Dyno/Tune experts, please step in..

QKSLVR Z · 10-31-2005, 06:53 PM

had my car dynoed over the week.. the car seems to fall everytime it reaches ~5300 RPMS all 3 pulls for just a bit. same time, same drop same RPM.. mainly in 4th gear.. on the highway, if i stand on it in 4th, when i reaches ~5300 RPMS, it feels like i took my foot off the gas..bogs pretty bad...but 1st, 2nd, 3rd pull to 6000 RPMS with no problem. during the run, when it drops, some fuel comes out the driver's side tail pipes. no check engine lights.

it's a 2000 FRC w/ 29,xxx miles

mods:
-halltech stinger
-Z06 intake maifold
-Z06 ti's
-Kooks 1 3/4" w/ 3x3 cats
- NGK TR55 gapped @ .035 w/ Z06 wires

the car has NO tune as of now. is this more of a tuning problem, or should i start looking at somewhere else? other than that problem, the car runs fine

thanks in advance,

vinnie

SteveDotenMotorsports · 11-01-2005, 11:41 AM

vinnie, not the exact fix, but seems like others are having the same problem
http://forums.corvetteforum.com/show...90&forum_id=86

QKSLVR Z · 11-01-2005, 06:30 PM

thanks for the link, steve.. i'm going to scan with fallen's hp tuner this week.. hopefully i'll get better answers then

you think it's more mechanical then tuning?

Corvette86 · 11-09-2005, 06:31 AM

Your AFR is fine so I would look other causes. Something is shutting down your ignition system, maybe rev limiter or spark knock. Did you do any datalogging while running your car on the dyno?

QKSLVR Z · 11-09-2005, 09:19 AM

i had an HP tuner hooked up.. not at the time of the dyno, but afterwards.. at 5000 RPM and higher, i get about 5 degrees of knock retard. hopefully a dyno tune will help

thanks

Corvette86 · 11-09-2005, 09:25 AM

Make sure you're not getting a false knock count due to something mechanical in the engine causing the KS to become active. Something as simple as a loose rocker arm could also cause this problem too....

Good luck

QKSLVR Z · 11-09-2005, 09:27 AM

thanks for the advice and info!