# Some pics from the event today



## ·clyde· (Dec 26, 2001)




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## EdCT (Mar 14, 2002)

·clyde· said:


>


Looks like you could use a bit more roll stiffness in the rear? :dunno: That right front wheel seems to be lifting up a bit.

Ed


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## ·clyde· (Dec 26, 2001)

Not much I can do about the rear in Stock stuck with the springs and bar that Mazda gave me. Going to test with a stiffer front bar at some point.


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## ·clyde· (Dec 26, 2001)

rumratt said:


> a) If the front is already lifting, does a stiffer front make sense?
> 
> b) changing the front is legal but rear isn't?


 a) we'll find out (and remember who you're talking to)

b) correct


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## SoloII///M (May 16, 2003)

I don't think the goal should be to make the front tire lift. 

The S2000 guys slap on a bigger front bar for weight savings and to make the car a bit less oversteer prone. The BMW guys slap on a bigger front bar to make the car less understeer prone. The RX-8 is closer to an S2000 than it is to an M3 with regard to suspension setup. I'm guessing the car doesn't need a bar. 

But... it might make it faster in transitions because it will keep the front roll more in check. 

We may have to test this!

:eeps:


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## ·clyde· (Dec 26, 2001)

SoloII///M said:


> I don't think the goal should be to make the front tire lift.
> 
> The S2000 guys slap on a bigger front bar for weight savings and to make the car a bit less oversteer prone. The BMW guys slap on a bigger front bar to make the car less understeer prone. The RX-8 is closer to an S2000 than it is to an M3 with regard to suspension setup. I'm guessing the car doesn't need a bar.
> 
> ...


So I guess you understand what I've been grappling with, then, huh?

Also, note the sidewall flex front and rear.


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## SoloII///M (May 16, 2003)

·clyde· said:


> So I guess you understand what I've been grappling with, then, huh?
> 
> Also, note the sidewall flex front and rear.


Well if what you say about the A3S04 changes for next year is true... it should fix that. Or you can pump them up more? 

What's really impressive is how flat the front outside tire is to the ground at full cornering force. You do NOT want to see what an M3 looks like in the same corner.

Explains why adding a bunch of static negative camber helps us but wouldn't help you.

John


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## ·clyde· (Dec 26, 2001)

SoloII///M said:


> Well if what you say about the A3S04 changes for next year is true... it should fix that. Or you can pump them up more?
> 
> What's really impressive is how flat the front outside tire is to the ground at full cornering force. You do NOT want to see what an M3 looks like in the same corner.
> 
> ...


 The fronts started each run with 51psi. The rears I worked down from 30 to 28 over the runs to try and tame the tail. I was also adding compression to the rear shocks and by my fourth run the tail felt better planted on corner exit (but still easy to rotate midturn). Unfortunately, my driving was so pisspoor and inconsistent yesterday that I don't know whether it helped make me any faster.

There's another aspect to the sidewall flex story...the 245 is wider than Hoosier suggests for an 8" wide wheel. The sidewall has to bow a little bit for the tire to fit the wheel. As I understand it, that bow makes the sidewall more susceptible to flexing. Moving to even wider tires would likely make that problem worse...if it's really a problem. I have no issues with turn in response or steering responsiveness which are the first places I would expect (perhaps wrongly) to see negative qualities due to the flexing. After that, it's about the size and shape of the contact patch.


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## Elwood (Dec 20, 2002)

Dude! Nice Pics!!

Love how they caught that cone in mid air :rofl:


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## SoloII///M (May 16, 2003)

·clyde· said:


> The fronts started each run with 51psi. The rears I worked down from 30 to 28 over the runs to try and tame the tail. I was also adding compression to the rear shocks and by my fourth run the tail felt better planted on corner exit (but still easy to rotate midturn). Unfortunately, my driving was so pisspoor and inconsistent yesterday that I don't know whether it helped make me any faster.
> 
> There's another aspect to the sidewall flex story...the 245 is wider than Hoosier suggests for an 8" wide wheel. The sidewall has to bow a little bit for the tire to fit the wheel. As I understand it, that bow makes the sidewall more susceptible to flexing. Moving to even wider tires would likely make that problem worse...if it's really a problem. I have no issues with turn in response or steering responsiveness which are the first places I would expect (perhaps wrongly) to see negative qualities due to the flexing. After that, it's about the size and shape of the contact patch.


