F & R Sway Bars For Bnr34

[kylieyeah]

Hey guys,

Just looking for opinions and recommendations on sway bars. So far I'm looking at purchasing the Cusco ones as they're a bit thicker than the whiteline. Any other brands you guys recommend, looking for a FAT solid one.

Thanks

[GTSBoy]

The Whiteline 27mm adjustable front + 24mm adjustable rear combo will be plenty stiff enough. Torsion bar stiffness increases with the 4th power of diameter. As an example of that, even though a 28mm bar is only 3% bigger than a 27mm bar, it is 15% stiffer.

[krzysztof]

27mm front, but if you have decent power you dont want the rear too stiff as you will struggle to get power down without losing the rear

[Hadouken]

I dont mean to hijack but this has been lurking in my mind for a little.

If you were to upgrade one before the other, which would be more beneficial? Front or rear?

[GTSBoy]

Front first. But it is very important to realise that if you have a skinny stock bar at one end and a big stiff bar at the other, then there will be a significant change in the balance of the car. Assuming the car is fairly neutral to start with, a very big front bar will turn it into an understeery bitch.

Example. My R32 had factory skinny rear bar on it, and some unknown 22mm front bar. The car was always fairly understeery, and I never bothered to work out that the front bar wasn't a stocker - I just glossed over it. Then I finally worked out what was going on and put a 24mm adjustable in the rear. Set that on the soft setting. Now the car is a little bit frightening. Turn in and mid corner grip at the front is excellent - but the rear is skatey. Now it needs the 24mm adjustable on the front to fix it the other way!!

[kylieyeah]

Since the whiteline's don't make a 27mm bar for BNR34's only 22mm on the front, I think I'll go with Cusco F & R 24mm. I noticed with whiteline you could have a bit of adjustment, but will it really matter?

Also, does anyone know if a BNR34 embodies; Oversteer, understeer or neutral nature?

Edited November 6, 2012 by kylieyeah

[GTSBoy]

Sorry, I had sorta skipped over the fact that it was for a GTR. I guess Whiteline don't think that the GTR needs as much bar as the RWD cars do, otherwise they'd have at least a 24mm adjustable front bar available for them.

Having a look at the Whiteline catalogue, I see that they do a 24mm rear bar. That makes me think that the R34 GTR tends towards understeer. I base this purely on what the result would be if you went from typical stock bar sizes to a 24 rear/22 front combo. It would shift the grip forwards.

[kylieyeah]

Yep. I completely with you on this one. Thinking that the GTR will be a understeer bias type of car. In reference to the Mine's GTR, they only upgraded the rear. But the coilovers they run are much stiffer then mine, so I think I would have to run both larger front and rear.

Going with Cusco will give me, 24mm (21mm stock) Front and 28mm (24mm stock) Rear which would in my opinion seems pretty optimal, would you agree?

[kylieyeah]

The Mine's GTR is the ultimate handling and response weapon, and it made me think that maybe I should only upgraded the rears due to the understeer nature of my car.

My coilovers are 10kg/6kg compared to their Fr.12kg/Rr.10kg

Would it be a better option to upgraded front as well due to my softer coilovers?

[GTRsean]

More caster in the front end is what it needs to help with turn in.

It's magic!!!

[dkbcleaner]

Yes before I upgraded mine to adjustable whitelines front and back car would understeer a lot. Now on tight corners it is much better but will still understeer if pushed to hard. Its a very good upgrade though and a must in my opinion with these cars especially if running a soft street coilover

[GTR-34A]

Yes before I upgraded mine to adjustable whitelines front and back car would understeer a lot. Now on tight corners it is much better but will still understeer if pushed to hard. Its a very good upgrade though and a must in my opinion with these cars especially if running a soft street coilover

What spec whitelines did you get? im also going to getting some aftermarket sway bars soon.

[GTSBoy]

The Mine's GTR is the ultimate handling and response weapon, and it made me think that maybe I should only upgraded the rears due to the understeer nature of my car.

My coilovers are 10kg/6kg compared to their Fr.12kg/Rr.10kg

Would it be a better option to upgraded front as well due to my softer coilovers?

There's a big difference in the relative spring rates between the Mines car and yours. Your front springs are much stiffer than your rears. The Mines car's fronts are not a lot stiffer than their rears. That means your basic spring rates are more inclined toward causing and understeer bias.

If I were you, I would buy a set of 8kg springs for the front of the car before doing any anti-roll bar mods. That is unless you are tracking it very very hard, in which case you might be better off buying some 8kg rears.

[kylieyeah]

Cool, well I just spoke with another well known mechanic from here in Sydney, IS Motor Racing.

Indy had told me not worry about the sway bars right now, and change my springs from F10kg/R6kg to F10kg/R12kg.

At first, I was feeling a bit weird when he said to go to 12kg in rear, but I know doing that it will definitely decrease the cars natural understeer feel and the extra added understeer from my 10kg/6kg coilovers at the moment.

What do you think about this?

[MrStabby]

Personally i would hate a car that stiffly sprung, and on anything but a perfectly flat track it would have hopeless roadholding. Putting heavier springs in the rear than in the front is odd. The spring rate difference should somewhat match the weight difference, and GTRs are front heavy. You then control roll, and the under/over steer balance with sway bars (mainly) and alignment.

+1 to GTSboy. Put 8kg in the front. Even then, that's a track friendly rate. If you're street only, and care about comfort, softer both ends would be better.

Please speak to a proper suspension place like Heasmans!

[XGTRX]

Just go for a drive in one first because if it's a daily might be hard to live with. I recon just go with the stiffer rear sway bar and see what it does to the balance. Might be all that's needed and the cheapest option. Cheers

[kylieyeah]

To be honest, I play on making my car more track based. In which I think I will go with a stiffer rear set up, so probably buy 8kg rear springs to fit with a rear sway bar to go. I know right now the car understeers like crazy, so I'll optimise oversteer. If that becomes too oversteery, I'll take out either the rear sway or refit the 6kg springs, which I doubt I'll do the latter because I've been told 6kg is way too soft as it is now.

My car is street driven 99% of the time, but it's barely driven to start off with so I don't mind the stiffer ride.

Thanks for your help guys! Any more imput would be great in terms of decision I made above.