At Marina running two events this weekend. ran with bmw club today and understeer is out of control. going to full soft stock bar. what else? pressure suggestions? car sux...

pda sorry

oh yeah...it's off corner as soon as I pick up th throttle. just can't steer with throttle or rotate the car. turn in is not quite as bad

Not too much front toe out and zero the rear toe.
That should help some.
FM

I would try to balance it out with tire pressures. I would start with 45 in the rear and 35 in the front and see where it's at. Of course, like you mentioned earlier, it's tough to get a car to handle well at Marina. You would think some of the local guys would have figured it out.

oh yeah...it's off corner as soon as I pick up th throttle. just can't steer with throttle or rotate the car. turn in is not quite as bad

:iamwithst Just wait longer to step on the gas. :lol:

At Marina running two events this weekend. ran with bmw club today and understeer is out of control. going to full soft stock bar. what else? pressure suggestions? car sux...

pda sorry

What are your car's alignment settings?

the bar won't help much in that situation

less rear camber
less rear toe
higher rear air pressure
more rear shock bump valving
possibly higher front air pressure if the corner rollover is too much
more front camber but you're probably maxed out

konis are full stiff rear. tried softening fronts, went too far started picking up inside rear. don' want to mess with alignment for one event, the car is good everywhere else. started at my normal 39f 37r ended up at 40f 36r...went wrong way? start at 38f 40r today and soften bar.
thnx

:iamwithst Just wait longer to step on the gas. :lol:

doesn't matter. still can't steer with throttle have to have wheel unwound before gas = slow

"WAIT" is a very bad word to use!!!
You can easily mess with toe at the site for tuning for the surface/weather you are running at.
FM

konis are full stiff rear. tried softening fronts, went too far started picking up inside rear. don' want to mess with alignment for one event, the car is good everywhere else. started at my normal 39f 37r ended up at 40f 36r...went wrong way? start at 38f 40r today and soften bar.
thnx

What's your current alignment setup like? It would help us to answer your question.

What's your current alignment setup like? It would help us to answer your question.

Sorry, I was posting using my pocket PC earlier and hate typing on the Qwerty key board...didn't want to take time to clarify for all. I run the "normal" B Stock alignment. -1.7f/-1.8r, 1/8" toe out front/zero toe rear.

I was just looking for one of the other BS guys who already know my set up (like ULLLLLLLLLLOSE, who has fought this understeer problem on concrete...and was of no help :icon_no2: ) to chime in with a quick fix, as I had a regional event today and discovered the issue yesterday. I figured that I needed a band aid fix, since I didn't really want to mess with the rear eccentrics and dial the car in for a surface which I (particularly now) have no interest in running on.

Anyhow, I did go to the softest setting on my modified stock bar and ran 39f/40r pressures to start. Big improvement, the car felt pretty darn good...unfortunately, the driver had problems, today. I don't think I even pax'ed top 10 :lol2:

Thanks for the help, though! :)

if your on V710s your front pressure is too low

I hate the concrete plow mode. I've tried going from 43 psi to 35 psi in the rear and it didn't feel better really either way.

if your on V710s your front pressure is too low

How do you figure? The roll over was right where I want it, about 1/16" of the shoulder surface is not being used.

I also noticed my car plowed some at Sebring (concrete) while it easily rotates at other tracks.

How do you figure? The roll over was right where I want it, about 1/16" of the shoulder surface is not being used.


you must not be driving hard enough then :dunno: we have to run 42-44 psig front pressure even on asphalt

but then I guess it depends what you're calling shoulder surface, when I looked at your 275 front HooHoos they were rolling way too far onto the sidewall IMO

^I must be much smoother and more precise with my inputs, I guess :spank:

you must not be driving hard enough then :dunno: we have to run 42-44 psig front pressure even on asphalt

but then I guess it depends what you're calling shoulder surface, when I looked at your 275 front HooHoos they were rolling way too far onto the sidewall IMO

Are you saying that using less of the tire creates more grip then more of the tire? That more flex in the tires creates less friction then a stiffer sidewall? Inquiring minds want to know?

Seriously, I'm a little lost with the 18's and uber short sidewalls....

