H-I-J '76 Nova re-fit.

[FireSale]

Originally Posted by Nmbr1GMfan

I clamped the test light wire to positive and stuck the "record wire", when I push the button the test light lights indicating ground. Also, I'll assume when the ignition is cut after the finish line it will stop recording when I get this sorted out? Now it records till I shut it off in the program.

I have an Innovate Motorsports air/fuel recorder that activates off a short to ground momentary button like your setup. It's very sensitive to power interruptions. If I forget to shut the SD recorder off by hand and kill the engine it will dump all data from that run. Killing the engine at the stripe might be corrupting your data.


Have you been able to get a readable file at idle in the shop?

[FED 387]

Todd-- look at the video --the launch RPM appears to be about 62-6300----- is that low ?? 1-2 shift was 72-7300 did she nose over or over rev the engine???-----2-3 shift is about 66-6700 is this too low???--------3-4 shift is again low in the 6600 range--- do you agree ??? Not sure what racepak is showing but the shift points are all over the place that might be what is giving you goofy ET's.---you have a fairly heavy car with a low HP engine and once you run out of gear going into high gear it just does not have enough power to recover and produce a real good ET.----Not being overly critical but the driver must aim for consistent shift points ---are your RPM shift points in the correct range not too high or not too low???---what is your finish line RPM it seems to be fairly low shouldn't it be in a higher range looks like low 6200-6300 range???--just my observations from the video----FED 387

[Mark Yacavone]

Originally Posted by FED 387

Todd-- look at the video --the launch RPM appears to be about 62-6300----- is that low ?? 1-2 shift was 72-7300 did she nose over or over rev the engine???-----2-3 shift is about 66-6700 is this too low???--------3-4 shift is again low in the 6600 range--- do you agree ??? Not sure what racepak is showing but the shift points are all over the place that might be what is giving you goofy ET's.---you have a fairly heavy car with a low HP engine and once you run out of gear going into high gear it just does not have enough power to recover and produce a real good ET.----Not being overly critical but the driver must aim for consistent shift points ---are your RPM shift points in the correct range not too high or not too low???---what is your finish line RPM it seems to be fairly low shouldn't it be in a higher range looks like low 6200-6300 range???--just my observations from the video----FED 387

It's because the clutch is slipping..It's not climbing and dropping in the gears.Probably toast by now. Also the wing, wing, wing and dump on the up throttle is hard on the clutch. Need to have enough clutch for 3rd gear burnout, without going to 7000 grand! ...and hold it there for a second, then drive out as the tires dry. IMO

[Rich Biebel]

Just going off the online Wallace calculators.

Your ET / MPH computed from your vehicle weight of 3400 pounds and HP of 390 is 11.99 seconds and MPH of 112.73 MPH. That's optimistic IMHO....The car did go 12.0 something so its not far off.....Don't know the MPH on that 12.0 run......MPH indicates HP better than ET....


11.99 x 112.73 =1351 and that is very high of a factor number for a limited cyl head type stocker...…..They are usually weak on MPH with fast ET's due to gearing. Your biggest ET gain is in the first part of the run with a Stocker...


Just yesterday at Maple Grove some H/SA cars were running 11.0's......at about 116 we'll say......11.09 x 116.7 I think I saw....do the math...thats1294...…..Very fast ET......not a lot of MPH....not sure if that was flat down on it......maybe off one or two MPH's at most...…. A Low compression 350...


I did not think the run sounded like the clutch was slipping badly at all....
RPM did not flair.....engine was weak and rpm did not climb....


Its been way to many years since I had a stick shift car. We had no rev limiters, just picked an RPM and held it there......


Most stick racers I watch put it to the mat on the first or second amber and on a chip...…


She's doing a pretty good job and just needs more laps......and some tuning to get the most out of what's there....It's Way harder than driving an automatic.....

[Nmbr1GMfan]

Originally Posted by FireSale

I have an Innovate Motorsports air/fuel recorder that activates off a short to ground momentary button like your setup. It's very sensitive to power interruptions. If I forget to shut the SD recorder off by hand and kill the engine it will dump all data from that run. Killing the engine at the stripe might be corrupting your data.


Have you been able to get a readable file at idle in the shop?

Only by hitting record in the program.

[Nmbr1GMfan]

Originally Posted by FED 387

Todd-- look at the video --the launch RPM appears to be about 62-6300----- is that low ?? 1-2 shift was 72-7300 did she nose over or over rev the engine???-----2-3 shift is about 66-6700 is this too low???--------3-4 shift is again low in the 6600 range--- do you agree ??? Not sure what racepak is showing but the shift points are all over the place that might be what is giving you goofy ET's.---you have a fairly heavy car with a low HP engine and once you run out of gear going into high gear it just does not have enough power to recover and produce a real good ET.----Not being overly critical but the driver must aim for consistent shift points ---are your RPM shift points in the correct range not too high or not too low???---what is your finish line RPM it seems to be fairly low shouldn't it be in a higher range looks like low 6200-6300 range???--just my observations from the video----FED 387

I lowered the launch rpm to 5800-6100, 6500 would be typical, we're just trying stuff. Optimum shift point will probabbly be between 7000-7100, shift light is at 6500 because I know she won't hit every shift. Not sure about the goofy ET comment, we made 3 runs without changing the launch rpm and the cars ET varied .017 and the 60's varied .011 WITH us changing other stuff on the car. Yes, she isn't hitting the shifts perfectly but I would also like to point out she is also NOT shifting clutchless per se. Correct, the car is not pulling in high gear and we have to work on the setup for that.

[FireSale]

Originally Posted by Nmbr1GMfan

Only by hitting record in the program.

If you have a trusted line lock or transbrake button to spare, wire it in place of the factory button to eliminate a failed switch as the issue.
If that still fails, wire a switch to the alternate contacts mentioned in the manual. It's possible the factory trigger circuit (blue button circuit) is faulty in the box.


EDIT: BTW, that switch is a $13 part.

[Nmbr1GMfan]

Originally Posted by Mark Yacavone

It's because the clutch is slipping..It's not climbing and dropping in the gears.Probably toast by now. Also the wing, wing, wing and dump on the up throttle is hard on the clutch. Need to have enough clutch for 3rd gear burnout, without going to 7000 grand! ...and hold it there for a second, then drive out as the tires dry. IMO

Mark, by an outsiders obsevation it seems you're quite a revered member of this site, with that being said, maybe you shouldn't comment about things that may derate your classracer social status. In other words, everything you said is wrong.

[gsa612]

FWIW,seeing you only made 1/8 mi. passes going by Wallace calc.your 1/8 et (7.27) and (93.50) mph says your 1/4 should be 11.55 at 115 which seems reasonable.That would be a big jump from Indy!...gsa612

[Nmbr1GMfan]

Originally Posted by Rich Biebel

I did not think the run sounded like the clutch was slipping badly at all....
RPM did not flair.....engine was weak and rpm did not climb....

This is exactly right, the clutch only seems a little light at the hit, which, as you mentioned the lower starting line rpm will have a hand in slippage running a counter weighted setup.


Here's the Waller 1/8 mile calculation, remember we only ran it just past the 1/8th.