I'm puzzled. You're dropping the rear pressure to tame the tail? :dunno: Furthermore, I would expect that additional rear compression damping would make the tail more lively coming out of corners. My reasoning is that more rear compression damping would resist transfer of weight to the rear tires, making for less rear traction on corner exit?

We could run 225's, but I suspect with two drivers the heat might be an issue. Hell, from what Nick and Ken saw, the temps might become an issue regardless! Mark suggested that 225's would be the hot setup on my car, but I really liked the 245s. I never did hit them with a pyrometer, so no way to know if I was heating them up.

We're going to have to see what Kumho does with the V710 sizes for next year. I think they would have a 245/35/18 on the planner. It's a fairly common size nowadays.

I personally would not worry about the sidewall flexing issue. Tune the tire pressure with a pyrometer and don't worry about what it looks like :dunno:

john V


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## ·clyde· (Dec 26, 2001)

SoloII///M said:


> I'm puzzled. You're dropping the rear pressure to tame the tail? :dunno:


In this case, yes. The first time I ran on the Hoosies I started at 42psi in the rear and let them climb. They were at 49 after the final run that day. Second time out, the rears were at 55 and I kept them there. Mark suggested 36 and that's where we started for the DC Tour (which was the next event on R comps for me) and we kept dropping them from there, but I'm not sure where we ended up (Mark?). The next one was the one where you drove the car. We started at 31 and you know what happened there. I was at 31psi when we ran the Saturday Tour course again. The following event, I started with 35 and it felt like the rears were on ice. I dropped a pound or two after each run and things got a little calmer each time. I ended up with 31psi. I used 31 on all runs for the September event and it was looser than I would have liked. Then on Sunday, I started at 30 and worked down from there.

The other thing to note is that when we ran the Saturday Tour course for the local event it was the last time that the tires felt really good. The following event (the one that i described as like the rears were on ice) I drove really poorly too, so I don't know how much was driver and how much was tire, but the two events since then have been significantly worse than they were early in the season. I don't know how that interacts with the tire pressure changes in the last few events.



> We're going to have to see what Kumho does with the V710 sizes for next year. I think they would have a 245/35/18 on the planner. It's a fairly common size nowadays.
> 
> I personally would not worry about the sidewall flexing issue. Tune the tire pressure with a pyrometer and don't worry about what it looks like :dunno:


275 sizing is what some other people looking at RX-8s are asking about. The guy in Texas used both 245 and 275 Hoosiers A3S03s and was much happier with the 275s. Brian is running on that guy's old 275 R3S03s for the last couple events and he's pretty much caught up to me (maybe not if my driving hadn't been so awful lately, but without a better metric than scratch times...)

I'm not worried about the sidewall flex, but they provide clues to how hard the tires are working and what the contact patches may look like. It's just data that I want to note that can be referenced in the future.


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## SoloII///M (May 16, 2003)

·clyde· said:


> In this case, yes.


Edited my post above to ask you about the compression adjustments you made.

We really, really need a pyrometer and a crewmember to take temps right after each run. And a book to log all the setup parameters.

And a pen. 

The only reason I can see running 275s is if the 245s were burning up from excessive heat, which is certainly possible.

John


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## ·clyde· (Dec 26, 2001)

SoloII///M said:


> Furthermore, I would expect that additional rear compression damping would make the tail more lively coming out of corners. My reasoning is that more rear compression damping would resist transfer of weight to the rear tires, making for less rear traction on corner exit?


Attending the Koni seminar in Topeka opened my eyes to some things. If I understood right, and I may not have (and thus be going further down a wrong path), compression mainly deals with how the car reacts to the surface. Rebound deals mostly with how the car reacts to driver inputs. That makes sense when you think about how adjusting each affets ride quality. From just past turn in through exit, the rear was staying better planted with each increase of compression.



> We could run 225's, but I suspect with two drivers the heat might be an issue. Hell, from what Nick and Ken saw, the temps might become an issue regardless!


My feeling about the Nick/Ken experiment was that their heat and grip issues had more to do with running non-heat cycled sticker tires than anything else.[/QUOTE]



> We really, really need a pyrometer and a crewmember to take temps right after each run. And a book to log all the setup parameters.
> 
> And a pen.
> 
> The only reason I can see running 275s is if the 245s were burning up from excessive heat, which is certainly possible.