^I must be much smoother and more precise with my inputs, I guess :spank:


Maybe too smooth and too precise because the people beating you are running that high too :dunno:

Maybe too smooth and too precise because the people beating you are running that high too :dunno:

Who? I believe Jason is right where I am, in terms of pressures :dunno:

Who? I believe Jason is right where I am, in terms of pressures :dunno:

Perhaps J handles the pressures better than you? :dunno:

Perhaps J handles the pressures better than you? :dunno:

I get it ;)

One thing which did become clear to me this weekend is that the RX8, as many of us have them set up, is pretty sensitive to rear tire pressure...much more so than the Z06 I ran, for example. Raising rear pressures by 4 psi made a significant difference in the handling, more than I would have expected, freeing up the back end a bunch. On the other hand, dropping rear pressures really didn't do anything. I'm not sure what this all means (maybe someone can take a shot at quantifying), but it is good information to have learned.

all the pieces are right in front of you, you just have to put them together ...

all the pieces are right in front of you, you just have to put them together ...

please elaborate, sensei...I'm not really good at snatching pebbles from an open hand...:)

Who? I believe Jason is right where I am, in terms of pressures :dunno:



Are you sure we run the same? Maybe I lied to you.....:FIREdevil The guys in Houston were smart enough to check my tires when thought I was pulling their legs, I felt so violated. :bootyshak

yeah, but we weren't smart enough to drop your pressures 15 psi during competition... :banghead:

The guys in Houston were smart enough to check my tires when thought I was pulling their legs, I felt so violated. :bootyshak

Are you sure we run the same? Maybe I lied to you.....:FIREdevil The guys in Houston were smart enough to check my tires when thought I was pulling their legs, I felt so violated. :bootyshak


Lie to me? Why would you do that?

I thought we had this tire pressure discussion a few months ago. :dunno:

Lie to me? Why would you do that?

I thought we had this tire pressure discussion a few months ago. :dunno:

Yeah. :)

OHHH....Evil "PUSH"...nm...I thought someone called...

it all depends on how accurate/calibrated your gauge is too, seen a lot of error over the years by people who never think to have them checked

it all depends on how accurate/calibrated your gauge is too, seen a lot of error over the years by people who never think to have them checked

Totally guilty of not recalibrating anything when it should be...and then kicking myself later for it...

Are you sure we run the same? Maybe I lied to you.....:FIREdevil The guys in Houston were smart enough to check my tires when thought I was pulling their legs, I felt so violated. :bootyshak

We were also smart enough to check our gauges against Jason's, so his pressures didn't end up being as far off from what we run as they first sounded...

We were also smart enough to check our gauges against Jason's, so his pressures didn't end up being as far off from what we run as they first sounded...


Well....we're waiting...let's hear the story, already:lol2:

Well....we're waiting...let's hear the story, already:lol2:

I think I was 6 psi higher than them. :uhh:

I think I was 6 psi higher than them. :uhh:

you still doing that :dunno:

http://www.rx8club.com/showpost.php?p=1572344&postcount=141

you still doing that :dunno:

http://www.rx8club.com/showpost.php?p=1572344&postcount=141

No, this is my good gauge it is only off 2 lbs. :scratchhe

So, the moral to the story:

Whether your pressure gauge is accurate doesn't matter...as long as it's consistent. Don't pay attention to what other drivers' pressures are, they may or may not be relevant. Determine your own pressures, using your own gauge, using the normal indicators: roll over measured, pyrometer, lap times and what "feels" right to you (this is the one that gets many in to trouble!) :)

So, the moral to the story:

Whether your pressure gauge is accurate doesn't matter...as long as it's consistent. Don't pay attention to what other drivers' pressures are, they may or may not be relevant. Determine your own pressures, using your own gauge, using the normal indicators: roll over measured, pyrometer, lap times and what "feels" right to you (this is the one that gets many in to trouble!) :)

Very true.... Last year the I gauge that I have used for the last 10 years did not make it to natls, that could have been bad. :banghead:

However when we used the same gauge to compare the guys in TX were 6 psi to low imho. :uhh:

However when we used the same gauge to compare the guys in TX were 6 psi to low imho. :uhh:

So, share the numbers...6 psi too low, comparing what to what on what type of surface?:)

So, share the numbers...6 psi too low, comparing what to what on what type of surface?:)

LOL, how soon they forget .... :lol2:

So, the moral to the story:

Whether your pressure gauge is accurate doesn't matter...as long as it's consistent. Don't pay attention to what other drivers' pressures are, they may or may not be relevant. Determine your own pressures, using your own gauge, using the normal indicators: roll over measured, pyrometer, lap times and what "feels" right to you (this is the one that gets many in to trouble!) :)

:spank:


.

