Revving past 8000+ rpms

[robz]

We have a stock pcm from an 03 vette and are trying to buzz the motor past 8000rpm.
The car is tuned alpha-n (TPS vs. RPM) and this table ends at 8000rpm.
Initially we were getting a fuel cutoff right at 8000rpm so we decided to populate the main VE table with the thought that the PCM would default back to the main VE after the TPS vs. RPM table ended.
It seemed to work somewhat as we were able to now buzz the car to 8235rpm, 8350rpm, and 8475rpm on consecutive pulls BUT the car still experienced an abrupt fuel cutoff.
It seems that we are making progress but are not sure why the fuel is being cut and why at different rpms. The only thing we changed was a slight adjustment in AFR during the above pulls on the dyno.
The fuel pressure is rock solid up to the point where it cuts out and it acts like it's hitting a rev limiter. My tuner has mentioned that he has raised all 3 rev limiter options above this point(9000+).

-Could the injectors be maxing out? But why the abrupt fuel cutoff?

-Any suggestions on how to get around this?

-Do you think we have to manipulate the PCM or the software?

We want to buzz the motor to aproximately 9000 rpms.
Thanks.
Rob

[dlove]

A little off topic, but are you going to have the car at the lsx shootout?

[edcmat-l1]

A little off topic, but are you going to have the car at the lsx shootout?

I don't think he's bringing to the shootout, but he'll be at MIR for the smackdown.

[geoff]

Just for grins have you tried using a MAF??? The car we had when I was at Thunder Racing in 2004 was being shifted at 8400 pretty consistantly. It had a MAF on it. Might be interesting to try it to see if it gives you any extention.

FWIW I have been on certain people here for a LONG time to do a custom OS to go past 8000 RPM. Still wish it would get done...I have a 3.25" stroke crankshaft sitting in my closet needing some exercise at about 9500 RPM

[GMPX]

RobZ, I sent Paul an updated .calz file for you to test with. It has the TPS VE Swap over RPM limit raised.

Geoff, I understand you'd like that, but majority rules in development priorities.

[robz]

RobZ, I sent Paul an updated .calz file for you to test with. It has the TPS VE Swap over RPM limit raised.

Geoff, I understand you'd like that, but majority rules in development priorities.

Thanks. I'll try it.

[robz]

I don't think he's bringing to the shootout, but he'll be at MIR for the smackdown.

We're headed down to the sticks on the 5th!

[edcmat-l1]

We're headed down to the sticks on the 5th!

See yas there!!!

[vetteboy2k]

RobZ, I sent Paul an updated .calz file for you to test with. It has the TPS VE Swap over RPM limit raised.

Geoff, I understand you'd like that, but majority rules in development priorities.

Ross,

To clarify some... in the custom OS5 after the TPS VE table A0007 reaches 8000 RPM does the car use the last column 8000rpm 100% TPS for fueling for the entire rpm or does it start back at 400rpm 100% TPS (ie revert back to the top where as 400rpm actually is 8400rpm)

If not anyway to get control of fueling past 8000 RPM, as the cars fueling requirements are less as the rpms climb that high.

[GMPX]

It will just use the last value in the 8000 RPM column, it doesn't wrap back around. The problem we had with Robz (which I never thought of) was the upper RPM threshold to switch back to the normal VE map was limited to 8,000RPM, so once they got above that it was jumping out of the TPS VE table, we just extended that allowable RPM up to 10,000.

Cheers,
Ross