LSD? To Have Or Not To Have

[Jason Isley BS RX8]

So I guess it's OK in Stock to disconnect the rear bar ... you just can't change it out ... right?

You should read the stock class solo rules.

[Steve Ekstrand]

A rulebook... Imagine.


BTW-Mako--Are you guys lifting that inside rear tire WITHOUT the broken front bar attachment?

[Aaron Goldsmith]

We had the rear rebound set to 5 turns off of full stiff on our Penske's at the last event ... after the front bar attachment point broke. Can't go much softer.

So are you having this problem when the front bar is on the car or just when it's broken? Seems to me this isn't a damping issue, it's a roll control issue.

This is for stock class right?

Are the other miata's in class not having this problem?

[Mako Koiwai]

Correct, it's been like that ever since we raised the car to legal ride heights (once I got involved with that car), ie. most of the year. We've been trying to deal with it in various ways, but then I recently found out that the dif of this car had been replaced with a handy used dif. I was wondering if they "accidentally" put in a open dif.

Rule Book ... of course. But you get people who you think are in the know saying things like disconnect the rear bar. Interesting idea, that I don't even recall being ever mentioned in the rule book. "Yes Doug, we have the oem rear bar ... it just doesn't happen to be connected." OK or Not ? Of course that oem rear Miata bar is a piece of spaghetti!

[Aaron Goldsmith]

Rule Book ... of course. But you get people who you think are in the know saying things like disconnect the rear bar.

I just said I disconnected it on a BSP car. Though the real fix would be to put a Clutch dif in the car. I've never run stock, the rules are your responsibility.

Sounds like something is broken or binding if the other Miatas in class aren't having the same problem.

[Jason Isley BS RX8]

One other factor that could contribute to your issue, is the balloons you are using for tires. The 225-50 might be helping your gearing, but it has raised your CG, softened your effective spring rate and can roll on the rim a lot more than a shorter tire. If that big tire pulls the front down more you are more likely to pick up the rear, as soon as you lift a tire with a Torsen it acts like an open diff.

[Mako Koiwai]

Aaron ... yes ... even with a properly attached front bar we're getting a lot of roll, which means the inside rear tire is coming off the ground, making it hard to get the power down on corner exit.

The first photo in the first message comparing our Miata with TIm's shows that they have the same attitude, but they aren't having our issue. Ryan said that they were at one point last year, but then Tim had the rear "overhauled," and it was "1,000 times better." We put in new bushings and had the Penske's rebuilt. Not sure what else we can do? Camber is maxed out like any CS Miata. Slight toe in.

We've got the 2nd to largest front bar: 1.125 inches ... there is a 1.25" bar available.

Going to check the reservoirs today at Henry's. If our front reservoirs have lost pressure, we would get more roll. Replacing the A arm with the broken sway bar attachment point today.

As an experiment, I lowered the rear as much as I could, and traction was immediately better. We had to raise it again in order for the spring perch and locking collar to clear the drive shafts, besides coming up to legal height.

[Mako Koiwai]

Understand the issue with the tires ... but we were having to constantly do the 2nd/3rd shift dance, and I was trying to spare Karen that trouble. btw. Tim is now using (short) 275's on his 15" skinny rims!

hmmm ... perhaps we should try raising the front a bit?

[Aaron Goldsmith]

Understand the issue with the tires ... but we were having to constantly do the 2nd/3rd shift dance, and I was trying to spare Karen that trouble. btw. Tim is now using (short) 275's on his 15" skinny rims!

hmmm ... perhaps we should try raising the front a bit?

Well.. removing grip from the front will alleviate the issue. Probably have to compromise somewhere given that it's Stock Class.

Next time you have things semi taken apart check to see if any of the bushings are binding.

[Jason Isley BS RX8]

Understand the issue with the tires ... but we were having to constantly do the 2nd/3rd shift dance, and I was trying to spare Karen that trouble. btw. Tim is now using (short) 275's on his 15" skinny rims!

hmmm ... perhaps we should try raising the front a bit?

Then dump the 10AE and get the right car for the class.... If you are going to try to keep up with the likes of Ryan you are never going to get there with what you have.

