Mont Tremblant July 07 - Experiments in Downforce

Words By Jesse Clark / Snaps By Jesse Clark / Edited by Mike Centola

DJ/Tom/Mickey (Mo-Hudders) and I headed up to Mont Tremblant for a COM Time Trial on Monday and Tuesday. I've never been to MT before so it took me a few sessions to nail down all the corners and start pushing down the times.

The competition:
James Price's bitchin' fast 911.


The other major players were a SERIOUS Roush Mustang Cobra and a 951. All 3 of them had dramatically more horsepower and tire than I did, so I attempted to find them on course and see how far off the pace I was. After a session up to speed, I laid down a 1:54.200, a second or so faster than the previous lap record.

The time trial runs start and two things go wrong.
Problem 1: Brake pedal is longer than it should be and I'm not getting max pressure in a predictable way, so on the long straights before heavy braking zones I'm having to lightly pump and prime the system so that when my mark came and I went to threshold brake, I'd have a predictable pedal. Didnt really slow me up too much, but added an extra step (literally) to each lap.
Problem 2: Fuel starvation. Whups. I ran down the tank to, what I believed to be, the optimum level for speed (read: as low as possible). However, in looong right hand corners, like turn 8, the fuel will rush away from the single fuel pump in the system and by the time I was out to corner exit and grabbing 4th gear, the fuel system burps and cuts power. Not fun. After another half of a lap, the same issue is occuring in turn 1 and 2 (consider them as one corner). Turn 8 is a flat hairpin, taken at maybe 65mph or so. Turn 1/2 is a STEEP uphill under hard lateral load and then down the other side, also under hard lateral load, which makes the starvation issue a little more dangerous. So now I'm adjusting my lines through both corners in order to keep fuel sloshed over towards the pump as much as possible. That means a sharp late apex in turn 8 and a wussy tight inside line up the hill in 1. You can feel the tenths adding up on the clock.

I've never had this problem before because I've never been on a course that had this specific type of turn that pulled fuel away long enough for the pump to run dry. Live and learn, and then get a second pump and pickup point on the other side of the tank.


Anyway, I end up with a 1:54.7xx for a fastest lap in the time trial. Not too bad, and still well under the previous lap record. Unfortunately, two of my competitors also beat the record...and me. The fastest time was a 1:54.5xx belonging to the 951 and another car came in second. That's right, the top 3 cars in the same class finish within 2 tenths of a second of each other. This isnt drag racing. It's a 2.5 mile, 14 turn road course that's nearly 2 MINUTES long. Impressively close competition. I'd kill to give it another shot with a another brake bleed and a few more gallons of Canadian 94 octane.

All in all, awesome event. We're most likely headed to more COM events in the future and I look forward to running with the same cars again, especially with a home court advantage at Watkins.

Tom should chip in with his story about splitting a car with Mickey. It invovled 2 spins at triple digit speeds, dead battery, trips to NAPA to buy car parts from the usual NAPA employees but speaking only FRENCH, backing into the NAPA truck, dueling with Turbo Miatas, etc. Arret! Hammer time.




Also was testing out some new aero parts. Last time I was at the Glen I was using the new rear wing with no front splitter (another one bites the dust). I never thought the wing would produce an effect that could be noticed by my butt dyno or the data logger, but low and behold, it showed up on both. High speed corners like the Esses and Turn 10 at WGI had a dramatic wash-out oversteer throughout the corner. You can see it on the Traqmate data clear as day when compared to my previous graphs.

The new beefed up splitter equals out the high speed wash-out effect on fast corners as far as the butt dyno can tell. I didnt have the Traqmate setup with me this time, but it wouldn't have mattered since I had no previous Tremblant data to compare to. MT has a LOT of long high speed (100-105+) corners and the old balance is back with none of the wash out. Mission accomplished.

For you aero junkies, opinions welcome. The wing doesnt extend more than .5 inch beyond the window line of the car at the c-pillar, and it is well below the roof line even if the slope in profile is continued, but it has plenty of pitch. The splitter is a beefed up replica of the OEM LTW piece used on the production LTW cars and the original BTCC E36 racers. Underpanel extends to the sway bar. I went with this option because the more hardcore splitters and come already-beefed up would rip off the front bumper and wheel well liners if I ever hacked it off on something. The gaps are all sealed from the back (except the huge ones in the fogs/nose/headlights/etc. Race car wanna-be.















That's it. And as usual, you're all huge homos for not coming to the track.