Factory Race Car Modification penalties

[claykos]

A comp coupe Viper has a full carbon fiber body which does not share a single panel with a street SRT10, it has basically a full tubeframe rear end that has little to do with a street viper, and factory developed flat bottom aero with front and rear diffusers. It also starts with an 8.3L motor that is obviously very torquey. It would be nearly impossible to duplicate a comp coupe starting with a street Viper, and if you did I believe you would have to do things in violation of the ST rules regarding changes to the frame.

 

Porsche GT3 Cups are just a standard GT3 tub which is plucked off the assembly line, has a nice but actually not especially elaborate roll cage put it and basic race car prep stuff. The main unibody, roof, and rear fenders are all identical to a street GT3. The basic suspension is also identical to street gt3 with standard cup cars and (depending on year) even retains rubber bushings. There is no particularly special aero other than a rear wing and a lower front air dam than the street car. It would be quite easy (although not too cost effective) to start with a showroom floor 911 GT3 and turn it into a cup.

 

As well you can race a factory built BMW motorsports M3 tub which has a very elaborate cage tied everywhere into the chassis. (Most of the ex grand am, rolex and speed GT cars were built using the factory "motorsports" tub).

 

So, given all this, why does a Viper Comp coupe get a -.2 while a Porsche cup gets a -.4 and no penalty for a BMW motorsports tub?

[Greg G.]

Clay my first question would be whether or not it meets this definition:

 

Any closed wheel/fendered production vehicle, approved for street use by the D.O.T., T.U.V., or

Japanese government, that complies with all NASA safety requirements in the CCR, and all of

the restrictions and limitations listed below in 7.2 and 7.3 is eligible to compete based on the

“Adjusted” weight/power ratios below:

 

Is that tub approved for street use by the DOT, etc. If not, are there changes that would potentially violate the other rules in ST?

If any of this is true, then why not file a protest?

 

If the car does meet all of the criteria, then it does not get extra mod factor because it is legal without an extra mod factor. I don't personally know enough about this tub to answer the first questions above.

[claykos]

Greg, the only thing on the BMW motorsports tub that would be questionable would be mods to the floor pan for side exit exhaust - but I don't think that is really against the spirit of ST. The cage is heavily tied to the strut towers and rear suspension, but I don't think this is a problem for ST.

 

However, the Motorsports Tub is a factory race tub with a factory installed cage - you buy it has a part from BMW and have to build it up. Similar to a Porsche Cup, it was never sold as a DOT approved street car and has a different chassis number that is not a normal VIN. You can buy the tub with cage as a part number from BMW motorsports (just like you can a Porshce cup replacement tub). So technically it is not a DOT approved vehicle (although built on the same chassis as a BMW M3).

 

I have not protested because I personally think it is a perfectly reasonable ST car - it starts as a BMW tub, a competant shop could take a street M3 and build one the same. I think it is inconsistant in the rules that the Porsche cup is penalized so heavily because it is also a totally production tub - just happens to have a cage installed at the factory. It's even sillier (in my opinion) that it the Cup is penalized more than the Viper which shares very little with the street car.

 

For example - this ex grand am car for sale has a motorsports tub. You can see pictures in the ad of how it comes bare and white.

http://www.turnermotorsport.com/image/gallery/forsale/gs-e46-m3/

[David M. Pintaric]

The Comp Coupe shares the same frame as the stree Viper.

[ViperRacer]

Come On Over & look at the Comp Coupe on the lift, and my 06 on the Lift you will see the same Frame

[claykos]

I am talking about the rear section with all the tube frame added to hold fuel cell and brace the rear suspension to the cage....

 

My point was that the comp coupe is further from a street viper than a porsche cup is from a street GT3 yet gets less of a penalty factor. Given the comp coupe has a full carbon body that doesn't share a panel with the street car and has extensive additions to the rear frame area as part of the cage (which the Porsches do not have).

[David M. Pintaric]

I am talking about the rear section with all the tube frame added to hold fuel cell and brace the rear suspension to the cage....

 

My point was that the comp coupe is further from a street viper than a porsche cup is from a street GT3 yet gets less of a penalty factor. Given the comp coupe has a full carbon body that doesn't share a panel with the street car and has extensive additions to the rear frame area as part of the cage (which the Porsches do not have).

 

Clay, I have been giving this some thought. I really think the issue isn't whether the Porsche should be penalized more than the Viper CC, but really whether the CC and Porsche should be penalized at all. While I don't know much about a GT3 Cup Car (but intend to soon!), what Dodge has done with a Comp Coupe is really stuff that anyone can do with aftermarket parts on a Corvette.

