Torque Arm Question (Mustang) and Class Comments

[Mason]

Over the weekend, I was at MSR and saw my first NASA time trial. I had a chance to review the rules and classing and had a few questions / comments.

 

My particular car is a 1997 Mustang Cobra which has been used for years in autocross competition in a E-Street Prepared. As such, I have added, among other things, a torque arm and panhard bar to the rear suspension. The PHB (+4) is covered expicilty in the rules, but the TA is not. Does the +8 points apply as a relocated suspension point? If so, it seems a bit much to get hit on points for both the TA and PHB. In the classes I have been involved in, the TA is considered a traction-bar more than a locating device. I am curious to hear your take on what point value should be assigned to an added OR upgraded TA.

 

Secondly, It seems odd to me that the C4 Vette, E36 M3, 05 Mustang and LT1/LS1 Camarobirds are classed lower than the '96-'02 Cobra / Mach 1 Mustangs. IMHO, the C4 and E36 M3 should be 1 class higher than the pony cars, including the ram air versions of the GM cars. The Vette and M3 are significantly stronger cars and deserve to be seperated, while the perfomance advangage of the ram air cars is pretty negligible compared to their "regular" counterparts. Just my unsolicited opinion.

 

Thanks for your time and feedback, and I'm looking forward to getting my car out on the track to play!

[mitchntx]

Mason,

 

You are correct when you claim the torque arm addition is a traction enhancement. It positively locates the pinion angle in relation to suspension travel. Not only traction under acceleration, but under braking as well.

 

The panhard bar allows the rear diff to be centered under the car after lowering the car.

 

The torque arm addition is a HUGE positive addition to Mustang's rear suspension. It gives a tremendous advantage over a Mustang without it ... as I understand it. It appears to be an appropriate adjustment.

 

The PHB is a seperate component, providing a seperate function. So, assessing an additional adjustment appears appropriate as well.

 

I do welcome data or precedent that would change my current assessment, though. I'm learning as I go ...

[jp99gt]

In our TT discussions, a TA and PHB combination is worth the 8 points. Sometimes people with other car types only install a PHB, which is the 4 point addition. In a Mustang, if you kept the UCA's but added the PHB you would add 4 pts (CMC cars would do this). Once you delete the UCA's and install a TA (AI/X allow this), you've changed the geometry and go to the 8 pt addition. They were not intended to be additive.

[mitchntx]

Thanks, Jim ...

[lonegunman]

In our TT discussions, a TA and PHB combination is worth the 8 points. Sometimes people with other car types only install a PHB, which is the 4 point addition. In a Mustang, if you kept the UCA's but added the PHB you would add 4 pts (CMC cars would do this). Once you delete the UCA's and install a TA (AI/X allow this), you've changed the geometry and go to the 8 pt addition. They were not intended to be additive.

 

Is it safe to assume that this is how SoCal is going to see it? Greg?

[Greg G.]

Yes,

Jim and I have discussed this in a prior thread I believe. We both agreed that the combo was worth 8 pts = to change in suspension mount points, but wasn't worth 12 points. The 4 pts. for the panhard rod was for cars that didn't go with the TA.

 

IMHO, the C4 and E36 M3 should be 1 class higher than the pony cars

 

Mason, are you serious? You think that a 240 hp BMW with a wt/hp ratio of 13.2 should be classified a whole class higher than a 320 hp Cobra with a wt/hp ratio of 10.3? BMW's clearly handle better when stock, but not enough to make up that kind of difference. You have a much better case for the C4 to be closer to the Cobra's class, but the stock C4 just doesn't end up performing that well at the track. The funny thing to me is that you can come with a 320 hp 2001 Cobra with a panhard rod and Hoosiers and still run in TTC, which is the class that I run in with my 260 hp front wheel drive SRT4. Seems to me that the Cobras don't need much more of a break. Also, Cobras have managed to win more than their share of TT Championships in 2004, and that was before they all got a functional downgrade in base class (by us adding the TTU class, but either decreasing, no change, or minimally upgrading the Mustangs by an *).

 

I do agree that depending on the mods that a Mustang has, it may get less of a functional benefit than some of the other cars, and still get the same number of mod points. Ie. a Mustang (esp. Cobra) can be heavily modded with mods that don't do too much compared to the stock vehicle, and end up in a class that's too high. That is an unfortunate byproduct of a system that must account for ALL vehicles. If mods are almost worthless, then one can take them off if they are worried about losing in a higher class. Also, if you think that your car is classified too high, you can always discuss it with your TT Director, because for our regional competitions they have the final say of what class you will run in.

 

I hope you join TT this year and have a great time.

[lonegunman]

Cool. I got some breathing room back, still in TTB.

[Mason]

Greg, thanks for taking the time to respond and to clarify how the torque arm and panhard bar should be handled with respect to points.

 

Yeah, I’m serious about the C4 and M3.

 

Stock-for-stock, the Cobra (’96) out-weighs the M3 (’96) by at least 225lbs and the Vette (’96) by at least 100lbs. The M3 is not exactly a slow car in a straight line; it is geared much better than the Mustang, which along with the weight, helps narrow the horsepower discrepancy. Edmunds (where I got the weights from) has the M3 3/10ths slower in the ¼ mile and the C4 2/10ths quicker than the Cobra. I know both the C4 and E36 M3 with run circles around the pony cars in an autocross given equal drivers and levels of prep, but I’ll see if I can dig up some more relevant information on the M3 for TT. The Vette on the other hand is a no-brainer. Less weight, lower CG, better power-to-weight ratio, more torque, larger wheels and tires, much better weight distribution, and a real suspension make it not worse, not equal to, but significantly better than ’96-’02 Cobras and Mach1/Bullitt in TTC, as well as, the pony cars in TTD. I just don’t see how the C4 can be considered, “not to perform all that well at the track”, especially be comparison to the pony cars.

 

I’m not in a position to say whether Car A should go here or Car B should go there, but it makes good sense to me that the V8 pony cars with similar HP / weight should be grouped together. As it stands, the ram air f-bodys and N/A cobras / bullitt / mach1 are separated from the very similar LS1 / LT1 Camarobirds, not to mention the ’05 Mustang GT.

 

The reason I bring this up is not to get MY car moved here or there, but to raise what I think may be a legitimate discrepancy in where a couple of cars are classed. It certainly won’t discourage me from coming out to play, but it may others. This series seems to be new (or maybe just in my neck of the woods) and these types of changes a much easier to iron out early on. I can certainly appreciate how difficult it is to make classing decisions since someone inevitably feels like they’re getting screwed.

 

My car was pretty well built under the Street Prepared rules I was running, so the mods are necessary and I am WELL into TTA. Very minor engine mods, mostly bolt-on suspension stuff that adds up. That's not something I have an issue with. It looks like the points award "stocker" cars, which is great for participation by greater numbers of people.

 

Again, thanks for taking the time to reply to my original quesiton and I look forward to hitting the track with the other local Texas TT guys soon!