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R34 Can't Boost Above 10psi

so_tred

By so_tred,
in Engines & Forced Induction

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so_tred Proficient

so_tred

Posted
Posted (edited)

and the story goes on..

Everytime the boost gets raised to 10psi or above the car starts missing at around 4000rpm.

I've got everything I need & more to get it running at 12psi which is all I want from it.

FMIC, full 3" exhaust, 040 fuel pump, SAFC II, SITC & AVCR controlling the boost.

The plugs have been changed and gapped down to .8

When I got the full exhaust on it would boost up to 10psi and everything ran fine..but ever since the AVCR has been installed there's been nothing but troubles.

and it has also developed a miss at idle...(which the plugs didn't fix)

I suggested coil packs but they seemed to think it wouldn't be them because the miss at high revs is extremely aggressive..

Has anyone else had similar problems...

I really can't think of anything else it could be apart from the coil packs..

Edited by so_tred
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boosted_32 Proficient

boosted_32

Posted
Posted

hi mate I had a simular problem in my s15 I was running a turbosmart boost controller which was spiking to the shithouse! I was running bout a bar which is close to the factory boost cut and soon as it spiked almost went flying through the window everytime.....not sure if this is your problem surley the facroty boost cut isnt around 12psi on a 34 is it?

so_tred Proficient

so_tred

Posted
  • Author
Posted (edited)

I didn't think Nissan's had boost cut as such, don't they just hit R&R when too much boost is being fed?

But I figure it's not that because they had the SAFC & SITC to work around R&R if that was it.

Oh yeah, not sure whether this makes any difference or not but I was told when he was trying to get it to run at 10psi it was making 195rwkw..could this amount of power be triggering something..? like something reaching max..injectors, afm?

Edited by so_tred
cheez Mentor

cheez

Posted
Posted

if the issue is from when the avcr was installed, i got another suggestion for you, get your self a hks adjustable wastegate actuator and bolt that on in replacement of the stock actuator. remove the avcr ad tune the safc with that actuator set at 12psi. i personally wouldnt go more than 10psi to conserve turbo life, but thats up to you.

have u tried removing avcr and running standard boost? problem dissappear? avcr could be prob.

also actuator is a cheaer and less 'cop bait' way of raising the boost and they are able to raise the boost and have no boost spike issues.

Evil34 Experienced

Evil34

Posted
Posted

If you car is making 195rwkw it is not running 10psi.

I have my car tuned on .75 of a bar and that is appoximately 10psi my car makes 184 rwkw and has no prolems at all.

i have a wlbro fuel pump, AVCR, turbo back exhaust, splitfire coil packs, platinum plugs and FMIC.

I found that when i had the AVCR installed my car was all ove the place when boosting, but have since taken it in and had i tuned properly and now have a great power curve and a reliable car. Note that they could not put anymore boost in as the factory computer was dumping timing and fuel with anymore boost.

Granthem Mentor

Granthem

Posted
Posted

cheers cheez...

i got mine on the dyno yesterday, and with the catback, pod and slight boost increase (however by peak power the boost had dropped back to standard so its not really any use for my power figure) my car made 161.2rwkw. I was showed a place where my af ratios are way too rich and if tuned out they said it makes the car alot more powerful through the revs.

not trying to steal the thread just thought i would ad my contribution

so_tred Proficient

so_tred

Posted
  • Author
Posted (edited)

I just checked the coil packs and it doesn't appear to be them so can cross that one off the list..

Next to check is the AVCR..

after that I'm stuffed for ideas..

Edited by so_tred
so_tred Proficient

so_tred

Posted
  • Author
Posted
If you car is making 195rwkw it is not running 10psi.

It was making 180rwkw without raising the boost & just a full 3" exhaust so I have no doubt he was able to get 195 on 10psi while also tuning the safc & sitc..

jase-r34 Mentor

jase-r34

Posted
Posted
If you car is making 195rwkw it is not running 10psi.

I have my car tuned on .75 of a bar and that is appoximately 10psi my car makes 184 rwkw and has no prolems at all.

Must agree with sam, the safc with a good tune will surely be enough for the extra 11kw...

Evil34 Experienced

Evil34

Posted
Posted

The only issue that i can figure is that the standard computer is fighting your SAFC, as my car was dumping timing and fuel with anything over 10 psi.

This maybe the same problem that you are having as my dyno graph looks terrible before i had it tuned correctly with the AVCR and great up to 10psi but all over the place again after 10 psi.

Luckily enough i have a power fc waiting to go in the car to remap everything, but i was told if i didnt have this a could go down the path of a FCD to fix the issue but it was not advisable.

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