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View Full Version : Gt cars in ALMS and Grand AM



jslone
31st January 2008, 03:38
How much of a difference are there in the rules for the gt cars in the Lemans series and GrandAm,they look just about identical on the outside,but what about the specs.If this has been brought up before,sorry I missed it.

FormerFF
31st January 2008, 04:28
If you want the full skinny, here's the two sets of rules:
http://grand-am.com/assets/GTRules.pdf
http://www.imsaracing.net/2007/aco/2007%20gt2.pdf

For the ACO (LeMans) rules that the ALMS uses, GT2 consists of modified 2 door production cars. From reading the rules, it sounds as if the ACO will accept any production car that meets this standard. In Grand Am GT, Grand Am specifies two sets of rules: one for modified production cars, and one for tube frame cars. Grand Am determines which rules each car can use.

What does this mean in practical terms? Use Porsche for an example. The standard production 911 now carries the designation 997. There is a faster streetgoing version known as 997 GT3. Porsche has a racing series for GT3s, and builds what it calls a 997 GT3 Cup model specifically for that series. A lightly modified GT3 Cup car is what races in Grand Am's Rolex series.

Further up in the performance spectrum, there is a 997 GT3 RS, and even further along is a 911 GT3 RSR. The ALMS car is a somewhat enhanced RSR.

The Mazda RX-8 that won the GT class at the recent Rolex 24 hr race, on the other hand, uses a tube frame chassis. So, while it looks like an RX-8, and uses some RX-8 parts, it isn't using a production chassis.

Both series make an attempt to equalize performance through weight or air inlet restrictions.

In terms of lap times, both series race at Mid-Ohio, the fastest ALMS GT2 car last year turned in the 1:19s, while the fastest Rolex series GT car came in in the 1:25s.

jslone
31st January 2008, 04:32
Thanks,there are differences,but did not think they were that much of a difference.

BobbyC
3rd February 2008, 05:55
The tubeframe rule is designed to allow teams to save money by taking the easy road with chassis for the sake of construction. Tubeframe cars are stiffer cars and are better to repair than monocoques. In some cases monocoques are entirely destroyed in bad crashes. A big reason the Chevrolet Corvette uses a ladder frame instead of a monocoque is stiffness, but it also has the ability to be repaired in case of a bad crash.

In fact, the C5-R that Dale Jr crashed at Infineon has been rebuilt and is a show car.

FormerFF
5th February 2008, 03:53
The tubeframe rule is designed to allow teams to save money by taking the easy road with chassis for the sake of construction. Tubeframe cars are stiffer cars and are better to repair than monocoques. In some cases monocoques are entirely destroyed in bad crashes. A big reason the Chevrolet Corvette uses a ladder frame instead of a monocoque is stiffness, but it also has the ability to be repaired in case of a bad crash.

In fact, the C5-R that Dale Jr crashed at Infineon has been rebuilt and is a show car.

For a given weight, a monocoque is stiffer and stronger than a spaceframe built of tubing, which is why all F1 cars employ monocoque construction. Grand Am has allowed tubeframe cars so that they can allow cars that wouldn't be competitive in their production format greater design latitude, such as moving the engine, or in the case of a front drive car, to make it rear drive. If you look at Grand Am's allowed car list, you will note that there are no prep rules for a tube framed Porsche. I have heard Porsche representatives say that in GT, they are only interested in racing a production style ("tub") chassis.

Mancinoxvii
11th February 2008, 14:39
Ah thanks everybody for this thread, I was sorta thinking of the same question myself about the difference in rules. I still don't understand the different chassis, but I'll look up the terms and figure it out myself.

dj4monie
14th February 2008, 07:38
The tubeframe rule is designed to allow teams to save money by taking the easy road with chassis for the sake of construction. Tubeframe cars are stiffer cars and are better to repair than monocoques. In some cases monocoques are entirely destroyed in bad crashes. A big reason the Chevrolet Corvette uses a ladder frame instead of a monocoque is stiffness, but it also has the ability to be repaired in case of a bad crash.

