7.5 lb class for GT

Dick Butler · 08-17-2007, 11:32 AM

Aerodynamics is in the picture but I agree with Lynn, probably less than people think.. All cars have some problem with head wind. Having raced at TOPEKA with an 89 camaro SS/AA and Beretta GT/GA and Sunbird GT/FA we ALL lost et and mph into the wind. I will not guess what it was but in the range of .1 to .15. I am checking with the kids for their memory.
With a rapid factoring system like the comp C.I.C. major differences might be corrected very early in the year if more class heads up racing were done.

Bryan Broaddus · 08-17-2007, 07:37 PM

Lynn,

You left out part of the equation. Frontal Area.
The combination of frontal area and coefficient of drag are combined to yield total drag.

Just Observing · 08-18-2007, 01:11 PM

Quote:

Originally Posted by Bryan Broaddus

Lynn,

You left out part of the equation. Frontal Area.
The combination of frontal area and coefficient of drag are combined to yield total drag.

x2. I couldn't agree more.

Racin Mason · 08-20-2007, 02:40 PM

Fishlips
7.5 lbs x 322 hp = 2415 +170 for driver = 2585. Shipping weight on a Cavalier is 2617 and Sunfire is 2771. By my math they will fit in 7.5 lb class unless the 2500 lb minimum applies to car only without driver. I don't have a rulebook handy and I don't have the FWD Comp, oops I mean GT rules memorized.
Regardless, a quick phone call to Glendora by the right folks would probably allow those cars in anyway. It's not like they haven't ignored the rulebook in the past.

I'm wondering how much appeal this new class might have? I can count the number of big blocks in division 7 on one hand and the number of big block GT/AA cars on one finger. We are a dying breed my friend.

Also, in terms of new cars being built, there are at least several dozen new Cobalts running around and Chevrolet has only been making them for 2.5 years now. McClanahan's Camaro is at least 3 years old and the other car mentioned has never been run. I think this is Dick's point in that the new cars are GT cars, not old school muscle.

Douglas Broaddus · 08-20-2007, 08:33 PM

Rulebook says minimum weight in GT with driver is 2670 pounds. The little teenie tiny small block cars won't measure up.

Doug

Fishlips · 08-21-2007, 12:33 AM

Dan,

I guess I just hate to see the death of the big block GT car. You know there are fewer and fewer each year. Maybe the answer would be to make a big block only class in GT.

All of the really killer big block engine combinations won't factor into a GT car. GT has become the haven of the small block. Small blocks are great little engines, no doubt about it, but why can't we get some of the real factory high performance engines in GT. There is no good reason not to allow them. All of the cars these days are built to accomodate the increased speed, just look at the modified cars, so why not allow a lighter GT car with a big block?

Super Stock is all about the factory high performance cars and engines, Hemi's, LS-6's, L-88's Ford 427 side oiler, 440 Six Paks, SD455's, Tunnel ram dual quad AMC's and many others. Since GT is a modern extension of Super Stock why can't we run these engines????? Talk about Crowd pleasers!! Could you just see a new style Mustang with a 427 running a new Cuda with a 426 Hemi?

Somehow I just can't imagine a new style Cuda with a 318 in GT/HA.

Fishlips · 08-18-2007, 12:16 PM

Lynn,

Here is the equation for total drag.

Total Drag:

D=CDA p/2 V2

Where
CD= Coefficient of Drag

A= Frontal Area

p= density of ambient air

V2= vehicle speed squared

This is a big difference when you compare a Cobalt or somthing little to the Older Super Stockers with a big wide front and tall roof line.

I believe your calculations used cars with similar frontal areas.

Lynn A McCarty · 08-21-2007, 01:07 PM

Quote:

Originally Posted by Fishlips

Lynn,

Here is the equation for total drag.

Total Drag:

D=CDA p/2 V2

Where
CD= Coefficient of Drag

A= Frontal Area

p= density of ambient air

V2= vehicle speed squared

This is a big difference when you compare a Cobalt or somthing little to the Older Super Stockers with a big wide front and tall roof line.

I believe your calculations used cars with similar frontal areas.

My software includes drag coefficient, frontal square area, ride height, it was all included. (cant get a number unless you enter all the numbers) You pick the vehicle from the data base for the frontal square area or you can do it yourself. Then you measure the height of the car off the ground. Yes we all know these are approximations,, and aerodynamics is a factor of many, but these big ET losses simply arent reality. (One guy told me 5 tenths)

On the other hand, how much is Ram Air, hood clearance, and wheel base worth? You gotta consider everything not cherry pick. If you want to try one I will run the software for you. I dont have all the body styles, but I have a pretty good list of the common ones.

Just think about it, you can scrub 5mph off at the end and it simply doesnt affect ET that much.

Lynn

JCQuinn · 08-21-2007, 02:47 PM

Quote:

Originally Posted by Lynn A McCarty

My software includes drag coefficient, frontal square area, ride height, it was all included. (cant get a number unless you enter all the numbers) You pick the vehicle from the data base for the frontal square area or you can do it yourself. Then you measure the height of the car off the ground. Yes we all know these are approximations,, and aerodynamics is a factor of many, but these big ET losses simply arent reality. (One guy told me 5 tenths)

On the other hand, how much is Ram Air, hood clearance, and wheel base worth? You gotta consider everything not cherry pick. If you want to try one I will run the software for you. I dont have all the body styles, but I have a pretty good list of the common ones.

Just think about it, you can scrub 5mph off at the end and it simply doesnt affect ET that much.

