Miss On High Boost (r32gtr)

[KMN]

Hi im having trouble with the car and its starting to do my head in, if any one can help it would be much appreciated.

Ill give a brief spec. R32 GTR (r33 engine), HKS gtrs turbos, Apexi power FC, Splitfire coils, Greddy iridium plugs, Tomei fuel pump,

Tomei pressure reg, Sard 555cc injectors, running around 500bhp at 1.3 Bar(when its running right).

The car runs ok flat out under 1 bar boost, it will give a slight pop just before the turbos come into action,

its when i turn the boost higher than a bar and the revs hit 5,000 the power just dissapears and the car starts to pop

and miss its not violent but the loss of power is very noticable. To make it strange you could push the revs on in third with

the car spluttering and as soon as fourth is engaged power returns with no miss.

I replaced the plugs 2 days ago with greddys and noticed a slight improvment(gap set at .6)

More recently with a slight load uphill the power comes and goes but with the o2 sensors

off this problem is all but gone.

If any one has any suggestions please help this is really starting to annoy me ive run out of things to check

and the moneys running as thin as my patience.

Thanks, Kieran

KMN

[Amec]

bit from left field but could be boost leak, you say it only happens on high boost, perhaps the system can hold the lower boost setting but when you run high boost it cant. your symptom will occur if there is a boost leak.

[ZILR]

what fuel pressure are you running, just a thought if your pressure reg is set to high it will run ok up to midrange but it might be over fueling it up top

also i would run 0.8mm with your plugs that could be another prob.

[KMN]

Hi thanks for the reply ive checked for boost leaks and it all looks good the car holds .9 bar without any loss of power,

but any higher and the problem increases with boost.

The origonal spark gap was around .75 but after changing to .6 the engine semed to run smoother in the higher revs.

I havent checked fuel pressure in a while, the last owner said the fuel pump is 5 or 6 years old so this is definatley

worth looking at. I had a run on a dyno and the fueling showed up lean top end i put this down to the map which was

done at a lower boost,

In the next few days i should have a loan of coils, a timing light and a fuel pressure kit

ill post up what i find.

Thanks for the help, if anyone has an idea do share.

KMN

[KMN]

Hi ran a fuel test today and found fuel pressure at idle 1.7 bar, with the return hose

clamped no difference and the vacuum removed from the regulator no difference,

adjusting the reg. made no difference until the screw was nearly fully out when

the pressure dropped.

I should have a pump friday but ill check to make sure everything is ok in tank

just in case.

Can anyone recommend a good pump for around 280 l/h with cost in mind.

Thanks, KMN

[DAN00H]

get a nismo/ sard/ HKS replacement.

I've got a nismo that you can have cheap if intersted? what reg are you using?

make sure your electrical fittings are all tightly closed for the splitfire wiriing harness.

[KMN]

I found a tuner with a walbro pump hes offered to supply and fit for around €200, too easy to pass up.

The car is running a tomei fuel reg.

I'm living in Ireland so postage and trying to pay you is just arwkward, thanks for the offer.

Ive priced a few good pumps and they work out about €500. I was thinking external pump

but its a lot of work and it means dumping rear seats or subs.

Ill post up what happens after the pump, hopefully ill have a dyno print out and a smile.

KMN