LOL, how soon they forget .... :lol2:



:spank:


.

I know what you're getting at, but am still interested in knowing why ULLLLLLLLLLLLLLLLLLLLLLOSE was saying the TX guys were 6 psi too low (on the same gauge)...which begs the question as to what kind of pressures we're talking about. Even with a 2 psi "noise" margin, for different gauge calibration, its interesting data....

I know what you're getting at, but am still interested in knowing why ULLLLLLLLLLLLLLLLLLLLLLOSE was saying the TX guys were 6 psi too low (on the same gauge)...which begs the question as to what kind of pressures we're talking about. Even with a 2 psi "noise" margin, for different gauge calibration, its interesting data....

I was at 40psi. :)

I was at 40psi. :)

So, they were running 34 psi front, Kumho 245, on asphalt? Was the K-U-M-H-O lettering wearing off, from rollover? :Eyecrazy:

JK, but it would be interesting to see the wear pattern being created. I was getting pretty significant roll over (like past the edge of the tread surface limit strip) at 37 psi front, on asphalt, before taking my fronts up to 39-40 psi...at which level I'm using most all of the tire, while still allowing about a 1/16 to 1/8" "chicken strip". That's with a full -1.7 front camber.:)

full? LOL ... sounds like a partial to me ...

full? LOL ... sounds like a partial to me ...

OK, bad choice of words. :)

You did get my point though? ;)

So, they were running 34 psi front, Kumho 245, on asphalt? Was the K-U-M-H-O lettering wearing off, from rollover? :Eyecrazy:

JK, but it would be interesting to see the wear pattern being created. I was getting pretty significant roll over (like past the edge of the tread surface limit strip) at 37 psi front, on asphalt, before taking my fronts up to 39-40 psi...at which level I'm using most all of the tire, while still allowing about a 1/16 to 1/8" "chicken strip". That's with a full -1.7 front camber.:)

I've got one tire that's got a little lettering worn off, but that's from a massive, smoky spin at about 75 mph at a local marque club event. :icon_no2:

Seriously though, we typically run in the low 30s on asphalt. We wear the tires right out to the edge, but under normal conditions (i.e., not spinning) we wear them right to the edge but no further. That's with -1.6 front camber.

We really haven't had a good opportunity since Houston to take some time and test, but we did a few test days last season in Jon's car on a surface similar to HPT and found that we both ran faster times with lower pressures.

Seriously though, we typically run in the low 30s on asphalt. We wear the tires right out to the edge, but under normal conditions (i.e., not spinning) we wear them right to the edge but no further. That's with -1.6 front camber.Wow. Does sound low. Did your better times with the lower pressures happen in the first few runs, or the last few runs? Are you able to be 99.9% consistent in driving to know that your better times were not a reflection of some other factor(s)?

Mark did some pressure tweaking for me at our last regional event, and imo the rear pressure changes (+/- 2 lbs.) were even more noticeable in handling than the fronts. Of course, that was on that course, that day, in those temps, in that direction. Too many variables.....

On our 18x8 rims and 245 Kumho's(on the Solstice though) we stay in between 33-35psi. That is the "fastest" pressures with our current setups according to our testing. We use Longacre digital gauges that self zero everytime you turn them that seem to be very accurate.
FM

Wow. Does sound low. Did your better times with the lower pressures happen in the first few runs, or the last few runs? Are you able to be 99.9% consistent in driving to know that your better times were not a reflection of some other factor(s)?

Mark did some pressure tweaking for me at our last regional event, and imo the rear pressure changes (+/- 2 lbs.) were even more noticeable in handling than the fronts. Of course, that was on that course, that day, in those temps, in that direction. Too many variables.....

