Slow pass on a slippery track...data inside.
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 397
From: Lakeville MI
Slow pass on a slippery track...data inside.
https://datazap.me/u/tequilaboy/strip1-120-mph?log=0&data=53-60-75-78-87-89-91-111-112-114-116-120&solo=116-120&zoom=420-696&mark=534-572
How can I improve?
Picked up 30 mph between the 660 and 1320 including an up-shift during the interval. Some wheel slip present in 3rd and 4th gear. 160 ° t-stat and 2 1/4" exhaust must be holding me back...
Lots of time spent off throttle and significant time spent at low speed due to short-shifting certainly hurt et.
The 2k ppm distance counter actually does a pretty good job of tracking the distance and helping to determine where you are on the track at any given time. It resets every 0.128 miles...but has enough range to cover an 1/8 mile between cycles.
Shift speeds despite wheelspin should have been made around 6400-6500 rpm (partial gear chart corrected for my 3.73 gear, MH5 4+3 trans and 769 rev/mile tire):
6000: 44 66 94 126 202
6100: 44 67 96 128 206
6200: 45 68 98 130 209
6300: 46 69 99 132 213
6400: 46 70 101 134 216
6500: 47 71 102 136 219
Gear chart is always fun to play with:
http://www.pszweb.com/car/gears.htm
How can I improve?
Picked up 30 mph between the 660 and 1320 including an up-shift during the interval. Some wheel slip present in 3rd and 4th gear. 160 ° t-stat and 2 1/4" exhaust must be holding me back...
Lots of time spent off throttle and significant time spent at low speed due to short-shifting certainly hurt et.
The 2k ppm distance counter actually does a pretty good job of tracking the distance and helping to determine where you are on the track at any given time. It resets every 0.128 miles...but has enough range to cover an 1/8 mile between cycles.
Shift speeds despite wheelspin should have been made around 6400-6500 rpm (partial gear chart corrected for my 3.73 gear, MH5 4+3 trans and 769 rev/mile tire):
6000: 44 66 94 126 202
6100: 44 67 96 128 206
6200: 45 68 98 130 209
6300: 46 69 99 132 213
6400: 46 70 101 134 216
6500: 47 71 102 136 219
Gear chart is always fun to play with:
http://www.pszweb.com/car/gears.htm
Last edited by tequilaboy; Feb 1, 2019 at 08:01 AM.
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 397
From: Lakeville MI
Same data, this time with markers inserted to show the approximate 60 ft, 660 ft and 1320 ft distances using the running distance counter (2k ppm pulse) which has been rescaled and expressed in feet:
https://datazap.me/u/tequilaboy/strip-120?log=0&data=60-107-116-120&solo=116-120&zoom=409-644&mark=468-535-569-482
This correlates pretty well with what I know from the timeslip ~90 mph at the 1/8th with 120 mph trap. Its not perfect, but gives a pretty good idea of distance/track position. With wheelspin, the distance counter will accumulate distance a bit faster than the car itself, so some error is expected due to slip.
https://datazap.me/u/tequilaboy/strip-120?log=0&data=60-107-116-120&solo=116-120&zoom=409-644&mark=468-535-569-482
This correlates pretty well with what I know from the timeslip ~90 mph at the 1/8th with 120 mph trap. Its not perfect, but gives a pretty good idea of distance/track position. With wheelspin, the distance counter will accumulate distance a bit faster than the car itself, so some error is expected due to slip.
Last edited by tequilaboy; Feb 1, 2019 at 09:15 AM.
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 397
From: Lakeville MI
Gotta look for the timeslip. Might be in my toolbox somewhere.
I know launch rpm was a bit too high...My A/C based launch rpm control function wasn't working due to an open low pressure switch. Took me awhile to figure out what was wrong and jumper the switch...might have a test log showing this in action somewhere...gotta do some more digging.
Note: I've got a pair of 88 16" wheels that are intended to be mated to bias-ply Hoosiers (likely the Quick Time Pro) which would solve most of my issues, but still interesting to talk about getting down the track under traction-limited conditions and the data can be interesting to look at. Datazap makes it easy to share log data since it is platform independent, but doesn't seem to be catching on with this crowd.
