Jump to content
SAU Community

Body Roll


Adz2332
 Share

Recommended Posts

Hey all

looking to stop some body roll on my track only r33gtst

im getting some HSD monocoils with 8kq front 7kg rear

ive had some shocking body roll problems. it only has a half cage at this stage, but will be adding side intrusion bars soon.

What would you recommend? still have stock sway bars etc

Link to comment
Share on other sites

to reduce body roll u have to upgrade swaybars, thats essentially whats controlling it.

harder springs wont really fix body roll.

cage/ bar work will only really affect body flex, not roll.

Edited by GH05T
Link to comment
Share on other sites

I agree, its interesting though that mca suggests using stock sway bars with their shocks and to control roll with spring rate. Personally i run whiteline bars but it's hard to argue with mca when you look at the performance of their time attack car.

Link to comment
Share on other sites

well, there is kind of a religious war out there about whether springs on their own are sufficient, or whether sway bars and springs are better.  In production cars we have to run stock sway bars so we run heavier springs (ie the MCA and common Japanese approach) but when I'm not doing prod cars I run heavier bars and lighter springs and I think it handles better, particularly over bumps.

The MCA time attack car is a good advertisement, but not really relevant for the average full chassis race car.  Only time attack cars run on the smoothest track, 1 lap at a time on super soft tyres and with massive downforce. The rest of us live in a world with compromised track surfaces or roads with plenty of bumps, little to no downforce and tyres that are expected to last hours of racing and not degrade.

Link to comment
Share on other sites

its definitely detrimental to go big sway bars for no reason and definitely bad to be too heavy, but same for spring rates.

fair to say though if you have heavier spring rates and still struggeling with body roll that the stock swaybar setup is not holding its own enough.

Edited by GH05T
Link to comment
Share on other sites

Very good explanation, thanks Duncan. Im quite happy with my bar setup although my rear unknown spring rates are probably a touch firm on the street. Quite good at the track though. I suppose you can't have it all without a bit of trial and error.

Link to comment
Share on other sites

17 hours ago, Adz2332 said:

looking to stop some body roll on my track only r33gtst

im getting some HSD monocoils with 8kq front 7kg rear

ive had some shocking body roll problems. 

What would you recommend? still have stock sway bars etc

Firstly - is the body roll causing problems? Or are you indicating a handling problem?  The real objective is to chase an acceptable balance front to rear for understeer/oversteer without spending big on components (eg why go to replacement bars if you can get a workable outcome without changing from OEM).

Tyre size and spec WILL influence what suspension spec is necessary or best.  eg. a set of 235 ADO8R vs 295 A050 will require different choices.

Secondly, a nose heavy boat WILL tend to flog its front tyres. That's unavoidable.

I'd review what ride height you have it set at, as this impacts roll centre and the tendency to resist body roll.

Then I'd contact MCA, speak with Josh about your needs and his prices and recommendations.  Then make a decision whether you want to run with their product or the HSD you have mentioned.

Quite probably it's going to require 13kg fronts at a minimum.  Ignore what GTR owners use, this is a 2wd chassis with different requirements.

Link to comment
Share on other sites

Upgraded my sway bars on the weekend to ARC ones (Auto Refine Company), fully adjustable etc.. Basically eliminated the body roll i had.. Not sure why I didn't do it sooner!

20171028_111245.thumb.jpg.9c240aeefd4f6060ff9e6dd73ad0ca42.jpg20171028_153746.thumb.jpg.599357a76e23883c4fd808ef01441000.jpg

 

Link to comment
Share on other sites

Be cautious mating the 24mm bars front and rear.  I have them on a 32GTSt (so I acknowledge not the same chassis set up, but nevertheless.....) set to max stiff front and min stiff rear.  I really feel that the mid corner balance would be better if I had a 22mm rear.  It's very happy to make the rear step out, which becomes progressively more alarming the faster you go.

Otherwise.....yes, just do it.  Or at least do something.  Stiffer front bar drastically sharpens the immediacy of turn in response.

Link to comment
Share on other sites

12 hours ago, GRKGTR said:

Upgraded my sway bars on the weekend to ARC ones (Auto Refine Company), fully adjustable etc.. Basically eliminated the body roll i had.. Not sure why I didn't do it sooner!

20171028_111245.thumb.jpg.9c240aeefd4f6060ff9e6dd73ad0ca42.jpg20171028_153746.thumb.jpg.599357a76e23883c4fd808ef01441000.jpg

 

Where did you get them from - and what diameter are they?

Link to comment
Share on other sites

Wow. OK. Understeeeeeeeeeeer.

Looked up the Cusco ones as a comparison (%'s compared to stock). 

Front

Cusco 24 dia, 192% stiffer.  ARC 30 dia (From your number) 240% stiffer.

Rear

Cusco 30 dia , 162% stiffer. ARC 30 dia 180% stiffer.

Guessing ARC quote the numbers with the drop links on their hardest setting.

Link to comment
Share on other sites

3 hours ago, djr81 said:

Wow. OK. Understeeeeeeeeeeer.

Looked up the Cusco ones as a comparison (%'s compared to stock). 

Front

Cusco 24 dia, 192% stiffer.  ARC 30 dia (From your number) 240% stiffer.

Rear

Cusco 30 dia , 162% stiffer. ARC 30 dia 180% stiffer.

Guessing ARC quote the numbers with the drop links on their hardest setting.

They are quoting 2.40 times stiffer at front and 1.8 times stiffer at rear
 

Link to comment
Share on other sites

I went for 12kg/10kg rates on BC Racing ER coilovers, still using stock sway bars.

Yes, it still rolls a little, but you also need to consider the relationship between sway bars and springs.  A thicker sway bar will help reduce roll, but you'll also lose some suspension independence and comfort (lol what's that anyway?) on the street.

I can still manage a 1:35 around Winton with a bit more in it, so I'd try going for a good shock and spring setup first before adding sway bars.

Pic is of my car (like yours - half caged) at pretty much full load.

Winton 20160911 3.jpg

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share



×
×
  • Create New...