Beyond 1.0 bar

[toby19]

My car was tuned in June and we managed to extract 178 rwkw and 408 Nm. The problem then (and partly that was because the guy was not familiar with e-manage features) was that when boost gets up to the 13.5+ psi (0.93 bar) mark the engine cuts out. Differing theories on what caused this include spark plugs, coil packs, injectors maxing out, boost limiter.

I've just recently played around with the e-manage and found a feature that is able to eliminate boost cut by clamping the air flow meter signal at the rpm point where boost cut occurs.

The boost cut has now gone and I've just run up to 14.7 psi (1.04 bar)!

Good thing these computers.

[krzysiu]

Fuel Pump?

[toby19]

  krzysiu said:

Fuel Pump?

Definitely the next thing lined up

[krzysiu]

That might be your problem.

[Lithium]

  toby19 said:

My car was tuned in June and we managed to extract 178 rwkw and 408 Nm. The problem then (and partly that was because the guy was not familiar with e-manage features) was that when boost gets up to the 13.5+ psi (0.93 bar) mark the engine cuts out. Differing theories on what caused this include spark plugs, coil packs, injectors maxing out, boost limiter.

I've just recently played around with the e-manage and found a feature that is able to eliminate boost cut by clamping the air flow meter signal at the rpm point where boost cut occurs.

The boost cut has now gone and I've just run up to 14.7 psi (1.04 bar)!

The air flow meter probably maxed out - mine reached around 5volts airflow on around 1bar... so I'd watch what I do with fuelling after the point that happens. Someone I know blew their RB25DET recently by not compensating for what happens after 100% flow of the AFM is reached - so more air, no more fuel, lean out - detonation, death :ghost:

[Roy]

  krzysiu said:

Fuel Pump?

:confused:...why would he need a fuel pump. LOL, its a late model R34 with std turbo and i doubt it has a lazy / failing fuel pump and at that power i wouldnt expect that he needs extra rail pressure...coudl be wrong but what make s you think he need a new fuel pump?

[skylinesteve]

yes i would have to agree with roy on that one u shouldent need a new fuel pump at all i would sugest u look into a fuel reg that would help a little

[EnricoPalazzo]

I think the guy solved the problem, hence his post. It was boost cut was still set at 13.5psi, he changed it and his car is now sweet

[toby19]

  EnricoPalazzo said:

I think the guy solved the problem, hence his post. It was boost cut was still set at 13.5psi, he changed it and his car is now sweet

:confused: I always seem to confuse others whenever I post...

The air flow meter was definitely maxing out hence the power cut: too much air too little fuel. There is the danger of detonation but that is fixed by adding a bit more fuel where its needed through the injector control map of e-manage. The boost limiter cut feature of e-manage "tricks" the ecu into thinking that the AFM has not maxxed-out yet but in reality more air is being pushed through (dangerous). Therefore, this situation needed to be compensated by adding more fuel.