Poor performance at high RPM - see my datalogs

bertelli_1 · Post by **bertelli_1** » Mon Apr 17, 2006 2:19 am

I'm running a V3 on a Mk2 Golf using all the standard injection parts. My rev limit is set at a conservative 6200RPM (6750 std) but the car struggles to get there in higher gears. It used to rev quite freely and I have compared it to my friends car just to be sure. My PW maxes out at around 88% (1 squirt/cycle) or 93% (2 squirts) and I have tried various spark angles (25 - 45) with no sucess. I've included a recent log but I'm just wondering if I'm missing something fundamental??

bertelli_1 · Post by **bertelli_1** » Tue Apr 18, 2006 9:20 am

C'mon - don't be shy....

ChevelleFan · Post by **ChevelleFan** » Tue Apr 18, 2006 11:41 am

The one thing I saw in your datalog snapshot was that the O2 looked full-rich. Have you verified the O2 signal is correct, and if so, have you tried leaning out the top-end of the VE table at all?

-Dave

bertelli_1 · Post by **bertelli_1** » Tue Apr 18, 2006 1:09 pm

Dave, you are right, it is very rich. I have tried 97 to 100% VE in that area but thinking about it since I'm not using full revs I could try leaning it out.

ChevelleFan · Post by **ChevelleFan** » Tue Apr 18, 2006 1:27 pm

Changing VE from 97 to 100 is a pretty small change. I would keep lowering it until you see a difference in your O2 signal. I usually make changes in the VE table + or - 5 or 10 and then fine tune from there. After 1 or 2 +-10 changes, you'll quickly find out about where you need to be.

It looks like you are running a narrow-band O2 sensor? Be careful using this to tune WOT. They're not very good for that purpose.

-Dave

bertelli_1 · Post by **bertelli_1** » Wed Apr 19, 2006 9:39 am

I realise tuning for WOT with a NB is difficult, thats why I'm running a bit rich in that area. As soon as funds allow I'll put a WB on it.

mops · Post by **mops** » Wed Apr 19, 2006 12:01 pm

bertelli_1 wrote:I realise tuning for WOT with a NB is difficult, thats why I'm running a bit rich in that area. As soon as funds allow I'll put a WB on it.

there... there you go. you just answered your original question. You will not make full power running way-over-rich. best to tune it it's dyno, wb is the second best option.

bertelli_1 · Post by **bertelli_1** » Sat Apr 22, 2006 7:59 am

I've now dropped my VE in that area to 90% which has improved it. Cheers guys. Just needs a bit more fine tuning, see you on the street...

bluetrepidation · Post by **bluetrepidation** » Sat Apr 22, 2006 11:34 am

OOOH Golf GTI..... I had a 85 GTI. Fun car.