IRS and drag racing

[Norm Peterson]

Sure, if you want a drag only set up, an old FOX body is great(I like the Futura). I got rid of an 82 a few yrs ago... Once upon a time, it had a 460 in it and was street driven.

Believe it or not, I understand this, or at least I do if I make a good enough analogy to a truly single-purpose road course car.


Norm

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[Rob WH]

I type too slow.

So do most of us. I don't, but I do read slow!

Makes sense. Maybe even too much sense for people looking to buy a new car for whatever reason. I hear what Rob is trying to say, but I think he's describing people who aren't quite serious enough.

How serious do I need to be? I actually have an 8 second car... which sits in the same spot as it has since... :headbonk:

The catch comes when you consider the (overly) strong general public association linking U.S. domestic ponycars and muscle cars with the dragstrip and "street challenges". And the perceived need to always beat the other guy by that tenth rather than lose by the same amount.

That's why... RACE CAR!

It will get interesting for the drag race fans and wanna-be's once all three ponycars are running IRS.

So... later this year. On that note: Aside from the way upper end cars, the 15 Mustang GT is exceedingly likely to simply smash the other 2 in most handling aspects. The entire reason in a word... BALANCE! It has a great weight bias(not stated exactly, but it's clear now), a solid power foundation, flat road holding characteristics, and ... finally... great brakes! Brakes have been the holdout for years, so it's great to see them finally using what should've been on the GT for the past 20yrs.

Believe it or not, I understand this, or at least I do if I make a good enough analogy to a truly single-purpose road course car.

That's a good point... That said, we're all going to be impressed, if not totally astounded, by the handling of the new Mustang... I definitely believe that. If not, I won't buy one. By that, I mean that it's going to be so much better overall than the current car, it's going to be seconds faster on various tracks. I'm personally looking forward to Mazda Raceway and VIR results.

Now, I don't expect it to beat the GT500 on the ring, but hey... I'm sure it will be all over it aside from those long stretches where the 500 will get to stretch its legs on top end.

 

[Norm Peterson]

How serious do I need to be? I actually have an 8 second car... which sits in the same spot as it has since... :headbonk:

Ummm, it's not your seriousness that I'm questioning. Not at all. For every person who actually is that serious, how many are just bench racers armed with magazine stats? They may think they're serious . . .


Norm

 

[Rob WH]

Ummm, it's not your seriousness that I'm questioning. Not at all. For every person who actually is that serious, how many are just bench racers armed with magazine stats? They may think they're serious . . .


Norm

That's why I was laughing Norm! Most people don't want to be that fast, so an everyday Mustang will do wonders for them. That came together perfectly!

 

[Trackaholic]

3:10-3:15 in the attached video shows some pretty severe axle hop in the Mustang.

[ame]

I don't think the solid axle is doing the car any favors in stock form.

-T

 

[scottpe]

3:10-3:15 in the attached video shows some pretty severe axle hop in the Mustang.

Yeah, that's a really clear shot. Lots of wasted energy there.

 

[Norm Peterson]

3:10-3:15 <snip>

I don't think the solid axle is doing the car any favors in stock form.

-T

The operative word being "stock" . . . and not all stock IRS arrangements are immune either. Not even FWD can avoid getting it, for that matter.


Norm

 

[scottpe]

The operative word being "stock" . . . and not all stock IRS arrangements are immune either.

Almost any specific behavior can be changed if you throw enough aftermarket parts at it. But that's beside the point. Doing so is almost always at the expense of some other aspect of the car's behavior (and/or cost prohibitive) that makes it unfeasible for a car that is intended for more than just track duty.

At any rate, I'm going to go out on a limb and predict that the 2015 will be better in this regard.

 

[Norm Peterson]

My point was more that devising immunity to wheel hop is not much of a priority at any OE, regardless of what kind of "axle" is used at the drive end of the car. Even though it might not take much trade-off in NVH to at least postpone the occurrence of hop to where you'd be pretty much just hooning around.


Norm

 

[scottpe]

My point was more that devising immunity to wheel hop is not much of a priority at any OE, regardless of what kind of "axle" is used at the drive end of the car.

How many other cars come stock with a line lock, track apps, launch control, etc... features that are about as squarely aimed at drag racing enthusiasts as you can get?

Just food for thought when considering what may have been among Ford's 'priorities' for their rear suspension design... ;)

 

[souprmage]

My guess is Line Lock came about like this...