 

CF body parts? There are at least two suppliers for C5s and C6s.

spherical bearings on the a-arms? yep

Aero improvements? WCGT parts for Corvettes are readily available.

 

Trust me, the CC is very close to a street Viper excepting for the body work, some frame x-bars in the front, a fuel cell, and the a-arms. I can't compare it to your Porsche, but I do know that Vettes can make all of those changes rather easily.

 

Vipers aren't your enemy!

[John Graber]

David,

We gonna see that new ride at Mid Ohio this summer????

[claykos]

 

Clay, I have been giving this some thought. I really think the issue isn't whether the Porsche should be penalized more than the Viper CC, but really whether the CC and Porsche should be penalized at all. While I don't know much about a GT3 Cup Car (but intend to soon!), what Dodge has done with a Comp Coupe is really stuff that anyone can do with aftermarket parts on a Corvette.

 

CF body parts? There are at least two suppliers for C5s and C6s.

spherical bearings on the a-arms? yep

Aero improvements? WCGT parts for Corvettes are readily available.

 

Trust me, the CC is very close to a street Viper excepting for the body work, some frame x-bars in the front, a fuel cell, and the a-arms. I can't compare it to your Porsche, but I do know that Vettes can make all of those changes rather easily.

 

Vipers aren't your enemy!

 

David, on many levels I completely agree with you. Why are these cars penalized if they are entirely production based? I can sort of see the logic in handing a factory built race car somewhat of a penalty over a shop built car because 99 out of 100 times the shop built car is just not going to be done "right" the same way the factory cars are. However - if we are getting penalties it seems very arbitrary to me that a cup gets twice the penalty as a comp coupe. We are talking a penalty in the ballpark of 30+ hp for these cars - which is a BIG deal.

 

There is a lot of variation over the years in cup cars with progressively more deviation from "stock" GT3 from 2000-current, but these cars all use a completely standard tub with no modifications other than a fairly simple 6 or 8 point cage (depending on year). They even have VIN numbers - just a different prefix than street GT3s.

[David M. Pintaric]

David,

We gonna see that new ride at Mid Ohio this summer????

 

Likely yes. I hope to be making enough HP to be competitive in ST1.

[claykos]

David,

We gonna see that new ride at Mid Ohio this summer????

 

Likely yes. I hope to be making enough HP to be competitive in ST1.

 

Take it you've gotten a cup?

 

That's the issue - the HP. At around 2700-2800 lbs and on slicks you can only make ~390 or so rwhp which makes it really tough to keep up with 500-550+ rwhp 3200 lb vipers and vettes on long straights....power to drag ratio is a big deal above 100 mph.

[David M. Pintaric]

Clay,

 

I am sorry for the confusion. No, I did not get a Cup car...yet. I am building a Viper Coupe for SCCA's STO class. The minimum weight for the class is 3300 lbs and I hope to make a bit over 500 RWHP with the 60mm restrictor plates required. Without the plates, maybe in the 530 range. I could lose some weight for NASA's ST1, though. But not more than maybe 100 lbs.

[claykos]

Clay,

 

I am sorry for the confusion. No, I did not get a Cup car...yet. I am building a Viper Coupe for SCCA's STO class. The minimum weight for the class is 3300 lbs and I hope to make a bit over 500 RWHP with the 60mm restrictor plates required. Without the plates, maybe in the 530 range. I could lose some weight for NASA's ST1, though. But not more than maybe 100 lbs.

 

Sounds like fun - kind of goes to the point of this thread. You could build your viper coupe up into a comp coupe, and have 30 or 40 more hp then a comp coupe...and have probably spent quite a bit more money than just buying a comp coupe and it will not have anywhere near the resale.

[David M. Pintaric]

Clay,

 

I am sorry for the confusion. No, I did not get a Cup car...yet. I am building a Viper Coupe for SCCA's STO class. The minimum weight for the class is 3300 lbs and I hope to make a bit over 500 RWHP with the 60mm restrictor plates required. Without the plates, maybe in the 530 range. I could lose some weight for NASA's ST1, though. But not more than maybe 100 lbs.

 

Sounds like fun - kind of goes to the point of this thread. You could build your viper coupe up into a comp coupe, and have 30 or 40 more hp then a comp coupe...and have probably spent quite a bit more money than just buying a comp coupe and it will not have anywhere near the resale.

 

Don't remind me of that last part, please.