What is this thing in '13 shelby gt500?

[eolson]

As it was explained to me, the X brace is further support counter acting the tendency of the rear inner wheel to lift in hard turns. If others feel the X brace is only for looks, please explain your opinion of why it's in the Boss LS

Anyone who has taken hard corner bumps with a PHB set up realizes there is a loss of grip as the car butt skips a hair with the lateral shift of the frame. That is something I have felt clearly with the PBH set up. That lateral movement does not happen with a watts link as the car dips or raises. Again, the very existence of the watts link implies that some have an issue with the PBH set up.

Again, if some feel the X brace is not controlling the chassis inner rear wheel lift, then I don't know why it's there.

The watts link is an immediate improvement on the street from my experience with planting the rear wheels in and out of bumpy hard turns. Yes I had the proper adjustable PHB and stronger brace, and the car still shifted laterally over hard corner bumps.
Other racers and Auto crossers have commented on their preference for the watts link.

Erik

[SEVEN-OH JOE]

Originally Posted by Ry_Trapp0

for instance, you mentioned the front splitter, which doesn't weigh a whole lot. but what you've missed is that ford found it neccessary to add a steel bracket behind the bumper to support the large load that the splitter produces at track speeds. without that bracket, the splitter supports would merely rip right out of the bumper. the standard boss doesn't have this bumper as its splitter doesn't produce as much downforce as the massive tongue included with the boss LS.

You mean that thing in the picture? That piece of superstructure from the Golden Gate Bridge?

BTW, as far as the boss LS "needing" the X-brace in question and the 1LE not "needing" it... well, lets just say that there are some very smart people with very capable S197 track/race cars that certainly don't have an X-brace in the rear. if that X-brace was actually worth anything more than looking badass(), kenny brown, griggs racing, agent 47, etc. would all be offering their own version of it and would be using it on their record setting race cars.

Uh, Ry, they do. It's called a roll cage, and includes reinforcement SPECIFICALLY for rear floor strengthening, so the flexi-flyer doesn't.

[SEVEN-OH JOE]

Originally Posted by Ry_Trapp0

i believe you missed my point about the rear X-brace. if it made a significant difference then these companies would offer their own version of it for sale.

So let me get this straight. SVT added a piece of phantom, weighty structure to the rear of the car, just for grins 'n giggles?

Gotcha! Makes sense! Mind if I quote you?

No wonder you 'n the Stang posse came over to camaro5 for some sanity and engineering sense.

[Tob]

Joe, nobody is claiming that the brace in and of itself adds no integrity. No ghosts, no phantoms. In fact, Donald Farr's excellent Mustang Boss 302 From Racing Legend to Modern Muscle Car utters the following blurb with respect to the brace...

The Laguna Seca's rear crossbrace, designed to stiffen the chassis by 10 percent, is installed at the Mod Center. (pg 149)

I'd prefer a more defined quote as opposed to the global terms used. Nonetheless - it helps. But as Ry intimated, the correlation between its use and any dramatic effect on the inside rear tire lift is truly phantom at best. As for looks, if it didn't look good - Ford wouldn't be doing it. I think most would agree, the look draws a positive reaction from quite a few. That certainly helped in the decision to use it.

[eolson]

So you are implying that the watts links does not add grip stability over the PHB set up over bumps, dips and uneven pavement? So Steeda, Griggs, the Fays 2 are all placebo effect parts? OK

I'm surprised since every time the car dips or rises with the PHB set up, the frame is sliding down to the lower left or rising to the upper right. Is this not true?

I'm sorry to say that the PHB set up does result in the car actually slightly changing position laterally on hard corner bumps. If you are saying that doesn't result in grip loss that's one thing, but the car does slip. This effect was felt and reported by dozens and dozens of Mustang owners on the forums early on with the 05. Erik

[eolson]

Question. What had the faster mph number for the MT figure 8 standard test, the Boss LS or the new GT500?? I can't find my Boss LS test issue. Thanks, Erik

[SEVEN-OH JOE]

Tob, we're honored to have you intercede on Ry's behalf. Welcome. And thanks for a proper non-rhetorical explanation, which youthful exuberance sometimes fails to deliver.

Like most manufacturers these days, most items present in new vehicles serve an engineered, useful purpose beyond mere cosmetics. And something of the X-brace's nature on the ultimate road-racy, weight-conscious, current-Gen showroom-floor-available Mustang does, as well.

[Supermaro585HP]

That my friend is why I won't buy a Shitstang....

[SEVEN-OH JOE]

Originally Posted by Ry_Trapp0

i said that it simply doesn't make a significant difference. now we could argue how significant a 10% difference in chassis stiffness is, but i think you'd be hard pressed to find anyone that could legitimately feel the difference. i also wonder if the difference on track could actually be measured as well.

Tob made the point, and, like you mentioned, did a much better job of it than my self

Only an automotive neophyte would consider a 10% increase in chassis stiffness as "insignificant". While that may NOT increase the ability to turn a faster "hero lap", it DOES dramatically increase the likelihood of repeatability, lap-after-lap-after-lap, which is the raison d'etre of such a necessity being present in the BOSS LS. And I'm sure your pal Ravin' can confirm what "10%" actually accrues...

As to Tob's clarification, via author Donald Farr (respected since his days at Dobbs Publishing, where I also freelanced...), it was susinct and to the point. Something noteworthy to budding auto enthusiasts and young forum friends everywhere.