Yes. Yes. Yes. Yes. Um, maybe. If 275s give us faster times, I want them regardless of what temps they get up to or what the sidewalls look like or anything else.

I also want some kind of data acquisition capability.


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## EdCT (Mar 14, 2002)

·clyde· said:


> Yes. Yes. Yes. Yes. Um, maybe. If 275s give us faster times, I want them regardless of what temps they get up to or what the sidewalls look like or anything else.
> 
> I also want some kind of data acquisition capability.


It would seem to me increasing rear roll stiffness would cause less weight transfer to the outside rear tire, in turn, reducing the side wall flex.

Absent being allowed to do that (due to restrictions) is causing you to look for other solutions.

I'm wondering why this is, that is, why the "it's ok to add stiffness in the front, but not the back" rule :dunno:

Seems a bit arbitrary.

Ed


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## ·clyde· (Dec 26, 2001)

EdCT said:


> I'm wondering why this is, that is, why the "it's ok to add stiffness in the front, but not the back" rule :dunno:
> 
> Seems a bit arbitrary.


Welcome to the world of SCCA Solo II rules.

:angel:


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## SoloII///M (May 16, 2003)

·clyde· said:


> Attending the Koni seminar in Topeka opened my eyes to some things. If I understood right, and I may not have (and thus be going further down a wrong path), compression mainly deals with how the car reacts to the surface. Rebound deals mostly with how the car reacts to driver inputs. That makes sense when you think about how adjusting each affets ride quality. From just past turn in through exit, the rear was staying better planted with each increase of compression.


You're probably right about Nick and Ken. I keep forgetting Nick didn't have those tires heat cycled.

Is the DA shock's compression high speed compression or low speed? If it's high speed I can certainly see you being right. Come to think about it, when I asked BobT about whether DA shocks would help my corner-exit push, he basically told me that they would not, implying that the low-speed damping aspect of the shocks wasn't affected by the adjustment.


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## Nick325xiT 5spd (Dec 24, 2001)

I've fairly certain it's high speed, given that koni states that it's intended to control the motion of unsprung weight over bumps.

too much compression will cause massive wheel hop.

one thing people need to realize is that lifting a front wheel is not in any way big deal. sure, it isn't something you want to tune for, but it's not somethign to worry about in any way.


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## ·clyde· (Dec 26, 2001)

SoloII///M said:


> Is the DA shock's compression high speed compression or low speed? If it's high speed I can certainly see you being right. Come to think about it, when I asked BobT about whether DA shocks would help my corner-exit push, he basically told me that they would not, implying that the low-speed damping aspect of the shocks wasn't affected by the adjustment.


Going from memory (can check when I get home), low speed compression is just very, very slightly affected.


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## FSelekler (Jan 15, 2002)

Well, here is another vote of confidence on the "8":

KC, who sold his National Champ WRX wagon, purchased an 8 to campain it in BS  I am sure he has been around the zoom-zoom boards already

You guys have some work to do at nationals next year, best of luck.


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## TeamM3 (Dec 24, 2002)

it needs a bigger front bar :hi: but not just any bar will do


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## TeamM3 (Dec 24, 2002)

SoloII///M said:


> Is the DA shock's compression high speed compression or low speed? If it's high speed I can certainly see you being right. Come to think about it, when I asked BobT about whether DA shocks would help my corner-exit push, he basically told me that they would not, implying that the low-speed damping aspect of the shocks wasn't affected by the adjustment.


that depends on the shock model and how it is valved, unless he valved them for you :dunno:

and small changes do not necessarily mean small effects, it just depends


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## ·clyde· (Dec 26, 2001)

FSelekler said:


> KC, who sold his National Champ WRX wagon, purchased an 8 to campain it in BS  I am sure he has been around the zoom-zoom boards already


He and I have been talking. 

There are others that were waiting for the SEB decision, which has now been made public. 00-03 S2000, Boxster and Z4 are all going to AS pending approval by the BOD in December. :banana:


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## ·clyde· (Dec 26, 2001)

TeamZ4 said:


> it needs a bigger front bar :hi: but not just any bar will do


Not just any bar?  I was planning on the Racing Beat bar, but if you have something else in mind... :eeps:

And where have you been this whole thread? :stickpoke :angel:


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## The Roadstergal (Sep 7, 2002)

2 second penalty...


