Cut off under WOT after installing downpipe?

[nelsonmxmarc]

No means at reviving an old post but i'm curious as to what else may be causing my car to fall flat on it's face between 5000-6000 rpm? (Seems to be spot on 5100?)

Can we agree that with the added mod of the downpipe and 3.75" back exhaust that were moving enough air to actually trip the ECU Ign/fuel cut?

Mods are pretty basic;
M's K&N pod
3" DP with 1.75" divorced wastegate, 3"-3.75" back
Stock Recirc BOV
BCPR6EIX-11 plugs gapped to .8mm.. Cleared up the series of misfires under wot.
Stock SMIC
Stock turbo
141 compression across
Stock fuel pump and injectors
AFR's - Mint - 10.8-11.9 at WOT through til cut off..
Fresh oil etc..

Stock boost is 14.9 on average - varying on temperature.

So; fuel cut? Bad fuel pump? Vac leak? Maxing injectors? AFM voltage maxed? Plug heat range? ..



My winter mods will, surely... HOPEfuly clear this up;
GTR injectors
GTR fuel pump
FMIC
z32 AFM

.. and a nice retune via Nistune at Almasi..

*Should hope to get a build thread started soon with all my carbon interior goodies soon!

Any info would be great guys!

[love_boost]

sounds like its running out of fuel, if you havent already change the fuel filter.
or plan to get the GTR pump now instead of later, i had the same problem got GTR pump and worked 100% better.
also the TPS could be set wrong if you havent checked the voltage.
but if your getting that kind of AFR i doubt fuel is your problem probably boost cut, i think boost cut happens at 16psi?

[mcfly]

Thanks Brian! However I believe I'm going to go with nistune and have it
dynoed at Almasi in the spring. I have an aem uego and have always seen great afrs. Oh well, almost winter anyways!

that's a very good choice as brian and his "business partners" idea of tuning includes getting someone to msn messenger a tune from 1000 km away with a what runs "best".

[Skym]

At 5100rpm is the safety fuel cut. Engine knocking could set it off. Turn boost level down with electronic boost controller. Probably only be able to drop boost level to wastegate spring pressure, which is around 12psi for RB20DET.

At 14.7psi+, probably will be the load limit fuel cut (Maxing MAF out). Also known as a boost cut if turbo overboosts.

[love_boost]

skym is that only with the stock ecu?
i had a wastegate hose come off and it boosted to 19psi, dont worry the beeper went so i pulled over!
but no boost cut? or Maxing MAF out

[Skym]

Stock ECU.

ECU could have been retuned in the past with load limit maxed out, so it won't engage fuelcut. Sticker on ECU casing usually gives it away. But in some cases, might not have a sticker on ECU casing.

[nelsonmxmarc]

Ok, my ideas exactly. Still a bit of a wonder though that with my EBC 'OFF' i'm still hitting a very consistent 15 lbs on average, of boost in the high rpm band. Mainly 4th, since it gives a good long haul through the rpm range. 1st through 3rd like i stated, all hit the limiter without an issue, and still with good, RICH AFR's.. Very odd!

My GTR pump, courtesy of Braden, should be in this week. I'm hoping that resolves my issue if it is in fact based on fuel starvation, however it is unlikely. Needs maf etc.. A good tune will obviously get to the bottom of this!

Thanks for the help guys! Much appreciated.