Norm Peterson

The primary reason for putting a rear bar on any live axle with the OE suspension or even most somewhat modified suspensions is not to reduce roll. Typically, a rear bar in this kind of application is the least effective of the four elastic suspension components at resisting roll (the others are front bar, front springs, and rear springs, roughly in that order of effectiveness at controlling the amount of steady-state roll).

What it's mainly there for is handling balance, by using the greater amount of rear lateral grip to help the front out. In some cases (like the Fox/SN95/GM live axle intermediates and fullsize) they actually stabilize the LCAs laterally and effectively change the axle roll steer toward slightly heavier vehicle understeer (safer for the public at large). Not every driver can appreciate this, hell, most drivers rarely drive hard enough for a rear bar or most other suspension tuning contributions to really amount to much.

The only time a rear bar specifically starts getting effective at reducing roll comes with one-off modifications to intentionally lower the rear roll center. When you do that, you need more rear roll stiffness to hold the roll angle somewhere near where it was before, and more to retain (or improve) the front to rear roll stiffness balance. Kind of a no-brainer to beef up the rear bar in such admittedly rare situations.


The large by huge drag race antiroll bars are there for that very specific purpose and the reason that they work in that application is by exaggerating what a rear bar does during acceleration anyway. Most of the drag racers that put those things on won't take them back off unless/until they move up to ladder bars.


I suspect that an IRS would have to be demonstrably better than the stick axle this time around, and not just with respect to ride quality. For Ford to go to an IRS that was not at bare minimum the equal of the Camaro's would be to shoot themselves in the foot.

The last time around for an IRS Mustang, there wasn't any IRS competition in the ponycar class to be compared against - not much ponycar competition at all, actually - so with that kind of fortunate timing it couldn't really lose against anything other than its live axle stablemates. Ford isn't so lucky this time around, so if it's going to be done again it's got to come out being done up right without any stumbles.

I truly hope that Ford learned from the recent difficulties with public happiness with Sync, MyFord, and whatever other electronic high-tech stuff that apparently wasn't quite ready for prime time.


Norm

JIM5.0

I would say that the Beamer is overpriced and delivers little. Have they had enough time to improve and tweak and refine their manufacturing to reduce costs? Yes.

But have they? Probably, but too bad it did not make its way into the M3.
Or if that refinement got into the M3, it sure did not shine through. Maybe the suspension tuning was neglected.
Or worse, that suspension refinement never made it into the M3 at all, and you have to shell out even more money for a higher model to get the best of Beamer suspension refinement because they could be greedy bastards who want to milk as much out of the buyer as possible.

Again, playing devil's advocate: It could be that BMW never spent money on suspension refinement. They could be investing their capital on other things, such as Vanos and Valvtronic (Vanos = Ford's TiVCT, Valvetronic = variable valve lift).

Afterall, the ZL1 also has IRS, and it demonstrated its IRS is very formidable.

Again, it all comes own to execution: Just because you have IRS does not mean you automatically handle like a nimble curve hugging precision machine, it has to be executed properly.

New Edge Termi IRS was executed poorly. ZL1 IRS was executed way better than the Termi IRS.

It goes back to the what JimC and I said:
Just because you have tech does not always make it better.
Conversely, just because you have tech does not mean it is always going to suck either.

If Mustang goes IRS, I hope it is execute well, not like the Termi.
But I agree with you and the others: if IRS is going to suck as bad on the Termi and solid rear axle will be superior, then I would prefer that solid rear axle would stay on just a little longer, until IRS can be perfected to be actually better.

jdmcbride

Jim - Do you really think that the Chevy Camaro SS has a better IRS than a BMW M3? Wow. BMW is called the ultimate driving machine for a reason.

BTW, at the other race track in Willow Springs, the 5.0 Mustang GT beat the Camaro SS with its "superior" IRS by a tenth of a second (137.60 vs 137.70 respectively).

ademantia

So that people will buy them?

jdmcbride

If you have driven a BMW, then you would know...

JIM5.0

No, actually, the I think the SS IRS was not excuted as well as Beamer's IRS. So I do think the SS IRS is inferior, or maybe at best equal to.

But I do think the ZL1 IRS is way superior to M3 IRS.


They lied, LOL

A tenth of a second is a very small margin. The GT and IRS could be driven over and over again and it could be an even toss-up. For example, out of ten runs each, the GT could win five, the SS the other five.

However, if the GT wins more timjes than loses, say 7 times it wins and loses onle 3 times, that consistency would validate the GT handles slightly better despit only 0.10 sec faster.

pascal

Are you for real?
Who calls themselves the "ultimate driving machine"??
BMW, no one else. Big LOL.

I can't think of any German cars worth a damn nowadays for the money you have to fork out for them.
Take the new M3 vs the well equipped Mustang GT for example...
There's about $30K difference between the two, lol.
And the bimmer sure isn't better in $30k worth of quality, double lol.

pdonket

IMO I do have to say that I think BMWs have a fit and finish feel to them that definitely does exceed everything I've ever felt in an American made car, but you definitely pay disproportionally for it.

One day I do see myself in a foreign car, but you definitely have to be raking in great money to manage it. I've always wanted to drive a C63 AMG.

jdmcbride

Yes, I am for real Pascal.

BMWs drive great IMO, a real driver's car - from the lowly 325i to the 750iL. German engineering speaks for itself, but does it warrant the premium that BMW charges for their vehicles? Hell NO. They are way over-priced!

Thank you for making my point though, a $37k Mustang GT with a "stick" axle matches the very best that BMW offers in a $67k M3 with an IRS.

Pascal - Sorry, I forgot about the grude that the French have with the Germans.

jdmcbride

Also, I have come accross some threads where Camaro owners are all gaga over converting their IRS to a live axle (some even mentioned installing a Ford 8.8 alxe in their Camaro). LOL