Boss 302 Advance Road Race Tire setup thread

[ArizonaBOSS]

Re: Boss 302 Advance Road Race setup thread

I'm pretty sure we need a group buy on these first.

Let's do this...

 

[blacksheep-1]

Re: Boss 302 Advance Road Race setup thread

I did, but I didn't do my homework

On the other hand, I didn't let out any air between races. Only running 4 sessions a day is much easier than the 6 I used to run when it was 4 + 2 TT. Now the tires come back down to the right pressures before each session/race.

So you should have seen an improvement in the later day lap times, as opposed to when you adjusted the pressure lower.

 

[Grant 302]

Re: Boss 302 Advance Road Race setup thread

I try to help and this is the help I get..

Not to make excuses for the amateur group...but it's hard keeping organized enough to get all the data logged when you don't have any help at the track. :'(

That said, I did have my temps and pressures pre-assignment from 9/15 at Laguna Seca. Temps are from an IR gun ~2" away, not a probe fwiw.

Car: '11 'Brembo' GT, Hankook R-S3 275/35-18, P springs, Boss shocks/struts, Camber -2.5*

Session 1:
....................Front....................
Driver...........................Passenger
P...39.5........................38.9
T...131...131...138.......138...132...131
....................Rear......................
P...37.0........................36.0
T...132...135...137.......124...129...134

Session 2:
....................Front....................
Driver...........................Passenger
P...41.0.........................41.0
T...130...138...149.......158...150...139
....................Rear......................
P...37.9........................37.3
T...115...120...125.......128...132...126

Drop fronts 2 lbs and rears 1 lb.

Session 3:
....................Front....................
Driver...........................Passenger
P...39.5........................39.0
T...124...136...135.......148...145...144
....................Rear......................
P...37.5........................36.0
T...123...130...131.......119...120...126

Drop fronts to 38 hot, drop Driver rear to 36 hot.

Session 4:
....................Front....................
Driver...........................Passenger
P...39.5........................41.0
T...140...152...162.......174...168...165
....................Rear......................
P...38.2........................38.2
T...145...146...155.......156...154...148

If given the time to do so at the track, I'd reduce camber to -1.9 to -2.1 or so. I opted to uncork my exhaust for session 4 instead

And I really wanted to take my cold pressures/temps at the end of the day, but after playing Mustang Tetris to get everything back in the car...it just didn't happen and I topped off the air for the ride back to the hotel and the trip back to SoCal. Otherwise I would have had the homework data before it was assigned!

 

[blacksheep-1]

Re: Boss 302 Advance Road Race setup thread

Ok a couple of questions, what was the starting temp (ambient) and the starting (cold) pressures?
Also in session #4 how many pounds did you take out of the tires? If you don't have those numbers, what were they after they cooled down? They should match the starting cold temps plus or minus any pressure changes made.
As an example
Start: 35psi - 2 psi (session #2) - "x" (session #4) = starting pressure when cold.
Try not to think of pressure as an absolute, as long as you stay within the manufacturer's recommendation, just add or subtract it during the day like you did in session 3. Then when the tires return to ambient ( same as starting pressure) you should now have anew starting baseline pressure.

And I really wanted to take my cold pressures/temps at the end of the day, but after playing Mustang Tetris to get everything back in the car...

LOL, Mustang Tetris... I'm going to be using that one

 

[blacksheep-1]

Re: Boss 302 Advance Road Race setup thread

I'd insert an excel table here but apparently I'm not getting along with the God forsaken computer. So here's some scans, make the best of it.
Don't read too much into the numbers they are incorrect.

Here's a setup sheet with all the right stuff on it..



You want to develop one of these

 

[Grant 302]

Re: Boss 302 Advance Road Race setup thread

Ok a couple of questions, what was the starting temp (ambient) and the starting (cold) pressures?
Also in session #4 how many pounds did you take out of the tires? If you don't have those numbers, what were they after they cooled down? They should match the starting cold temps plus or minus any pressure changes made.
As an example
Start: 35psi - 2 psi (session #2) - "x" (session #4) = starting pressure when cold.
Try not to think of pressure as an absolute, as long as you stay within the manufacturer's recommendation, just add or subtract it during the day like you did in session 3. Then when the tires return to ambient ( same as starting pressure) you should now have anew starting baseline pressure.

After session 3, I dropped the pressures:
-1.5, -1.0
-1.5, 0.0
To get to the 38 hot front and 36 hot rears.

I don't have the cold temps either before or after. Wish I did for this data, but I usually set my street pressures 'warm' after I drive around for a bit. Usually in the 100-110 degree range 39 front and 35 rear. Cold temps here are so unreliable with one side of the car in the sun and one in the shade. There's often a 20 to 30 degree difference right there.

LOL, Mustang Tetris... I'm going to be using that one

Credit Drew for that term! I'm just a copy cat.

