Sway bars

[mitch_f1]

So I am looking at upgrading sway bars next. Reason being that I am noticing my inside rear lifting and spinning on tight corners such as fishook at WP and the final turn at MDTC, and was told that a sway bar adjustment should fix that? Is that correct?

Just interested to know if anyone knew what diameter the JDM sway bars were, or if they were any different to the AUDM cars (mine is an import)

What sizes are people running in their cars?

Is it worth leaving the front sway bar standard and just getting adjustable links, and getting a rear adjustable sway bar?

[Hellmun]

Get a vernier and measure the bars you've got. It's an easy thing to swap so there's a good chance it's already been changed by someone if it's an import. If your getting an actual wheel lifting that sounds like an overly stiff rear bar is already in use as the stock rear bar on all MX5's is pretty thin (12mm from memory). If you put on adjustable end-links you can drop the pre-load off a bit which increases the allowance in height difference between the two sides. You don't get an awful lot of adjustment though. Hell they could just be adjustable bars already that are set wrong holes

As far as I know the stock bars were the same on the AUDM Vs JDM models. I personally run a 24mm front bar and 16mm rear bar on an NB8B. I've heard this much rear bar is very bad for an NA though if you've got one. Stock bars were 21mm and 12mm for my car IIRC. Depends on how much chassis bracing you have though. I find my car feels great with the 16mm rear bar, I actually run full hard on the front bar, medium on the rear. Whereas Irwin8er who's pretty close in lap times runs a stock rear bar on his car because he found it wanted to oversteer too much on his NB8A with the 16mm even on it's softest setting. We're both running tein monoflexes at the same height and similar damper setting. The cars are incredibly similar with bracing being the main difference. So it really is car Dependant.

[mitch_f1]

Gosh, such an idiot, didnt' think of that, sorry. So yeh, I have stock sway bars F+R.

In terms of bracing I havea FM style rear subframe frace (was a GB here a little while ago for it), I also have front lower control arm braces and a strut brace.

So to get that rear wheel back on the ground then what would be the best way to go about that? I guess a thicker sway bar, even if it is adjustable probably wouldn't be the best option?

[rascal]

So to get that rear wheel back on the ground then what would be the best way to go about that? I guess a thicker sway bar, even if it is adjustable probably wouldn't be the best option?

You need to stiffen the front to stop the front of the car rolling and taking the stiff rear with it and/or soften the rear to allow the wheel to better stay in contact with the road.

[Guran]

It's been said many times before but I'll say it again. Forget about doing more modifications until your laptimes are approaching the limits of your car. With the mods you describe, your car would be capable of doing 1:16s at Wakefield with regular street tyres. But are you? Practice practice practice! Fun fun fun!

For the record, my standard NA6 can do 1:15s (possibly 1:14s) on R specs and 1:17s (probably 1:16s) on Adrenalins. And I get plenty of inside wheel spin at the fishhook and turn 10.

[rwf]

LSD

[mitch_f1]

You make a good point Guran, but it's just interesting to know what adjustments would be made.

[Hellmun]

Torsens only work if both wheels are on the ground so it has to be a clutch type and a relatively tight one to not have any slip. If it's a full-on race car you can just go a spool though. 2 way Clutch packs and spools both cause a lot more understeer so be warned.

Front bar is a good starting point as Sway bars don't break the bank but can have some pretty large effects on handling.

So I am looking at upgrading sway bars next. Reason being that I am noticing my inside rear lifting and spinning on tight corners such as fishook at WP and the final turn at MDTC, and was told that a sway bar adjustment should fix that? Is that correct?

Here's why it works if you want to understand a little more. Lifting a rear wheel in the air means that weight distribution is shifting to the diagonal opposite front wheel of the car. A bigger front swaybar means that the difference in movement between the two front wheels is limited further as it will not twist as much before it exerts it's force or essentially locks the two wheels together. The effect this has is that when the outside front wheel under highest load compresses far enough to start the swaybar transferring force to the other front wheel it starts pulling the other front wheel up. So the front swaybar size increase is actually taking grip away from your front inside wheel to distribute it among the other 3 wheels. This is beneficial if your finished turning and trying to get on the power as you want as much grip going to the Front outside and both rear wheels. If your trail braking though and still turning in you'll actually go slower because you want weight on the two front wheels and outside rear. So until you start accelerating out of the corner you've actually compromised how fast you can turn in. So is this actually faster with a bigger front swaybar? Well it will completely depends on the drivers ability, the stiffer front bar will mean the car will spend less time rolling and moving the weight to where you want it. This is why race cars are generally really stiff things.

Hope that makes sense and is right because it's how I tuned my car

[93_Clubman]

Just interested to know if anyone knew what diameter the JDM sway bars were, or if they were any different to the AUDM cars (mine is an import)

NA6 in Australia at least ran 19mm front & 12mm rear, except for '93 LE which ran 19mm & 11mm. There were some differences country to country, i.e. Australian Clubman to US R Package was 20mm & 11mm versus 20mm & 12mm. Also some of the JDM NA6 seem to have the orange-red MazdaSpeed 14mm rear.

MX5 OEM sway sizes:
NA6: 19mm Front & 12mm Rear (except on the 1993 na6 limited edition which were 19 & 11mm)
NA8: 19mm F & 11mm R (US standard Packages: 19mm F & 11mm R)
NA8 Clubman: 20mm F & 11mm R (US R Package: 20mm F & 12mm R)
NB8A: 22mm F & 11mm R
NB8A 10AE: 21mm F & 12mm R
NB8B: 22mm F & 12mm R
SP: 22mm? F & 12mm R
SE: 23mm F & 14mm R
NC1: 21mm F & 12mm R
NC2: 23.5mm F & 11.5mm R