1/4 Mile Times

[Polecat]

Went to Houston Raceway Park last night and made 3 passes:

 

1. First Pass
    
   60': 2.335
   1/4: 14.642
   MPH: 97.19
    
   
2. Second Pass
    
   60': 2.414
   1/4: 14.439
   MPH: 99.78
    
   
3. Third Pass
    
   60': 2.469
   1/4: 14.352
   MPH: 99.66
   

 

As you can see from my 60' times, I'm not getting the car to hook up. Tried 3 different RPM launches and dropped 10 lbs of tire pressure prior to the 3rd run. The placed was packed, so 3 runs was all I could get in. I feel confident that, with more seat time, I can knock a half second off my 60' times and thus drop to a high 13 but, I gotta say, I'm a little disappointed with this.

 

There was a stock Hertz Rent-a-Racer (automatic) that had his car re-tuned and he ran a 13.44.

 

In a couple of a weeks, FastLane is adding Kooks long tube headers and re-tuning and in late November, I'm going back to make some more passes. I'll keep you posted.

 

BTW: my buddy, who drives a C-6 with cam, long tubes and just added a 150 shot dry nitrous ran an 11.3 at 124.88. He was escorted off the track and told he could not return until his car was caged! He was ECSTATIC!!

 

Polecat

[csm198]

Went to Houston Raceway Park last night and made 3 passes:

 

1.  

    

2. First Pass

    

   60': 2.335

   1/4: 14.642

   MPH: 97.19

    

    

3. Second Pass

    

   60': 2.414

   1/4: 14.439

   MPH: 99.78

    

    

4. Third Pass

    

   60': 2.469

   1/4: 14.352

   MPH: 99.66

    

 

As you can see from my 60' times, I'm not getting the car to hook up. Tried 3 different RPM launches and dropped 10 lbs of tire pressure prior to the 3rd run. The placed was packed, so 3 runs was all I could get in. I feel confident that, with more seat time, I can knock a half second off my 60' times and thus drop to a high 13 but, I gotta say, I'm a little disappointed with this.

 

There was a stock Hertz Rent-a-Racer (automatic) that had his car re-tuned and he ran a 13.44.

 

In a couple of a weeks, FastLane is adding Kooks long tube headers and re-tuning and in late November, I'm going back to make some more passes. I'll keep you posted.

 

BTW: my buddy, who drives a C-6 with cam, long tubes and just added a 150 shot dry nitrous ran an 11.3 at 124.88. He was escorted off the track and told he could not return until his car was caged! He was ECSTATIC!!

 

Polecat

 

 

THE SHELBY GT IS NOT A DRAG RACER. SO UNLESS YOU WANT TO CHANGE THE WHOLE SETUP DONT EXPECT TOO MUCH FROM THE DRAG STRIP. INSTEAD MAY I SUGGEST AN AUTOCROSS OR ROAD COURSE.

[DreamRide]

THE SHELBY GT IS NOT A DRAG RACER. SO UNLESS YOU WANT TO CHANGE THE WHOLE SETUP DONT EXPECT TOO MUCH FROM THE DRAG STRIP. INSTEAD MAY I SUGGEST AN AUTOCROSS OR ROAD COURSE.

 

 

Wow! Why you yellin? :D

 

 

 

When you go next time,

 

 

 

 

Drag Radials, Different LCA's, ect..........

 

Remove the front sway bar so you can get the wieght transfer.

 

 

 

The way the car is set up from SAI, It is a road car, not a drag car. 2 different animals.

[Polecat]

I hear you, but I'm still gonna keep working these times down. I have no intention of changing anything with the suspension but I am pressing on with some more changes.

 

I think I'm gonna add 4.10 gears too. I already had an 07 GT with these gears and the same setup that Shelby puts on the car and I liked it better. Actually, it was FRPP's drag pack, so it had shorty headers too.

[DreamRide]

I hear you, but I'm still gonna keep working these times down. I have no intention of changing anything with the suspension but I am pressing on with some more changes.