 

[blacksheep-1]

Re: Boss 302 Advance Road Race setup thread

After session 3, I dropped the pressures:
-1.5, -1.0
-1.5, 0.0
To get to the 38 hot front and 36 hot rears.

I don't have the cold temps either before or after. Wish I did for this data, but I usually set my street pressures 'warm' after I drive around for a bit. Usually in the 100-110 degree range 39 front and 35 rear. Cold temps here are so unreliable with one side of the car in the sun and one in the shade. There's often a 20 to 30 degree difference right there.
Credit Drew for that term! I'm just a copy cat.

So if my math is right..I get this.....

LF is 39.5 @ 133, 41 @ 139, (-2) 39.5@132, (-1.5) 39.0. @151
RF is 38.9 @ 134, 41 @ 149, (-2) 39 @ 146, (-1.0) , 41 @ 169
LR is 37 @ 135, 37.9 @ 120, (-1) 37.5 @ 128, (-1.5) 38.2 @ 149
RR is 36 @ 129, 37.9 @ 129, (-1) 36 @ 122, (-0.0) 38.2 @ 153

Now some of those numbers don't make sense, but that's not completely uncommon. have you built a graph of this yet? It should clear things up. The BOLD numbers are completely verifiable by being within 1 PSI or 5 degrees of my numbers for the same size tire. Keep in mind you can string those numbers together on your graph, so you are actually accumulating data X4. (as long as they are the same size or similar) So I see 7 verifiable numbers to start your psi/temp graph.

WARNING NINJA EDIT
(1 psi or 5 degrees of temp, since you guys are using air and an IR thermometer, I'm going to call that close enough, also the temps are "averages" across the tread width)

 

[Grant 302]

Re: Boss 302 Advance Road Race setup thread

So if my math is right..I get this.....

LF is 39.5 @ 133, 41 @ 139, (-2) 39.5@132, (-1.5) 39.0. @151
RF is 38.9 @ 134, 41 @ 149, (-2) 39 @ 146, (-1.0) , 41 @ 169
LR is 37 @ 135, 37.9 @ 120, (-1) 37.5 @ 128, (-1.5) 38.2 @ 149
RR is 36 @ 129, 37.9 @ 129, (-1) 36 @ 122, (-0.0) 38.2 @ 153

Now some of those numbers don't make sense, but that's not completely uncommon. have you built a graph of this yet? It should clear things up. The BOLD numbers are completely verifiable by being within 1 PSI or 1 degree of my numbers for the same size tire. Keep in mind you can string those numbers together on your graph, so you are actually accumulating data X4. (as long as they are the same size or similar) So I see 7 verifiable numbers to start your psi/temp graph.

*Bing* Well, the light just came on how powerful this data can be...especially for guys who want a track specific pressure profile...and don't want to dick around for the first session or two figuring out what pressures to set. I'm just glad that this thread has gotten me to start a log book and writing things down. Keeping things straight in your head only gets harder as you get older...

 

[blacksheep-1]

Re: Boss 302 Advance Road Race setup thread

*Bing* Well, the light just came on how powerful this data can be...especially for guys who want a track specific pressure profile...and don't want to dick around for the first session or two figuring out what pressures to set. I'm just glad that this thread has gotten me to start a log book and writing things down. Keeping things straight in your head only gets harder as you get older...

My work here is done............... 8)

 

[Grant 302]

Re: Boss 302 Advance Road Race setup thread

My work here is done............... 8)

Negative. 8) I'm still trying to think of questions that don't have proprietary answers about general suspension setup...but I'm thinking a lot of my questions would come down to driver preference.


Okay, how about this...
On a CCW course, I've considered making additional left turn biased adjustments. I already do it to some extent with tire pressures, but have considered running less negative camber on the driver side. Maybe something like half a degree difference, so it's not that noticeable. Ever do anything strange like that?

 

[blacksheep-1]

Re: Boss 302 Advance Road Race setup thread

Biased suspension settings are not uncommon, but don't give too much up on the right hand turns. Before you do that have you maximized every other suspension or tire change? A lot of guys do this minutae stuff but miss the big stuff. As an example, the best suspension setup in the world will rarely beat a set of sticker tires...for about 3 laps.

 

[blacksheep-1]

Re: Boss 302 Advance Road Race setup thread

bump ttt

 

[steveespo]

Re: Boss 302 Advance Road Race setup thread

Heading down to summit for the weekend. I with try some of Pappy's "New Tire Math" and log temps and pressures. Hope to have some decent weather, last Friday the forecast was 70 degrees and 0% chance of rain, now cloudy with 30% chance of showers.
Steve

 

[blacksheep-1]

Re: Boss 302 Advance Road Race setup thread

Print up some of those set up sheets, that's why I posted them.

