Flat Spot 4-6000Rpm

[Pope]

Hi,

I have recently fitted a Turboetech Boost controller to my car, and after winding the boost up to 9 PSI, the car now has a bad flatspot on acceleration between 4000 and 6000RPM, after 6000 it Revs past it, and seems to be fine. Between 4-6, its not like its missing, but just generally lacking power, like it can't breathe or something - but will rev past it in all gears.

Initally when I installed it, the car started missing badly, so I gapped the plugs to 0.8MM, and siliconed up the coils. The missing got a lot better, but I thought the flatspot was the same problem. I ordered and fitted spkitfire coils today, but the car still has the flatspot. It seems to mainly be when the car makes full boost - after 6000RPM it tapers off to about 8.5PSI and the fault seems to clear and car accelerates better - can feel the shove after 6000 - not sure if boost tapering is just a coincidence....

I have also tried an ECU reset, and have driven the car while watching readouts in OBD Scantech, nothing really stoodout as being massively wrong. There were no faults logged either. Also had quick check for boost leaks, none visible.

A couple of things I have seen on forums is checking ignition timing, or possible turbo breathing issues. I would have thought at this boost turbo would not be an issue. As for ignition timing - what should it be? Can probably check timing tomorrow arvo.

Anyone have any suggestions, or similar issues that have been resolved? Let me know if any more info is needed..I took a log using OBD Scantech, from about 2500RPM in third all the way to redline, as per zip file below Boost was max 9.2 PSI in this run

Thanks, Russel

.

Full list of mods/history

Car is 1993 series 1 R33 GTST

FMIC

Splitfire Coils

GFB StealthFX BOV

Cat-back 3in Exhaust

New plugs/fuel filter/all fluids

test run, third gear.zip

[Shazza24]

ECU, if standard may be the problem. TBH a good dyno print out could help, along with a good tuner to help diagnose the problem. May cost dollars but who cares, or wait for more people to comment! Come on mad082, I know your lurking some where!

EDIT: BOV may also be a problem, how was it before BOV?

Edited December 20, 2010 by Shazza24

[Pope]

Bov was installed by previous owner. I have put all new seals in the bov, and checked/adjusted it. Was thinking I could take it to a dyno to check afr at least, but will be hard before Xmas...

[Don Dada]

Sounds like you're rich and retarded.......pretty normal for gtst owners

[Pope]

How retarded is retarded? Watching timing on the road, was sitting about 25deg BTDC, fairly normal I thought? Either way, did not think it would rev through r&r?

[StealthX]

Sounds like you're rich and retarded.......pretty normal for gtst owners

LOL!

Sig'd.

[Don Dada]

It would rev thru r&r but it would just feel like the hand brake is up

I saw as little as 2* and afrs in the low 10s when this happened

I believe i have a vid.....i'll check for it later when i get home

Either way it IS your ecu

[Don Dada]

LOL!

Sig'd.

Nice!!!

[Pope]

Hmm, so apart from a tune (which will be soon) how can I get around it? Seems like heaps of people run 10-11 pound on stock computers?

[Don Dada]

Every car is different...i was able to run 10psi before i started to get it

Air temp will affect it also so if you live where its colder it would be worse

Until then turn down the boost

[Pope]

Just watched the log file, had only seen live....it appears R&R is spot on, at about 4200RPM it drops timing back to 12 deg, at almost exactly 6000RPM it goes straight to 20deg, and works up to about 25 or so after that. So painful that its doing it at such low boost

Thanks for the help.

Edited December 20, 2010 by Pope