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Old 11-01-2020, 05:50 PM   #208
11 Second Club / Meet Coordinator
IROCZman15's Avatar
Join Date: Dec 2004
Location: Roxbury, NJ
Posts: 1,850
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Finally getting a chance to sit down and type all this up. Too many other important things earlier this week, but the rainy day today allowed me to get this all typed up.

Had planned to go to Island on Friday night for TnT and had the car fully loaded and packed. All I had to do was throw some drinks and snacks in a bag and hit the road. A guy on TGO who was going to bring his thirdgen that runs 12.3s sent me a message saying Island was canceling due to impending fog. I was definitely bummed out because I planned on racing Friday night and then doing a big car show/fundraiser on Sunday. It did turn out that there was significant fog later at night and the DA was not great either, so Island was correct in decideing to cancel it. I decided to skip the Sunday car show and race at Island instead, so my Test and Tune happened Sunday, which was also the NETO, vs MANDRA vs Gassers event so there was a good amount of cars on the property. Weather was pretty good that day, slight wind with the occasional gust but it was crisp and cool so the DA was helpful.

On the way to the track, almost just as I was passing by Larry's shop, my speedometer went dead, so I checked the cable and without taking things apart determined that it was a cable issue, not a dashboard. turned out that I was right, the end of the cable broke off about 3" from where it enters the tails haft housing. Due to the trans tunnel of these cars, the area is tight and the cable bend is pretty sharp...even by nature from the factory. I'll get a new one. ATP-Y-814 like $10 at advanced autoparts. In fact I think I have the receipt from when I bought this exact cable in May of this year and it has a 1 year free replacement.

On Wednesday of last week I took out 30 minutes to wire up the 2-step rev limiter feature on the holley sniper just to see if it would help me launch at a steady set-higher rpm. Holley makes it super easy since it is a ground-trigger input and no relay is needed. Just wiring and a button. I will relocate my button over the winter, as its not in the most user-friendly spot being at the oem ash tray... more on this later.

testing 2-step at 2,500 and 3,500:

and at 5,000:

I had created a pretty good tune file for the day and was feeling pretty confident. New spark plugs gapped at .035 and I also took some time to learn how to "index" them with indexing washers. Kept the front struts at the low setting 1 out of 5 and the rear shocks at the 2/5 all day. Rear tire pressure was at 19 psi and the front drag skinnies at 38/37 psi. The plan for the day was to shift at 6,600 rpms because of some math and calculators that I discuss in my other "shift and launch" thread on this forum.

Pass 1:
Temp was 47*, 60% humidity, and DA was -447. Did a 4 second burnout and shallow staged. Decided to try to launch using the 2-step rev limiter which I had pre-set to hold 1,600 rpms. I wasn't concerned about reaction time, more about a clean launch, which did happen! Launched at 1,676 and Shifted 1->2 at 6,573 and 2->3 at 6,632 while tagging the rev limiter a bit, and crossed the stripe around 5,842. Checked the data log and the afr looked great but I am still getting a rich spot right after the launch when the converter flashes. it is the pink dip on the datalog right after the 80 second mark.. As usually seems to be the case at most of the dragstrip days I've done this last half of the yea... my best pass of the day was my first pass.


Pass 2:
Temp was 49* with 53% humidity and a -246 DA reading.
Moved the rev limiter up to 6,800 and moved the 2-step rev limiter to 1,800 rpm. a 4.5 second burnout and tried to launch off the 2-step again. Couldn't get the button and my foot on the brake pedal to release cleanly so I boogered up the launch pretty bad. Launched at 1,803 rpm and 1->2 shift at 6,597 and 2->3 shift at 6,612 crossing the line at 5,723 rpms. Pretty happy with my shifting being very close to my target shift point of 6,600 but bummed out that I ruined the launch. Noticed a lot of -CL comp on the datalog, as well as the rich dip at the converter flash point, but aside from that dip, the AFR was dead on.


Pass 3:
It had sprinkled rain in between my last pass so they had to take some time to dry the track. At 51*, 52% humidity, and a -139 DA. Put the rev limiter to 6,800 and the 2-step to 2,000 rpms. Did a 5.5 second burnout and launched at 1,911. Boogered up the launch again, this time because I think the car started to creep and I didn't release the button/brake pedal clean also. First weekend ever using a 2-step, but it was worth a shot. Shifted 1->2 at 6,648 and 2->3 at 6,638 rpms so I crossed the line at 5,907 rpms. Cl comp was better after I had adjusted a little bit of the VE table up top and the learn table had all small numbers too. Still a momentary rich pocket at the converter flash in 1st gear.


learn table after 3 runs:

Pass 4:
Temp was 51* with 52% humidity and a -118 DA. Decided to go back to foot braking off the launch and aimed for a 1,200 rpm launch point so I wouldn't creep past the beam. Did a 5.5 second burnout and launched at 1,188 rpms. Shifted 1->2 at 6,361 (a little too early) and shifted 2->3 at 6,604 which put me crossing the line around 5,748 rpms. I had puled a little more fuel out of the area of the usual rich pocket and saw much less of a dip on the datalog (pink line). There were a few rain drops on my windshield at/during the run and I was super hopeful for one more pass, but sadly the rain came and the track closed for everyone. I packed up my gear and got the car setup for the drive home as is started to rain more.


On the ride home I noticed the engine oil pressure on the oem style dashboad gauge was reading higher. Both at idle and while driving. I kept an eye on it and listened to the engine the whole way home, so no radio. The oil pressure gauge is incorporated into the tachometer on my car, and this tachometer I got from Cajun Tach supply back in the spring because it had a different redline and higher oil pressure gauge value readings. Since last week I have ordered a mechanical oil pressure test gauge online and it will be here in a few days. As part of my winter routine I also plan to pull the oil filter, cut it open and examine it along with an oil change. I now have +3,000 miles on this engine since it was installed back in February. I changed the oil and filter at 500 miles, at 1,500 miles, and now (soon) at 3,000 miles. I am hoping just the oil pressure sending unit or filter is having an issue, or even the needle on the dashboard gauge. Any thoughts?

That pretty much wraps up my racing for this year and car shows are done also. I would have loved to have an 11.7x timeslip and I tried like hell to get one, but the best slip of the year was the one from Pass 1 on this past Sunday.

1987 IROC-Z - modified

Last edited by IROCZman15; 11-01-2020 at 05:54 PM.
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