swaybars.. how big is too big?

vicious_fishes · 11-30-2012, 08:09 PM

i know it's a bit of an open-ended question but is there a rough point where you're doing more harm than good?

i say this having just picked up a 22mm adjustable rear and with a 20mm front. i was going to get a 22mm front to match but, 24's and i believe 27's exist also.

i currently have RCE yellows and am trying to move to a set of kw v3's in the future. my intention was to get a pair of 24mm front/rear adjustables to suit, and tune on the adjustable holes to how i like the car.

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Back Road Runner · 11-30-2012, 10:38 PM

Big is relative. Some of it has to do with how you want the car to behave. Big sways on soft suspension can be tricky. You can get a nice ride, but there is so little damping that the car can be a bit springy side to side which can make the car twitchy and snap oversteer if you're too aggressive with the steering wheel.

There is somewhat of a balance going on where you get enough spring rate to force enough damping to offer enough damping to reasonably control the chassis with bigger sway bars. You will find that the car is more stable and less twitchy to hard inputs if you stay with softer sway bar sizes. You will use the damping for the main springs to control the car well during dynamic maneuvers. Not having a lot of sway won't introduce much more spring into the system and retain a very well mannered car even during hamfisted use.

So, how big can you go? Well, with STI rates, I know 24mm is too big because the car will snap oversteer with hard steering inputs. However a 20mm to 22mm range is better. 24mm is fine at stiffer rates like that of the Yellows. 25mm to 26mm may be pushing it again and make the car twitchy.

You will also notice that you can add a lot of spring rate and retain a pretty nice riding car if you keep the sways small. The car will stay more planted and calm over rougher terrain when you don't have sways interfering heavily over every uneven bit. I just like springs more than I like sways, but I also like damping because it better controls the chassis and improves car response.

jamal · 11-30-2012, 11:20 PM

It really depends on the tires and rest of suspension and what you are doing with the car.

A Subaru tends to like big bars because it is a tall and heavy sedan with less than ideal geometry.

24mm bars front and rear would be a good start if you are looking for track and on road performance with street tires using RCE yellows or standard v3s. To really get the most out of a car on track with good street tires (like a Hankook RS3) 24mm bars with standard v3 spring rates isn't enough. On street tires you need to go to something like RCE T2s with more rate to avoid getting into 27mm bars, and for R-comps or slicks most of the fast cars I know of are using the big 27mm bars.

vicious_fishes · 11-30-2012, 11:43 PM

assume for track usage guys

tarmac II's are only about 10% stiffer than KW v3's. 500lb/in vs 455. reason i'm looking at v3's is i can score a set delivered for about $2k. couldn't find tarmac II's for less than 2400 + post. in fact i can't find them at all any more.

jamal · 12-01-2012, 01:07 AM

The difference between the rear springs on the v3 and t2 is greater, which really changes how weight is transferred and the front tires are loaded. The v3 has a really soft progressive rear spring which is not good for track use, so once you convert to a linear spring you are better off with the RCEs. Plus the damping force is geared more toward track use and will handle more spring.

Whichever you go with doesn't make that much of a difference for swaybars. With the V3s you will likely end up with the rear on full stiff and the front on soft, with t2s you can add in front bar to keep the tires in better contact with the ground and have room to play with in the rear.

JDwhiteWRX · 12-01-2012, 02:39 AM

I run d-specs with RAR springs 6/5kg, front bar is 24mm and rear is 22mm. My best lap times are with rear bar on stiff and front on soft. With the front on stiff and rear on stiff I get too much corner exit push, even with my aero although a decent LSD front diff would probably help me a lot. I would like to try a 24mm rear bar next and run the front bar on stiff.

vicious_fishes · 12-01-2012, 07:14 AM

ah seems like it may be a bit of a non-issue guys. biggest front bar i can get for the RS is a 22mm. already have an adjustable 22mm rear so i guess i'll just have to work it out with spring rates. kw v3's come with 455 up front so i'm thinking 400 in the rear should be about right?

JDwhiteWRX · 12-01-2012, 07:26 AM

Check out the KW Clubsports.

vicious_fishes · 12-01-2012, 08:45 AM

holy crapola for $4g's they'd want to be pretty good.

iAintFamous · 12-02-2012, 04:01 PM

The 24mm on MY00 RS was too big, for reference

Back Road Runner · 12-02-2012, 07:05 PM

Depending on your exhaust, you may be able to use turbo sways and go bigger.

vicious_fishes · 12-03-2012, 06:22 AM

Quote:

Originally Posted by Back Road Runner

Depending on your exhaust, you may be able to use turbo sways and go bigger.

not with the standard exhaust no. i have a turbo manifold for the track, but daily i zip around with the stocko on.

thanks though

11-30-2012, 08:09 PM	#1
vicious_fishes Scooby Specialist Member#: 158864 Join Date: Sep 2007	swaybars.. how big is too big? i know it's a bit of an open-ended question but is there a rough point where you're doing more harm than good? i say this having just picked up a 22mm adjustable rear and with a 20mm front. i was going to get a 22mm front to match but, 24's and i believe 27's exist also. i currently have RCE yellows and am trying to move to a set of kw v3's in the future. my intention was to get a pair of 24mm front/rear adjustables to suit, and tune on the adjustable holes to how i like the car. * Registered users of the site do not see these ads.

