Boss 302 square tire setup, sway bar size?

[Rabee]

I have 2013 Boss 302 ( all stock except CC plate ) and I am planning to go square tire setup (293/35-18) for the track.
People have gone square on the Boss and they noticed an increased oversteer due to the fact that the stock suspension was setup for staggered tire sizes with 255 front and 285 rear.
So, naturally, I would think putting a smaller rear sway bar will help resume the neutral handling characteristics.

The question is, how small should I go?

My stock Boss rear sway bar is 25mm, GT is 24mm and the V6 is 22mm. Rehagen also carries 19 and 20mm too.

I understand there is no perfect answer, most people say use an adjustable rear SB or even both front and rear adjustable SBs, but I am resisting the bug strongly, hence I am aiming to replace the rear SB only and hopefully it will be a takeoff part from either GT (24mm) or V6 (22mm).

Thanks

Rabee
Detroit

 

[sheizasosay]

I have 2013 Boss 302 ( all stock except CC plate ) and I am planning to go square tire setup (293/35-18) for the track.
People have gone square on the Boss and they noticed an increased oversteer due to the fact that the stock suspension was setup for staggered tire sizes with 255 front and 285 rear.
So, naturally, I would think putting a smaller rear sway bar will help resume the neutral handling characteristics.

The question is, how small should I go?

My stock Boss rear sway bar is 25mm, GT is 24mm and the V6 is 22mm. Rehagen also carries 19 and 20mm too.

I understand there is no perfect answer, most people say use an adjustable rear SB or even both front and rear adjustable SBs, but I am resisting the bug strongly, hence I am aiming to replace the rear SB only and hopefully it will be a takeoff part from either GT (24mm) or V6 (22mm).

Thanks

Rabee
Detroit

I would just go square setup and drive it and make decision after that. Or buy an adjustable rear bar.

You might find you like it without a bar change. Drive it and decide.

 

[Rabee]

I would just go square setup and drive it and make decision after that. Or buy and adjustable rear bar.

You might find you like it without a bar change. Drive it and decide.

Good approach, but as I stated above some people who are way better drivers than me tried it out and did not like the unsettling oversteer on high speed sweepers, which to me, might mean the last oversteer in my life

 

[csamsh]

I second the "get a set of adjustables" and tune it to your liking

 

[frank s]

My impression is that the softest setting on adjustable bars is equal to or stiffer than the standard bars. Here's a very recent list by a valued contributor to this forum (it seems to show I'm off by 26 lbs/in on the Boss 302 bar):

Ford 20mm Solid (2005-2010 GT): 96 lbs/in
Ford 22mm Solid (2011+ V-6 standard): 146 lbs/in
Ford 24mm Solid (2011+ 5.0, GT500): 193 lbs/in
Ford 25mm Solid (Boss 302): 250 lbs/in
Ford 26mm Solid (Boss 302 Laguna Seca): 275 lbs/in

Actually, here are the updated rates for our new rear bar:

Position 1: 224lb/in
Position 2: 259lb/in
Position 3: 302lb/in
Position 4: 356lb/in

 

[Rabee]

Frank, what adjustable bar are you referring to?

 

[JPC]

I have 2013 Boss 302 ( all stock except CC plate ) and I am planning to go square tire setup (293/35-18) for the track.
People have gone square on the Boss and they noticed an increased oversteer due to the fact that the stock suspension was setup for staggered tire sizes with 255 front and 285 rear.
So, naturally, I would think putting a smaller rear sway bar will help resume the neutral handling characteristics.

The question is, how small should I go?

My stock Boss rear sway bar is 25mm, GT is 24mm and the V6 is 22mm. Rehagen also carries 19 and 20mm too.

I understand there is no perfect answer, most people say use an adjustable rear SB or even both front and rear adjustable SBs, but I am resisting the bug strongly, hence I am aiming to replace the rear SB only and hopefully it will be a takeoff part from either GT (24mm) or V6 (22mm).

Thanks

Rabee
Detroit

Rabee,
Have you investigated Watts Links?
I have the Whilteline
Really fixes the rear on the track

If you are in the Dallas area ping me for a test ride.
I'll be at Five Star Ford of Plano Track Day Sat May 24th (co-organizer)
https://www.facebook.com/events/665990030108855/?source=3&source_newsfeed_story_type=regular

There'll be ALOT of Mustangs and Bosses running

ping me for details: [email protected]

 

[JPC]

Rabee
Sorry I did not see you were in Detroit....
Maybe fly in for May 24th...lol...

 

[sheizasosay]

So now we're talking about spending $1000 to fix oversteer? Take the rear swaybar off and pay me $100.

Think of the savings.

