MJP911

I have a question prompted by a thread in another forum. What is the max deceleration (g's) you are seeing in the SPB?

Thanks

Lemming

The only good data I have at this point comes from Barber Motorsports, where the only hard breaking point is the hairpin which is down hill. There I see just over 1g (1.01 - 1.03) based on Traqmate.

ProCoach

Is the Traqmate ABSOLUTELY level with the car, while the car is on a level surface?

sbelles

1.20

Lemming

It should be fairly close as I have very little rake in the car; I'll throw a level on it when I get home.

Would you not expect less g's for a downhill braking zone?

ProCoach

If canted forward (nose down) in relation to the car, it can make a difference in the absolute readings (although it’s still ok for comparisons only with that car’s TM generated files).

I will look at some of my IMSA and Historics F1 files, but I would not expect to see a significant difference between T5 and say, T1, in sustained deceleration between them.

What are you getting in T1? T2? T14?

katmeho

Ill get you my MoTec GG graph from Laguna tonight.

Lemming

Just measured the traqmate, -1o (lower aft).

Looking through data for Barber now, seeing the following g's (greatest value from a few laps)

T1 0.92
T2 0.6
T5 1.11
T14 0.6

I don't consider T1, 2, or 14 hard braking zones.

tahoelife

I can achieve 1.2 depending on fresh tires and track surface however max avg is 1.1 in this image you can see 1.2 however I hit the abs on this lap in the zone just prior I achieved max BPS and was able to bleed off before ABS kicked in (still need a lot of improvement in brake release) however only saw 1.07 for max deceleration. Whats interesting is had a semi pro drive the car and they had consistently braked at 1500 psi achieving 1.1 max decel therefore always staying out of ABS but achieving 99 % of max decel everytime so much to continue to learn...

ProCoach

If it's lower aft, then that would interfere slightly with forward braking and augment acceleration, but sounds like you're in the ballpark. 1.11 is good, you just need to do that every time. On T2, you should be doing better. T1 looks ok.

Cool! And great takeaway!

katmeho

I thought the ABS is kicking in around 600 lbs of pressure on these cars???

ProCoach

It's the attack, or rise time, coupled with the friction loading on the tire, not the absolute brake pressure in psi, that does it.

ProCoach

Not an SPB, but fun to look at, nonetheless!

tahoelife

I think the #(psi) measurement is dependent on how the individual sensor/system is configured. The sensor in my car is 0-2000 so I set the voltage range on the TM to use 2000 as the max. I agree he ABS hits in different scenarios at different psi my abs hits more frequently as tires go off and is something i need to learn how to adjust for. hitting the abs is not optimal as it upsets the car and lengthens the brake zone

katmeho

1.22 from Laguna