July 10, 2010

Changes since July 4th race: 

We were crashed in the Show-Me Showdown Feature race last weekend -- that made for a LONG week in the shop. A car ran up and over my engine breaking and bending a lot of important stuff.

First and foremost, my modified throttlebodies and air-filter box were hit hard and damaged. The airbox was fine, but I had to replace a destroyed Intake Air Temperature Sensor (IAT). Of course, the sensor that MoTeC recommends is extremely hard to find, but Car Quest of Independence had one in stock, so we're in business there. The throttle pull was bent significantly and actually broke off the side of the throttlebodies. Luckily, the throttle pull is made of ductile metal; thus, I was able to bend it and hammer it back into shape. We then tack welded it back into position and the throttlebodies were ready to go back on the car.

The engine valve cover was hit and a hole punched into it; thus I had to disassemble the cams to remove pieces of magnesium from the head. Teresa and I found all the "big" chunks and many small flecks and after piecing them together determined we had found and removed all the pieces that could cause problems to the valve train.

The transmission Shift Shaft was hit and pushed sideways, bending it's retainer and shoving it into the clutch gear. This required disassembly of the right side engine case and removal of the clutch. Sure enough, the steel Shift Shaft Retainer was bent beyond repair, but luckily, the aluminum case where it is installed was not cracked or broken. It would take two weeks to get a replacement Retainer from Honda; thus, I fabricated my own from 1/8" bar stock. I had to work on the clutch gear (bend some spring retainer ears back into place) since the Shift Shaft had hit it, but it looks fine. Reinstalled the clutch and side cover (another late night).

Some electrical connectors for the ignition and fuel injection were smashed in the crash; thus, I replaced and actually improved the wiring for them.

We put it all back together and fired the engine -- no funny sounds - looks like we're OK.

Hot Laps: 

The track is narrow and tacky. The car runs pretty well, but I have understeer off the corners and struggle at corner exit.

Changes before the Heat:

Track is getting slick with a usable cushion.

Tightened the car:
Changed RR air pressure (6psi)
Moved top wing back and increased angle.
Started with the shock compressions at: LR and RR set to #3 position I also added rebound to both rear shocks to hold the rear end down coming off the corner.   

Heat Race: (started 3rd / finished 3rd) 

Started on inside second row - the front row has two fast cars and they pull away from me by running the cushion. My engine runs decent, but has a slight miss. I cannot run the cushion with the missfire and this setup - I am too tight and have a massive push entering the corner on the cushion. The car feels horrible - feels like I am ON TOP of the track instead of IN the track. It just slides around the turns and has no side bite. That was a long 10 laps, but we manage to hold on for a third place.

Changes before Feature: 

One of my car builders (Jerry Whitworth) saw exactly what I felt in the car - it is NOT rolling over and biting like it should. We agree there must be a bind in the suspension, so we go to work. We focus on the Jacobs Ladder Assembly. The Jacobs Ladder locates the rear axle side to side and is shaped like a "W". Each leg of the W must move freely to allow the car to roll into the corner properly. We believe the link in the middle of the W (where it attaches to the axle) is binding up; thus, we enlarge the mounting hole and lube it up. We'll see if that helps!

Review the engine data logs and make a few changes to clean up the missfires.

Track is sealed over (slick) and wide with a cushion pushed wide - the cushion is usable, but I decide not to setup the car to use it.

Tightened the car:
Changed right rear tire to a lesser grooved RD12 compound with a 5psi bleeder.
Set RR and LR shocks to #2 compression position to start the race and put more clicks into the rebound on both rear shocks.
.   

Feature: (started 1st, finished DNF) 

Starting on the pole (luck of the draw) - man, I hope this thing handles!

All I can say is Wow! We fixed something - I out drag race the outside pole car into turn one and run away from the field. The car is amazing through the slick part of the track and build nearly a 1/2 lap lead by lap 12. Caution flies and I have numerous lapped cars between me and second place for the restart so this is looking pretty good. Then, it all comes apart! Under the caution, the engine begins to lay down - popping, bucking and even shutting off and restarting. We appear to have an ignition issue. Try as I might I just cannot fix this situation from the cockpit and I have to take the car to the infield and record a Did Not Finish (DNF). It is hard to watch a race you were dominating from the infield! Nathan Benson in his #2 Stallard Yamaha comes from mid field and wins the race convincingly. I believe he and I would have had one heck of a race, but that will be for another day.

Wrapup:

Once back to the pit area, we plug in the laptop and find battery voltage errors in the data logs. Something has happened to the electrical system and the MoTeC computer is not happy. Might be another long week in the shop trying to sort this deal out.

Ok, we may have thrown away a race win - but all-in-all, I am not too upset. We have our excellent handling car back, my driving confidence is back and when the engine hits on all four cylinders it is a rocketship. Can't wait until next weekend!