 

[todcp]

Sam Strano likes a softer bar on the S197's and offers a nice adjustable. Here is a comparison from his site. Give Sam a call and get some advice from a national autocross winner that know our car very well.
Comparison vs. Ford OEM:
Strano Performance Parts 8419 1" tubular: 162, 185, 225 lbs/in
Ford 20mm Solid (2005-2010 GT): 96 lbs/in
Ford 22mm Solid (2011+ V-6 standard): 147 lbs/in
Ford 24mm Solid (2011+ 5.0, GT500): 193 lbs/in
Ford 25mm Solid (Boss 302): 250 lbs/in
Ford 26mm Solid (Boss 302 Laguna Seca): 275 lbs/in

 

[sheizasosay]

Strano bars. The rates start almost 100 in/lbs lower than what your Boss bar is. That would probably work. Good post todcp.

 

[ArizonaGT]

Rabee I sent you a reply to your PM on BMO but my advice would be to get the Strano adjustable rear bar in 7/8" diameter (22mm). That's what I run on my car. In the "middle" setting it works well for higher speed tracks, and you can adjust it to the shortest setting for tighter tracks where you want the car to rotate more.

 

[jayel579]

Rabee I sent you a reply to your PM on BMO but my advice would be to get the Strano adjustable rear bar in 7/8" diameter (22mm).

You might have one of Sam's early bars. His early rear bars were 7/8", I believe mine is a 1" rear bar.

But for the OP, keep a square setup and learn to drive the car. At this point you are trying to make adjustments for something you haven't experienced yet. Figure out your driving style and what your car is doing then make the changes. Otherwise you might throw yourself into a whirlwind of mods that will just frustrate yourself and your budget.

 

[csamsh]

Hey here's another idea- the regular GT has square tires, and the Boss has the regular GT front sway. If you want to do a simple/easy fix, just find a stock GT rear sway.

 

[Norm Peterson]

I know I'd recommend an adjustable rear bar in this situation, or an adjustable pair of bars. Don't really understand what the objection could be.


I have Sam's 22 mm rear bar. Best I can estimate, it's somewhere around 60% of the stiffness of the newer 25 mm bar at each adjustment hole. The new bar is 162/185/225 per Sam's site, so the old bar is fairly soft but still stiffer than the OE solid 20 mm bar.

I don't know if the 22mm rear bar can still be obtained.


Norm

 

[pass1over]

If your intent on swapping it out to a smaller one, I'll trade you my stock rear GT bar for your stock rear Boss bar, heh

 

[frank s]

Frank, what adjustable bar are you referring to?

Looks like BMR Tech's posts #57 and 58 in his rear swaybar sneak peek thread.

 

[Rabee]

Rabee
Sorry I did not see you were in Detroit....
Maybe fly in for May 24th...lol...

Thanks for the offer man! Yes I like the idea of watts link, however I want to learn my car in its stock form, learn it very well..then start modifying it as needed.
The reason I am going square is giving me the ability to rotate the tires which, I hope, it will save me some money in the long run.

 

[Rabee]

Hey here's another idea- the regular GT has square tires, and the Boss has the regular GT front sway. If you want to do a simple/easy fix, just find a stock GT rear sway.

I thought about that too, however the boss springs are stiffer than the gt ones.

 

[Rabee]

I know I'd recommend an adjustable rear bar in this situation, or an adjustable pair of bars. Don't really understand what the objection could be.


I have Sam's 22 mm rear bar. Best I can estimate, it's somewhere around 60% of the stiffness of the newer 25 mm bar at each adjustment hole. The new bar is 162/185/225 per Sam's site, so the old bar is fairly soft but still stiffer than the OE solid 20 mm bar.

I don't know if the 22mm rear bar can still be obtained.


Norm

My only concern about adjustable strano bar is the possible fitment issues with some relocation brackets ( I honestly do not know which).

I went to Rehagen racing today and they thought the rear 20mm bar (2005-2009 GT) will do the trick.
I asked a lot of people and most recommended adjustable front and rear bars.
Some said go as soft as 20-22mm...etc
I am leaning toward 20-22mm due to the following reasons:

1) the turn in and mid corner balance will still be good ( theoretically) due to wider and stickier Rivals at the front. There is a huge difference between 255 p zero and 295 rivals. Obvious.

2) putting the power on corner exit effectively is expected when going 20mm rear sb due to better articulation of the rear tires and it is especially needed on a solid axle system like ours. Again 295 rivals will be stickier than 285 p zeros, which is a plus. Setting the rear damper to low numbers helps too.

3) One change only means less money to spend, obviously if done correctly, otherwise it might end up in a financial disaster.

Norm, correct me if I am wrong, please.