overboosting normal even with a boost controller? I got told that it's normal if you tune for X psi and it goes over that if you have a modified exhaust system. Didn't sound right to me. 

Edited August 31, 2024 by silviaz

[GTSBoy]

18 minutes ago, silviaz said:

Is overboosting normal even with a boost controller?

Well....no. But yes. But no.

First up, let's ask what you yourself specifically mean by "overboosting"? Because there is "overboosting" and there is "overboosting".

If the boost pressure exceeds the maximum value that you want to run, then technically that's overboosting. But even the very best boost controller will still exceed that maximum, even if only by a little bit. And fancy PID control actually even fully expects an overshoot of the target while attempting to achieve it. The images on the left, particularly the bottom one, show what PID control typically looks like with some overshoot.

But, if you are not talking about a proper electronic boost controller, and instead are talking about some simple boost tee style thing (which is really just a spring based pressure relief/regulator type thing) then....they can be either pretty good or pretty bad. The pretty bad ones can have terrible control and allow either quite large overshoot on the way to achieving target, or they might even allow the boost to creep way up over target towards the end of a pull, well, after the initial achievement of target.

Even a fancy electronic boost controller might not be able to prevent overboost, by which I mean the longer term creep way above the target, if the exhaust and/or boost control mechanisms (the actuator and the wastegate) are not capable to actually giving you the control.

In your case.... You're pretty stock right? There's no situation where you should find yourself with problematic overboost. Even a shitty boost controller shouldn't cause you troubles. it might "overboost", but that shouldn't be a major issue. Except of course, if you're running without a tuned/tuneable ECU. In which case.... you've probably already been told to stop f**king with it until you do have.

[silviaz]

1 minute ago, GTSBoy said:

Well....no. But yes. But no.

First up, let's ask what you yourself specifically mean by "overboosting"? Because there is "overboosting" and there is "overboosting".

If the boost pressure exceeds the maximum value that you want to run, then technically that's overboosting. But even the very best boost controller will still exceed that maximum, even if only by a little bit. And fancy PID control actually even fully expects an overshoot of the target while attempting to achieve it. The images on the left, particularly the bottom one, show what PID control typically looks like with some overshoot.

But, if you are not talking about a proper electronic boost controller, and instead are talking about some simple boost tee style thing (which is really just a spring based pressure relief/regulator type thing) then....they can be either pretty good or pretty bad. The pretty bad ones can have terrible control and allow either quite large overshoot on the way to achieving target, or they might even allow the boost to creep way up over target towards the end of a pull, well, after the initial achievement of target.

Even a fancy electronic boost controller might not be able to prevent overboost, by which I mean the longer term creep way above the target, if the exhaust and/or boost control mechanisms (the actuator and the wastegate) are not capable to actually giving you the control.

In your case.... You're pretty stock right? There's no situation where you should find yourself with problematic overboost. Even a shitty boost controller shouldn't cause you troubles. it might "overboost", but that shouldn't be a major issue. Except of course, if you're running without a tuned/tuneable ECU. In which case.... you've probably already been told to stop f**king with it until you do have.

Nope mine is quite modified, I went from 12 max psi to almost 15 I don't want to blow my stock turbo. I had my car tuned btw I forgot to mention.

Edited August 31, 2024 by silviaz

[GTSBoy]

Anything with a stock turbo is not "quite modified". It is basically stock. You're describing essentially what my car is. Doesn't matter what exhaust, intercooler, injectors, AFM, coils, etc etc you have. The stock turbo is good for about 200 rwkW at best, and that is not "quite modified".

And.....your stock turbo can and probably will blow up even at 12 psi. I ran mine at 12 psi for....probably 10 years, maybe more. Then one day it exploded the turbine. There are many other examples of the same, and many examples of them dying even without ever having been turned up. Some died when nearly new. Others died only after protracted abuse.

I even ran my RB20 stocker at 17 psi for a while (without realising that that was why it was so fast) because of a little problem with my boost controller. It was fine (and luckily, apart from the risk of the turbine exploding, the engine could take it because I had fuelling and tuning to suit). But it might have died on the first occasion.

