The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

Sways and Square Setup - specific question

Now that there's a fair amount of suspension tech and different setups out there, I'm curious as to which way you would go with a rather specific scenario.

Let's say I wanted to run a square setup - 275 R6's on 18x9.5's on all corners. Assume that I can put on multi-adjustable dampeners and springs, and will be looking to firm up everything as much as I can for the track. The first thing you'd want is adjustable sways, of course, but that's the catch - what if you could not have adjustable sway bars? You could swap stock sways from basically any S197 Mustang to tune this, but no non-OE sways, and no adjustables.

So, the questions:

1. Would you use the lower diameter sways from another Mustang? This is a one-way street - while every other S197 Mustang has lower diameter sways that can be used, no other has stiffer sways than that of the stock Boss, at least that I have found. So you can go softer, but not stiffer. Say, a 20mm rear sway from 2010 GT, as an example.

2. Would you try and dial out oversteer with dampening and spring rates?

3. If you absolutely couldn't do it any other way, would you get adjustable sways if it meant you had to use skinnier tires?

Curious to see which way you guys would jump... ???
 

JScheier

Too Hot for the Boss!
LateApex said:
Let's say I wanted to run a square setup - 275 R6's on 18x9.5's on all corners. Assume that I can put on multi-adjustable dampeners and springs, and will be looking to firm up everything as much as I can for the track. The first thing you'd want is adjustable sways, of course, but that's the catch - what if you could not have adjustable sway bars? You could swap stock sways from basically any S197 Mustang to tune this, but no non-OE sways, and no adjustables.

Just for clarification, going to a square setup on an OEM boss 302 is going to result in over steer. Solution is to either soften the rear or stiffen the front:

1. Would you use the lower diameter sways from another Mustang? This is a one-way street - while every other S197 Mustang has lower diameter sways that can be used, no other has stiffer sways than that of the stock Boss, at least that I have found. So you can go softer, but not stiffer. Say, a 20mm rear sway from 2010 GT, as an example.

either a larger front bar or a smaller rear bar

2. Would you try and dial out over steer with dampening and spring rates?

My preference (and my eventual route) would be to get good adjustable dampers and tune the car using springs to get it as neutral as possible with (my preference) just a hint of over steer. Tune with dampers and springs. Fine tune with swaybars.

3. If you absolutely couldn't do it any other way, would you get adjustable sways if it meant you had to use skinnier tires?

Not sure why you would need skinnier tires. 305s will fit at all four corners of my car with adjustable sways on each end. Pretty sure I could get 315s in there if I had the correct offset wheels and/or spacers.

FWIW, I used to experiment with OEM sways all the time. On my 86GT I ran a 4cyl front bar and it worked great. On my M3, I had 325 & 328 bars that I would swap in and out. The upside of an adjustable bar(s) is that you don't have to carry 6 bars to the track to do tuning. Just a couple of wrenches and jack stands (or ramps).
 
JScheier said:
LateApex said:
Let's say I wanted to run a square setup - 275 R6's on 18x9.5's on all corners. Assume that I can put on multi-adjustable dampeners and springs, and will be looking to firm up everything as much as I can for the track. The first thing you'd want is adjustable sways, of course, but that's the catch - what if you could not have adjustable sway bars? You could swap stock sways from basically any S197 Mustang to tune this, but no non-OE sways, and no adjustables.

Just for clarification, going to a square setup on an OEM boss 302 is going to result in over steer. Solution is to either soften the rear or stiffen the front:

1. Would you use the lower diameter sways from another Mustang? This is a one-way street - while every other S197 Mustang has lower diameter sways that can be used, no other has stiffer sways than that of the stock Boss, at least that I have found. So you can go softer, but not stiffer. Say, a 20mm rear sway from 2010 GT, as an example.

either a larger front bar or a smaller rear bar

2. Would you try and dial out over steer with dampening and spring rates?

My preference (and my eventual route) would be to get good adjustable dampers and tune the car using springs to get it as neutral as possible with (my preference) just a hint of over steer. Tune with dampers and springs. Fine tune with swaybars.

3. If you absolutely couldn't do it any other way, would you get adjustable sways if it meant you had to use skinnier tires?