 

I think I'm gonna add 4.10 gears too. I already had an 07 GT with these gears and the same setup that Shelby puts on the car and I liked it better. Actually, it was FRPP's drag pack, so it had shorty headers too.

 

 

 

 

If anything, get a set of DR's cause with those 4.10's you will spin even more...............

[SGT2666]

What he said DR's will make a significant difference.

[ilmor]

When you made those runs - was your traction control on or off? I agree w/ the tires advice; nothing will make a bigger difference. Also, is your SGT modified in any way currently? Do you have 20" wheels by any chance, as that will slow it considerable. Lastly, when you run, make sure the car is a light as possible, including a low fuel level.

[SWEDESHELBY1]

When you made those runs - was your traction control on or off? I agree w/ the tires advice; nothing will make a bigger difference. Also, is your SGT modified in any way currently? Do you have 20" wheels by any chance, as that will slow it considerable. Lastly, when you run, make sure the car is a light as possible, including a low fuel level.

 

 

Who said the 20" Razors w/ 20" tires will slow the car considerably? At the least it should be the same or a taste better, I thought. Please deescribe your theory for me and if you can post back-ups to this theory I would appreciate it. B)

Thanks-

[AFBLUE]

Who said the 20" Razors w/ 20" tires will slow the car considerably? At the least it should be the same or a taste better, I thought. Please deescribe your theory for me and if you can post back-ups to this theory I would appreciate it. B)

Thanks-

 

http://www.sportcompactcarweb.com/tech/050...ght_wheels.html

 

Going up an inch in wheel diameter and running a lower profile tire is a good thing. A lower profile tire has shorter, stiffer sidewalls, which improve response to steering inputs and hold the tread flatter to the road surface during cornering load. However, it can be overdone.

Ultralow-profile tires are more sensitive to suspension tuning and camber changes. And stiff sidewalls don't conform to road surfaces easily. This makes ultralow-profile tires sensitive to shock, as the short, stiff sidewalls have very little compliance. Harsh surface inputs can make these tires skip and hop across the surface instead of digging in and finding grip. Large wheel and tire combinations also increase rotating and unsprung weight.

For example, most enthusiasts driving small-bore four-cylinder front-wheel-drive cars run 17x7-inch wheels with a 205/40-17 tire. The big wheel and low-profile tire look cool, but this combo is too large and too heavy for optimal performance. Hard-core track geeks driving these same cars almost always fit a lightweight 15x7-inch wheel with a 205- to 225/50-15 tire.

Huge wheels also increase your car's final drive. Their added weight increases the flywheel effect, slowing the car's acceleration and increasing load on the brakes. This means wheels larger than 18 inches are rarely used for performance, so even for large cars, 18 inches is the maximum practical wheel diameter. There are few choices for DOT-legal race tires larger than 18 inches anyway.

 

It's also interesting to note that when the Grand Am Mustang racer (FR500) debuted, they did the photoshoot with 20" wheels, but they raced with 18" wheels.

[SWEDESHELBY1]

http://www.sportcompactcarweb.com/tech/050...ght_wheels.html

It's also interesting to note that when the Grand Am Mustang racer (FR500) debuted, they did the photoshoot with 20" wheels, but they raced with 18" wheels.

 

 

AFBlue: They are talking about cars with no real HP, are they not? So that would be a question to leave to the professionals, the people that have actually done it and posted times, weights and classes of cars. Not rice burners with oversized tires/wheels and no real horsepower. Also there is a link on this forum that shows the 20" Razors are serveral ounces lighter than the stock 18" wheels and tires that come with the Shelby GT. All this being said, AFBlue we all know you want 18" Razors not 20" razors, to each there own.

[AFBLUE]

Swede, yes I want 18" razors, but that has nothing to do with this discussion (prefer the look of 18" wheels, not doing it for performance reasons).

 

You asked for info, I did some research and posted. Sorry that the info I provided did not support your point of view

[SWEDESHELBY1]

Swede, yes I want 18" razors, but that has nothing to do with this discussion. You asked for info, I did some research and posted.

Maybe someone you don't consider "biased" will chime in on this issue.