Your turbo is now 25 years old. It is on borrowed time regardless of what you want. It will die at some point. Just be prepared to put a new turbo on it. I'd been waiting for a decade for mine to go when it finally did.

Do not run your turbo at 15 psi though. It can probably take it spinning up there briefly, if that's only a brief thing until the controller gets control. But extended operation at that speed will kill it.

But remember what I said above - it is a lottery.

And also, there is no way that a boost controller should be allowing the stock turbo to run well over your boost target. Not a good boost controller anyway. I have a million year old Profec and it will hold 9, or 10, or 12, or 14, or whatever I ask it to.

[silviaz]

11 minutes ago, GTSBoy said:

Anything with a stock turbo is not "quite modified". It is basically stock. You're describing essentially what my car is. Doesn't matter what exhaust, intercooler, injectors, AFM, coils, etc etc you have. The stock turbo is good for about 200 rwkW at best, and that is not "quite modified".

And.....your stock turbo can and probably will blow up even at 12 psi. I ran mine at 12 psi for....probably 10 years, maybe more. Then one day it exploded the turbine. There are many other examples of the same, and many examples of them dying even without ever having been turned up. Some died when nearly new. Others died only after protracted abuse.

I even ran my RB20 stocker at 17 psi for a while (without realising that that was why it was so fast) because of a little problem with my boost controller. It was fine (and luckily, apart from the risk of the turbine exploding, the engine could take it because I had fuelling and tuning to suit). But it might have died on the first occasion.

Your turbo is now 25 years old. It is on borrowed time regardless of what you want. It will die at some point. Just be prepared to put a new turbo on it. I'd been waiting for a decade for mine to go when it finally did.

Do not run your turbo at 15 psi though. It can probably take it spinning up there briefly, if that's only a brief thing until the controller gets control. But extended operation at that speed will kill it.

But remember what I said above - it is a lottery.

And also, there is no way that a boost controller should be allowing the stock turbo to run well over your boost target. Not a good boost controller anyway. I have a million year old Profec and it will hold 9, or 10, or 12, or 14, or whatever I ask it to.

Yeah, I'll need to check with the tuner it sounds like. I only wanted 12 psi max. I had the mechanic check the shaft play and they told me it was good. I'm hoping I didn't do damage when I did a quick pull and hit 15 psi.

Did you thrash your car regularly for 10 years or was it just a hit here and there? I'm trying to get an idea of how long I can rock this. Ideally I don't replace the turbo lol. But yeah it's a lottery at the same time like you said.

Edited August 31, 2024 by silviaz

[WMDC35]

2 hours ago, silviaz said:

Yeah, I'll need to check with the tuner it sounds like. I only wanted 12 psi max. I had the mechanic check the shaft play and they told me it was good. I'm hoping I didn't do damage when I did a quick pull and hit 15 psi.

Did you thrash your car regularly for 10 years or was it just a hit here and there? I'm trying to get an idea of how long I can rock this. Ideally I don't replace the turbo lol. But yeah it's a lottery at the same time like you said.

Shaft play won't tell you much in this case, the ceramic wheel is bonded to the shaft which is where it lets go

[GTSBoy]

1 hour ago, WMDC35 said:

Shaft play won't tell you much in this case, the ceramic wheel is bonded to the shaft which is where it lets go

This.

Shaft play is not "broken". Turbine in thousands of crumbs in your cat converter. That's broken.

It will explode suddenly and you will immediately lose all boost and any hope of ever making boost again.

It can happen today, it can happen tomorrow. It might take another 5 years. It can happen at 10 psi, at 12 psi, at 17 psi. Mine blew as it came on boost so it wouldn't have even spooled all the way up and was probably only making 5 psi at the instant it let go.

3 hours ago, silviaz said:

Did you thrash your car regularly for 10 years

Yes. I drive it hard regularly. Most miles are done commuting, but it gets the arse hung out on every roundabout, every on ramp and no wanker in a Commodore is allowed to win at the lights.

[silviaz]

4 hours ago, WMDC35 said:

Shaft play won't tell you much in this case, the ceramic wheel is bonded to the shaft which is where it lets go

Ah right.