Typical G loading?

[Tom Szelag]

I'm curious how grippy these cars are. What peak lateral and longitudinal g's would one see on most tracks?

[Wright D]

We have routinely seen over 2 g's in a corner and 2.5 g's or more in braking.

The g's we see change dramatically with tires, wings, and drivers.

[RussMcB]

I just looked at my data from Barber and saw 2.65 lateral G's once. It was in a valley with the car pressed hard into the track. I wasn't very fast, so I'm sure other FB guys were seeing more.

Geez. My braking G's aren't even 1.5. I guess I need to work on that.

[James Michael]

I've seen 2.7g's in a corner and 2.1 g's under braking. This is for data collected at Texas Motor Speeway or MSR Houston.

James Michael
Stohr F1000

[Rick Ross]

An FB car should achieve approximately the same lateral accelerations as a modern FC. You may want to post this question to the FC guys also. Keep in mind that the driver will be the largest variable.....but tires, shocks, downforce, etc. will also play a role. The peak lateral g-forces normally occur in fast corners with some track banking and/or positive elevation change.

[Tom Szelag]

Interesting. That's a lot more than I had expected. Surprised significantly more in cornering than braking. That's 2.6-ish real g's, not "blip" loading (eg been filtered over ~.1 s or so)?

[Mike Devins]

Rick,

I would expect to see a slight increase over the FC guys: less weight, larger tires, bigger diffuser.

[RussMcB]

Interesting. That's a lot more than I had expected. Surprised significantly more in cornering than braking. That's 2.6-ish real g's, not "blip" loading (eg been filtered over ~.1 s or so)?

Tom, I think if our corners were more consistent, like for instance we ran ovals, then you could get a clearer answer. However, there are so many variables in road racing that the G forces are going to be all over the place. The driver and car set-up make a big difference, too. I hesitated to post my numbers because the data was from my recent driving, which has not been great. You shouldn't base any opinions on my data points.

It would be interesting to hear the peak numbers for a hot shoe in a high speed corner with new soft compound wide tires, high downforce set up and a section of the track that really pushes the car down towards the surface.

[FC63F]

I looked at the data logs (Race Technology) for Waterford Hills and Mid Ohio. Waterford is tight and technical and Mid Ohio is... Mid Ohio

Mid Ohio
1.9 lateral g's in the left turn up and out of Thunder Valley
2.1 sustained lateral g's for turn one with a blip to 2.4
2.0 g'stheat the turn in to keyhole
1.7 g's through carosel
braking Mid Ohio - end of back straight 2.25+ dropping to 1.75

Waterford
Swamp - range of 1.7 to 2.1 at the exit - increaseing radius turn
carosel - slowish but 1.5 to 1.7
Braking at 6 from the back straight - 2.2+

Your results will vary - I would guess there is some improvement in fb due to bigger tires and a more modern suspension than my Reynard

David Keep

[PaulL]

I'm in a Radical DSR, but I thought you'd find this interesting.

Most of the tracks around here (Colorado) are about 4,000 - 5,000 feet in elevation.
When I went to Mid America a couple of months ago (200 or 300 feet in elevation), my lateral g forces increased by about 3 or 4 tenths due to the increased air density!

[Tom Szelag]

Tom, I think if our corners were more consistent, like for instance we ran ovals, then you could get a clearer answer. However, there are so many variables in road racing that the G forces are going to be all over the place. The driver and car set-up make a big difference, too. I hesitated to post my numbers because the data was from my recent driving, which has not been great. You shouldn't base any opinions on my data points.

It would be interesting to hear the peak numbers for a hot shoe in a high speed corner with new soft compound wide tires, high downforce set up and a section of the track that really pushes the car down towards the surface.

Only reason I bring up the "blip" loading is the artificially high g's on initial aggressive cornering and braking... or really any input... roll or pitch rate acceleration multiplied by distance from CG to accelerometer. Worse the stiffer the car is or the greater that distance.

Can just get rid of it if your lat accel is exactly at the height of the sprung mass cg.. but I find it easier to just filter by a tenth to an eight of a second. Knocks the peaks down a few tenths and gives a better idea of "real" G's.

Or at least that's my 2 cents.