Running no rear sway bar on track?

[Tri-bar]

My. $.02, I run a very small rear bar, smaller than most would run. It's a 1/2 inch bar, then I tune with springs and shocks. For the street i run 350-400lbs fronts with 200 rears. Front sway bar is 36mm Eibach set on stiff most of the time. At the track springs can be anything from 500 fronts and 300 rears to anything lower. The 1/2 inch bar keeps things tied together. The physics change with I completely remove it. I also have a 18mm and 20mm I take depending on how the track is feel on any given day. When I remove the RSB completely, it get a little squirrely, rear end jitters as it where. Even if i up the shock settings. I like the rear to be as soft as I can get it and still keep the balance.

 

[Norm Peterson]

What else is going on, to make getting squirrely happen by apparently making the rear's share of roll resistance LESS?


Norm

 

[Tri-bar]

What else is going on, to make getting squirrely happen by apparently making the rear's share of roll resistance LESS?


Norm

Really, it's just a odd feeling the rear has without the rear bar, More movement than really needs to be there. less connected. When I add the 1/2 rear bar it all goes away. In no way less grip without the rear bar or more for that matter. That's why I like the little bar. I prefer the why it feels with the springs doing most of the work. Either way my rear grip levels are the same. It all changes when I move up to a 18mm bar since it dose have affect on the rear. Tighter the track, bigger the rear bar. But for me I have tried the no rear bar.. I just don't like the feel. Strange I know.

 

[Fabman]

I'm finding that spring companies with aftermarket stock OD springs aren't offering up spring rates.
How does one compare without purchasing and rating each spring yourself?

 

[Norm Peterson]

The rates of some springs can be found on American Muscle's site (scroll down the specific spring's page and click on the 'Tech' tab).

BMR includes rate information for several of their springs in the text describing each.

Other spring rates have been posted in various threads here and elsewhere.


Norm

 

[Tri-bar]

This is what I have been able to put together so far.


Mustang GT (2011+) Stock: Ft 122 lbs./in Rr 154 lbs./in * Source, Maximum Motorsports

Brembo Stock: Ft 131 lbs. /in. Rr 167 lbs./in

Boss Stock: Ft 148 lbs./in. Rr 185 lbs./in

Boss LS Stock: Ft 137 lbs./in. Rr 191 lbs./in

Eibach Pro-Kit: Ft 159 lbs./in Rr 193 lbs./in * Source, Maximum Motorsports

FRPP K Springs: Ft 188 lbs./in Rr 221 lbs./in * Vorshlag Tested

FRPP P Springs: Ft 204 lbs./in Rr 165 lbs./in * Vorshlag Tested

FRPP T Springs: Ft 204 lbs./in Rr 221 lbs./in

Steeda Competition: Ft 225 lbs./in. Rr 185 lbs./in

Steeda Sports: Ft 200 lbs./in. Rr 175 lbs./in

Steeda Boss Springs: Ft 225 lbs./in. Rr 195 lbs./in

Steeda Ultra-lite: Ft 195 lbs./in. Rr 175 lbs./in

Eibach Pro street Coilover: FT 225 lbs./in Rr 90-200 lbs./in * Eibach Spec sheet

Eibach Pro R1: Ft 225 lbs./in Rr 250 lbs./in * Eibach Spec sheet

H&R RSS Clubsport: Ft 630 lbs./in Rr 515 lbs./in * H&R Spec sheet

H&R Race Springs Ft 325 lbs./in Rr 285 lbs./in

302S: Ft 600 lbs./in Rr 350 lbs./in * Official Ford 302S manual

KW V1/2/3: Ft 342 lbs./in Rr 200 lbs./in * KW confirmed. Rates are @ static load/ride height

FR500s Ft 500 lbs./in Rr 300 lbs./in

Roush Track Pac/KW Ft 515 lbs./in Rr 400 lbs./in * Unconfirmed by Roush or KW

Maximum Motorsprots Ft 320-360lbs./in Rr 260-380lbs./in









OEM GT ................L .............165..............L..................142
05-09

OEM GT Vert............L .............144..............L..................122
05-09

OEM GT ................? .............?................?..................?
2010

OEM GT Vert ...........? .............?................?..................?
2010

OEM GT500 .............L .............190..............L..................166
07-09

OEM GT500 .............? .............?................?..................?
2010

H&R Supersport.........P. ............?-275 ...........P..................?245

Steeda Ultralights ....L .............195 .............L...................175

Steeda Sport ..........L .............200 .............L ..................175

Steeda Comp ...........L .............225 .............L ..................185

FFRP K Springs* .......P .............173-239 .........P ..................195-236

Ebach Pro* ............P .............173-239 .........P ..................195-236

Ebach Sportline .......L .............Way Too Stiff, FOR RACE USE ONLY!!

BMR (pn SP009) ........P .............160……............L ..................140


CDC Ford Motorsport kit lowers one inch. front 185........rear 165

 

[Stephen31201]

IMO Big sway bars as a whole are the band aids to improper spring rates due to wanting to keep a plush ride but corner well. I hardly see a 35-36mm bar as fine tuning. The way tri-bar is doing it I think is smart. A small bar fine tuning a correct spring rate. I plan on finding or fabricating the smallest bar I can for the front as well. The V6 bar is the smallest I have seen at around 26mm. I am waiting to hear back on what GC thinks is the correct spring rate for my car with the tires, weight and purpose that I am using it for. Maybe it will work, maybe Ill create a wooden wagon. I guess Ill find out. I am not saying that anyone's way is wrong, I just feel that removing load from an inside front tire in a corner in order to transfer spring rate to the outside tire seems counter productive.

