Test & Tune - Sunday March 7th

RodneyWright · **Posted:** Mon Mar 08, 2010 9:49 pm

michaelsmiller wrote:

I had a great time at TNT. Thanks to all. I tried to burn up what was left of the OEM tires and learn how to drive a FWD car with lots of HP after years of driving a 2006 Miata. I can’t believe these cars are from the same company. Ones a hammer and the other is a micrometer. Driving the MS3 is an experience of extremes. I vacillated from too much throttle to too much brake. My steering disappeared whiles turning. The damn thing should have rotated. My times were 26.3 right and 26.4 left, not to bad for crappy 215 wide tires. I felt as though I was fighting excess all of the time. The hammer, that’s work. I’m used to my car going where I want it and doing what it’s told. Out of all the complaints I’ve heard about the MS3, I didn’t even notice the torque steer. The real difference is that in the Miata one gets into a smooth flowing driving style. I just couldn’t pick up the rhythm of the MS3, everything was too abrupt. I’ll be getting new tires next week. Maybe that will help. If anyone can give me suggestions as to how to drive the car better, I would appreciate it. I hope to track it next month. I did succeed at destroying the tires. What wear bars? :evil:

Sounds like you and Brice need to start comparing notes....

Steven Carter · **Posted:** Mon Mar 08, 2010 10:38 pm

Noah Fleming drives his black MS3 pretty quickly as well. I've not met him, but I bet he's got some tips.

here's an intersting thread:

http://www.mazda3forums.com/index.php?topic=121013.0

I suspect higher rear tire pressure would be helpful as well. IIRC you've got about 63/37 weight distribution, so any trick to get the rear out will help.

@James, jokingly...and turn off VDC :roll:

JamesShort · **Posted:** Mon Mar 08, 2010 10:40 pm

Steven Carter wrote:

@James, jokingly...and turn off VDC :roll:

Don't remind me, ughh. What I'm surprised about is that I didn't notice it but a few times (most definitely at the final two cones near the finish gates....vibrating steering wheel...throttle cut). The alignment slightly covered up the VDC castration. On my checklist I have for crap to bring to the events, I typed: "Sticky note on steering wheel: TURN VDC OFF!!!"

.\

Ha, I love how they (the MS3 folk in that thread) are amazed at a 285 on a 7.5" wheel. My jaw dropped at Feinberg putting a 265 on a 6" wheel

.

BriceJohnson · **Joined:** Thu Apr 13, 2006 7:33 am **Posts:** 2230

RodneyWright wrote:

michaelsmiller wrote:

I had a great time at TNT. Thanks to all. I tried to burn up what was left of the OEM tires and learn how to drive a FWD car with lots of HP after years of driving a 2006 Miata. I can’t believe these cars are from the same company. Ones a hammer and the other is a micrometer. Driving the MS3 is an experience of extremes. I vacillated from too much throttle to too much brake. My steering disappeared whiles turning. The damn thing should have rotated. My times were 26.3 right and 26.4 left, not to bad for crappy 215 wide tires. I felt as though I was fighting excess all of the time. The hammer, that’s work. I’m used to my car going where I want it and doing what it’s told. Out of all the complaints I’ve heard about the MS3, I didn’t even notice the torque steer. The real difference is that in the Miata one gets into a smooth flowing driving style. I just couldn’t pick up the rhythm of the MS3, everything was too abrupt. I’ll be getting new tires next week. Maybe that will help. If anyone can give me suggestions as to how to drive the car better, I would appreciate it. I hope to track it next month. I did succeed at destroying the tires. What wear bars? :evil:

Sounds like you and Brice need to start comparing notes....

Hehe, I wouldn't exactly say I drive smoothly, or that my car has a lot of precision. Driving a FWD is definitely very different than RWD (and not in a good way). I've also got a bigger rear sway bar that helps a lot.

JamesShort · **Posted:** Tue Mar 09, 2010 10:29 am

Brice, how is the front camber adjustable on the 3? Eccentric bolts on the strut clevis to knuckle?

In that MS3 thread, they were getting more neg camber by loosening the inboard LCA bolt and hammering a wedge in to somewhere and then tightening it down. Did you have to do that?

Anyway, Mike, coming from someone whose car is a pusher in stock form, when I bumped my camber out from ~0 to -1.0 (with the stock eccentric bolt) and running just a hair of toe out (1/32" or less per side...1/16" total), it was NIGHT and DAY. The car became so much more balanced....doesn't push as much. I can actually get some throttle lift rotation. My average speed in sweepers feels higher and I can get back on the throttle much sooner at turn exit. All I have done other than that is the 25mm FSB. Still on the stock tires (Dunlop Sport SP 01.....more a performance all season than a summer tire).

