If the new ACR makes 1,500 lbs of dowfroce at 150 mph . . .

PhoenixGTS · Dec 16, 2007

I was dreaming about the new ACR and the claim that it will make 1,500 pounds of downforce at 150 mph and all of a sudden it hit me, with that downforce and Sport Cup tires the car is going to have crazy braking power at the end of a long straight on a road course.

sween · Dec 16, 2007

I thought it was 1,000 pounds of downforce?

Lee00blacksilverGTS · Dec 16, 2007

It is 1000.

Paul Hawker · Dec 16, 2007

Yes, crazy braking force, and also tremendous ability to generate Gs in sweeping corners.

Combination of lowered rotational mass, downforce and sticky tires is gonna make this ACR a force to be feared on the tracks.

Wonder how it will be classified at ViperDays?

ViperRay · Dec 16, 2007

I wonder what the down force is at a more common cornering speed of about 80mph.

Tom Sessions mentioned to me that they were going to have to alter all the classifications at Viper Days due to the 2008's but he didn't mention the ACR. The previous ACR didn't have its own class but the new one has more significant differences compared to the new coupe. I would say the ACR would run in the supermodified class and most current cars will be downgraded a class. It could be messy.

Chuck 98 RT/10 · Dec 17, 2007

My old 97 ****** is in SM and it doesn't stand a chance against the 08 ACR. The ACR should have it's own class.

Call it the "God" class.

ViperRay · Dec 17, 2007

Chuck 98 RT/10 said:
My old 97 ****** is in SM and it doesn't stand a chance against the 08 ACR. The ACR should have it's own class.

Call it the "God" class.

LOL!
I'm trying to lobby for a lower class out of self interests!

j-rho · Dec 17, 2007

If it makes 1000lbs. @150mph, then it *should* make 250lbs. @75mph. Still pretty good actually, that's about a 7% increase in normal force, which could mean a 5-6% increase in grip, at that spped.

Kenneth Krieger · Dec 17, 2007

Remember, the downforce is building exponentially as speed increases. This car is going to be an animal on the track.

Paul Hawker · Dec 17, 2007

Would not be surprised if the ACR does not compete evenly with Comp Coupes, especially with equilevant tires.

Viper X · Dec 17, 2007

I'd still like to know how much down force a GTS or a new coupe generates without aero.

B767DRIVER · Dec 17, 2007

Viper X said:
I'd still like to know how much down force a GTS or a new coupe generates without aero.

Dan, Here is part of an article about the '06 Coupe. Not sure how much the '08 hood changes things...

While no special efforts were made to make the frame any stiffer, increased platform rigidity was a happy byproduct of the enclosed bodywork. Torsional rigidity goes up about 30 percent, although bending stiffness remains about the same. There are also miniscule-but-measurable aero benefits to the coupe's new skin, the Cd dropping from the roadster's 0.40 to 0.39. The front end produces no meaningful lift or downforce, but there's about 100 pounds of downforce on the tail at 150 mph.

xlr8ion · Dec 17, 2007

I am hoping the ACR will be competive with gt3 cup cars.They put out 400hp and weigh 2700 pds.What do you think???

FrankBarba · Dec 17, 2007

i'm hoping that all you that are talking about getting one the track with these cars plan to put cages in them.....

REDSLED · Dec 17, 2007

FrankBarba said:
i'm hoping that all you that are talking about getting one the track with these cars plan to put cages in them.....

Exactly Frank. Just as when the previous ACR debuted in 99. The driver (not the car) will determine the full potential. Comparing a Comp Coupe (factory, purpose-built race car) to the ACR (street car) is apples to oranges. A Porsche GT3 Cup Car is also a factory built race car. Have driven one several times on the track and they are on par with Comp Coupes. I guess until one shows up at the track with a competant driver, who is familiar with the car, we will never know

Vypr Phil · Dec 17, 2007

FrankBarba said:
i'm hoping that all you that are talking about getting one the track with these cars plan to put cages in them.....

Words of wisdom indeed, Frank :2tu:

Totally agree with you and actually wonder why this is not a factory supplied OEM item or a factory option at the very least.

Regardless, I will get an ACR but the first mod will be a full roll cage, before any track time.

To me the ACR is a "Comp Coupe Lite" and a wonderful compromise since it is still street legal. Really wonder how it compares to the Comp Coupe, but we will have to wait a few more months before we get the answer to this one. Maybe by the first 2008 "Viper Days" event?

Phil

Y2K5SRT · Dec 18, 2007

The 2008 ACR will beat the Comp Coupe around the track stock-for-stock. Realize the Comp Coupe is not available with the 600 HP motor as far as I know...yet.

Vypr Phil · Dec 18, 2007

Y2K5SRT said:
The 2008 ACR will beat the Comp Coupe around the track stock-for-stock. Realize the Comp Coupe is not available with the 600 HP motor as far as I know...yet.

Interesting observation Chris, but keep in mind that the Comp Coupe is a purpose-built race car, is probably close to 10% lighter than a full roll cage equipped ACR and may also be better in the aerodynamics department.

All of this being said, I believe that it will be really, really close!

Power to weight ratio probably very close;
Aerodynamics: advantage Comp Coupe;
Lighter weight: advantage again to Comp Coupe;
Engine: advantage ACR, more displacement & horsepower, don't know off hand about torque but would speculate in favor of ACR as well.

In the end, probably a driver's race, but Redsled is right, we are kind of comparing apples to oranges (but hey, what an orchard!), one is street legal and the other one isn't.

So for me at least, overall advantage: ACR!

Never thought I would come to this conclusion as I am a major Comp Coupe fan.

Phil

Viper X · Dec 19, 2007

"The 2008 ACR will beat the Comp Coupe around the track stock-for-stock. Realize the Comp Coupe is not available with the 600 HP motor as far as I know...yet."

I find that hard to believe Chris..... but it will be fun to see if it is possible.

1 - Comp coupe is lighter and on slicks vs PS Cups

2 - Horsepower is close, torque is closer

3 - Comp coupe has a lower center of gravity and a better CD

I do wish that the new ACR came with a roll bar.

See you in AZ

Dan

Vipermann · Dec 19, 2007

j-rho said:
If it makes 1000lbs. @150mph, then it *should* make 250lbs. @75mph. Still pretty good actually, that's about a 7% increase in normal force, which could mean a 5-6% increase in grip, at that spped.

Yes, but the ACR will absolutely 'run away' from everything else on the track on portions of the track with 120mph+ banking ... it will look silly, like the ACR is on rails and running faster without any fear of the wall ... it will run faster down the end of the straight going into the banking, and deeper at speed, because 'lifting' won't upset that big rear wing at 150mph+ at the end of the straight, and those rear tires will stay planted ... it won't be fair to other cars (vettes) on the track

As for comparisons to the CC, I think the advantage flips around, since the CC has aero too ... the ACR might have the edge on shorter/tighter tracks in that case

bluestreak · Dec 20, 2007

xlr8ion said:
I am hoping the ACR will be competive with gt3 cup cars.They put out 400hp and weigh 2700 pds.What do you think???

I think it depends on who's driving the cup car, most cup car drivers are bad, and if you are a good driver, you can beat them easily. Changed to similar tires, add some motons, and a good track setup with negative camber and corner balance, and you shouldnt have a problem.

Of course it depends on the track too.

If the new ACR makes 1,500 lbs of dowfroce at 150 mph . . .

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