I know launch rpm was a bit too high...My A/C based launch rpm control function wasn't working due to an open low pressure switch. Took me awhile to figure out what was wrong and jumper the switch...might have a test log showing this in action somewhere...gotta do some more digging.
Note: I've got a pair of 88 16" wheels that are intended to be mated to bias-ply Hoosiers (likely the Quick Time Pro) which would solve most of my issues, but still interesting to talk about getting down the track under traction-limited conditions and the data can be interesting to look at. Datazap makes it easy to share log data since it is platform independent, but doesn't seem to be catching on with this crowd.
Last edited by tequilaboy; Feb 1, 2019 at 09:13 AM.
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 397
From: Lakeville MI
A/C (IAC) based launch rpm controller in action:
https://datazap.me/u/tequilaboy/ac-launch-rpm-control-test?log=0&data=57-60-66-72-93-116&solo=72-93&zoom=563-951
Press button...wait...launch from idle @ 1800 rpm...pedal it from there...
This works by exploiting the A/C on Idle Speed Adder along with appropriate adjustment of throttle stop screw and tps. IAC can add about 1,000 rpm to the base idle if properly adjusted.
I forgot to mention unplugging the A/C compressor also helps. Nobody wants A/C compressor drag while drag racing.
Sometimes the links don't show the expected content...You may have to play around a bit to turn signals on/off or zoom etc. something going on with the parsing of the links.
https://datazap.me/u/tequilaboy/ac-launch-rpm-control-test?log=0&data=57-60-66-72-93-116&solo=72-93&zoom=563-951
Press button...wait...launch from idle @ 1800 rpm...pedal it from there...
This works by exploiting the A/C on Idle Speed Adder along with appropriate adjustment of throttle stop screw and tps. IAC can add about 1,000 rpm to the base idle if properly adjusted.
I forgot to mention unplugging the A/C compressor also helps. Nobody wants A/C compressor drag while drag racing.
Sometimes the links don't show the expected content...You may have to play around a bit to turn signals on/off or zoom etc. something going on with the parsing of the links.
Last edited by tequilaboy; Feb 2, 2019 at 04:05 PM.
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 397
From: Lakeville MI
Here's another launch rpm example (this time actually triggered by the A/C switch):
https://datazap.me/u/tequilaboy/launch-test?log=0&data=11-57-60-72-93-116&solo=72-93&mark=20-40
Original log file also includes 2 launches and full passes, but I need to trim it down for datazap first. File is too big to upload.
Launch rpm control in action again...in 2nd gear this time ha-ha:
https://datazap.me/u/tequilaboy/laun...0&zoom=330-629
https://datazap.me/u/tequilaboy/launch-test?log=0&data=11-57-60-72-93-116&solo=72-93&mark=20-40
Original log file also includes 2 launches and full passes, but I need to trim it down for datazap first. File is too big to upload.
Launch rpm control in action again...in 2nd gear this time ha-ha:
https://datazap.me/u/tequilaboy/laun...0&zoom=330-629
Last edited by tequilaboy; Feb 1, 2019 at 03:21 PM.
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 397
From: Lakeville MI
Thanks for the feedback.
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Race Director
Joined: Sep 2003
Posts: 16,838
Likes: 341
From: Database Error Indiana
Thank you. I posted about this years ago. Nobody seemed to understand. My tires did not squeal when spinning and it took a while to determine the cause of the knock counts. If the car hooked, no counts at all. A bit of sand on the blacktop and the knocks counted up.
Thread Starter
Melting Slicks
Joined: Aug 2003
Posts: 3,403
Likes: 397
From: Lakeville MI
Here's another: IAC Launch rpm control active, 1st gear this time....skating pedal-fest....but still fun:
https://datazap.me/u/tequilaboy/1st-gear-launch?log=0&data=4-15-18-24-30-58-62-67-71&solo=30-67-71&zoom=6530-6931
Hit the rev-limiter in 2nd gear spinning around 70 mph, then recovered after fuel cut...almost looks like a traction control event.
https://datazap.me/u/tequilaboy/1st-gear-launch?log=0&data=4-15-18-24-30-58-62-67-71&solo=30-67-71&zoom=6530-6931
Hit the rev-limiter in 2nd gear spinning around 70 mph, then recovered after fuel cut...almost looks like a traction control event.
Last edited by tequilaboy; Feb 2, 2019 at 05:44 PM.