 

[KBBOSS1086]

Re: Boss 302 Advance Road Race setup thread

Changing the direction from tire pressure and temp but still related to setup...

I visited an acomplished Grand AM / SCCA team and spent some time with the owner touring his shop last spring. I noticed that all their Mustangs were not lowered very much (less than 1'). I asked him about this and he told me that most people make the mistake of lowering their cars too much. The chasis was designed and subsequently performs its best with a higher roll center. He claimed that they did significant testing with cars lowered more than 1" (with proper roll center adjustment) vs cars lowered less than 1" (no front roll center adjustment needed and only a panhard bar & LCA relo-brackets in the rear). He claimed that the results were very convincing in favor of the higher ride height. So much so that they refuse to sell and install suspension systems that lower the car to a point that it requires the front roll center be corrected (even though they could make more money doing so).
It may go without saying, but he told me the key to the handling of our cars is high quality dampers and identifying the correct spring rates for your driving style and track (conditions).

 

[blacksheep-1]

Re: Boss 302 Advance Road Race setup thread

I would agree with most of that, the part about the shocks and springs are right on, I'm sorta on the fence on the ride height issue, whenever you can lower the center of gravity it's a good thing, unless you screw up the suspension geometry, which he is addressing... in a way.

 

[Hermes]

Re: Boss 302 Advance Road Race setup thread

Picked up a couple of books on suspension design and vehicle dynamics and one of the books 'HIGH PERFORMANCE HANDLING FOR STREET OR TRACK' has a good discussion on analyzing tire temps. The author claims that:

'Since tires make the most traction in a corner with a small amount of dynamic negative camber, the inside edges of the front tires should show temps between 5 and 10 degrees hotter than the outside edges.'

So according to him, the temps that Grant showed in his first session are right in that ball park in terms of camber adjustment. As a reference the temperature examples they show in the book are higher absolute numbers [180-200] than what Grant had which may come down to how quickly they were able to get a probe on their tire.

 

[blacksheep-1]

Re: Boss 302 Advance Road Race setup thread

200 degrees is considered the high end of the "safe" temps for most applications, but I've seen them at 270-280 and the tire hasn't chuncked...yet. At Indy, the first year on the old tires temps were well over 250 on a lot of cars. Grant's numbers are not bad at all, but could be higher overall, that might be (as you said) a function of time.

 

[2012YellowBoss]

Re: Boss 302 Advance Road Race setup thread

Here are some numbers but I'm not sure they will help unless you know the track (Daytona) since it is not really a true road course. Remember this is a left hand track and it does not need a lot of camber but I don't change from track to track.

Started LF 29.5 RF 28.5 LR 28 RR 27.5 Set in garage, morning, not in the sun looking for 39 front CTSCC Slick not GT-I and looking for 36 in the Rolex conti rear

Session 1 Dry, lots of traffic, no clean full speed laps, 8AM start, slow last lap and taken in paddock
O M I
LF 37 added .5 141 140 154
RF 37.5 144 140 150
LR 34 Added 1.5 137 131 136
RR 34.5 Added 1.5 140 134 138

Session two, dry, few laps run, black flags, no clean hard laps, long time back to paddock
LF 36.5 133 132 144
RF 36.5 132 131 142
LR 36 135 131 140
RR 36.5 138 132 137

Session 3 Dry Some clean harder laps but still a lot of traffic, long time back to paddock from track
LF 40 152 151 161 Changed tires so no adjustment
RF 38 152 147 159
LR 38 -1 157 150 158
RR 38.5 -1.5 161 154 162

Day 2 Same starting pressure as day one, front GT-I CTSCC same Rolex rear type

Session 2 track damp, very slick, not running hard, long time to padock
LF 36 139 142 158
RF 37.5 150 145 155
LR 36 -.5 137 140 138
RR 35.5 140 156 143

Session 3 dry, taken in the HOT pits after 6 or so laps?, Clean hard laps
LF 41.5 -2.5
RF 41.5 -2.5
LR 37 -1 158 161 167
RR 37.5 -1.5 160 161 167

Seeing a 12.5 increase in the fronts, 9.5 in the rear, could have started lower but I did not want to start too low at this fast track.

 

[blacksheep-1]

Re: Boss 302 Advance Road Race setup thread

I'll work on those in a bit..
FWIW I was doing "therapy" from my surgery today....and tried a little experiment that I thought I would pass along. I normally run my Contis at about 26-28 psi, but today I decided to up them to 36 and 38 psi .(auto-x tires generally don't get "hot" they never have time to) The reason behind this is because (my reasoning) is that at as autocross tires never really heat up, by bumping the cold pressure nearer to the max, the tire will heat faster and work better. I gradually bumped the pressures a few psi per "lap" until I got to the above stated PSI and my little experiment worked, the grip increased and the temp increase was, as expected minimal, so it was a success.......at least today,.... at this track.....