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Old 10-23-2022, 08:53 AM   #504
IROCZman15
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Join Date: Dec 2004
Location: Roxbury, NJ
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Whew, its been a busy week for sure, so I have not had a chance to get all the videos, datalogs, photos, and typing done until now...a week later. Damn!

I went to Island Dragway last Sunday, Oct 16 for the Test-N-Tune portion of the Mopar Event. Weather was pretty good and with no chance of rain, I knew that I would get at least 4 passes in. I ran into a snag beforehand though, because Bruce's Speed shop (and the other place in Belville) are both out of all Nitrous-Oxide for refills. Orders have been delayed and delayed again, next delivery date is supposed to be November 3rd. So I only had half a bottle of nitrous to work with. I decided I could experiment with the nitrous stuff at the end of the day, and I was going to experiment with different launch and shifting stuff on the all-moto passes early on. So that's what I did. FYI: I haven't really had a chance to dive deep into the datalogs just yet, but i did take a look at some of them the day at the track and a little bit while I was taking the below screenshot datalog photos; I do need to dig into them a little more before hitting the track again.

Pass 1:
Rear tires at 17.2 psi, rear shock a tad lower than previous events at 1.5 drivers and 2.0 passenger side. Rear air bags at 5psi Drivers and 18 psi passenger.
Since I put the engine in the car and began racing it back in the Spring of 2020, I have always force-shifted the gears on every pass. I never had just left the shifter in D (not D-overdrive, but just D which is 1-2-3), so this was a good opportunity to see exactly what the trans does and how the converter acts also. I did this for Pass 2 also, but with a different launch technique. So, on this pass, I did a 5 second burnout and rolled to the line. I decided top launch from a dead idle, which was at 956 rpm as per the datalog. The car left and converter flashed at 4797 rpms. It made the 1-2 shift EARLY which was at 5530 and brought eth rpms down to 5043. It then shifted the 2-3 shift real quick, almost instantly, and also low in the rpm band, at 5244 rpms and dropped it to 5019 rpms in 3rd gear. It was a long long pull all the way through 3rd gear, and I crossed the finish line at 5980 rpms. I fully expected something like a 12.60 time on the timeslip, so I was quite surprised when it showed an 11.81 at 113.3 mph ! The low rpm shifts and that very quick 2-3 shift right after the 1-2 shift was interesting.


Timeslip:



Datalog:
look at the rpm trace. wow. way different and more tame than the past few years!


Video:
https://www.youtube.com/watch?v=Pfux4Xn5zsw



GoPro Video:
https://www.youtube.com/watch?v=RdvV7fHXbHI



Pass 2:
I kept the tune file and all the airbag, shock settings, and tire pressure 917.2 psi) the same. 5. second burnout. All I did on this pass differently, was launch the car from a higher footbrake rpm, but I still let the car shift itself. I wanted a good 60 foot comparison between launching off an idle (pass 1) and launching from a footbrake rpm. The car looks like it held up to 3211 rpms on the footbrake and after I launched it flashed to 4540 rpms. It did spin the rear tires just a bit, and you can hear it slip/grab on the video. It shifted itself at 5413 rpms and into 2nd gear at 4958 rpms. Sidenote- my TPS (green line) is not at 100% wide-open-throttle because during this point in the run, I noticed my windshield mounted rear view mirror must have vibrated itself loose recently and it began shaking all wildly so I was partially noticing that. Anyways, it shifted the 2-3 shift at 5195 and this dropped rpms to 5001 in 3rd gear. I crossed the finish line at 6050 rpms, mirror still shaking but not falling off.

Timeslip:



Datalog:
TPS trace is wiggly as I was half watching the mirror about to vibrate itself off. whoops!



Video:
https://www.youtube.com/watch?v=eFFdVGlnaHk


GoPro:
https://www.youtube.com/watch?v=GxfFpvTkSGg




Pass 3:
Shock and airbag settings are the same, but I brought the rear tires down to 16.4 psi. These next two passes I wanted to shift the car where I typically shift but launch as I did in pass 1 and 2 for some comparison data. I did a 7 second burnout, and launched the car from a dead idle, which was 947 rpms. It flashed the converter to 4851 and then I shifted 1-2 at 6449 and it dropped to 5147 9which is more of a drop than I've seen in recent weeks using this new converter?). I made the 2-3 shift at 6279 rpms, and it dropped to 5152. Crossed the finish line at 6006 rpms. The big drop-off in rpms between the shifts is all of a sudden similar to my results with the Edge Racing converter, so that confused me. The yank converters datalogs can be seen in previous posts I made during the recent month since installing it. Strange, but ok? IT launched good, pulled the wheels up, and I shifted real close to my target rpms, nothing outrageous happened, so it is good comparison data to pass #1 where I launched from an idle also. sixty foot times were close, but E.T. i went faster on pass 1 which had MUCH lower rpm shift points.

