Sway Bars

MN · Post by MN » Tue Jun 13, 2006 3:44 pm

Has anyone changed the sway bars on an NA?

The various tuning books make mention of different size bars being useful for autocrossing (in the States). I'm now getting understeer when pushing hard (rallying) and have been told a stiffer rear bar may dial it out. Any comments or thoughts?

Shift4Brains · Post by **Shift4Brains** » Wed Jun 14, 2006 9:25 pm

I changed mine to the Racing beat hollow sway bars a few years ago and felt that the car cornered flatter. After the rear bar snapped, I switched to Whiteline 3 way adjustables. I haven't had a chance to play much with the various settings, but it gives me some extra options when setting up the suspension. I'm not sure bigger sway bars prevent understeer, in my experience they help prevent 'wallowing' and keep the car more level round the corners.

Last time I went to Pukekoe I got my wheel alignment set to Larry's specs (from miata.net) and while that setup was fun at the track it was horrible on the road. It gave me lots of understeer which I hate. That went away when I went back to a more standard alignment. Perhaps you just need to play with your wheel alignment......

Ian · Post by **Ian** » Sun Jun 25, 2006 1:31 pm

Hi Mark...
NAs should be neutral/sight oversteer (pe 93 facelift) eg with12mm factory rear bar. (assuming standard springs are fitted, aftermarket springs where the rate ratio front/rear has been changed - very common, will also affect understeer/oversteer, as will wheel alignment, tyre pressures, tyre gri, weight distribution and a whole lot of other suspension tuning aspectsI barely understand...)

You say that your car has 'started to understeer' which suggests something has changed or been changed? (checked your rear bar bushes??)

I am still setting mine up so cannot comment from track experienceyet... but I will be starting with a whiteline 22mm front (19mm is standard) combined with a 12mm rear (my early 1.8 has the 11mm rear), both bars with aftermarket bushes including the links, with a torsen diff and yokohama AO 32Rs. I suspect/hope(?) I will have very slght understeer for circuit, which is how I like a race car....

Just changing the rear barand link bushes from the standard rubber ones, will give you more rear bar....

Hope this helps.

Cheers, Ian

MN · Post by MN » Mon Jun 26, 2006 9:25 pm

Tks for the comments. It is due for an alignment so it will interesting to see how its moved. The bushes haven't been changed for a while so they will also be on the list. Tyre pressures are a whole black art

When I'm rallying I want neutral handling and responsive. However I'm now finding the harder I drive understeer is starting to develop, but only on medium speed corners (probably not brave enough on the high speed ones!) and only after the tyres are up to temperature. Maybe it is pressure.

russellsmithies · Post by **russellsmithies** » Mon Jun 26, 2006 10:38 pm

Who's the agent for WhiteLine in NZ and what are a pair of bars worth?
I'm thinking of replacing the standard ones on my NA.

Growler · Post by **Growler** » Wed Jun 28, 2006 3:26 pm

MN wrote:Tks for the comments. It is due for an alignment so it will interesting to see how its moved. The bushes haven't been changed for a while so they will also be on the list. Tyre pressures are a whole black art

When I'm rallying I want neutral handling and responsive. However I'm now finding the harder I drive understeer is starting to develop, but only on medium speed corners (probably not brave enough on the high speed ones!) and only after the tyres are up to temperature. Maybe it is pressure.

If you are understeering through a mid range corner you have too much grip on the rear. I wouldn't touch the front roll bar but increase the rear if you can. Increasing the front will give you more understeer. You need to measure the temperature across the tyre in three places (inside, middle and outside) to see what pressure's are ideal for your suspension setup. The aim is to get the temperatures within 10 degree's of each other. This takes into consideration what your camber and caster are set at. (I usually work on 32psi around town and 33 - 34psi max for the track. I wouldn't go over that as the car only weighs around a ton and you would start to loose grip as the centre of the tyre would be touching the road. You could try increasing the width of your front tyre if you don't want to change anything on the suspension...or button off on the throttle! (Not too much or you will have weight transfer and could spin). Are you taking the correct line through the corner? Are you turning too sharply?
There are many points to take into consideration!

Growler.

Euen · Post by **Euen** » Thu Jun 29, 2006 11:43 pm

Hi Mark

Have a chat to Ron Scanlon at Total Performance in Petone. Ron is considered a bit of a suspension guru and my be able to help you sort it out.

Cheers
Euen

MN · Post by MN » Fri Jun 30, 2006 11:19 pm

Tks, all useful. Petone is just down the road.

If anyone's interested in such things the car in full rally trim with 2 up and varying amounts of fuel weighs between 1208-1235kg (Targa weighbridges). Its already running 205's so tyre width isn't the issue.

Keith Jones · Post by **Keith Jones** » Sat Jul 08, 2006 3:31 pm

Rear sway bars definitely do make a big difference to handling. When I first started racing my Pro7 car I stiffened up the front, with both considerably stiffer springs and sway bar, but left the rear sway bar standard. In my first outing at Pukekohe the thing was oversteering like crazy. Talking to some of the other Pro7 guys they said to take the rear sway bar off completely, which I did and it transformed the handling to neutral with slight oversteer on the limit.

I have just encountered the same problem with my MX5 at Taupo, which is really tight on the new section. The car was initially set up with Whiteline swaybars front and rear, 24mm front, 16mm rear. This was fine for Puke but is diabolical at Taupo. So I have just refitted the standard 12mm rear bar. The next outing a couple weeks will tell if that has fixed it, if not I'll soften the rear springs.

Keith

Ian · Post by **Ian** » Sat Jul 08, 2006 5:09 pm

Hi Keith...

Have yet to run my car at Ruapuna. Will be on Yokohama Race tyres and running 22mm whiteline plus 12 mm rear bar (in plastic bushes complete with end links in plastic bushes). I believe Whiteline also do a 14mm rear bar.
My info from the US suggests that 24/16 will give you significant oversteer and 24/12.7 combo will give you slight understeer. The type of LSD you have will affect the above...a torsen will let you run a slightly larger rear bar than a viscous
Also had a Pro 7 so can relate to your comments.

Cheers

Sway Bars

Sway Bars

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