Not sure why you would need skinnier tires. 305s will fit at all four corners of my car with adjustable sways on each end. Pretty sure I could get 315s in there if I had the correct offset wheels and/or spacers.

FWIW, I used to experiment with OEM sways all the time. On my 86GT I ran a 4cyl front bar and it worked great. On my M3, I had 325 & 328 bars that I would swap in and out. The upside of an adjustable bar(s) is that you don't have to carry 6 bars to the track to do tuning. Just a couple of wrenches and jack stands (or ramps).

Great reply, thanks!

The reason I'd have to run smaller tires if I got adjustable sways is a NASA TT points spend issue, nothing technical. I am working out if I can save the 2pts. on sways in an acceptable fashion without losing much (or anything at all, ideally).
 

OLOABoss

AKA OLOABoss
For NASA TT if it didn't come on the Base Model as listed you will need to take the 2 points. ie putting Laguna Seca sway on a Boss will cost 2 points.

Peter
 
OLOABoss said:
For NASA TT if it didn't come on the Base Model as listed you will need to take the 2 points. ie putting Laguna Seca sway on a Boss will cost 2 points.

Peter

Hmm, dunno about that. My reference is section 6.6 of the current 9.2 rules:

"Updating and backdating of parts between different model years of the same vehicle model is
legal provided that the competing vehicle is in the same or higher base class than the donor
vehicle, and that the entire assembly is replaced."

As NASA considers a Boss just another Mustang according to how they title and classify them, that's my angle ;D
 
They list the Boss separately but did not see the LS version so I guess it would just be a Boss. I would like to update to the LS suspension on mine then square with the 2nd tier tires and a sway bar, but not sure the LS bits would not get me points. Can't run the 1st tier tires at all or it throws you out of the class but iirc you have 2 points to spare if you go 2nd tier. I don't know if you can be competitive in 2nd tier tires though.
 

JScheier

Too Hot for the Boss!
Pretty sure the boss is going to be a TTS car... at least for the next year or so until it gets reclassed on the same line as a regular mustang.

TTA* is a tough pill to swallow when a standard Mustang GT can can come in VERY well setup in TTA.
 
Yeah, you aren't kidding there - TTA* is just an awful placement.

My thinking right now is this:
7 pts for the *
3 pts for shocks
2 pts for springs
1 pt for the Torsen I have

Which then leaves me 6 for tires, which will get me into 275 R6's, or maybe something like 285 NT555R2's, but really, it's hard to ignore the Hoosiers. I am basically out of the Hoosiers altogether if I have to burn 2pts on sways, unless I am on really skinny ones, but they would wear like hell and overheat FAST on a heavy high HP car like this, so I would really rather not. Would adjustable sways and square 275 NT01's be superior? I can't say, but I think it's unlikely.

I have gone back and forth on this for ages it seems, but I really do think I will make a go of it next year. TTA got rocked with the "cheater" tire rule fix, and Hoosier backing down their sponsorship a bit. Been seeing more and more TT guys on 2nd and 3rd tier tires lately, also many on scrubbed Contis from the Grand-Am guys, so who knows, the landscape has changed now. Maybe...
 

JScheier

Too Hot for the Boss!
I ran (and still have) 285x35 Hankook RS3's that I've been running along with 275x35 Hoosiers. Thank goodness I get points back for running smaller than 295's.

Unfortunately, I'm moving to a real suspension, so TTS is in the very near future.
 
LateApex said:
OLOABoss said:
For NASA TT if it didn't come on the Base Model as listed you will need to take the 2 points. ie putting Laguna Seca sway on a Boss will cost 2 points.

Peter

Hmm, dunno about that. My reference is section 6.6 of the current 9.2 rules:

"Updating and backdating of parts between different model years of the same vehicle model is legal provided that the competing vehicle is in the same or higher base class than the donor vehicle, and that the entire assembly is replaced."

As NASA considers a Boss just another Mustang according to how they title and classify them, that's my angle ;D

You can try the 22mm bar from the V-6 or the 24mm from the 2012 V-6 Performance package, see below.

I couldn't attach the Excell so I attached it as a jpeg.