[SEVEN-OH JOE]

Ry,Ry,Ry. A "hero lap", as you've so willingly participated in that egregiously long (200 pages) and repetitive (5000 posts) and highly defensive (and certainly offensive to most) thread at svtsomething.com, is that one-and-only lap that sets the clocks but is seldom/never repeatable, lap after lap. Road racing. Not from heat soak. Not from smoked brakes. Not from cooked tires. Not from excess avoir du pois. But from a too-flexible chassis that therefore suffers from inconsistent feedback to the driver and, therefore, inconsistent over time/duration laps.
Talk to some real racers, Ry, and ask them if they DON'T prefer the stiffest possible CHASSIS/FRAME. Not suspension but chassis/frame. And ANYONE who says "Yes" is on a temporary pass from the ravin' loonie bin.
You won't get a "Yes" from Danny Popp. Even in auto-X and pro-solo WHERE ONE LAP @ A TIME is run. NOT several at a time.
As to a single-lap event like auto-X, perhaps it plays to Mustang's shortcomings with its telephone pole rear axle to have the car flop around like a flounder out of water, just to get some rear sticktion.
What was that about neophyte? Maybe Tob, or Sid, could come and bail that flounder back into the water.
Sussinctness is not the only shortcoming I see. An "army of one" seems apparent, as well.

[eolson]

All I know is that when Randy Pobst drove and compared the Boss 302 LS directly to the ZL1, in the corners and on the corner curbs bumps he felt that the car's solid rear axel was jumpy laterally. The Watts link was designed to reduce that effect of the car sliding laterally on the frame.

I guess we'll have to wait until the major mags actually test a custom aftermarket Mustang with some weight loss, a Watts link, X brace, other chassis stiffening, full a/m suspension, actual wide tires and wheels with great summer rubber, and see what it pulls on the slalom, figure 8 and lateral G's tests. We know this will never happen of course. God forbid that you would throw an extra 12 grand onto a Mustang and actually run it against all the other much more expensive cars that come fit and finished from the factory, unlike the Mustang, and post those times and test results in a Major publication.

Again, does anyone have the MT figure 8 time for the 2013 GT500 compared to the Boss 302 LG? I would hope that the lighter weight and "incredible" X brace might make a difference for the Boss in a purely lateral G-force comparison.

By the way, did anyone see that the ZR1 attained 77.3 mph in the C&R slalom test. That pretty much makes all this mute I guess. Erik

[Tob]

Moot Erik, moot.

I think you'd be making quite a leap were you to conclude that the inclusion of the 'X' brace was somehow related to G-forces recorded between two vehicles with different weight distribution, tire/wheel sizes, spring rates, bar sizes, etc.

You are correct, Pobst didn't prefer an 'unsettled' S197 chassis over the ride the ZL1 offered. But his comments weren't geared towards your so-called "effect of the car sliding laterally on the frame."

The Watts reduces migration, yes. Have you any idea how much potential lateral movement there is on a Boss or GT500 (with respect to axle and chassis)? I'm just curious if you know how to calculate it and what the approximate numbers are.

In addition, your mention of Pobst's time with the IRS equipped ZL1 vs the solid axle of the GT500 - are you implying that his times would have improved in the Boss with a Watts as opposed to the panhard bar? Do you think that the solid axle Mustang would no longer be 'jumpy laterally' were Pobst to be driving a version that was Watts equipped?

[eolson]

Yes, I think a 2005-2010 Mustang is more stable while cornering over bumps with a Watts Link as opposed to a pan hard bar set up.

That has been my direct experience with my car in hard bumpy corners, the car no longer skipped slightly laterally with the watts link.

So unless you have driven a car fast over the exact same series of bumpy corners over and over again with the stock pan hard bar and brace, then the Steeda Adjustable Pan hard bar and brace, then the Saleen Generation 1 Watts link(where the support arms were improperly short by 3/4") and then finally with a Techco Watts link with the proper length action arms, and brace.

After direct back to back experiences on the same corners, same tires, same basic air temps, progressively with each of these items added on to the car.

The stock Pan hard bar and brace and the Steeda replacement Bar and brace still had clear lateral deflection, slightly skipping the rear end to the outside of the turn.

The Saleen generation 1 Watts Link displayed a slight deflection of the rear, but not as much as the Pan Hard Bar set ups(action arms to short by a bit).

The Techco Watts link displayed no detectable lateral deflection on the same hard bumpy series of corners as the other items. The generation 2 Saleen Watts link also had the correct action arm lengths, but still had the weaker center bolt throughout the pumpkin, and had reported brakes or failures. The Techco Watts link has had none that I have seen reported, and mine is still working great.

What I was experiencing in my Mustang originally as deflection or butt skip was real, and I searched out and was told by numerous shops and high performance race shops, that the effect was caused by the lifting of the solid axel and the sliding on the frame of the PHB set up. Passengers in my car exclaimed while driving with me over hard curve bumps "what the Hell was that" when they felt the skip or shift in the car.

It is real and present in Mustangs. The Techco Watts Link I have, no matter what the technical explanation is, does in fact, completely eliminate this lateral deflection or butt skip. Weather it is a combination of the solid axel not lifting or effecting the tire grip as much in combination with the diagonal slide of the car on the frame with the PHB being removed as well, I don't know.

All I know is that my car, as well as many, many other drivers, reported the elimination of that lateral momentum hop to the side while in hard corner bumps that is present with the Pan Hard Bar set up. My car now takes those same hard corners as smooth and stable as many (IRS) BMW's, Acura's and other rental cars I've driven over those same exact bump corners.

To repeat, the actual real, lateral rear hop and slight slide present with the Fixed axel in combo with the PHB, is longer present in my car with this properly designed Watts link, and has been reported as being no longer present with dozens of other Mustang owners with properly designed Watts links. Thank you, Erik

[eolson]

Really? No placebo effect? Hmmmmmm.... Erik