Went to the track last weekend for the Nostalgia Spring Event. Street drove the car there, loaded with gear, long line to get in, packed house. I went into the N2 bracket group for 10.0-10.99 cars since I planned on using the bottle after a shakedown all motor pass. Everyone was allowed to get two test runs, which is what I hoped for. Jerry was also there that day, running his chevy. First time testing out the new UMI drag bar and not relying on the rear air-bags to compensate for body roll. I lowered both of those airbags to 5 psi and left them there until it was time to drive home after the event. Used the same EFI tune all day, and kept the Koni yellow rear shocks set at a soft 1.5 setting. Put more air in the MT drag radials at 19.6 psi and 19.4 psi. Made no adjustments to the new drag bar; it is set in a zero-preload setting currently.
Pass 1:
Simple All-motor pass, shakedown after the winter off season.
Foot-braked the car to 2331 rpms, and it launched good. Shifted 1-2 at 6329 rpms and then after only 1.2 seconds climbing in 2nd gear it shifted into 3rd (datalog shows it happened at 5668 rpms of second). It was a long slow haul in 3rd gear but I crossed the stripe at 6168 at the finish line. Still ran a decent e.t. and nothing else on the car was problematic.
Timeslip:
Datalog:
Track photo:
Dashcam video:
https://www.youtube.com/watch?v=W7QctOw0Kes
Pass 2:
Turned the bottle on for the 150 progressive shot.
Foot-braked the car to only 1717 rpms and let it fly to a 1.36 sixty foot! Shifted 1-2 at 6399 rpms and then shifted into 3rd at 6254 rpms. Activated the converter lockup at 6126 and the car crossed the line at 6355 rpms. I noticed during the run that nitrous bottle pressure dropped heavy from 1000 psi to almost 675 psi at the end of the run (can be seen on the top gauge of my A-pillar gauge cluster in the GoPro video). I had some issues with the purge solenoid/button earlier in the lanes, but it worked before the run to get line pressure down before the run; it was a brand new bottle just filled. Not too worried because the car ran within two hundredths of its personal best, so I knew I was on the right track to hopefully set a new pb. But I was stunned by the 1.36 sixty foot and can even cut that down more I think. The odd transmission issue from last run didn't happen again either.
Timeslip:
Datalog:
Dashcam video:
https://www.youtube.com/watch?v=M2aeOO8eIgc
GoPro video:
https://www.youtube.com/watch?v=WkETbkfdbnY
Launch video in slow-motion:
https://www.youtube.com/watch?v=e2c_BDWmzC8
Pass 3 (Round 1 Eliminations):
Kept the tune the same, everything the same in hopes of duplicating that run with steadier bottle pressure and going 10.5x. So I dialed in a 10.57 after talking with Jerry who steered me back from the greedy 10.52 I wanted to dial-in.
Launched the car lower in the rpm band, at only 1407 rpms and it launched great again, with another 1.36 sixty foot. However, when the two front tires came down, they sent a reverberation through the steering system that had me pedal the car and drive through it. Shifted into second at 6445 rpms in the rev limiter, and I also over revved 2nd gear a bit too but while in 3rd it never got the converter locked up and finished at 6433 rpms. Regardless, the other car broke-out on the dial-in and I got to move on to round 2 for another chance at a 10.5x slip. FYI I did do the UMI ball-joint relocation kit and had all the alignment dialed in last spring, so I'm surprised it shook those front wheels like that (see slow-motion video). Nitrous bottle pressure held consistent throughout the run and the trans didn't quick shift 2-3 again either.
Timeslip:
Datalog:
Dashcam video:
https://www.youtube.com/watch?v=LAsISIRm64s
GoPro video:
https://www.youtube.com/watch?v=aq_5YJdzGA4
Slow motion launch video showing front tires shaking for a while!:
https://www.youtube.com/watch?v=tHHTCiLPpcI
Pass 4 (Round 2 Eliminations):
Same tune, same everything. None of the other problems from previous runs had yet repeated, so it was time for something new to happen! Footbraked to 2618 rpms (too high) and went 1.38 sixty foot. In the process, I got too excited and earned a red-light, definitely knew it too. I Shifted too high at 6394 rpms, shifted 2-3 too high also at 6339 rpms, activated lockup higher than usual at 6229 rpms, and while lockup was slowly coming on, I was just getting into the revvlimiter while on the nitrous button. AFR's were good on both gauges, but at 6394 rpms and about 10 feet from the finish line, it made a pop and shot out a real fast fireball from the sniper and I saw it through the hood! Of course I got off the throttle, looked at every gauge I could, shifted into neutral and watched the dash. Engine actually decelerated fine and I drove the car totally unscathed back towards the pits. Was fully prepared to cut the engine off if I noticed anything else awry. Got my timeslip and was thrilled to see a new PB 1/4 mile et, of 10.588, because I have been stuck in the 10.6's for 3 long years. Checked some stuff over on the car while jerry and I packed up tools. Aired up the tires and the air-bags, and drove the car home without any sign of any of the 4 different issues I had experienced earlier.
Timeslip:
Datalog:
Dashcam video:
https://www.youtube.com/watch?v=_eDC9aIV0fs
GoPro video (with fireball under the hood):
https://www.youtube.com/watch?v=6Og8jK5f8hg
The oxygen sensor readings from the new sensor are definitely much more in range with what my eye needs to see. The UMI drag-bar is already proving itself well worth it too. Only one time during the day did the car experience the key/ignition/starter no-crank, and I had about 40 key cranks of the car throughout the day. I did buy a replacement Powermaster Max Torque starter and its in the garage, but I'm dragging my feet on blindly putting it in until I keep troubleshooting the issue more. I definitely have to take the header off to get the starter job done, so that takes some time.
I drove the car over to the local car show and elsewhere and son I am going to try to get it shined up for the GM nationals event in Carlisle which is about 2 weeks away. I am not in the display this year, just going to go as a normal showfield car. I will be checking the spark plugs, steering system, and some other stuff, after I switch the wheels.