1CAMWNDR

iTrader: (21)

When I made a few power runs to check KR and the O2s, I power shifted 1-2 and the log showed 6400+rpm How is that possible when my fuel cut-off is still 6200? I have a shift light set to light at 5,800 so I know I wasn't 600 rpm late. Just to check I slowly reved the motor up to red line and sure enough it started breaking up right at 6,200. WTF .
If I need to check something besides fuel cut-off please let me know.

foff667

iTrader: (2)

you'd be suprised how many rpms it jumps while shifting...even powershifting. Figure it takes you 200 rpms to react then another .300-.400 to actually make the shift...its not far fetched.

TAQuickness

iTrader: (28)

I have my limiter set at 6750 and I frequently log speeds of 6998

SmokingWS6

iTrader: (1)

But his limiter is set at 6200. I guess its possible but I find it hard to believe the motor can spin another 200 rpm due to momentum past fuel cutoff. Are you sure the fuel cutoff is set right?

foff667

iTrader: (2)

I dont, ive seen it many times on many cars.

txhorns281

iTrader: (12)

HumpinSS

iTrader: (1)

The pcm takes a little bit of time to realize it is over the rev limiter. Chris from HPtuners told me it was 25 ms. With mine set to 6700 it sees 69-7000 sometimes

SmokingWS6

iTrader: (1)

I have an auto. didn't know it could to that. Something to keep in mind with setting a limiter, it can still go higher.

Tomcat

Are you sure about the quality of your scan data , never been able to get mine to free spin past the fuel cutoff point

Robert56

iTrader: (2)

One more thing to consider is, a lot of vette guys report that tach lags behind a couple hundred rpm. I have tested mine against two different window switches and it is right on. But others report different results.

Camaro ChriSS

As someone mentioned, it could also be your scan tool. Does it happen regularly?

I use Atap, and I have seen on one occassion a real high rpm when it didn't make sense. Had the shift points at 6400 rpm, but the couple of frames of data showed that my 2-3 shift in a fraction of a second went from

Frame 1: 6200 rpm at 48 mph
Frame 2: 6300 rpm at 53 mph
Frame 3: 6970 rpm at 86 mph (shift)
Frame 4: 4550 rpm at 61 mph
Frame 5: 4625 rpm at 65 mph


Frame 3 was way out of whack, and I am assuming it did not really jump 700 rpm and 30 mph in that split second. More typically it would be 6450 rpm and 57 mph, or close to that. So, I dismissed it as a data error. It may happen.

foff667

iTrader: (2)

depends on how many fps your taking too...when i had autotap and a cheap laptop it would do the same thing.

1CAMWNDR

iTrader: (21)

My scan tool is in HP Tuners and I have a 1 year old Dell 5150 laptop. I know the dash tachometer is slow in first gear, but I thought the scanner in HP Tuners would read directly from the vcm. I just can't see me hitting 6,400 rpm during a shift and the fuel cut-off never stepping in.

aNuBiS

iTrader: (25)

if it was for a real quick period of time then its entirely possible. the computer never had a chance to react and shut you down. believe me, if it sees a problem it'll step in!