S197SwayBars-SpringRates-1.jpg
 
There were two guys at Watkins Glen last week that were running square setups with Contis (Grand Am takeoffs) on their Boss 302's. I questioned them as to what they did to the suspensions to run the square setup and they stated that the suspensions were stock. No changes at all! I rode with one of the guys and was impressed with how it handled. I am no expert by any means, but it sure seemed like the car had no understeer or oversteer and he was runnning fast laps. Never heard a noise from the tires at all (not sure if you do with Contis?) and wearever he pointed the car, it went. Makes me think about going square eventually.
 
That's an interesting observation.

Looked at another way, that brings up something else. A 2012 Mustang GT is setup square from the factory. It has a 24mm rear sway instead of the Boss 25mm, but aside from that, what else exactly makes a GT setup square that has been altered in design for a Boss? The spring rates between the two are more or less linear, Boss is just stiffer. If I am putting shocks, springs, CC plates and a 24mm rear sway on a Boss, then in theory I should have everything covered to run square with no issues, no?
 
I'm not an engineer but I have read a few books on race car engineering...............so if someone reads this let me know If I got it wrong.

OK, first the larger tire on the rear of the Boss 302 INCREASEs mechanical grip on that end and is balanced out front to rear, by the Ford engineers selection of sway bars/spring rates/damper valveing, etc. and it all comes together based on the tires Ford put on our cars from the factory. Everyone comments on how well the car behaves, “great turn in” “neutral handling” “balanced” etc.

So of course we now want to run the car outside of the carefully set of parameters the factory set the car up for in the first place, why because R-Compounds are fun!

So now we want to go to a really grippy tire and run the same size all the way around so we can swap tires from the front to the rear to balance out the tire wear and get max life out of the tire.

I decided to go with a 275-40/18. So I'm gaining a little grip at the front 275 vs the 265 and losing 20mm in the rear.

Going to a square setup I just described you LOOSE mechanical grip at the rear, so now you have an imbalance and the car will want to over steer; back end will want to come around.

In general you want to address the end of the car that is causing the problem. So yes going to a smaller rear sway bar will soften the rear and increase grip.

The 24mm bar is the way to go if you have to adjust in a class that restricts what you can run.

You then can play with tire pressures to counter over steer/under steer at initial turn-in / mid corner / corner exit.
 

ArizonaBOSS

Because racecar.
Moderator
8,523
2,331
Arizona, USA
You're not losing any mechanical grip in the rear going to a square setup, but you're increasing the amount of mechanical grip in the front vs. stock, upsetting the balance of the car. The smaller swaybar in the rear reduces the rear roll stiffness and thus increases rear grip to a level on-par with your new found additional front grip, restoring balance to the car and the universe.
 

drano38

Wayne
1,130
318
06mach1 said:
There were two guys at Watkins Glen last week that were running square setups with Contis (Grand Am takeoffs) on their Boss 302's. I questioned them as to what they did to the suspensions to run the square setup and they stated that the suspensions were stock. No changes at all! I rode with one of the guys and was impressed with how it handled. I am no expert by any means, but it sure seemed like the car had no understeer or oversteer and he was runnning fast laps. Never heard a noise from the tires at all (not sure if you do with Contis?) and wearever he pointed the car, it went. Makes me think about going square eventually.

Someone can correct me if I'm wrong, but if a staggered car has understeer, going square w/o suspension mods can fix that understeer and make it handle fine. But in theory, our Boss was designed properly.
That's what a friend did with his BMW staggered Z4. Going square allowed front/back tire rotations, and eliminated his understeer, a win-win from his standpoint.
 
I have run a square setup with no other changes and the balance seems fine. I was told be Dean @ Rehagen that the cars respond well to the square setup. On the track I have found myself both in neutral and understeer conditions in high speed corners (Turn 1 @ Mid-Ohio). When I would occasionally get the understeer I could power through it. At times when the car would take a set with slight oversteer it would be easy to modulate with the gas pedal.

Note though that I have a lot of track experience. People with little experience may prefer to intentionally add more understeer to be on the safe side.
 

TMO Supporting Vendors

Latest posts

Buy TMO Apparel

Buy TMO Apparel
Top