Yeah, we use rear pressure changes to tweak the handling of the car for particular courses/surfaces (we have five distinctly different local surfaces). However, changing the f/r pressure differential by 2lbs isn't the same as upping your baseline pressure at all four corners by 2lbs, or even by 4lbs for that matter.

BTW, you don't need to worry about my testing protocol or familiarity with tire grip characteristics - I'm an engineer by trade, and I spent far too many late night hours during college doing tire testing for Dr. Wood's Formula SAE team (I'm a UTA alum). :)

I guess I'm trying to understand why everyone seems to want to run so much pressure in their tires. I could see using 40psi if I were trying to pinch a 225/50-15 on a 6" wide wheel like I used to do with my Miata (where you've got a tall sidewall tire on a wheel that's too narrow), but the 245/35-18 V710 on an 8" wide wheel is pretty well supported. After all, we're not getting any rollover at the pressures we use, and it's not like a 35-Series sidewall V710 needs high pressures to compensate for a tall or soft sidewall.

Well if nothing else this discussion has me thinking I should "stay the course" and come up with my own pressures.....

My guess is that the higher pressures loosen up the tail of the 8 a little bit so you can decrease push.
FM

After all, we're not getting any rollover at the pressures we use, and it's not like a 35-Series sidewall V710 needs high pressures to compensate for a tall or soft sidewall.


It is when you're generating max G loading :stickpoke

Not only is the additional loading going to cause more body roll, but then the front outer tire corner is going to further compress and rollover more

This is a Stock car, not FSAE. You can't make the necessary adjustments in the conventional race car sense. In Stock you have to resort to the unconventional to achieve the desired result

This is a Stock car, not FSAE. You can't make the necessary adjustments in the conventional race car sense. In Stock you have to resort to the unconventional to achieve the desired result

Like running full rear rebound? :)

Don't get me wrong - I'm not married to the pressures we currently use, and we'll be doing some more focused testing with datalogging later this season to see if we can get repeatable, measurable improvements with a change in air pressures. However, I'm of the opinion that any potential gains are going to be small enough to be lost in the noise of a regular local event, so I'll stick with what I like until we have a chance to really do some controlled testing.

I never ran full rear rebound, I personally recommend 50% and that was running a stiff front bar no less

did Woody pull a TeamRX8 and cone all his runs yesterday :dunno:

I never ran full rear rebound, I personally recommend 50% and that was running a stiff front bar no less

I know. My point was that there is no single "absolutely right" way to set up a car, even with the unconventional choices that Stock class rules sometimes dictate.

did Woody pull a TeamRX8 and cone all his runs yesterday :dunno:

Nope, I really drove that poorly... :(

The surface fell apart in the afternoon (literally)...Look at National Champ Vic Sias' times in the SM car...about 2 seconds off of the fastest morning times :Eyecrazy:

Still, I just had major problems/spins/crxp in the run group. I did 3 fun runs right after and each run was 1.7 to 2 seconds faster than the time I stood on in class :puke:

Nope, I really drove that poorly... :(

The surface fell apart in the afternoon (literally)...Look at National Champ Vic Sias' times in the SM car...about 2 seconds off of the fastest morning times :Eyecrazy:

Still, I just had major problems/spins/crxp in the run group. I did 3 fun runs right after and each run was 1.7 to 2 seconds faster than the time I stood on in class :puke:

So does that mean you made it into the 39's? I was pretty bummed about the surface yesterday even though I think it helped me drive a little more conservative and potentially smoother. Still, I thought Oakland was the last location that was half way decent. :mad:

Here's a video of my last run if you want to disect the course (and my driving) some more. Fun course, too bad there was no grip.

http://www.youtube.com/watch?v=KcHAOUgfu80

I thought about sticking around to adjust the rear toe and do some fun runs, but I was kind of beat as it was. We had grip problems in the early sessions too. I was completely sideways and lost all my momentum on my fast time. tried to smooth it out on my last run and just went slower. The car felt like it had a low 40 in it ...

I'm surprised the results aren't up yet, I can get to the actual and PAX time list, but not the basic results ... Glenn told me they'd be posted that night

I'm surprised the results aren't up yet...

It's up late Sunday night when I checked, http://www.sfrscca.org/solo2/Results/2007/Championship/round12.html. You can always get the event result link from baautox.com faster than waiting for the main site to be updated.