Lynn

Lynn is this something you do commercially or just for your own edification? If you don't mind I am curious how an 85 Mustang would stack up against the Colbalts.

Racin Mason · 08-21-2007, 02:49 PM

I am wondering why GT starts at an 8 lb weight break in the first place. I wasn't around for the beginning of this class, so I wonder if anybody remembers the logic for this. SS starts at 6.0, so why wouldn't they just make it the same? There has to be a reason.
I agree WHOLE HEARTEDLY that a 2009 Camaro or Challenger should have a big block in it. I bet the marketing guys at GM and Chrysler would agree too.

08-17-2007, 11:32 AM	#1
Dick Butler VIP Member Join Date: Oct 2002 Location: Richmond Indiana Posts: 1,196 Likes: 5 Liked 32 Times in 19 Posts	Re: 7.5 lb class for GT Aerodynamics is in the picture but I agree with Lynn, probably less than people think.. All cars have some problem with head wind. Having raced at TOPEKA with an 89 camaro SS/AA and Beretta GT/GA and Sunbird GT/FA we ALL lost et and mph into the wind. I will not guess what it was but in the range of .1 to .15. I am checking with the kids for their memory. With a rapid factoring system like the comp C.I.C. major differences might be corrected very early in the year if more class heads up racing were done.

08-17-2007, 07:37 PM	#2
Bryan Broaddus Member Join Date: Jun 2002 Posts: 104 Likes: 2 Liked 18 Times in 4 Posts	Re: 7.5 lb class for GT Lynn, You left out part of the equation. Frontal Area. The combination of frontal area and coefficient of drag are combined to yield total drag. __________________ Bryan Broaddus 7568 STK ,SS

08-20-2007, 02:40 PM	#4
Racin Mason Junior Member Join Date: Jun 2003 Location: San Clemente, CA Posts: 58 Likes: 0 Liked 0 Times in 0 Posts	Re: 7.5 lb class for GT Fishlips 7.5 lbs x 322 hp = 2415 +170 for driver = 2585. Shipping weight on a Cavalier is 2617 and Sunfire is 2771. By my math they will fit in 7.5 lb class unless the 2500 lb minimum applies to car only without driver. I don't have a rulebook handy and I don't have the FWD Comp, oops I mean GT rules memorized. Regardless, a quick phone call to Glendora by the right folks would probably allow those cars in anyway. It's not like they haven't ignored the rulebook in the past. I'm wondering how much appeal this new class might have? I can count the number of big blocks in division 7 on one hand and the number of big block GT/AA cars on one finger. We are a dying breed my friend. Also, in terms of new cars being built, there are at least several dozen new Cobalts running around and Chevrolet has only been making them for 2.5 years now. McClanahan's Camaro is at least 3 years old and the other car mentioned has never been run. I think this is Dick's point in that the new cars are GT cars, not old school muscle.

08-20-2007, 08:33 PM	#5
Douglas Broaddus Junior Member Join Date: Aug 2007 Location: Anaheim Hills Posts: 1 Likes: 0 Liked 0 Times in 0 Posts	Re: 7.5 lb class for GT Rulebook says minimum weight in GT with driver is 2670 pounds. The little teenie tiny small block cars won't measure up. Doug

08-21-2007, 12:33 AM	#6
Fishlips Junior Member Join Date: Jun 2007 Posts: 9 Likes: 0 Liked 0 Times in 0 Posts	Re: 7.5 lb class for GT Dan, I guess I just hate to see the death of the big block GT car. You know there are fewer and fewer each year. Maybe the answer would be to make a big block only class in GT. All of the really killer big block engine combinations won't factor into a GT car. GT has become the haven of the small block. Small blocks are great little engines, no doubt about it, but why can't we get some of the real factory high performance engines in GT. There is no good reason not to allow them. All of the cars these days are built to accomodate the increased speed, just look at the modified cars, so why not allow a lighter GT car with a big block? Super Stock is all about the factory high performance cars and engines, Hemi's, LS-6's, L-88's Ford 427 side oiler, 440 Six Paks, SD455's, Tunnel ram dual quad AMC's and many others. Since GT is a modern extension of Super Stock why can't we run these engines????? Talk about Crowd pleasers!! Could you just see a new style Mustang with a 427 running a new Cuda with a 426 Hemi? Somehow I just can't imagine a new style Cuda with a 318 in GT/HA.

08-18-2007, 12:16 PM	#7
Fishlips Junior Member Join Date: Jun 2007 Posts: 9 Likes: 0 Liked 0 Times in 0 Posts	Re: 7.5 lb class for GT Lynn, Here is the equation for total drag. Total Drag: D=CDA p/2 V2 Where CD= Coefficient of Drag A= Frontal Area p= density of ambient air V2= vehicle speed squared This is a big difference when you compare a Cobalt or somthing little to the Older Super Stockers with a big wide front and tall roof line. I believe your calculations used cars with similar frontal areas. Last edited by Fishlips; 08-18-2007 at 12:20 PM.

08-21-2007, 02:49 PM	#10
Racin Mason Junior Member Join Date: Jun 2003 Location: San Clemente, CA Posts: 58 Likes: 0 Liked 0 Times in 0 Posts	Re: 7.5 lb class for GT I am wondering why GT starts at an 8 lb weight break in the first place. I wasn't around for the beginning of this class, so I wonder if anybody remembers the logic for this. SS starts at 6.0, so why wouldn't they just make it the same? There has to be a reason. I agree WHOLE HEARTEDLY that a 2009 Camaro or Challenger should have a big block in it. I bet the marketing guys at GM and Chrysler would agree too.