SCEDA's last race - not recommended. SCEDA had their Shootout (race of
champions) on Saturday, and being the last of their series the place was packed fence to fence. We only got 1 qualifying run before eliminations. Today (Sunday) two of the other racing series are having their championship finals. It's gonna be more of the same.

I love racing SCEDA - but the season's last race is not for casual racers like me.

Mark & Matt & Branko were there. Matt lost first round as did I. Mark lost in the second round. Branko was still in when I left at 6:30. I'm guessing they won't finish any of the races.

The Nova's RT is slow with the new setup. My RT, on the one qualifier lap, was 0.137 ( 0.637 at Irwindale ). Too slow to be competitive. Had to do something... doing nothing was a sure loss. I needed to pick up a tenth - too much for the usual tricks like front tire pressure, idle speed & etc.

I decided to try a two step launch - and set the car up as such. I was expecting to be called for our second qualifying pass - so I'd have at least one shot at adjusting from there.

We were all caught off guard when they called us for eliminations round 1 instead. Hosed.

The good news is it launched like a rocket. I went 11.56 @ 115. I dialed 11.65. Pretty close - eh? Previous attempts to launch on the two step, at Irwindale, blew the tires off. The new 4-link setup is working good. The bad news is I went -0.091 red (Irwindale 0.409 ). But now I have a baseline. I'll start the process of slowing down the two step launch if it still hooks at Irwindale.


Please let me know if you have any insight/opinions on the following issues:

AIR/FUEL RATIO:

The attached A/F ratio graph is typical, even with the vacuum carburetor. On this one you can see the RPM coming up to the two step limit of 1600 RPM. The first lean spike, at 4.7 seconds, is when I opened the throttle. Then the accelerator pump pushes it down to 12. The converter hits at 5 seconds and there is a lean spike as the car launches. The next lean spike at 6 seconds is an anomaly, but then there are two more lean spikes at the shift points.

Those lean spikes represent lost performance. I want that performance back.

Mark suggested they may be caused by the rear jets being uncovered at points of acceleration - like on launch, and when I shift. I'll take that suggestion and install jet extensions to keep the jets wet.

BAD VIBRATIONS:

This is the first time on the 1/4 mile with the new 4-link setup. Starting at 1/8 mile a vibration builds. In the traps my vision is blurring. Violent rattling. Tire unbalance was suggested - but I don't think it fits the pattern. Tire unbalance usually occurs in a narrow speed range, it has a resonant frequency. And I think the vibration was at a higher frequency than tire shake that I remember from tire pressure experiments at the big end.
The rattle was sharp and violent.

I'm thinking U-joints and pinion angle. I think Fast Eddie missed the boat on this one.

When I had the work done, I attempted to engage Eddie in a discussion on correct pinion angle. Eddie wanted to set the pinion angle 2 degrees down relative to the drive shaft. This is not correct in my opinion - but Dave Morgan flat out says to do that in his book. My attempts at dissuasion solicited a blank stare, so I decided to be the door knob and maybe learn something.

Jerry Bickle's book is a little more helpful. Both Dave and Jerry make the same example, to set the pinion angle relative to the drive shaft, but they both are assuming that the transmission drive line and pinion shaft are coincidental, they meet each other in a straight line. Jerry, at least, alludes that to this.

Tim's take - The pinion angle should be 2 degrees down from normal. The normal angle is when the pinion drive line is parallel with the transmission drive line, whether they are above, below, beside each other or coincidental or not - and they are usually not. So the pinion angle should be two degrees down from the transmission drive line, not the drive shaft. That's how I've done it all along.

I'll make that change today.