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Old 11-23-2008, 01:26 AM   #21
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actually we passed through there too went out at 9:30pm came home at 4:30am
but you are correct: too much traffic and cops. it was a spur of the moment thing, and Ill make sure to scope out some better roads if we go again
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Old 11-23-2008, 01:30 AM   #22
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Now that I've read your last post I do have a thought or two. Crappy tires will result in crappy, unpredictable, and potentially very dangerous handling. So will old or improperly inflated tires. And possibly so will tires (on a Miata) which aren't balanced in size from front to back, though I'm not sure about that. But, perhaps it's your tires.

You also mention noticing a change when you switched to a Torsen rear end. I came across this article a few days ago by Nick Adams, the project manager for the Federal (American?) version of the Lotus Elise:

"The Elise was always designed from the outset to work without an LSD. We have recently started to offer an LSD as an option on the Toyota engined cars, primarily in response to market demand from the Autocross enthusiasts in the USA, who need one to be competitive when accelerating away at full throttle from very slow, tight corners in first or second gear.

In this type of competition they do not tend to run high speed (100mph +) corners and therefore the increase in understeer on this type of corner which you get with an LSD is of little negative consequence to them and they therefore are better off with an LSD.
In our experience an Elise or Exige equipped with an LSD is at a disadvantage to one without an LSD on a typical European race track. On top of that the LSD bluntens the steering feel and response of the car which we don't like.

If you want an LSD then by all means fit one, but please understand that there are negative as well as positive effects. In the instance you describe, instead of spinning the inside wheel as you accelerate away at full throttle (which can be easily fixed by modulating the throttle! Very Happy ) a car with a 2:1 LSD like the obne we supply will provide twice the torque to the outside wheel as it does to the inside one. This will increase the slip angle of the outside wheel and the car will tend to oversteer heavily on corner exit, requiring a reduction in throttle if you are not to spin.... It isn't much quicker, honest.

The optional diff we supply is a Torsen unit; the aftermarket unit supplied by Motorsport is a plate diff, with a similar 2:1 bias and no preload so in terms of action it mimics the Torsen closely."


So you having experienced increased oversteer after changing to a limited slip differential isn't unprecedented; Nick Adams might have told you to expect it. Chances are the change in rear ends has simply exaggerated a characteristic your particular suspension/alignment/tire setup already had. Now all's you've got to do is fix it; a cheap and easy way to begin by checking the expiration date on those tires.
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Old 11-23-2008, 01:45 AM   #23
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phenomenal info there. I completely agree as well..without the torsen I was able to keep it under control..right now there is no "buffer" zone: it simply lets out in the blink of an eye. That I will have to learn to modulate better (or react to its fast actions quicker). The tires are also CRAP...complete and utter generic shitty looking CRAP. Here is what Ill do: remove the rear sway (If anything it wont hurt) and start shopping for tires. No more spirited runs till they are bald and switched out for something along the lines of falken rt615s or something similar. dont know about miata's, but on a friends sti they feel GREAT.
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Old 11-23-2008, 01:58 AM   #24
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2 things....

Get real tires....

Learn to drive the car. It's not a WRX and requires a different technique. It's nearly IMPOSSIBLE to give a diagnostic of why a car is handling one way or another over the internet. It needs to be driven by someone with a good bit of knowledge of setting up and making a Miata handle. Try finding a local who runs in any SCCA events or someone in the area known for top-notch alignments.... and not your local 'canyon carving' buddy.


I also disagree with the "take your rear sway bar off" bullshit. It's total garbage advice. I'm running my front at the lower setting and my rear on full stiff with NO problems of oversteer (unless caused by trail braking or too much throttle too soon). Removing the rear sway is something not for RWD street driven cars.

Last edited by Doppelgänger; 11-23-2008 at 02:08 AM.
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Old 11-23-2008, 02:01 AM   #25
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well sure its not a wrx, but I have driven a 240sx many times on the same road, and didnt have this problem. I will be experimenting with everything mentioned and report back what I found to be the best
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Old 11-23-2008, 02:09 AM   #26
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Quote:
Originally Posted by 18psi View Post
well sure its not a wrx, but I have driven a 240sx many times on the same road, and didnt have this problem. I will be experimenting with everything mentioned and report back what I found to be the best
Stop comparing it to other cars....it just doesn't work that way.
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Old 11-23-2008, 03:43 AM   #27
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Quote:
Originally Posted by Doppelgänger View Post
Removing the rear sway is something not for RWD street driven cars.
I've pulled my rear sway on several occasions to calm the rear end down a little bit and it's worked very nicely. Problem is that it causes the car to push pretty badly on corner entry. With no rear sway, as you turn in, the inside rear corner drops down to max droop and keeps the car in line. With a rear sway, even a tiny stock one, the inside rear will only drop down a few tenths of an inch further than the outside rear corner. That's a difference of a couple of inches in some cases, which is huge. I have an RB tubular front sway and an MSM rear sway.

