I had hoped to get to the track in mid/late April, but both weekends were rain-outs. However, I did make it there this past Sunday, May 3 for a Sunday Test-and-Tune event. The air was freaking great with D.A. in the single and double digits as I arrived, and eventually only getting to around 400 by late afternoon. The gameplan was a basic shakedown of the car after winter which included having the transmission out, new rear shocks, reconfigured converter, etc. When I decided to re-do the converter I knew it would be a little slower off the line and on all-motor passes; and this seems to be true at this point. I tried foot braking and stalling the converter up like I used to, but I think in the future, this converter will be quicker if I flash it from a mid-high idle speed instead.
Pass 1:
Decided to use the saved tune file from my last event which was at Maple Grove back in November of last year for pass 1 just because I know it worked, but I had a modified version of this tune file to use for the rest of the day afterwards. Set the rear tire pressure to 20.4 psi (on the very worn out MT street radials) and set the new Viking Warrior shocks to settings of 8 compression and 3 rebound/extension. Sidenote - I completely forgot to empty the 25 psi of air from the drag-bag air-bags... so this mistake was my fault, and I realized it after pass 1. I footbraked to 1593 rpms and the converter flashed to 3280 rpms. I had the trans in 2 which means that IT will make the 1-2 shift, and it did, but it made it way too early, at only 5032 rpms (and dropped to 4255 rpms in 2nd gear). I let 2nd gear pull until 6281 rpms (dropped to 4768 in 3rd gear) and then went across the finish line at 5859 rpms. Timeslip was acceptable for an all motor shakedown run, but the slower 60 foot is what I noticed the most.
Timeslip/Datalog:
Video:
https://www.youtube.com/watch?v=qCPWNDZe5pE
Pass2:
Switched over to my other tuneup file, lowered the rear tire pressure to 19.6 psi each, kept shocks the same settings...and removed all air from the drag-bag air-bags. I still foot-brake stalled on the launch and left at 2001 rpms. The converter flashed to 3504 rpms, and this time I shifted the 1-2 gear change. I shifted from 1st gear at 6381 rpms ( a bit too high) and it dropped to 4726 rpms in 2nd gear. I took 2nd gear to 6170 rpms and it dropped to 4700 rpms in 3rd gear before crossing the finish line at 5906 rpms. Felt better, but still a slowwww 60 foot.
Timeslip/datalog:
Video:
https://www.youtube.com/watch?v=qTh-AzsZgss
Pass 3:
My last all-motor pass of the day, and I switched over to the right lane. I added in a little timing earlier in the rpm band because the previous converter zipped right past the 2000-3500 area of the timing table at the track, but now it needs a little help in that area. I also have to take out some fuel from my base-fuel table because it keeps going rich for a moment at the WOT hit. I don't think its any of the A.E. modifiers, but I'll dig into it more before modifying the base fuel table area. Foot-brake stalled to 1479 rpms and then the converter flashed to 3561 rpms. I wanted to try shifting around 6000 rpms this pass, so i took 1st gear to 6073 rpms and it dropped to 4570 rpms in 2nd gear. I then shifted out of 2nd gear at 6005 rpms and it landed in 3rd gear at 4629 rpms. I went across the finish line at 5851 rpms.
Timeslip/Datalog:
Video:
https://www.youtube.com/watch?v=-7I-Z5vkebw
Pass 4:
Shocks still the same, 8 compression 3 rebound. Tire pressure same at 19.6 psi. turned on the nitrous with a slow 1.2 second ramp-in, and decided to foot-brake the launch from 1949 rpms. I still had the nitrous programmed to activate at 3800 rpms because I was curious about how quick it would come in with the new converter. Turns out the car left lazy (on motor), the converter flashed to 3434 rpms, kept slowly climbing, and then the nitrous hit at 3819 rpms and started its ramp. So it wasn't a clean ride in 1st gear, plus I early shifted it at 5399 rpms and it dropped to 4836 rpms in second gear. Drove second gear to 5806 rpms and it dropped to 4955 in 3rd gear. I ran 3rd gear out to the finish line at 6222 rpms. No need for locking up the converter, or having to shift into OD like usual so thats good. The mph was pretty good with all things considered, but the ET was slow (my fault).
Timeslip/Datalog:
Video:
https://www.youtube.com/watch?v=eUYzir6L08U
Pass 5:
They were just closing the lanes but I was able to get in for one more pass. Figured I would try a lower rpm foot-brake on the launch, and I moved the activation rpm for the nitrous from 3800 rpms to be at 3000 rpms. Footbraked from only 1281 rpms, then launched and the car took off good. The nitrous activated at 3101 rpms and I can't determine what the converter flash rpm was on the datalog because it happened at the same time as the progressive shot was spraying. I had the shifter in 2 again, so the car would make the 1-2 shift, which it did at 5582 rpms and dropped to 4872 rpms in 2nd gear. Had a huge brain-fart at this exact moment in time and I then mistakenly IMMEDIATELY shifted from 2-3! Whoops! It was only in 2nd gear for half a second, from 4872 rpms to 5013 rpms. damn. So after I cut the cars legs off and it got into 3rd gear (at 4805 rpms) it lugged itself down the dragstrip for another 8.3 seconds and crossed the finish line at 6262 rpms. Jeez, dumb mistake, as you can see in the datalog, it was only in 1st and second gear for a total of 2.3 seconds. Lets not do that again! The timeslip was decent, but I can tell that there is a good bit more E.T. and mph to be gained next outing. For reference, my all time PB is 10.55 and this terrible pass was a 10.62 so I'm thinking I have some new PB's ahead this year.
Timeslip/Datalog:
Pass 5 launch:
Video:
https://www.youtube.com/watch?v=XaWratv6pBI
Packed up, drove home with no issues; actually the only casualty of the whole day was the battery in my garage door opener's remote went dead, so I'll take it as a generally successful shake-down session with the car. Still having a shake somewhere in the driveline at certain rpms, really feels like the rear pass wheel so I sent it to my buddy to have it checked and rebalanced (again) if possible. I do think that flashing the converter from almost a 1000-1100 rpm launch is going to be best for all motor and for nitrous passes, but I won't know until next time at the track. I will be due for new rear tires very very soon and I am either going to buy these exact same MT ET Street SS drag radial tires or the MT ET Street Radial Pro. The tire size will be 275/60/R15. Could explore the new Hoosier DR3 drag radial too. The new Viking shocks did work good but with these very lazy launches, I did not get to lean on them as hard as I would have liked just yet.
Anyways, I plan on getting back to the track next weekend for the Spring Nostalgia event. I have had good luck with quick launches at this event and the track is prepped pretty good.