 

[Mark Aubele]

IMO Big sway bars as a whole are the band aids to improper spring rates due to wanting to keep a plush ride but corner well. I hardly see a 35-36mm bar as fine tuning. The way tri-bar is doing it I think is smart. A small bar fine tuning a correct spring rate. I plan on finding or fabricating the smallest bar I can for the front as well. The V6 bar is the smallest I have seen at around 26mm. I am waiting to hear back on what GC thinks is the correct spring rate for my car with the tires, weight and purpose that I am using it for. Maybe it will work, maybe Ill create a wooden wagon. I guess Ill find out. I am not saying that anyone's way is wrong, I just feel that removing load from an inside front tire in a corner in order to transfer spring rate to the outside tire seems counter productive.

You are thinking a little too much. These are big, heavy cars. Unless you want to run 1500lb springs, you need a fairly stiff front swaybar.

Just an example, 550/300 springs, 35/22 bars, front on full stiff rear in middle (exhaust prevents being on softest setting), 315 R6 scrubs. Still a fuckton of body roll. Ideally I would run much more spring up front but don't have the damping to handle it yet.

 

[Fabman]

There was a time when guys were taking the front sway bars off oval track cars.
What they found was that on the dirt tracks the car was less inclined to dart when it ran over bumps and being on dirt, the tires ran cool enough to get away with it.

When the asphalt boys started picking up on this they found that to keep the same wheel rate the springs were so stiff that they would overheat the tires.
Sure the roll couple was the same in the corners with the sway bars but on the straights when the sway bars weren't being used the tires had time to cool off, so that idea was abandoned.
A few years later a Winston cup car put a sway bar on the rear and set the world on fire. Now they all run rear sway bars.
I ran and won with a rear sway bar long before it was "cool" and I've also won without a rear bar, but no front bar just wouldn't work well for all but the very lightest of cars.
The trend even today is to go lighter springs and bigger sway bars but you'll find different strategies work for different people . Your mileage, of course, my vary.

 

[Stephen31201]

I am king of overthinking. That does look like a lot of roll considering your spring rates, sway bar size and settings. But I also see that your inside tire is barely touching which is the point I was making. Correcting the spring rate to maybe 800/300s and you could run much smaller bars and not reduce the inside tire contact and load. But then again I haven't ran anything stickier than r888s so I cant really compare. I am running 525/250 with a 36f/29r both full soft and it corners like shiz. Total spring rate on my car I think is too much.

Any idea where to find out what spring rate the bars add? Without doing that big azz formula I found on the net.

 

[dontlifttoshift]

what does corner like shit mean? Where does it corner like shit? Entry, middle, exit?

 

[DocB]

I believe it was mentioned before in this thread, but something to seriously keep in mind and consider is whether of not the driver uses the curbing on the track, and to what degree. This is in reference to spring rates, but also alludes to shock settings, being a function of the spring rate.

Just throwing this out there as something else to consider, perhaps secondarily. Very stiff springs tend to upset the car on big curbing. Not that a good strut can't control the upset, just that perhaps a slightly softer spring would allow greater speed over that same curb.

Spring rates first, then fine tune with the bars.

Just my two cents, at this time, as I am also sorting this out presently.

 

[Stephen31201]

The car understeers with front bar (36) fulls soft and rear (27) full soft. At this setting the car lacks traction on exit. I took the bar off (I also am running a watts link) and the car has great traction on exit but then pushes on exit under throttle. I think both bars are too large and I have no room for adjustment. I think if I install a smaller bar up front and rear it will give me room for adjustment without hurting traction on exit. My driving style may also be a factor. I see some guys coast through corners and I grew up racing motocross. Brake early and then accelerate through the corner. Someone else could probably drive the car and like it if you coast through corners.

 

[Stephen31201]

I agree on the spring rates first and bars after. The problem is that 99% of all sway bars that are offered are for the relatively stock suspension mustangs that dont have the spring rates. Just no money in making and selling sway bars that only 5% of the market would need. Just my thoughts.

 

[csamsh]

Understeering on exit, with power on? I'd be more suspect of the rebound in your front dampers than a sway bar. Add front rebound, remove rear bump.

Also....what are your tire sizes?

 

[kcbrown]

Understeering on exit, with power on? I'd be more suspect of the rebound in your front dampers than a sway bar. Add front rebound, remove rear bump.

Huh?

Power on at exit means weight transfer away from the front. If he's understeering, then his front has less grip than he wants. Won't increasing front rebound slow the ability of the front tires to maintain contact with the ground, thus increasing the understeer?

 

[Stephen31201]

I have the front at full stiff unfortunately and the rears at full soft. I think the slow rebound keeps weight at the front and helps the car to stay planted in the front pretty much from mid corner out (My assumption). That was with 275/35-18 r888s.

 

[csamsh]

Huh?

Power on at exit means weight transfer away from the front. If he's understeering, then his front has less grip than he wants. Won't increasing front rebound slow the ability of the front tires to maintain contact with the ground, thus increasing the understeer?

Weight is being transferred inward and rearward on corner exit- adding power, removing steering.

Reference Neil Roberts' "racing dampers 201" article-

http://www.theoryinpracticeengineering.com/resources/dampers/neil roberts Racing Dampers 202.pdf

 

[SlowJim]

Rear diff has a large bearing on corner exit behavior as well.

 

[kcbrown]

Weight is being transferred inward and rearward on corner exit- adding power, removing steering.

Reference Neil Roberts' "racing dampers 201" article-

http://www.theoryinpracticeengineering.com/resources/dampers/neil%20roberts%20Racing%20Dampers%20202.pdf

Yes, exactly. So if you increase rebound damping, it means that the front wheels extend more slowly, and therefore the contact force between the front tires and the ground is temporarily less than it would be with less rebound damping, and less contact force means less front grip, which means more understeer.