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PLEASE HELP! Problems with boost.

Ethan_R32

By Ethan_R32,
in Engines & Forced Induction

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Ethan_R32 Community Regular

Ethan_R32

Posted
Posted

Hi guys I really need some help on this.

I took the GTR out for a quick spin tonight, and theres something worng with the boost.

First up it went right up to 1.2bar of boost and felt pretty strong. But then 5 minutes later it would only do .9bar boost.

It sounded like the engine was revving hard, but not as much power.

It did have a leaking BOV, which occured before I got it, and was fixed. But maybe its this again? Or a boost leak from somewhere else.

After the drive I had a quick look to see if there were any hoses/pipes a bit loose, but nothing. Checked the rear bumper to see if there was lots of black stuff in case it was running rich, but nothing.

I know this sounds stupid but can someone tell me where the BOV's are?? I want to check these out.

Please give me some suggestions guys.

Andrew

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https://www.sau.com.au/forums/topic/12006-please-help-problems-with-boost/
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CNG Contributor

CNG

Posted
Posted

More Specifically to KamikazeR33's post, they are almost right next to the drivers side exit of the intercooler end tank. If you kneel and look into the bumper on that side, you should see two silver cylindrical things hanging off the IC piping.

This is only correct however, if you still have the 2 standard GTR BOV's in place.

I hope for your sakes that it is just a boost leak somewhere in the system (which is most likely), and not anything more major!

Jay95R33 Grand Master

Jay95R33

Posted
Posted

G'day Andrew.

I remember reading a thread on SDU about this exact thing.

Someone's GTR would run at 1.2 bar for 5 mins and then wouldn't go past .9 bar.

I can't remember what the problem was (I'll do a search tomorrow - too damn late now) but I think it might have had something to do with heat build up and then the ECU retarding timing and boost maybe..... But I can't be 100% sure.

Do you have a EBC of some sort, or are you running it without the restrictor in to get the higher boost?

J

400HP Experienced

400HP

Posted
Posted

I have the same problem in my car occasioanlly..... I'll drive for 20 mins fine .. just normal driving then all of a sudden the boost doesn't go over 0.6 bar!! which is even lower than yours...

I am thinking it is definitely a controlled thing by the ECU as stopping the car and restarting it fixes the problem. As far as I know I don't have any leaks anywhere.

It is possible a safety mechanism from the ECU. to control what I do not know though.

Ethan_R32 Community Regular

Ethan_R32

Posted
  • Author
Posted

Thanks for the suggestions guys.

I remember last night was pretty cool, and the boost spiked to 1.2bar. So maybe the ECU then brought it back down to .9bar itself??

Yes it still has the stock BOV's, but how do I get to them to check the piping? Do I have to remove the front bar?

Jay: yeah mate that would be great if you could find that thread. Then maybe I can get this sorted. Im running the boost with a simple bleed valve. Its just a little pipe that is connected near the boost restrictor that has a hole drilled in it, and a screw to adjust it I spose. Dont know too much about it really.

400hp: how often does it happen to yours? With mine it cant be becoz of heat, because I drove home from melbourne to here (550k's) and it didnt happen then. But last night I remember before it happened I was in 5th and floored it at only around 100k's, so maybe it detected some pinging when it went up to 1.2bar.

Ethan_R32 Community Regular

Ethan_R32

Posted
  • Author
Posted

Well i just got back from a quick spin and it all seems fine now?!?!?!

I also noticed that the boost spikes to just over 1.2 bar (not good) and then settles down to 1.1bar.

So it obviously isnt a boost leak, and must have been the ECU detecting some pinging or the boost was too high.

Since the ECU took out boost and timing, will this affect my car now that the boost is back to normal? Will the power curve still be the same?

400HP Experienced

400HP

Posted
Posted
400hp: how often does it happen to yours? With mine it cant be becoz of heat, because I drove home from melbourne to here (550k's) and it didnt happen then. But last night I remember before it happened I was in 5th and floored it at only around 100k's, so maybe it detected some pinging when it went up to 1.2bar.

It has happened about once every one or two months. I noticed I ALWAYS have less than half a tank left as well when it happens. I know mine isn't due to heat either because its ALWAYS at nite and when I haven't been particularly rough with the car. This didn't happen to me when I was at the track either.

I'm not almost certain its ECU controlled.

400HP Experienced

400HP

Posted
Posted

Oops sorry - I meant I AM almost certain. It shouldn't be mechanical because if it was restarting the car won't fix the problem. Resetting ECU won't help either because this issue has occured before and after ECu reset. Less boost MAY help but I doubt it will solve the problem.

If it IS in fact an ECU control mechanism then I doubt it really is a "problem" that can be solved.

predator Grand Master

predator

Posted
Posted

Sounds just like the automatic boost cut in the ECU, and probably some of it is controlled by another parameter (read: sensor) that's its not liking occassionally. Maybe the automatic boost sensor is playing up due to a dodgy pressure hose?

Jay95R33 Grand Master

Jay95R33

Posted
Posted

Andrew,

I can't find that thread on SDU :P Had a good look, but nothing...

I'm pretty sure it has somthing to do with the ECU retarding timing and/or boost due to slight pinging.

Try to resist giving it a bootfull for a few days and see if it'll still bost to 1.2 bar, and see what it does after that.

Or try a bottle of the pro booster octane stuff in the tank. That might fix it..

J

Ethan_R32 Community Regular

Ethan_R32

Posted
  • Author
Posted

Well I took it out for a quick spin this morning and it boosted to 1.2bar easily again.

Although I dont want it at 1.2bar, it should be at 1.1, so maybe that might help if I change it a bit.

Also might be the fuel. With BP Ultimate it was fine, put some Optimax in it and thats when it took out the boost.

I think I will try some octane booster, and set the boost to 1.1bar.

Thanks for your help guys, if anything else occurs, Ill post it here again.

  • 4 months later...

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