Timeslip:



Datalog:




Video:
https://www.youtube.com/watch?v=2jgbantIaVQ


GoPro video:
https://www.youtube.com/watch?v=poDYweKiyhg






Pass 4:
Rear tires were both at 16.6 so I left them there. Decent 6 second burnout. Brought the rpms up to 2564 and left off the footbrake. Flashed at 4856 rpms, and shifted 1-2 at 6450 which dropped it to 5233 in second gear. Shifted 2-3 at 6285 and dropped to 5331. Crossed the finish line at 6013 rpms.

Timeslip:


Datalog:




Video:
https://www.youtube.com/watch?v=TjSUdVNCnYc


GoPro Video:
https://www.youtube.com/watch?v=_X-69XNWX_M




I figured I had gotten some good info for comparing footbrake vs idle launches and me shifting vs trans shifting itself, and I might enough time to turn on the nitrous bottle and make two passes. Remembering that I had been overfueling the nitrous the other weekend, I did two things to compensate for it; in hindsight, I should have just done one. First, I left the fuel jet set for the 150 shot and put the nitrous jet for a 175 shot in the plate. I left the ClosedLoop Compensation fueling range to =/- 20% thinking this should cover it. The other thing I did, and this was because for a few months I have had a substantial PSI difference in what my two nitrous system pressure gauges are reading. The one mounted to the bottle never zeroes out even when system is disconnected, it is always reading 175-200 psi. The one in the a-pillar drops down to zero. The gauge at the bottle I have had probably 8 years now, so its seen its life, but I wasn't sure which one to trust. In recent months I have still trusted the bottle gauge, so when I have been making nitrous passes, I let it get to 1,000 psi and in-turn, the one on my a-pillar is reading in the 850 range. However, for Sunday's race day, I decided to try to rely on the a-pillar one and I heated the bottle up so that the A pillar gauge read 1,000 psi. Therefore, the gauge at the bottle was 1,200 psi, probably closer to 1,225. Again, experimental situation here.


Pass 5:
Tires at 16.6 psi all other settings the same, did a 6 second burnout. Launched from a 957 rpm idle and the nitrous was set to start coming on at 3300 rpms. It did, and it flashed the converter to 5976 according to the datalog. It spun the tire a very slight amount, I did a quick pedal of the throttle, Shifted 1-2 at 6353 rpms and this dropped it to 5639 in second gear. Should have started looking more intently at my AFR gauges, because AFR was dangerous, but thankfully the safe-guards I put into the tune-file caught it and turned off the system. I have the high side limit set to anything over 13.5 afr for more than .5 seconds, it kills the nitrous and runs all motor. But here is where I am still confused, as the rest of the lame and confused pass, the AFR still stayed pretty lean.. see the pink line, thats actual AFR and it should be very tight to the light-blue line (target AFR) that is below it. Not good. Got nervous after that run, which was unsuccessful in having a good timeslip whatsoever. Event eh 60 foot was off, it should be at least low 1.4s, yikes.

Timeslip:



Datalog:



Video:
https://www.youtube.com/watch?v=29Otnd0TRF8


GoPro video:
https://www.youtube.com/watch?v=kocRzpdDlPY




Pass 6. I knew lanes were closing and I had almost no time. I pulled up to my spot in the pits, gabbed the computer and a spark plug socket and went right into the lanes before they closed. Pulled two plugs and thankfully they looks ok. wow, whew. I didn't have time to change the nitrous jets, so I did what I thought was my only option, I opened up the ClosedLoop Cfuel compensation limits to 60%. and re-uploaded the file. In hindsight, now that I think of it... I could have simply lowered bottle pressure, and kept the jets and CL comp the same, but it did not dawn on me until the ride home. This time instead of leaving from an idle, I footbraked to 2209 rpms and it flashed at 4691. AFR numbers were getting wild, so I abandoned the run.


Timeslip:



Datalog:



Video: no need for video here, just a bad run.






Packed up the tools and headed home, this time it was NOT raining so that was a bonus.
Typing this up hopefully will help me get my brain into the data I obtained regarding if all-motor the car launches faster and runs a better ET if I footbrake, and/or if I let it shift itself vs me power-shifting. Wish the nitrous passes went better, but I was experimenting. I called Bruce's speed shop again and hopefully I can get a bottle filled November 3rd and ALSO buy a new in-line nitrous PSI gauge to mount at the bottle, as I do think the 8 year old gauge is reading incorrectly.







Any launch photos are of the car all-motor as the photographers were not taking photos during the late afternoon nitrous attempts/fails.





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Last edited by IROCZman15; 10-23-2022 at 11:48 AM.
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