 

Sorry if the info I provided was not to your liking

 

 

AF: Come on now, that is NOT what I mean. We, as you know, have had this posted for many to see and hear and those posts have ALWAYS stated that 20" Razors were lighter than the 18" factory wheels & tires. So the poster was wrong and not totally informed is all I am saying. The poster that you had simply said "all" HUGE wheels were heavier then smaller wheels and added to the fly wheel weight which in turn slowed the car down, which is obviously not the case.

 

Sorry my post was not to your liking either and came out the way it did but I am just bringing up what we have already discussed and found out in earlier posts. 18" or 20" they all look good and to each their own.

[AFBLUE]

Swede, we are good.

 

I would assume that, 2 sets of wheel and tire combos, both having the same weight and same overall diameter would perform the same as it pertains to acceleration (I would love to hear from an expert on this).

 

When it comes to handling I would assume they would behave differently (as the article above discusses)

[SWEDESHELBY1]

Swede, we are good.

 

I would assume that, 2 sets of wheel and tire combos, both having the same weight and same overall diameter would perform the same as it pertains to acceleration (I would love to hear from an expert on this).

When it comes to handling I would assume they would behave differently (as the article I quoted discussed).

 

 

Thanks AF!

 

 

I have not yet pushed my 20" Razors to the max yet, but I will positively say this: My 18" factory wheels and tires seem to ride better than the 20" Razors & tires.

[mywickedshelby]

ding!

Round one is over, both of you to your corners. :P :D

[AFBLUE]

ding!

Round one is over, both of you to your corners. :P :D

 

 

No, now we are both coming after you! :D

[mywickedshelby]

No, now we are both coming after you! :D

 

 

 

bring it, fly boy~ :huh: :P

[clawsonbob]

Swede, we are good.

 

I would assume that, 2 sets of wheel and tire combos, both having the same weight and same overall diameter would perform the same as it pertains to acceleration (I would love to hear from an expert on this).

 

When it comes to handling I would assume they would behave differently (as the article above discusses)

 

 

 

I am no expert and you are right about "same weight and same overall diameter would perform the same as it pertains to acceleration " except for the following

 

The further the rotating mass (RM) is from the center of wheel, the more rotational resistance. So if the 20" RM is further from center of wheel than the 18"RM, the 20 would reduce acceleration.

 

Rotational Dynamics

For linear motion, we used Newton's Laws of Motion and, in particular, Newton's Second Law of Motion,

 

F = m a

and

 

 

The rotational equivalent of F = m a is

 

= I

where (the lower case Greek letter "alpha") is the angular acceleration we have just seen and (the lower case Greek letter "tau") is the "torque" or "rotational force" we recently saw in our study of static equilibrium and I is the "moment of inertia" or the "rotational mass".

 

I = m r2

That is, the rotational mass depends upon the distribution of the mass. Here are a few sample values of this "rotational mass":

[clink_merged]

Where can you find 20" drag slicks? I checked several tire companies and have not found real drag slicks. On the internet only thing that comes up are Nitto, Goodyears and and some others but these are the 20" tires ours come with already. There are a lot of 14 through 18" DS.

Clink

[DreamRide]

Where can you find 20" drag slicks? I checked several tire companies and have not found real drag slicks. On the internet only thing that comes up are Nitto, Goodyears and and some others but these are the 20" tires ours come with already. There are a lot of 14 through 18" DS.

Clink

 

 

 

I have never seen any slick that size. The only thing you are going to find are the Drag Radials. If you want to run full on slicks (Your going to break stuff) you are limited. Most i see running are 15" Bogart wheels and slicks. One of the guy's at Barona runs a low 7 sec. (1/8th) mustang Gt and he is running Mickey Thompson ET Drag slicks, 28x10.50-15 and they are a very close fit.

 

I was going to get another pair of the black bullits thats on my SGT and mount racing tires (DR's) then just switch when going to the track.

[DreamRide]

Thanks AF!

I have not yet pushed my 20" Razors to the max yet, but I will positively say this: My 18" factory wheels and tires seem to ride better than the 20" Razors & tires.

