Corvette vs. Marinello.

[Speck]

According to the article I got, the 'Vette are running a Hewland LSGA 6-speed 'box (at least from last year). This replaced the 5-Speed Hewland Super ST from mid 2000.

[gttouring]

good to hear- perhaps Autoweek is incorrect? or the 5 spd was the double disc sequential no lift tranny?

[JAG]

A LM 2003 Vette ran a sequential for the first time. Previouly the car ran a H-pettern gearbox.

Sequential gearboxes were allowed in ACO GTS for the first time in 2003.

[RacingManiac]

According to the PR guy of Corvette Racing posted on SPEED's forum, the sequential gearshift is new, but the gearbox isn't. It was the same 6 speed Hewland tranny on the older car, but updated with the sequential shift mechanism. Also, the new Vette was not at Atlanta due to the 50th anniversary celebration where the new car with the patriotic livery had to be there(after being recently shipped back from France). The new car is reportedly 33% stiffer than the older model(which now won Sebring and Road Atlanta), along with new downforce gained. And the car will reverted to the yellow livery when the new car is raced at Sonoma.

[gttouring]

ah so will the C6R be better, because so far the 'new' car isn't the same calss ans the old 33% floppier car

[ViperACR]

JAG the previous poster said it correctly when he said that engine temperature will go up with higher revs. The F1 cars do not go for 24 hours. They are also small very short stroke engines. F1 engines are like lawnmower engines with their short strokes. That kind of engine can survive at the higher revs but it still could not go through a 24 hour race. The torque on F1 engines is very small. The chevys will not lose the ALMS series

Originally posted by JAG
Lets also bear in mind, these days high revs is relative. F1 engines are reving to 19,000 rpm. The 3.5l cars showed that a car with high revs can win LM.

[JAG]

Take your point. But you can never say never.

The Peugeot 905 won LM in 92/93 with a 3.5l V10 'F1' engine.

I think the Prodrive Ferraris will win a couple of races at least.

In FIA GT the BMS run Prodrive 550 has won 5 out of 5 against the best Vipers, Listers and unrestricted Saleens.

[ViperACR]

The best Viper is not running in the FIA GT series, but they would probably lose anyway if they were their. It seems that Prodrive have it all together with their Ferraris. I hope the Vipers will be back next year with the new factory Vipers. It will make everything very interesting if they were

[cybersdorf]

A Judd has already won the Daytona 24. Also, 6th for RFH this year.

[Dani Filth]

indeed . an ex F1 engine ...

[JAG]

Originally posted by ViperACR
The best Viper is not running in the FIA GT series, but they would probably lose anyway if they were their. It seems that Prodrive have it all together with their Ferraris. I hope the Vipers will be back next year with the new factory Vipers. It will make everything very interesting if they were

I would say the Labre and current FIA GT Vipers are quicker than the Carsport America car.

[Chevyguy]

JAG, substantially quicker.

ACR is talking of a factory team, gotta wait a few years, bro. But, is their any news of a new Viper racecar being developed?

[JAG]

ORECA are talking to Chrysler again.

Hughes De Chaunac says IF a new Viper GTS car is built it will have to be a homologation special in the mold of the original GTS-R in order to compete with the new generation GTS cars.

[veeten]

this should get interesting...

Corvette C5/6Rs, Viper GTS-LM (my designation), Lamborghini Murcialago GTS, Ferrari 575 Maranello/Enzo GTS... and this is just the start. Imagine the additions from those looking to get in the ALMS/LMES combine racing, and GT could get red hot.

[pitviper]

hey jag...e-mail me with any info you have on ORECA talking with chrysler, both fact and rumor...i think you have my addy...thanks man...

pit

[LandOfSnow]

The power and the torque are basically the same thing.

Torque is the actual force the engine produces. Power is calculated from the torque to show the effect the gearing has to actual "thrust" ("torque at wheels" ie. how fast the car is gonna accelerate forwards).