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11-30-2012, 10:38 PM	#2
Back Road Runner Scooby Guru Member#: 60082 Join Date: Apr 2004 Chapter/Region: MWSOC Location: Minnesota Vehicle: 2004 Forester STI Silver	Big is relative. Some of it has to do with how you want the car to behave. Big sways on soft suspension can be tricky. You can get a nice ride, but there is so little damping that the car can be a bit springy side to side which can make the car twitchy and snap oversteer if you're too aggressive with the steering wheel. There is somewhat of a balance going on where you get enough spring rate to force enough damping to offer enough damping to reasonably control the chassis with bigger sway bars. You will find that the car is more stable and less twitchy to hard inputs if you stay with softer sway bar sizes. You will use the damping for the main springs to control the car well during dynamic maneuvers. Not having a lot of sway won't introduce much more spring into the system and retain a very well mannered car even during hamfisted use. So, how big can you go? Well, with STI rates, I know 24mm is too big because the car will snap oversteer with hard steering inputs. However a 20mm to 22mm range is better. 24mm is fine at stiffer rates like that of the Yellows. 25mm to 26mm may be pushing it again and make the car twitchy. You will also notice that you can add a lot of spring rate and retain a pretty nice riding car if you keep the sways small. The car will stay more planted and calm over rougher terrain when you don't have sways interfering heavily over every uneven bit. I just like springs more than I like sways, but I also like damping because it better controls the chassis and improves car response.

11-30-2012, 11:20 PM	#3
jamal Scooby Guru Member#: 71875 Join Date: Oct 2004 Location: Montana Vehicle: 98 2.5GT my wheels fit	It really depends on the tires and rest of suspension and what you are doing with the car. A Subaru tends to like big bars because it is a tall and heavy sedan with less than ideal geometry. 24mm bars front and rear would be a good start if you are looking for track and on road performance with street tires using RCE yellows or standard v3s. To really get the most out of a car on track with good street tires (like a Hankook RS3) 24mm bars with standard v3 spring rates isn't enough. On street tires you need to go to something like RCE T2s with more rate to avoid getting into 27mm bars, and for R-comps or slicks most of the fast cars I know of are using the big 27mm bars.

11-30-2012, 11:43 PM	#4
vicious_fishes Scooby Specialist Member#: 158864 Join Date: Sep 2007	assume for track usage guys tarmac II's are only about 10% stiffer than KW v3's. 500lb/in vs 455. reason i'm looking at v3's is i can score a set delivered for about $2k. couldn't find tarmac II's for less than 2400 + post. in fact i can't find them at all any more.

12-01-2012, 01:07 AM	#5
jamal Scooby Guru Member#: 71875 Join Date: Oct 2004 Location: Montana Vehicle: 98 2.5GT my wheels fit	The difference between the rear springs on the v3 and t2 is greater, which really changes how weight is transferred and the front tires are loaded. The v3 has a really soft progressive rear spring which is not good for track use, so once you convert to a linear spring you are better off with the RCEs. Plus the damping force is geared more toward track use and will handle more spring. Whichever you go with doesn't make that much of a difference for swaybars. With the V3s you will likely end up with the rear on full stiff and the front on soft, with t2s you can add in front bar to keep the tires in better contact with the ground and have room to play with in the rear.

12-01-2012, 02:39 AM	#6
JDwhiteWRX Scooby Specialist Member#: 190502 Join Date: Sep 2008 Chapter/Region: International Location: Sydney, Australia Vehicle: 2005 VF36 WRX	I run d-specs with RAR springs 6/5kg, front bar is 24mm and rear is 22mm. My best lap times are with rear bar on stiff and front on soft. With the front on stiff and rear on stiff I get too much corner exit push, even with my aero although a decent LSD front diff would probably help me a lot. I would like to try a 24mm rear bar next and run the front bar on stiff.

12-01-2012, 07:14 AM	#7
vicious_fishes Scooby Specialist Member#: 158864 Join Date: Sep 2007	ah seems like it may be a bit of a non-issue guys. biggest front bar i can get for the RS is a 22mm. already have an adjustable 22mm rear so i guess i'll just have to work it out with spring rates. kw v3's come with 455 up front so i'm thinking 400 in the rear should be about right?

12-01-2012, 07:26 AM	#8
JDwhiteWRX Scooby Specialist Member#: 190502 Join Date: Sep 2008 Chapter/Region: International Location: Sydney, Australia Vehicle: 2005 VF36 WRX	Check out the KW Clubsports.

12-01-2012, 08:45 AM	#9
vicious_fishes Scooby Specialist Member#: 158864 Join Date: Sep 2007	holy crapola for $4g's they'd want to be pretty good.

12-02-2012, 04:01 PM	#10
iAintFamous Scooby Newbie Member#: 249919 Join Date: Jun 2010 Chapter/Region: NESIC Location: Southern New Hampshire Vehicle: 2000 2.5RS Sedan BRP	The 24mm on MY00 RS was too big, for reference

12-02-2012, 07:05 PM	#11
Back Road Runner Scooby Guru Member#: 60082 Join Date: Apr 2004 Chapter/Region: MWSOC Location: Minnesota Vehicle: 2004 Forester STI Silver	Depending on your exhaust, you may be able to use turbo sways and go bigger.