Keith Vail · **Posted:** Tue Mar 09, 2010 11:01 am

JamesShort wrote:

Ha, I love how they (the MS3 folk in that thread) are amazed at a 285 on a 7.5" wheel. My jaw dropped at Feinberg putting a 265 on a 6" wheel

.

It is harder to mount the 285/30/18 on the 7.5 inch wheel than the 275/35/15 on the 6 inch wheel mainly because of the amount of sidewall. The 18 has almost none. Either way I still preferred mounting the 285's on the 7.5 compared to the 245/35/18 V710. Those are the worst tires in the world to get to bead up.

BriceJohnson · **Joined:** Thu Apr 13, 2006 7:33 am **Posts:** 2230

There is no real camber adjustment for my car. Eccentric bolts won't work with the knuckle/strut connection design on the car. The only real way I could see would be to slot the holes at the top of the strut mount (which I would worry about it slipping). I REALLY don't understand how that wedge solution you're describing works. Eccentric LCA bushings would do it, but nobody makes them. There is a set of camber plates available for the 3, but they suck from what I hear, and they cost a mint (you have to get them from australia). I've always got that option, being in ST, just not something I've taken the plunge on yet (although I probably will this year).

JamesShort · **Posted:** Tue Mar 09, 2010 11:41 am

BriceJohnson wrote:

There is no real camber adjustment for my car. Eccentric bolts won't work with the knuckle/strut connection design on the car. The only real way I could see would be to slot the holes at the top of the strut mount (which I would worry about it slipping). I REALLY don't understand how that wedge solution you're describing works. Eccentric LCA bushings would do it, but nobody makes them. There is a set of camber plates available for the 3, but they suck from what I hear, and they cost a mint (you have to get them from australia). I've always got that option, being in ST, just not something I've taken the plunge on yet (although I probably will this year).

My hunch is that they loosened the 2 connections between the LCA and the subframe, and hammered a wedge behind (inboard) of the ends of the LCA to take advantage of some loosness in the bolt and bolt holes (possibly even precompressing the bushings a bit in doing so).

BriceJohnson · **Joined:** Thu Apr 13, 2006 7:33 am **Posts:** 2230

the small bushing, right? You could of course make sure that you're taken up all the slop in the two holes that locate the big bushing, but theres no way to really preload the bushing (not to mention it would be a bad idea as that bushing has a tendency to tear). I've actually torn that big bushing on both sides of my car (granted, its got 126k miles on it with a lot of autocross duty, but its clearly a weak point). Its never torn catastrophically, but I'm pretty sure that these bushings wearing has been responsible for some pretty extreme tire wear for me (if its weak, it will toe out).

JamesShort · **Posted:** Tue Mar 09, 2010 12:04 pm

BriceJohnson wrote:

the small bushing, right? You could of course make sure that you're taken up all the slop in the two holes that locate the big bushing, but theres no way to really preload the bushing (not to mention it would be a bad idea as that bushing has a tendency to tear). I've actually torn that big bushing on both sides of my car (granted, its got 126k miles on it with a lot of autocross duty, but its clearly a weak point). Its never torn catastrophically, but I'm pretty sure that these bushings wearing has been responsible for some pretty extreme tire wear for me (if its weak, it will toe out).

Yeah, if you read that thread that Steve posted, those guys were running some pretty absurd toe out on purpose though part of it must have been due to this non-ideal method of creating negative camber. And yes, looking at that diagram, the front/small bushing is the only one where this wedge 'trick' could work. Is the front suspension pretty similar from 3 to MS3? Just different shocks/springs?

Vincent Keene · **Posted:** Tue Mar 09, 2010 12:27 pm

BriceJohnson wrote:

There is no real camber adjustment for my car. Eccentric bolts won't work with the knuckle/strut connection design on the car. The only real way I could see would be to slot the holes at the top of the strut mount (which I would worry about it slipping).

You've seen how camber plates work and are tightened right? Mine use four tiny allen head screws and trust me they don't slip. I actually went to camber plates beacuse the eccentric bolts would always slip even if tightened with a 36" breaker bar.

Another, albeit radical, option is to reinforce the LCA and relocate the ball joint outward. It's been done before on car's like mine. Yeah, yeah, I know...the damn rule book doesn't allow it for your class.