The power allows comparison of the "thrust" between two different engines at any speed on optimal gearing to that speed. Ofcourse in the real life the gearing isn't always optimal but as we're talking about international level racecars, it's close enough.

If any car has more torque, at any given revs, it also has more power at those revs in the same proportion. and vice versa.

Power = angular speed (rpm) X torque

Torque tells more about the engines ability to turn fuel into kinetic energy.

Power tells you how fast the car is gonna go.

It's wrong to state that a bigger engine is always more powerful than a smaller on, as it's wrong to state that a 2-valve engine of a certain size is less powerful than 4-valver of the same size. Both of the parameters affect the power but there's many many others that can limit/increase the power even more significantly. Every engine has a weakest point that limits the power. (the number of valves doesn't affect the power, valve area does)

[ViperACR]

Very good technical synopsis about the relationship between torque and power. What you are saying describes why both the Chevy and the ferrari are using engines that are sonsidrably bigger than what they have on theri street cars. Chevy does not use a 35 because it would not create the same torque as the bigger engine as well as the ferrari. Torque is just as important as anything else. A short stroke F1 engine could not produce not near as much as the bigger engines as the GTS cars have. It compensates by having a much higher rev limit but still the torque on the F1 cars is around 300ft/Ibs which is nothing. The ferrari won the lemans due to the long straightaways but in a road course the engine with the higher torque would out accelerate the smaller engine. it has been like this since the beginning and always will be. It is the laws of drag racing

Originally posted by LandOfSnow
The power and the torque are basically the same thing.

Torque is the actual force the engine produces. Power is calculated from the torque to show the effect the gearing has to actual "thrust" ("torque at wheels" ie. how fast the car is gonna accelerate forwards).

The power allows comparison of the "thrust" between two different engines at any speed on optimal gearing to that speed. Ofcourse in the real life the gearing isn't always optimal but as we're talking about international level racecars, it's close enough.

If any car has more torque, at any given revs, it also has more power at those revs in the same proportion. and vice versa.

Power = angular speed (rpm) X torque

Torque tells more about the engines ability to turn fuel into kinetic energy.

Power tells you how fast the car is gonna go.

It's wrong to state that a bigger engine is always more powerful than a smaller on, as it's wrong to state that a 2-valve engine of a certain size is less powerful than 4-valver of the same size. Both of the parameters affect the power but there's many many others that can limit/increase the power even more significantly. Every engine has a weakest point that limits the power. (the number of valves doesn't affect the power, valve area does)

[gttouring]

i like that, very nice.
Now how about the gearing? how could this have played into ferarri's favor?
not only do we have to deal with the 6 drive gears, but the final differential gear as well.

[LandOfSnow]

ViperACR: If there are two otherwise identical cars, one has 500Nm torque and 400hp, the other 300Nm & 600hp.

The drivers can keep the cars in the power range and the range are somewhat similar in widht.

The car with 600hp will accelerate faster in proportion 3/2 (600/400) because the power allows the comparison of the "thrust".

In real life the difference isn't that big 'cause the high rev engines tend to have 'peakier' power graphs than cars in lesser state of tune, but the car with more power is still faster.

In a case of a standing start (drag racing) the low revving, big displacement, high torque engines, have the upper hand. When the car is stationary there's zero revs at the wheels. The clutch is dropped and the cars begin to build up revs. The hi-torq engine's usable power (POWER, not torque) begins at, let's say, 2000rpm while the hi-power engine's begins at 4500rpm. The hi-torq engine has considerably less revs to build up before the engine begins to really work and it wins a lot of time. I endurace/GT-racing this is rather irrelavent as there's just one strat in the race.

The reason large displacement engines are used in GT's is the restrictor. When the engine is revved high there's less time to fill the 'burn chamber'(?) properly and friction etc. losses increase. As the amount of air to be used to burn fuel is limited (the restrictor); you want to use the air you can get as efficiently as possible. So you go and build engines more suitable for economy competitions, farm machinery & trucks... ...if I may exxaggerate a little.