Basically, get a big-*** front sway.
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Old 11-23-2008, 04:03 AM   #28
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looking at rb hollow and solid front sways...cant figure out wtf is the big difference. I want the hollow rb front right?
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Old 11-23-2008, 04:11 AM   #29
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The hollow is stiffer and lighter. You want the RB tubular hollow.
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Old 11-23-2008, 09:22 AM   #30
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Jesus Tapdancing Christ Doppelganger... Don't be a tool. The only garbage here is your comment. Let's spell it out for you since you cannot see beyond your nose.

Assuming you get some good tires, adjust the pressures, and you still have a problem, removing the rear sway is a quick and easy way to check for sway bar bias. If it helps, and you like the improvement, and have to have a rear sway, then try a larger front sway and reinstall the rear sway.

The point here Doppel, is that someone can try the change in sway bar bias approach out for FREE with the STOCK bars. Several with non-stock springs have removed the rear sway to correct oversteer with good success, including me.
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Old 11-23-2008, 11:00 AM   #31
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FWIW, I have the biggest tubular sway RB makes (1-1/4") and I ran it on the stiff setting with the rear bar and the car was a little too easy to unsettle. It was very unforgiving if there was ANY change in road surface condition mid-corner.

So I put the front bar on the soft holes and left the rear bar on. The car was less unsettled, but too oversteer biased.

So I pulled the rear bar and now it's a very happy little car. (front still on "soft" which is about equivalent to a 1" solid bar).

This is with Tein 7(400)/6(330) rates and a clutch type LSD with a lot of locking. With the clutch diff (as opposed to 18psi's torsen) it tucks in nicely for corners.
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Old 11-23-2008, 11:37 AM   #32
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I have had my FM sways (front/rear) matched with AGX's and FM springs since I've owned the car. The only time I have oversteer is when I am too heavy on the throttle. I've never been out for a drive and had the car just kick out on me without me knowing I was gonna do so.

I agree, take out the rear sway since its free and easy and see where that gets you. I do bet you are a little heavy on the gas through corners coming from a WRX. Thus taking out the rear sway, might be your ticket. Try it today dude.

Vash-
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Old 11-23-2008, 12:28 PM   #33
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Quote:
looking at rb hollow and solid front sways...cant figure out wtf is the big difference. I want the hollow rb front right?
You might want the hollow, or you might want the solid, but first you've got to understand that an anti-sway bar transfers load from the heavily loaded side to the less heavily loaded side of the suspension.

In doing so it sacrifices a bit of traction in exchange for reducing roll. That's why removing the rear bar increases grip in the rear (more roll and more grip) and installing a larger bar in the front increases apparent grip in the rear. What really happens is that the front has less roll and less grip in comparison to the rear which now "seems" to hook up better but which is actually hooking up pretty much the same except its better now in comparison to the front. This pretty much sums it up:

Quote:
Originally Posted by y8s View Post
i just like to add traction before taking it away. plus it costs less to remove the rear than to add a new front sway
And a smaller bar will take away less traction.

So, and like everything else, it's a compromise. The hollow bar will reduce both roll and grip in comparison to the solid bar. What you need to achieve balance front to back depends on the remainder of your set-up as well, and either bar might be appropriate depending on that setup.
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Old 11-23-2008, 12:58 PM   #34
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Well, maybe I have some kinda of dumb luck tuning method because I have NO such problems with the back end of my car coming out. Like I said, maybe the best way to diagnose is to have someone else who knows the cars very well drive the car.