BriceJohnson · **Joined:** Thu Apr 13, 2006 7:33 am **Posts:** 2230

Yeah, slotting the holes just worried me cuz if it doesn't work, there's no real good fix without welding the actual unibody of the car, which I'm trying to avoid (more of). Camber plates, if they slip, and they suck, I take them off, and no harm no foul. I'm not sure if I want the added harshness that comes along with pillowball mounts, but we'll see.

And yes, James, the suspensions are exactly the same except for control arms (MS3's is shorter to correct camber for the lower ride height), swaybar endlinks, swaybars, shocks, and a rear camber link as well.

Steven Carter · **Posted:** Tue Mar 09, 2010 1:26 pm

Keith Vail wrote:

JamesShort wrote:

Ha, I love how they (the MS3 folk in that thread) are amazed at a 285 on a 7.5" wheel. My jaw dropped at Feinberg putting a 265 on a 6" wheel

.

It is harder to mount the 285/30/18 on the 7.5 inch wheel than the 275/35/15 on the 6 inch wheel mainly because of the amount of sidewall. The 18 has almost none. Either way I still preferred mounting the 285's on the 7.5 compared to the 245/35/18 V710. Those are the worst tires in the world to get to bead up.

OK, so I'm a total ignorant fool when it comes to tire fitment. Is it trial and error that dictates what section width of a particular tire will fit on a specific rim? For the WRX there is clearly room between the sidewall and strut (and the outer sidewall and fender) for a wider tire, but apparently (since Internet forums are the Fount of Truth :wink:

) nothing bigger than 225 fits on a 7" wheel. They don't mention fender rubbing or other space constraints--is it just the stock wheel won't fit, or is it specific to R-compound tires vs street tires?

Sorry for the threadjack, but I didn't think it was worth a separate thread...thanks!

Chuck Branscomb · **Posted:** Tue Mar 09, 2010 1:37 pm

Steve,

My experience, which I think is mostly common, is that the V710 is a monster (impossible in some cases) to fit to narrower wheels. It has extremely stiff sidewalls that simply become close to 100% stiff when pinched enough.

A few years ago GRM did a test of tires, 285/30-18 I think, and when they tried to fit the V710 on their 8" (I think) wheel, the sidewalls just crumpled. I had a set of 245/35 that were almost impossible to get to take air and seat the beads on an 8" wheel...enough that the Kumho engineer/support guy I was talking with about it said that depending on the wheel type they had experienced trouble too.

A 245/35-18 Hoosier A6 will just pop right onto an 8" wheel and air up with no issues -- any installer could do it in 60 seconds.

So the deal is, "in general", V710s are nightmares to try to squeeze on minimum spec size or smaller wheels. Hoosier A6s are no problem -- I think Jim has put a 275/35 A6 on a 6" wheel or something crazy like that. BFG R1s have much stiffer sidewalls than an A6, but you can get them to seat and take air on smaller wheels, just not as small as the A6 will go. I've had a 265/35-18 R1 mounted on an 8" wheel for example. It wasn't an A6-piece-of-cake, but it fit and aired up.

JamesShort · **Posted:** Tue Mar 09, 2010 2:29 pm

Chuck Branscomb wrote:

Steve,

My experience, which I think is mostly common, is that the V710 is a monster (impossible in some cases) to fit to narrower wheels. It has extremely stiff sidewalls that simply become close to 100% stiff when pinched enough.

A few years ago GRM did a test of tires, 285/30-18 I think, and when they tried to fit the V710 on their 8" (I think) wheel, the sidewalls just crumpled. I had a set of 245/35 that were almost impossible to get to take air and seat the beads on an 8" wheel...enough that the Kumho engineer/support guy I was talking with about it said that depending on the wheel type they had experienced trouble too.

A 245/35-18 Hoosier A6 will just pop right onto an 8" wheel and air up with no issues -- any installer could do it in 60 seconds.

So the deal is, "in general", V710s are nightmares to try to squeeze on minimum spec size or smaller wheels. Hoosier A6s are no problem -- I think Jim has put a 275/35 A6 on a 6" wheel or something crazy like that. BFG R1s have much stiffer sidewalls than an A6, but you can get them to seat and take air on smaller wheels, just not as small as the A6 will go. I've had a 265/35-18 R1 mounted on an 8" wheel for example. It wasn't an A6-piece-of-cake, but it fit and aired up.

Thanks for that Chuck.

Let me just switch from r compound to street tires. Why would one (the internet

) suggest not going any higher than 225 on a 7" wheel when there are plenty of people running 245+ r compounds on 7" wheels. Is it due to less stiff sidewalls on the street tires? And because of that, there is a greater risk of debeading it under heavy lateral loads if the sidewall is flimsy?

THSCC Forums

Test & Tune - Sunday March 7th

Who is online