This was our first outing for 2019 testing the new 372 SBC in our ’57. It was a beautiful Spring Day with excellent track prep from the crew at PR.
Off the trailer the car ran a new best of 10.258 @ 130.43 MPH leaving at 5800 RPM. After looking at the clutch data we lowered the launch to 5700 RPM and lowered the wheelie bars 1-turn. The car responded with a 10.255 @ 130.10 MPH going thru the lights at 8150 RPM. We were pleased with these results with a mild tuneup on the new bullet, and the new front Wilwood disc brakes worked GREAT!
Video capture of 1st hit launch
The 3rd hit was aborted when I missed 2nd gear as the car carried the nose a LONG way out as the track got tighter. Here’s the video Pam captured below from our initial outing. My many thanks to Chris, Paul & Pam for all their hard work and support getting the old buggy ready for 2019! And my personal thanks to DG Machine for all their excellent work on the new bullet! – Roger
2nd hit on March 30, 2019
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Sunday morning I checked the valve lash, retorqued the intake manifold & headers, all looked great! Chris checked the shifter adjustment and it is slightly out of adjustment but will be a quick fix when we get it up in the air before the next outing.
We’re only going to make minor adjustments to the chassis setup, we were very pleased with the clutch data we collected on Saturday!
On Facebook there has been much discussion about our clutch setup. After this Saturday, we have 12 total runs on the Ram adjustable clutch with TWO different engine combinations. Yes we could use a lower 1st gear with less base pressure but the budget doesn’t include a new clutchless 5-speed for 2019. Frankly, I think we’ve done an excellent job on getting a handle on the new clutch and are proud of our efforts when others have been chasing clutch settings for years!! JUST MY OPINION FOR WHAT IT IS WORTH!
Yes, we are still getting a handle on the new clutch. For example, on the 2nd run this day we lowered the launch rpm by 100 and the engine rpm on the launch dropped 400 rpm from the first hit and the driveshaft speed was slightly lower but the acceleration G’s were higher shortly into the 2nd run and 60-foot time improved! Was there more tire spin on the first run? Was clutch heat a factor where on the 2nd run the clutch locked up sooner? Was the traction getting better? Or did the older slicks hook harder on the 2nd run? My point, there are many variables and we are learning as we collect the clutch data from run to run! Indeed it is a challenge but one we enjoy learning!
On the third and aborted pass here are some clutch data facts:
At 0.615 seconds into the run it was at 2.35 G’s acceleration
The lowest the engine RPM dropped to on the hit was 5864 RPM at 0.224 into the run which was actually an increase since we launched at 5700 RPM and recorded a 1.405 60-foot time.
WE’RE VERY CLOSE!!
I have checked with Liberty and they have the 1st gear set that will lower our 1st gear from 3.11 to 3.19. We will install these prior to the B.C. Super Shifters race in June and take about 90# of base pressure out of the clutch.
If/when we change the two input gears it will impact the gear ratios as follows:
1st Gear: 3.19 to 3.29
2nd Gear: 1.99 to 2.07
3rd Gear: 1.49 to 1.53
4th Gear: 1.21 to 1.24
High Gear remains 1:1