Wow, Mike, 39sec run? I heard 40.2 on your fun run while getting ready to leave. There is no doubt you are faster than all of us in BS and other SFR folks, in my mind. I'm sure all the talks about Shelby GT in FS is getting you a bit too pumped up for your own good and that of RX-8 :yelrotflm

did you actually click the event results link, it just brings me back to the results index page :dunno:

when I was looking on baautox.com they weren't posted yet, late Sunday night EDIT: they have the same link = failure, sent JM an email

you can get to the PAX and Fastest Actual Time page, but not the overall results page with the run by run times, fun runs, etc.

http://www.sfrscca.org/solo2/Results/2007/Championship/round12_lists.html#oa

It's up late Sunday night when I checked, http://www.sfrscca.org/solo2/Results/2007/Championship/round12.html. You can always get the event result link from baautox.com faster than waiting for the main site to be updated.

Wow, Mike, 39sec run? I heard 40.2 on your fun run while getting ready to leave. There is no doubt you are faster than all of us in BS and other SFR folks, in my mind. I'm sure all the talks about Shelby GT in FS is getting you a bit too pumped up for your own good and that of RX-8 :yelrotflm

I can just see it now......"Mwood at Oakland collesium, nobody else is there, all the cones have been picked up and it's getting dark but he's still out there try to beat Matts' time"......Seriously, if nothing else I admire your ambition to be the best.
:beer05:

I got to the actuall run-by-run result from the link posted on baautox as of Sun nite. The link always increments the event number but stays the same format/syntax.

The homepage link has been known to screw up.

I've been clicking on it since Sunday night, same result. I was incrementing the number before the results index page was updated that night and it was doing the same thing then. Somebody else noted having the same issue, 2nd post in the baautox.com results notice thread, :dunno:

Seriously, if nothing else I admire your ambition to be the best.
:beer05:


lol, his ambition is not to be the brunt of Ulllose's pointed stick :lol:

I don't know about any ambition, I just made such a mess of the official runs and, since fun runs were immediately after our group, I figured I might as well stick around. I went 40.003 and then got greedy and slowed to a 40.22, so no 39x, but nearly 2 seconds faster than my class time...but, that's with the benefit of an additional look at the course! Matt did great, as did CRX, both coming through when it counted :)

Being humbled is not a "bad" thing...I should know, I have plenty of experience with it! :lol2:

I don't know about any ambition, I just made such a mess of the official runs...Matt did great, as did CRX, both coming through when it counted :)

Being humbled is not a "bad" thing...I should know, I have plenty of experience with it! :lol2:

What mess? Just a spectacular spin right before the showcase straight =)

We all knew that you had a bad day, while us having a better day than usual. I wouldn't expect anything less but you coming out and beating on us. I should know, since I get humbled every single event.

as Ullose has so amply demonstrated, the capability to go fast is meaningless, going fast when it counts is all that counts ...

as Ullose has so amply demonstrated, the capability to go fast is meaningless, going fast when it counts is all that counts ...

That sums it up nicely.

But, more seat time is more better, so, while practice runs don't win jackets, there's nothing wrong with 'em...:)

Something else discovered at the Oakland event: The course developed quite a bit of gravel and sand off line, by the afternoon, with some of the crxp actually on line, as well. After my first run, I dropped tire pressures front and rear by a good margin, thinking that might somehow help on the low grip surface...and, it didn't really do anything. For the "fun runs", I just let the tires go back to wherever they wanted, ending at about 40f/38r with no real difference noted in grip. So, I'm beginning to believe that tire pressures, with the V710's very stiff sidewall, are not really of that much importance...as long as you're not getting big time roll over. On the other hand, I do think that f/r pressure differential is a significant factor.

Reza and I were running 38/35 before run, up 1 down 2 on the f/r hot psi right before my last run.

Many have pointed out the indifference of V710 re tire pressure. F/R bias is indeed more critical, accounting for rollover.

obviously less lateral grip = less rollover forces on the tire so running lower overall pressures makes sense

the asphalt we've been running on in NV has much more grip than the stadium, we see excess front edge rollover if the pressure drops below 42 on our gauge, 44 provides the best turn-in response and control there

I should be at the next several Oakland events, we can compare gauge readings