How are you going to change ride height and be legal? All of your perches have to be set at the stock location.

[Jason Isley BS RX8]

Rule Book ... of course. But you get people who you think are in the know saying things like disconnect the rear bar. Interesting idea, that I don't even recall being ever mentioned in the rule book.

Which is why you need to read it and know it.

[Mako Koiwai]

How are you going to change ride height and be legal?

Of course ... need to double check it ... the front seems a bit low while the rear is correct and looks high.

Who would ever go after Ryan! Unless he's driving a VW.

Just trying to get the next couple of races behind us ... then the Miata might go back to the DD Class, while we contemplate SK2 with a new WRX, or SK1 with a used S2000.

[Will Kalman]

Mako, ask Tim if you can take a run or two in his car and/or have Tim/Ryan drive yours.

The Stock rules allow unlimited adjustments (and modification?) of the driver! Seriously, you may find that some of your problem might be driver-induced.

[Mako Koiwai]

Ryan has driven our car ... and noted the lack of traction, besides being down on power. Interesting ... Ryan said the new MS-R Miata is SO MUCH EASIER to drive fast then our old CS Miata's ... because it's lowered and stiffer.

Did a Obd scanner check on it recently and it suggested a new Coil Pack ... which I replaced yesterday. New spark plug leads went in a few weeks ago. We check compression recently, and found we were way down ... but so was Tim's, Steve C, and one other Miata we checked. Tim thought his new engine should have read much higher ... so perhaps the gauge was off? With all of the plugs our, throttle open, we were getting readings in the 140 PSI range ... while oem is 209 according to the shop manual. No, we didn't do a leak down test, add oil to the cylinders, etc. We were just comparing our different engines. We have a CA twin CAT model while I believe Tim's engine has the 49 state exhaust manifold, ie. only one CAT.

Tim's been having issues with his car's handling also ... but related to his new DA's. Lots of oversteer that he can't seem to dial out. He was at the end of his adjustments ... and going to have them rebuilt again. Ryan probably likes it the way it is.

[Jason Isley BS RX8]

Who would ever go after Ryan! Unless he's driving a VW.

Just trying to get the next couple of races behind us ... then the Miata might go back to the DD Class, while we contemplate SK2 with a new WRX, or SK1 with a used S2000.

WOW, that is a low blow.

S2K: http://www.baautox.com/forum/index.php? ... rt=0&rid=0" onclick="window.open(this.href);return false;

[Mako Koiwai]

Hey ... I'm sympathizing with him! WE know how outstanding he is .... :king:

[Jason Rhoades]

How about a bigger/stiffer front bar?

[Mako Koiwai]

we have the 2nd largest bar ... 1.125 vs 1.250 ... I TOLD her to get the largest bar!

[Aaron Goldsmith]

we have the 2nd largest bar ... 1.125 vs 1.250 ... I TOLD her to get the largest bar!

haha, I figured you just didn't want to run a larger front bar, that's why you were still asking questions.

[Mako Koiwai]

That bar went in, with a lot of difficulties getting the HD mounts in ... you have to de-weld the oem mounts ... before I was "involved" with that car. ;)

[Jason Rhoades]

Front bar change should be a lot easier than monkeying with the diff.

You can go bigger than 1.25 if needed.

There is no such thing as the "largest" bar.

[Bob Beamesderfer]

That bar went in, with a lot of difficulties getting the HD mounts in ... you have to de-weld the oem mounts ... before I was "involved" with that car. ;)

You can't take the stock mounts off and put the Mazdaspeed mounts in. AFAIK, you can't do that in SP.

[Mako Koiwai]

I checked various sources and they said the mounts themselves were OK but not the "reinforcement" parts.

[Jason Isley BS RX8]

You can't take the stock mounts off and put the Mazdaspeed mounts in. AFAIK, you can't do that in SP.

Another guy that needs to get familiar with the rule book. Try Appendix F.

[Bob Beamesderfer]

You can't take the stock mounts off and put the Mazdaspeed mounts in. AFAIK, you can't do that in SP.

Another guy that needs to get familiar with the rule book. Try Appendix F.

I was misinformulated.