Brunton Stalker at MSR Cresson 1.7 ccw

[Croc]

I just re-watched your video again after reading your car profile post. The more details I see the more impressed I am with the specifications on your car. That is some serious speed on a fairly small track.

 

Did you feel any downforce effects from the major aero wing package you were running? Or was Cresson just too slow for average speeds to get any meaningful benefit?

[xcarguy]

I just re-watched your video again after reading your car profile post. The more details I see the more impressed I am with the specifications on your car. That is some serious speed on a fairly small track.

 

Did you feel any downforce effects from the major aero wing package you were running? Or was Cresson just too slow for average speeds to get any meaningful benefit?

 

Croc,

 

Unfortunately, the only data I have for comparison on how my car performs with the aero is between the two track days I’ve done with this car at MSR Cresson (MSRC). MSRC is the only track I’ve ran the car on thus far and I have never run the car without the aero mods. So, as for noticeable down force, I’ve never had a chance to do a side-by-side comparison of the car at speed with and without the aero, so not sure what the down force differences (if noticeable at all) would feel like. However, I do believe the aero is coming into play at speeds north of 80mph (my best guess base on entry speeds, sustained speeds and exit speeds on the track). Aero would probably also be better with the front fenders removed, but I like the protection from rocks the fenders yield. A few years ago, I took a rock to the elbow and cut a tendon; hurt like crazy and took forever to heal.

 

The first track day was run on April 13 at MSRC and was run CW. The second track day was run on June 1; same course, run CCW.

 

In between running those two track days, I made a few changes to the car and changed my driving technique a bit.

 

Here are the particulars for the April 13 event:

· MSRC 1.7mi course, CW

· Rear wing installed

· Front wing installed

· Front fenders installed with louvers

· Front springs—600lb

· Rear springs—400lb

· 1/16th to 1/32nd tow in

· Avon slicks—21.5x10.7x15 at all four corners

· 15x10 wheels with 4.5 offset at all four corners

· Front tire pressure—20psi

· Rear tire pressure—20psi

· Down shifts from forth to third at all corners entries

· High for the day--78°F

· My max speed for the day—somewhere between 125 and 130mph

· My best estimated lap time for the day—1:25.5

 

Particulars for the Jun1 event:

 

· MSRC 1.7mi course, CCW (I’ve been told the track is somewhat faster when run CCW as opposed to CW; it does seem to flow better)

· Rear wing installed (no change)

· Front wing installed (added out wing extensions)

· Front fenders installed with louvers

· Rear diffuser installed

· Head lights removed

· Brooklands windscreens removed

· Front springs—600lb (no change)

· Rear springs—400lb (no change)

· Near-zero tow in

· Avon slicks—21.5x10.7x15 at all four corners (same slicks)

· 15x10 wheels with 4.5 offset at all four corners

· Front tire pressure—20psi

· Rear tire pressure—19psi

· All turns entered in forth gear with the exception of two

· High for the day--92°F

· My max speed for the day—somewhere between 135 and 140mph

· My best estimated lap time for the day—1:22

 

If you went back and compared my videos from April and June, June would reveal better setup in the corners as well as higher entry and exit speeds. As for how much difference the aero is making on the MSRC track, I can’t say. I will say that—with all things considered—the car handled better, had incredibly better grip and felt much more solid in the corners in the June event vs. the April event.