Also, is the car stepping around when going from throttle to braking or when feathering the throttle in a corner or when simply lifting off the throttle when turning or just on turn-in? On my NA, I had some bad turn-in oversteer because I had the rear shocks set too soft.
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Old 11-23-2008, 07:00 PM   #35
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the car spins pretty much under any conditions. let off, it spins. keep the throttle the same, it spins. give it a little more gas, it spins less at first, but on exit absolutely loses it. I would be more than happy to let an experienced miata driver drive it and tell me if im on crack. any takers?

Oh and I will be taking off the bar tonight hopefully. keeping fingers crossed
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Old 11-23-2008, 07:40 PM   #36
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There are lot's of Miata guys running with no rear sway. What worked for Dopple isn't what's working for most. The RB hollow is popular as it is light. It's not stiffer than a similar solid bar though. The FM sways are a good balance and have proven to work well. You can remove the rear bar for free and see how you like it. Easy and affordable to upgrade sways so if just eliminating the rear doesn't solve the problem it's not a huge expense to add a big front bar. If that's overkill you can always put the rear stocker back on.

Crappy tires are certainly a potential problem but other than buy better and matching tires what is there to say?

Alignment can be a big issue. I'm using 949's settings. What is your ride height? If your numbers are right in the earlier post you aren't running nearly enough camber. Also the camber front and rear should be more balanced if 949 knows his stuff at all. Here is his set up suggestions. Miata Setup Info

With a moderate ride height he's something like -2.8 front and -2.5 rear. I'm using his settings and really like it. Not the most tire friendly set up but I like the handling and wear better than when I was running Icehawk settings. Doesn't wear as well but handles better than the FM suggested settings. 949 runs more camber but less caster than FM. I like the feel much better that way.

Of course you already have FM springs you could easily do their bars and settings. It's all designed to work together! (at least thats what they say. he he)
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Old 11-23-2008, 11:52 PM   #37
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I'm fairly certain if I had removed my rear bar sooner I wouldn't have destroyed my last car...

I would lose my rear so unpredictably before I tossed it in the trash. Now it takes a great bit of effort for it to step out, and it if it does, it's very predictable and easy to maneuver and correct.

This is with FM springs...
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Old 11-24-2008, 12:06 AM   #38
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Quote:
Originally Posted by y8s View Post
FWIW, I have the biggest tubular sway RB makes (1-1/4") and I ran it on the stiff setting with the rear bar and the car was a little too easy to unsettle. It was very unforgiving if there was ANY change in road surface condition mid-corner.

So I put the front bar on the soft holes and left the rear bar on. The car was less unsettled, but too oversteer biased.

So I pulled the rear bar and now it's a very happy little car. (front still on "soft" which is about equivalent to a 1" solid bar).

This is with Tein 7(400)/6(330) rates and a clutch type LSD with a lot of locking. With the clutch diff (as opposed to 18psi's torsen) it tucks in nicely for corners.
If you bumped your front springs up to 9kg, and put the rear bar back in, the car would turn in nicer and stay solid on exit. You NEED a rear bar to alleviate low-speed push, especially with a clutch-type diff. It's something you'd never notice on the street.
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Old 11-24-2008, 12:32 AM   #39
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Quote:
Originally Posted by Savington View Post
If you bumped your front springs up to 9kg, and put the rear bar back in, the car would turn in nicer and stay solid on exit. You NEED a rear bar to alleviate low-speed push, especially with a clutch-type diff. It's something you'd never notice on the street.
Wonder if I should be installing my stock sway or my FM rear sway when I go and autocross then, makes sense.
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Old 11-24-2008, 12:39 AM   #40
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I had Tein Flex with the standard 7/6 springs and a hollow front RB bar and no rear bar and the "Icehawk" alignment. I now have 9/6 springs with the hollow front RB bar and a stock (11mm I think?) rear bar. I like the feeling of my current setup much more. I also have a fairly aggressive alignment now. Zero toe up front, 1/16 total toe in at the rear. -2.3 camber up front and -2 in the rear. Middle of the road caster, somewhere around 3-4 degrees.My first setup would push initially in turn in and the rear felt less controlled. I don't know the technical explanation but the inside rear would feel as though it were lifting up as if it wanted to oversteer but the front would still push. Now everything stays flat and just turns and feels like it's working together. It now feels neutral with oversteer/understeer controllable with the gas pedal. What I'm saying is changes in spring rate or sway bar alone will change the over all nature of the car but it's a balance and fine tuning of all of them that really makes the car feel good. It can oversteer and not feel great just as it can push and not feel great.
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