R34gtt Boosting

[R31Nismoid]

I wouldnt have thought boost would rise too, but it did for me. Perhaps the factory boost gauge is not as reliable as it is.

Are you saying your making 12psi... by way of the stock boost gauge?

If so... time to purchase a boost gauge

THEN come and tell us its running 12psi

[ODessA]

there should be a rule on sau about posting problems where the stock boost gauge is involved

[nuffsaid]

Wow can I stock boost gauge really be that bad? Whats the point then aye! If it looks like I am running 0.7kg/cm, could I actually be running more? Ill probably just wait until I get my EBC, a couple of them display the boost level. Thats accurate right?

But yeah GTX, why not get your timing pushed back to where it was then youll be sweet, no need for a ECU/SAFC even! Your car was running fine before so get it back to the same state dude.

Edited March 15, 2006 by nuffsaid

[R34GTX]

OK guys. Sorry about the time to get back, but I have been snowed under at work and busy trying to test the car also.

Sydneykid, you were right. I managed to get a hold of a boost guage and tested the actual boost the car was seeing. Strange thing was that at low boost, it was reading fine, but once the boost increased slightly, the stock boost guage would be reading higher. These are the reults thus far with everything stock (brass restrictors in)

Car guage 0.8 Bar/11.6Psi = Actual 0.65/9.4Psi Bar

When car goes into "limp mode":

Car guage 0.5 Bar/7.25Psi = Actual 0.45 Bar/6.5Psi.

So I guess the only questions left to ask:

1. To fix this problem, I can either reduce the air flow (put more restriction into exhaust pipe or

2. Buy SAFC2 and tune appropriately?

Another thing, in theory if I removed the stock brass restrictors between T piece and turbo, should this problem disappear? I am asking cause I have tried it and it has made no change to the "limp" mode.

Thanks for all your replies guys.

Pete

[666DAN]

Just for reference we tested the gauge on both my car and Petes, I can rip a decent 0.75 - 0.8 Bar without the car trying any cRaZy boost reducing tactics. We've got very similar set-ups, only difference my one is a series 1 R34

[Nightcrawler]

on a similar note:

I brought in my R34GTT sedan which was completely stock, except for a 3" HKS SilentPower zorst. Car ran fine, no idea what boost it made, but seemed to go fine and went hard. Even with Aus fuel in it, it ran fine, even when flogging it.

Fast forward to today - mods as follows:

- same HKS 3" zorst

- Batmbl mild steel segregated front/dump pipe

- Xforce 3" high flow cat

- Apexi ECV

- Apexi pod in custom CAI (with plenty of fresh air via ducts)

- JustJap (Hybrid copy) FMIC

- Autometer smoked boost gauge

Now when I got the car back from complaince, I fitted pretty much everything in a 1 week period, and reset the ECU. Problem is, I don't think the ECU actually reset (which leads me to think my ECU has been tinkered with). So, when I am running with the ECV completely open, I make a solid 10psi by 2,500rpm, 12psi by 3,500rpm and it spikes up to around 13psi right at the top. But - right at the top of the rev range, when I am booting it, it makes this brief horrible sound, which a mechanic mate thinks is detonation. I think it sounds more like a boost/fuel cut than detonation, as there is no tinny note to the noise.

Anyhow, my real question is, how can it possibly hit 13psi with the stock ECU - I thought this was impossible (which also makes me wonder whether my ECU has a Mines upgrade or similar - but why then didn't the car have other mods - and before you say it - it doesn't look like it has been stocked out prior to sale). Has anyone else experienced anything like this?

Also I want to note that by closing my ECV, I can adjust the boost (as you'd expect) - it is quite linear. With the ECV closed it will only boost to 1psi, and obviously the car is dead silent, and has significantly less power. It is a handy device.

So that is another option - get an ECV, and you can run with the ECV partially closed and that will limit your boost!

[R34GTX]

OKAY GUYS!!! I think the problem has been sorted.

Daniel (3lite 32) Elite Racing Developments managed to hook a consult up to check on what was exactly happening with my car. To start with, YES my boost guage was reading high, but only in the higher boost areas. At low boost it was reading spot on.

Once Daniel had the consult up and running, it was obvious almost instantly that my car was running way advanced timing, even though you could hear no noticeable knocking sounds. So all in all my car was suffering from a severe case of R&R via very aggressive R34 detuning!! (Good to know my car will not self destruct without letting me know in advance)

A quick stop with Daniel adjusting the CAS and all seemed to be working fine. Boost was measured at a solid 9.5 -10Psi with CES turbo back exhaust and K&N Panel Filter.

I quizzed my mechanic and he said he did the same thing the first time, bu the problem came back. He still seems to think there are other underlying problems that are casuing my timing to wander??

Anyhow time will only tell. for all of your input. I tried a few of the easier fixes you guys recommended and learnt heaps about the car.

Big thanks to the other guys (in no particular order) who spent hours putting up with me bitching and whinging about my car. 666DAN, Choyda, JLnewton, Afro..... actually I bitched to anyone who would listen and even those who wouldn't.

Cheers

[R34GTX]

on a similar note:

I brought in my R34GTT sedan which was completely stock, except for a 3" HKS SilentPower zorst. Car ran fine, no idea what boost it made, but seemed to go fine and went hard. Even with Aus fuel in it, it ran fine, even when flogging it.

Fast forward to today - mods as follows:

- same HKS 3" zorst

- Batmbl mild steel segregated front/dump pipe

- Xforce 3" high flow cat

- Apexi ECV

- Apexi pod in custom CAI (with plenty of fresh air via ducts)

- JustJap (Hybrid copy) FMIC

- Autometer smoked boost gauge

Now when I got the car back from complaince, I fitted pretty much everything in a 1 week period, and reset the ECU. Problem is, I don't think the ECU actually reset (which leads me to think my ECU has been tinkered with). So, when I am running with the ECV completely open, I make a solid 10psi by 2,500rpm, 12psi by 3,500rpm and it spikes up to around 13psi right at the top. But - right at the top of the rev range, when I am booting it, it makes this brief horrible sound, which a mechanic mate thinks is detonation. I think it sounds more like a boost/fuel cut than detonation, as there is no tinny note to the noise.

Anyhow, my real question is, how can it possibly hit 13psi with the stock ECU - I thought this was impossible (which also makes me wonder whether my ECU has a Mines upgrade or similar - but why then didn't the car have other mods - and before you say it - it doesn't look like it has been stocked out prior to sale). Has anyone else experienced anything like this?

Also I want to note that by closing my ECV, I can adjust the boost (as you'd expect) - it is quite linear. With the ECV closed it will only boost to 1psi, and obviously the car is dead silent, and has significantly less power. It is a handy device.

So that is another option - get an ECV, and you can run with the ECV partially closed and that will limit your boost!

Thanks Nightcrawler, but I think I have it sorted now. If I do choose to boost higher or mod more at a later time, I will definately look at this option along with a SAFC2.

[32vspecII]

my boost didnt increase at all with a 3inch hiflow cat and catback (stock dump/front) and k&n panel . It gets to .6 (kg/cm2 , very close to .6 of a bar ) and stops there . Its behaviour is very much like and EBC , ie gets to .6 and stops exactly , no spike , no drop off .

I have nismo gauges and a digital boost gauge on the turbo timer and they both show the same .

my question is I was under the impression theres a stock electronic boost controller . So wouldnt this do what my car is doing and stop any increase in boost above its set level , despite freeing up the exhaust ? that doesnt seem to be what others are seeing

sorry for the mini hijack

Edited April 6, 2006 by arkon