September 12, 2009

Changes since August 29th race: 

We didn't plan on racing the Friday night (September 4th) race in order to work on our new fuel injection throttlebodies. Turns out, it rained that night of racing out so I didn't miss anything! I took the day off work Friday September 4th and Jerry Whitworth and I went to work on the throttlebodies. Again, these were not built for our Honda engine; thus, we had to respace them from 3.1" between cylinders to 2.914". This doesn't sound like much, but it took us all day due to the welding, bending, re-bending, re-welding etc... We then had to seal up the lower injector holes (we only use injectors mounted in the airbox above the throttlebodies) and do some other miscellaneous modifications. Saturday, we modified our airbox to fit the new throttlebodies and once complete, we decided to go watch the $3000 to win Modified race at Central Missouri Speedway.

By 11:00am Sunday the car was running with our new intake system. It took a little while to even out the idle and syncronize the four cylinders, but it now sounds real good! If everything goes right - we should be a little LEAN on top end as these throttlebodies should breath a lot better than the previous ones.

Hot Laps: 

The track is tacky, so we start with right rear air pressure at 8 psi, move the right rear out 1" and move the wing forward. The car runs pretty good. I drove at 100% throttle for three laps (never backed out) and held my own with everyone on track. Car handled pretty good, but the track will change dramatically before our heat race -- there are a lot of cars here tonight (23 in the Open class).

Changes before the Heat:

Reviewed the Hotlap data log and sure enough - we are lean on top end just like I thought these new throttlebodies would react. I richenend it up by 5%.

Track is getting slick and wide.

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

Heat Race: (started 6th / finished 5th) 

Started on outside third row - engine runs strong on the start, but it then starts to have a slight misfire (did I go too rich?). The misfire stays pretty constant, but that isn't the big problem - I am LOOSE getting into the corners and it kills my momentum. We struggle home 5th (maybe 4th - I really don't remember). The track doen't have that black slick look, but man it was SLICK. We needed our feature setup for the heat!

The engine is pretty good, but the misfires have me stumped. We'll analyze the data logs and try to fix the problem.

Changes before Feature: 

Starting 4th:

Reviewed the data logs trying to solve the misfire issue -- I really cannot find the exact problem - but it looks real rich at part throttle lower RPM (coming off the corner). That might affect the spark plugs, but I just don't think it is THAT rich. There are no diagnostic errors for the ignition system and it doen't misfire when revved in the pits. We'll hope we've fixed it with fuel.

Track is sealed over (slick) and wide with a cushion pushed way wide - no one's going to win on the cushion in this race!

Tightened the car:
Changed right rear tire to a lesser grooved RD15 compound with a lot of siping and a 5psi bleeder. We also moved the RR tire in one inch.
Set RR and LR shocks to #2 compression position to start the race and put four more clicks into the rebound on both rear shocks (10 total clicks).
Changed to big sideboard wing.

  

Feature: (started 4th, finished 4th) 

This blog is a little long, but A LOT happened in this race tonight!

The car JUMPS on the start and I try to go between the front row starters, but I get pinched and have to breathe the engine. I come out of turn two in fifth position. The engine is still misfiring (even worse than in the heat). It is NOT a fuel problem, this is definitely ignition as it is constant. This track is slick enough that it will not require tons of horsepower, so we'll keep on runnin' with the misfire.

The car is so good in the middle of the track and we quickly get up to second. The leader (Cole Melby #36) has about six car lengths on me, but within one lap I catch him and make a move around the outside. I pull up to his right rear, but he doesn't know I'm there and he pinches me against the backstraight wall. A caution then flies and I line up behind him for the restart.

On the restart, I dive low into turn one and pull even and pass for the lead just in time for another caution. Luckily for me, the caution was for Cole, so we retain the lead. For the next six laps, it looks like a runaway - we put a staightaway on second place and have no problem lapping cars. Then the caution flies. On the restart, I again pull away quickly, but the engine is still misfiring. Another caution, and this time there are no lap cars between me and second place (Tim Koch #14). My engine woes cost me on the restart as Tim outruns me into turn one and forces his way around. He then gets loose in the middle to 3 & 4 and I try to pass him, but he pinches me into the berm and I spin. That left Nathan Benson no where to go and we hit nose to nose damaging my nose wing. Luckily, it was a straight on hit and my front suspension is undamaged, but the nose wing is pushed back about six inches and twisted.

I start dead last with 27 laps to go (40 lap feature tonight). I take it easy for a few laps to make sure the suspension is OK and to work with my top wing adjuster to rebalance the car. We then get going pretty good passing cars every lap. I get up to sixth place and stalk the fifth place car for way too many laps. I am a little nervous to go to the middle with the nose wing torn up so I try lap after lap to pass him low coming off the corner. Caution again flies on lap 35 - this race had a lot of caution laps and I look down at my fuel pressure gage and it is bouncing between 35 and 43 psi (it should be a constant 43psi!!!!) -- we're running out of fuel. My fuel pickup is located at the rear of the tank, so if we get back up to speed the remaining fuel will run to the back of the tank, we might make it, but will we make it FIVE more laps?

On the restart, the fuel pressure holds a constant 43psi and I go back to work on 5th place all the while watching my fuel pressure. The fourth place car runs out of fuel (we are now 5th). Finally, on lap 38 I go for it and drive into turn 3 just above him. It works and I pull even as we take the white flag. We end up 4th and as soon as I back out the throttle, the fuel pressure drops to 20psi and finally to zero - that was cutting it close!

Wrap-up: 

The car misfired all feature long - very frustrating because I feel that was the primary reason Tim was able to beat me on that restart. The problem is not fuel, it is definitely ignition and sure enough, I discover the problem as they prepare to check my engine's bore and stroke at post race technical inspection. I am embarrassed to say this, but #1 cylinder spark plug was LOOSE! I mean real loose (not even hand tight). Stupid me, the guy who prides himself on his weekly maintenance! This will bother me for days to come!

The car handled awesome before we killed the nose wing and it was pretty darn good even after. Thank goodness for a cockpit adjustable top wing. I was able to compensate for the nose wing by moving the top wing forward.

Man, when we get this engine hitting consistently - this car will be incredible!

I am upset with myself due to the loose spark plug, but I am also proud of how we fought back to a top five finish considering all we overcame. My confidence in the chassis is growing each week and I know we are CLOSE to getting the engine to it's full potential. I see no one able to drive through the black of the track the way this car does and that will be our advantage!

Once again; Becky Hand video taped the feature. It is in two parts due to the length of the race. Thanks again Becky!

http://www.youtube.com/watch?v=ML7V6voFMyo  Part One   

http://www.youtube.com/watch?v=EGKn16O8_c4  Part Two