 

 

They will because there is more sidewall then the 20's making for a little softer ride.

[ilmor]

Who said the 20" Razors w/ 20" tires will slow the car considerably? At the least it should be the same or a taste better, I thought. Please deescribe your theory for me and if you can post back-ups to this theory I would appreciate it. B)

Thanks-

 

 

I have gathered some information. The 20" Razors weigh 4 lbs. each more than the the 18" Bullits. The information is available at Tire Rack, as noted below;

 

20" Shelby Razors

$248 Front and Rear Fitments

 

20x9

 

Original Price:$0 (each)Now 0% Off:$248 $248 (each)

Price:

$0 (each)

See price in cart Offset: +40mm

Bolt Pattern: 5-114

Rec. Tire Size: 255/35-20

Weight: 29.0lbs.

Note: OE Sensors Required

 

 

 

Bullits

 

18x8.5

 

Original Price:$0 (each)Now 0% Off:$180 $180 (each)

Price:

$0 (each)

See price in cart Offset: 50mm

Bolt Pattern: 5-114

Rec. Tire Size: 255/45-18

**Lightweight: 25.0lbs.**

Note: OE Sensors Required

 

I believe the 20" tires will also weigh more than 18" tires. I will verify this, as well as the overall outside diameter, later when I get more time.

[stump_breaker]

Bullits

 

18x8.5

 

Original Price:$0 (each)Now 0% Off:$180 $180 (each)

Price:

$0 (each)

See price in cart Offset: 50mm

Bolt Pattern: 5-114

Rec. Tire Size: 255/45-18

**Lightweight: 25.0lbs.**

Note: OE Sensors Required

 

Isn't there a difference between the stock Bullit wheels and the aftermarket ones advertised as lightweight?

Not to throw a kink in your research or anything.

[ShelbyGT/SC]

Okay, okay, here is my expert opinion:

[DreamRide]

Okay, okay, here is my expert opinion:

 

 

I would also like to add....................

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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[AFBLUE]

ilmor, make sure you use the chrome 20" wheels, they weigh more than the non chrome

[ilmor]

Isn't there a difference between the stock Bullit wheels and the aftermarket ones advertised as lightweight?

Not to throw a kink in your research or anything.

 

 

No, I don't believe that there is any difference. Tire Rack just designates some wheels as "lightweight" in their respective sizes. I bought a set of these exact wheels for winter tires and I don't "feel" any difference in the weight at all. I am going to actually weigh a tire/ wheel assembly this weekend.

 

AFBlue - the chrome 20's weigh 31.5 lbs each....OUCH!

[SGT2666]

I found same Ilmor. Its more complicated then that though, if you are just looking at unsprung weight and its effects then the added weight is all that matters, but if the weight is farther out on the circumference of the wheel it gets multiplied making it harder to get the wheels moving and stopped. I love the look of the 20's but my small amount of research says no.

[Reino]

No offense Wado.......

 

All i hear is blah blah blah "weight is farther out on the circumference of the wheel it gets multiplied making it" blah blah blah......

 

Holy crap guys, what are we racing? Have you calculated the weight and location of the tire pressure sensor? I guess the farther out that it is the more weight youll have to add as the tire pressure sensor is indictivitive of the atmospheric pressure multiplied by the weight of the rubber alone as its equal to a big ol pile of poo poo :blink:

 

Ill be putting on what looks pretty. :D

[mywickedshelby]

No offense Wado.......

 

All i hear is blah blah blah "weight is farther out on the circumference of the wheel it gets multiplied making it" blah blah blah......

 

Holy crap guys, what are we racing? Have you calculated the weight and location of the tire pressure sensor? I guess the farther out that it is the more weight youll have to add as the tire pressure sensor is indictivitive of the atmospheric pressure multiplied by the weight of the rubber alone as its equal to a big ol pile of poo poo :blink:

 

Ill be putting on what looks pretty. :D

 

 

 

I agree....the wheels you think look better and a lean cuisine......DONE!