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## SoloII///M (May 16, 2003)

Meanwhile, in left field...



The Roadstergal said:


> 2 second penalty...


Mark, what makes you say it needs a front bar? And how would we figure out which front bar? Clyde, do you have specs on the available bars (including stock?)

I think it took him this long to get "TeamZ4" changed to "TeamM3." :eeps:

John V


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## ·clyde· (Dec 26, 2001)

SoloII///M said:


> Meanwhile, in left field...
> 
> Mark, what makes you say it needs a front bar? And how would we figure out which front bar? Clyde, do you have specs on the available bars (including stock?)
> 
> ...


In a cursory look, I only turned up thickness and pricing. No other details (beside the RB bar having beefier endlinks available as well).

Front bars
Stock: 27.0mm
Mazdaspeed: 27.2mm
Racing Beat: 32.0mm
Tanabe: 30.4mm


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## racerdave (Sep 15, 2003)

·clyde· said:


> Going from memory (can check when I get home), low speed compression is just very, very slightly affected.


Doesn't that seem counterintuitive? Wouldn't it be better for Koni to adjust slow-speed damping?


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## Nick325xiT 5spd (Dec 24, 2001)

racerdave said:


> Doesn't that seem counterintuitive? Wouldn't it be better for Koni to adjust slow-speed damping?


 That's why you pay for triple adjustable. High speed damping is as much as most will need anyway, although my Konis are just a touch past their limits for the springs rates I like and will likely go to.


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## ·clyde· (Dec 26, 2001)

racerdave said:


> Doesn't that seem counterintuitive? Wouldn't it be better for Koni to adjust slow-speed damping?


 Until you think about what the high speed damping adjustment is being adjusted for. Would you want a similar level of high speed compression damping for billiard table smooth, fresh asphalt as you would for old bumpy and broken concrete?


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## racerdave (Sep 15, 2003)

I must've missed the compression part. I could see that for compression, but for rebound, used as a tuning tool in stock classes, wouldn't you want to adjust slow-speed? That would seem to pay the biggest handling dividends.


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## ·clyde· (Dec 26, 2001)

The ranges of rebound and compression adjustments have different curves.


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## racerdave (Sep 15, 2003)

Gotcha...


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## Hercules (Jul 15, 2002)

After reading this thread...

I realize I don't understand **** about autoxing other than _it's fun_


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## TeamM3 (Dec 24, 2002)

·clyde· said:


> In a cursory look, I only turned up thickness and pricing. No other details (beside the RB bar having beefier endlinks available as well).
> 
> Front bars
> Stock: 27.0mm
> ...


Is the OE front bar solid?

Are all those other bars solid or are the larger ones tubular.

If tubular, what are their wall thicknesses?

Are they adjustable?

If they are adjustable, how so; multiple hole positions, infinite slider, etc?


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## ·clyde· (Dec 26, 2001)

TeamM3 said:


> Is the OE front bar solid?
> 
> Are all those other bars solid or are the larger ones tubular.
> 
> ...


I think that the OEM bar is tubular with a wall thickness of 0.134". AFAIK, the Racing Beat bar is also tubluar with a wall thickness of 0.1875" and is not adjustable.

Don't know about the others...


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## TeamM3 (Dec 24, 2002)

I'd highly recommend an adjustable bar. Isn't Tim Pryor running an aftermarket bar? Do you know what he has?


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## ·clyde· (Dec 26, 2001)

TeamM3 said:


> I'd highly recommend an adjustable bar. Isn't Tim Pryor running an aftermarket bar? Do you know what he has?


Adjustable would be my preference, but I dont' think there are any available yet (and I don't know of any in development).

Tim has the Racing Beat bar and I think that's what Ron and Annie Bauer are starting with too.


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## SoloII///M (May 16, 2003)

Get that GT logo out of your avatar. Blasphemy!


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## TeamM3 (Dec 24, 2002)

do you know where we can get our hands on an OE bar and end links to use as a pattern? :dunno:


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## ·clyde· (Dec 26, 2001)

I have a couple ideas...


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