Eng1: Hmmm, if we go to IRS, the drag guys will be addle: and think we're
Eng2: How about we add Line Lock and make them
Eng1:


Me: :lol:

 

[Norm Peterson]

Offering features like that is marketing's job. Properly supporting them is engineering's. Obviously something got lost in the translation, or else engineering never even got the memo.


Norm

 

[B Gordon]

I switched from a solid axle setup (99 Firebird Formula) to an IRS (03 Infiniti Coupe).

Not sure how well the new Mustang is going to do the job but right off I noticed that the Infiniti IRS doesn't have the "stutter" or "vibration" feel that the Formula had on hard launch at the drag race test & tune days.
Granted, the two are probably not apples to apples, but probably neither would a comparison of the 11 year old Infiniti IRS to the newest design Mustang IRS. The Infiniti just squats a bit in the rear and launches, nice and consistent. If the Mustang works in a similar fashion I will be very happy.

It is not straight line talk but I really noticed stuttering during hard cornering when driving the Formula at a two day SCCA driving class I took. It would have been down right scary if I had been doing the same thing on a public street. The rear end would go from gripping great to putting me sideways with no notice. You had to know the limits because the car was not giving any feedback. Solid and steady to all of the sudden front end push with the car plowing wide or the rear taking a swing and putting me into a drift that maybe I could control and maybe I couldn't. No way for me to know how much was a function of the stock shock and/or suspension and how much was specific to the style of rear axle. only change I made for the class was fresh tires and new brake pads.

What I can say for sure is that I am much more confident as a driver that my present IRS car will act in a consistent and usable fashion.
Maybe that is what Ford was looking for when they switched.

 

[Don's Stang]

If you really want to drag race get a 2011-2014 automatic mustang. Install a supercharger, do the sway bar relocation kit, or a white line sway bar, upgrade the rear control arms, install a aluminum one piece driveshaft, stock springs with drag shocks, and put a set of 15 inch wheels with MT ET Street Pro's

That's the drag race setup, and I bet there going to be a bunch of them on the market soon, for pretty cheep money

If you just want to make a run down the drag strip once in a while I am sure a S550 will be ok, but not a serious drag race car

 

[Norm Peterson]

I switched from a solid axle setup (99 Firebird Formula) to an IRS (03 Infiniti Coupe).

Not sure how well the new Mustang is going to do the job but right off I noticed that the Infiniti IRS doesn't have the "stutter" or "vibration" feel that the Formula had on hard launch at the drag race test & tune days.
Granted, the two are probably not apples to apples, but probably neither would a comparison of the 11 year old Infiniti IRS to the newest design Mustang IRS. The Infiniti just squats a bit in the rear and launches, nice and consistent. If the Mustang works in a similar fashion I will be very happy.

If your Infiniti has enough power, you're probably just spinning the rear tires, which is made easier by the rear wheels going further into negative camber as it squats. Being IRS, you don't get the planting of the LR and unloading of the RR that you do with a stick axle car, and from that you can expect to have a straighter launch as well.

It is not straight line talk but I really noticed stuttering during hard cornering when driving the Formula at a two day SCCA driving class I took. It would have been down right scary if I had been doing the same thing on a public street. The rear end would go from gripping great to putting me sideways with no notice. You had to know the limits because the car was not giving any feedback. Solid and steady to all of the sudden front end push with the car plowing wide or the rear taking a swing and putting me into a drift that maybe I could control and maybe I couldn't. No way for me to know how much was a function of the stock shock and/or suspension and how much was specific to the style of rear axle. only change I made for the class was fresh tires and new brake pads.

Without knowing anything about your Formula's wheels and tires, I'm thinking shocks and possibly the OE suspension tuning (I've driven an ESP-level 4th gen on R-comps at autocross). My '08 GT is pretty easy to steer on the throttle, and all it's had done are dampers (Koni yellows), adjustable sta-bars, poly/spherical LCAs, 18x9.5 wheels with 255/45 tires, and an out-of-spec camber setting that's been there since before I picked the car up brand new with 5 miles on the clock. I've never felt any shuddering while cornering in that car, ever (and I've had the tires singing a nice steady tune through the turns at both NJMP and Mid-Ohio).

If you really want to drag race get a 2011-2014 automatic mustang. Install a supercharger, do the sway bar relocation kit, or a white line sway bar, upgrade the rear control arms, install a aluminum one piece driveshaft, stock springs with drag shocks, and put a set of 15 inch wheels with MT ET Street Pro's

Better yet, start with a Fox.


Norm

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