sway bar question

[Fatty]

guys, i'm upgrading my stock standard NA6 suspension. the car is a road car with the occasional track day and i'm keen on getting it right for the track. this is a new area for me and i'm pretty clueless. so far i have got a set of tein ss and the full superpro bushes set to install.

i am looking for advice regarding sway bars. phil / manga blue tells me that the car can get pretty taily with the teins and poly bushes setup and standard sway bars. i trust his judgement so i'm seeking advice.

as far as i know there are 2 options. option 1 is to remove the rear sway bar alltogether. option 2 is to replace the front bar with a stiffer one. can i please have your thoughts on which option is better and why? one thing i love about the mx is the steering feedback. i think a stiffer front bar may reduce the feedback? but then, if it works better and keeps the car flatter thru the corners, i guess i'd be willing to sacrifice that a bit.

so i don't really know what i'm talking about but i'm keen to hear some opinions on what i should do. thanks.

[Rob E]

Gday James, i am not sure of the spring rate on your SS, but normally would be 7kg/6kg which is what i am running on my NA6.

I have gone with a larger front bar (Racing Beat hollow) and left the stock rear. To be honest i have not yet really pushed the car, however from suspension spreadsheets at fatcatmotorsport.com it looks to be fairly neutral. That said, i will not really know until i get it on the track.

I would suggest getting an adjustable front bar and setting on the middle position. Leave your rear bar in place.....see how the car goes then adjust from there, if still too taily then you can remove the rear bar.

[Matty]

Hey Fatty. I ran numerous setups on my NA6, and I'll tell you, if you can use the FCM spreadsheet then stick to a FRC% as close as possible to the OEM setting (and by that, I mean within 1%).

With my Tein HA (5/4kg F/R) and superpros, I found the most neutral balance was with either a big (22mm) front sway and OEM rear sway, or with the OEM front and no rear bar.

A 15/16\" front bar (23.8mm) and OEM rear was just a little pushy for my taste, but pretty fast actually.

When I first installed the Teins I had RB sways front and rear, and lets just say: oversteer through turn 1 at the Island is not fun.

Removing the rear is obviously the cheaper option, and more comfy on the road, with plenty of roll resistance provided by the stiff springs.

[Rob E]

Looking at the FCM data it looks like a 23mm front bar and no rear bar will work well with 7kg/6kg.

My RB Hollow bar and stock rear bar with 7kg/6kg is within 1% of OEM FRC (just slightly higher) so should work fairly well.

[Fatty]

thanks for the info rob and matty, that helps a lot.

[StanTheMan]

can anyone ltell me the Standard sway bar size of

1989 NA6 Australian delivery Front & rear
1998 Nb8A Aussie del.

The standard spring rates for standard Konis...... Mine must be 8YO now.

[Fatty]

i measured minw with a vernier but i can't remember the numbers, sorry. i think they can vary, so best to measure yours to check.

[StanTheMan]

I don't have standard sways anymore. i'm just rethinking suspension set up.
I believe I have NB8A's front & rear.

I cut bumpstops last week & it has made it considerably better.

[manga_blue]

Hey Fatty. I ran numerous setups on my NA6, and I'll tell you, if you can use the FCM spreadsheet then stick to a FRC% as close as possible to the OEM setting (and by that, I mean within 1%).

Matty's spot on. Remember I bought his Teins and took that advice then - all good - but we were dealing with 5/4 while I'd say you have 7/6 springs.

That said, you're putting a torsen in as well and that often gives a slightly stronger propensity to push. Better to go 1 or 2 % under with FRC (towards oversteer) rather than over. Stock is 58.9% for yours, a 23.8 mm front bar gives 56.9 (doable), an RB hollow bar gives 59.6 (a bit too pushy). I don't have the dimension data for the adjustables, so can't calculate them yet.

Does advice that sound right to you, Matty? (BTW oversteer through turn 1 sounds very interesting. James S. may be able to elaborate further.)

Give me a call if you need help with the FCM stuff.

[Matty]

Hey Fatty. I ran numerous setups on my NA6, and I'll tell you, if you can use the FCM spreadsheet then stick to a FRC% as close as possible to the OEM setting (and by that, I mean within 1%).

Matty's spot on. Remember I bought his Teins and took that advice then - all good - but we were dealing with 5/4 while I'd say you have 7/6 springs.

That said, you're putting a torsen in as well and that often gives a slightly stronger propensity to push. Better to go 1 or 2 % under with FRC (towards oversteer) rather than over. Stock is 58.9% for yours, a 23.8 mm front bar gives 56.9 (doable), an RB hollow bar gives 59.6 (a bit too pushy). I don't have the dimension data for the adjustables, so can't calculate them yet.

Does advice that sound right to you, Matty? (BTW oversteer through turn 1 sounds very interesting. James S. may be able to elaborate further.)

Give me a call if you need help with the FCM stuff.

Not having tracked a car with a Torsen, I can't confirm or deny. However, a Torsen doesn't lock up in the same way that a clutch type LSD does, they have far less effect on trailing throttle, so turn in should not be affected.

And on the flipside, an LSD will be prone to give more oversteer on exit (under power).

I'd stick to my starting point with a Torsen.

Oh yeah, and I wasn't quite in James' leauge of oversteer at Turn 1 - at least I stayed on the track.

[Juffa]

Fatty,

You are welcome to take Tweety for a drive.

Torsen Diff, Tein Flex coil overs, super pro bushes, whiteline adjustable front sway, and no rear sway.

Not sure when the next track day is, but might be worth you trying a few cars and see what suits your driving style.

J

[Mr Starlet]

I've got Tein SS 6/5kg (F/R), Whiteline adjustable front and rear swaybars on medium, only just installed, not sure whether the swaybars would be too stiff or not, will have to wait for a proper alignment and bit of a spirited dash to find out. Feelings so far for everyday driving; will definately need to go softer on the bars...might even go all the way back to stock.

[Matty]

I've got Tein SS 5/4kg (F/R), Whiteline adjustable front and rear swaybars on medium, only just installed, not sure whether the swaybars would be too stiff or not, will have to wait for a proper alignment and bit of a spirited dash to find out. Feelings so far for everyday driving; will definately need to go softer on the bars...might even go all the way back to stock.

Suggest you try what I had: OEM rear, or OEM front and no rear.

[Mr Starlet]

Suggest you try what I had: OEM rear, or OEM front and no rear.

I'm still a novice when it comes to track but just trying to visualise what stiffer front and even no rear sway bar would feel...front minimal roll, rear much more roll...less under steer, better turn in?

[manga_blue]

Minh, you can't look at sway bars in isolation. They work in concert with the springs. e.g. If the rear springs are relatively stiff then you don't need extra stiffening from sways.