In fact, the C5-R that Dale Jr crashed at Infineon has been rebuilt and is a show car.

That is the worst excuse to use a tube frame car. Porsche and Ferrari cost alot because the darn street car cost a bunch!

Their race cars are based on the same car you can buy, not some one-off maze of tube and welds.

The RX8 wasn't designed to compete with them.

If it was, Mazda would have designed a turbocharged RX like they did before.

But like Nissan they wanted to return back to their affordable sportscar roots and the RX8 in stock form is painfully SLOW.

Also the reason why when a certain European team with extensive GT and Touring car experience built their own 350Z GT2 car and found it whoefully uncompetitive in FIA GT2, they nixed the program.

Its the illusion that GT racing Grand Am style is cheaper than say ALMS/ACO/FIA style GT's.

Speed Source couldn't race their way out of a paper bag because if they could they would be racing a Mazda supported Lola in ALMS LMP2....

While GT racing Grand Am Prep 2 style might be cheaper, you also win NOTHING in prize money and don't even go to Le Mans...

CHiP
24th February 2008, 20:23
That is the worst excuse to use a tube frame car. Porsche and Ferrari cost a lot because the darn street car cost a bunch!

Their race cars are based on the same car you can buy, not some one-off maze of tube and welds.

The RX8 wasn't designed to compete with them.

If it was, Mazda would have designed a turbocharged RX like they did before.

But like Nissan they wanted to return back to their affordable sportscar roots and the RX8 in stock form is painfully SLOW.

Also the reason why when a certain European team with extensive GT and Touring car experience built their own 350Z GT2 car and found it whoefully uncompetitive in FIA GT2, they nixed the program.

Its the illusion that GT racing Grand Am style is cheaper than say ALMS/ACO/FIA style GT's.

Speed Source couldn't race their way out of a paper bag because if they could they would be racing a Mazda supported Lola in ALMS LMP2....

While GT racing Grand Am Prep 2 style might be cheaper, you also win NOTHING in prize money and don't even go to Le Mans...


I don't know much about the teams that have tried to race 350Zs in GT2, but there a many reasons why even a team with extensive experience can find themselves woefully uncompetitive and nix a program. I don't think that the 350Z is necessarily a poor platform for a GT2 car. It is at least no worse than the Porsche 911, and the Porsche 911 GT3 RSRs have been reasonably competitive. I personally don't expect for the RSRs to be very competitive this year, except maybe at Sebring because of the usual attrition during the long, brutal race, they are very reliable, and that the Flying Lizard team is a great team.

racefanfromnj
29th February 2008, 01:07
That is the worst excuse to use a tube frame car. Porsche and Ferrari cost alot because the darn street car cost a bunch!

Their race cars are based on the same car you can buy, not some one-off maze of tube and welds.

The RX8 wasn't designed to compete with them.

If it was, Mazda would have designed a turbocharged RX like they did before.

But like Nissan they wanted to return back to their affordable sportscar roots and the RX8 in stock form is painfully SLOW.

Also the reason why when a certain European team with extensive GT and Touring car experience built their own 350Z GT2 car and found it whoefully uncompetitive in FIA GT2, they nixed the program.

Its the illusion that GT racing Grand Am style is cheaper than say ALMS/ACO/FIA style GT's.

Speed Source couldn't race their way out of a paper bag because if they could they would be racing a Mazda supported Lola in ALMS LMP2....

While GT racing Grand Am Prep 2 style might be cheaper, you also win NOTHING in prize money and don't even go to Le Mans...

did you notice the fleet of cars from Farnbacher and TRG to name just a few chasing the Speed Source car at the 24? Id say they got out that wet paper bag ok. When did Mazda say they would support their effort to run a LMP2 car? But they are interested in supporting them in GA GT o well cant have them all.