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Old 10-11-2020, 01:35 PM   #203
11 Second Club / Meet Coordinator
IROCZman15's Avatar
Join Date: Dec 2004
Location: Roxbury, NJ
Posts: 1,850
iTrader: (7)
Short Version:

- Drove car to Atco
- Made 5 passes, best ET was 11.845 (pass 1) best mph was 115.94 (pass 5) best 60ft was 1.667 (pass 5)
- I have WOT ignition timing and AFR dialed in and set to perfection
- still working on finding optimal 1-2 and 2-3 shift points.
- nothing broke, nothing weird happened, car did its job
- packed up car and drove it home

Long version:

I decided to take the car down to Atco Dragway on Friday night for the Test and Tune. Rumors are that Atco might be closing its doors permanently as a drag racing track at the end of this season so I wanted to make some passes there as kind of a bucket-list type thing for myself. Atco is 2+ hours from me with no traffic, and despite me leaving my house at 1:30 pm, I still hit a bunch of NJ Friday afternoon traffic. I sat in traffic basically bumper-to-bumper for a good 45 minutes on rt 287 in Piscataway and the engine temperature never went above 191 deg. Made it down there right around 4:30 and unpacked my hundreds of pounds of spare parts, tools, a wheel, and misc gear. Went through tech, which was super easy and effortless. Got the tire psi, shocks, tune file, and fluids all set.

Pass 1:
6:18 pm DA was 669 53% humidity and 67*F. did a decent burnout
Launched from 920 rpm idle, converter flashed at 2,861 rpms. Shifted 1-2 at 6,567 (rev limiter) and shifted 2-3 at 6,072, crossed the stripe around 5,831 rpms. Checked my AFR readings, CL comp, and learn numbers in the file and those were great so I re-saved the file and used it the rest of the night.
- Had hoped that I would simply improve upon my timeslip as the night/weather got better, but just like several previous drag events at Island.. my first pass was my best timeslip of the whole night.. I don't know why that keeps happening to me!


Pass 2:
7:51pm DA 195, 66% humidity and 61*F
-same tire pressure, same shock settings, longer burnout. lowered my shift light so I could try shifting at a lower rpm
Launched from a 937 rpm idle and converter flashed at 2,975
short shifted my 1-2 shift at 6,096 and then really short shifted 2-3 at 5,765, crossed the stripe at 5,537 rpm
short shifting the 2-3 really killed me up top, but the pass felt solid and the datalog traces looked good despite the pass being my slowest of the night


Pass 3:
9:37 pm DA was -39 with 70% humidity and 58*F
left the front shocks the same but tightened the rear shocks half-a-turn since my 60foots seemed a little slower than last month at Island. rear tire psi had dropped to 18.4, so I left it there. raised the shift light up a bit and also moved my rev limiter from 6,500 to 6,700 rpm.
- launched at 921 rpm, flashed at 2,770. Shifted 1-2 at 6,648 (rev limiter kicked in for a split second) and then shifted 2-3 at 6,377, crossing the line at 5,777 rpm. Noticed on the datalog (upper green line) that I was not at 100% throttle until I got into 3rd! wtf!


Pass 4:
10:50 pm DA was -127 with 73% humidity at 57*F
aired up rear tires to 19.5 psi but had just a touch of tire spin off the launch. Tried launching at 1,300 rpm also. Did not get get a datalog this pass (must have not pressed "start"), but I know I short-shifted the 1-2 shift and revved out the 2-3 shift a little higher.


Pass 5:
11:12 pm DA was -107 with humidity at 74% and 56*F
- launched at 922 rpm and converter slashed at 2,843 rpm. no tire spin off the launch and it was my best 60ft of the night. Short shifted the 1-2 at 5,902 and then shifted 2-3 at 6,353 which had me crossing the stripe at 5,641 rpms
- if you look at the top green line on the datalog, I was only at 76% throttle all of first gear and then i got out of the throttle a little bit for the 2-3 shift. Damn it Dave! somehow, this pass had my highest MPH of the night (and ever) at 115.94mph.

They shut off the track lights a few minutes after my last pass so I packed up my car of all the gear and aired up the tires just as they were shutting off the parking lot lights and closing the main gate. They had a track rental earlier in the day so I think everyone was just ready to close the gates and get done. Nice easy drive home on the highways with only a few weirdos pulling up next to me and trying to play around. The car ran great and simply put the torque converter lock-up ON and cruised on the turnpike for a long time doing 85 mph at 2,450 rpm and the engine temp stayed at 158-165*F the whole trip. Fueled up once on the ride home and pulled into my garage at 1:50 am. No leaks, no weird noises, no mechanical issues what-so-ever. Turned off the battery kill-switch, shut the garage door, went inside and passed out.

Overall, I am super happy I made the trip and got some timeslips at Atco before it potentially closes its doors for racing. It was well worth the trip and the fuel cost. I improved on my previous best ET which was 11.855 at Island last month, to 11.845 at Atco. I have the drag race tune file optimized for 35* timing at WOT and the target AFR for 12.5:1 at tq peak and then leaned out to 12.7:1 at the HP peak. The AFR is staying really dialed in (pink and light blue lines in datalog). The best 60foot times come from launching the car off of an idle and my drag radials at 19psi with a 2/5 or 3/5 rear shock setting. I would like to scientifically determine my optimal shift point. I am thinking about creating a separate forum post to discuss shift points and use science and math to help me (us) determine my target 1-2 and 2-3 shifts.

1987 IROC-Z - modified

Last edited by IROCZman15; 10-11-2020 at 02:56 PM.
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