shelby gt500 12.48@110

[Fourcam330]

:read: :idea: :beer: epper:

im going with fourcam on this one. here is why:

- Ranger -
'06 Z06 red 33 passes; launch not dialed-in
Bone Stock Stock Tires.11.31 127.52 1.90 60' Details
Bone Stock DRs...........11.20 127.55 1.84 60' Details
'02 Z06 sold C5Z06 Launch Techniques
Bone Stock Stock Tires.11.81 117.26 1.78 60' Details
w/Halltech CAI & DRs...11.52 120.21 1.64 60' Details

06 z, the same mph with drag radials as with stock tires? yes

02 z, 3 mph increase with drag radials and intake as with stock tires? yes

from where i sit, the majority of local drag racers do not know how to optimize launch with different sets of tires, hence the loss of trap speed. when a drivers changes technique to compensate for these different conditions speed over the course of the 1/4 is not loss.epper: have a good day.

You got it. Not just the vast majority of local drag racers though, the vast majority of drag racers period. ;-)

 

[Purvis]

:read: :idea: :beer: epper:

im going with fourcam on this one. here is why:

- Ranger -
'06 Z06 red 33 passes; launch not dialed-in
Bone Stock Stock Tires.11.31 127.52 1.90 60' Details
Bone Stock DRs...........11.20 127.55 1.84 60' Details
'02 Z06 sold C5Z06 Launch Techniques
Bone Stock Stock Tires.11.81 117.26 1.78 60' Details
w/Halltech CAI & DRs...11.52 120.21 1.64 60' Details

06 z, the same mph with drag radials as with stock tires? yes

02 z, 3 mph increase with drag radials and intake as with stock tires? yes

from where i sit, the majority of local drag racers do not know how to optimize launch with different sets of tires, hence the loss of trap speed. when a drivers changes technique to compensate for these different conditions speed over the course of the 1/4 is not loss.epper: have a good day.

ON D BIT
Do you have any idea what you are talking about? Any at all????
Ranger did not use ET streets on his C6!!
Also the comparison with the C5 Z doesnt make any sense. Of course hes going to trap higher with CAI vs being stock.:bash:

Again, I swear half the people in this thread dont even understand what ET streets are.:bash: They are street leagal SLICKS. Same rubber and basic design as slicks.. Only difference is, they have a slightly different side wall that doesnt crinkle quite as much, and two little "slits" for tread.:rollseyes

Fourcam.
I respectfully dissagree on ET street vs Radials ..
To oversimplify things for the sake of argument..

If you took 2 sets of rear tires, each with equal traction..
One set was a slick based tire at 12psi. and the other were DR radials at 25 psi.
The car would trap faster, all other variables being equal, with the radials.

Now if you took regular old street radials, and compared them with slicks..
If the car with the radials was severly traction limited, there is a chance that the car might trap higher with the slicks since there might be more hp applied. (I.E. the guy with the radials might not keep his foot in it)

But radials will generally trap slightly higher than slicks because of rolling resistance. Sorry guys this is fact.:shrug: And to all of you who dont know to put extra air in their front tires at the drag strip...oke:

One thing is for certain though.. This is defiantely not worth debating anymore..
So you guys win!

 

[Fourcam330]

I respectfully dissagree on ET street vs Radials ..
To oversimplify things for the sake of argument..

If you took 2 sets of rear tires, each with equal traction..
One set was a slick based tire at 12psi. and the other were DR radials at 25 psi.
The car would trap faster, all other variables being equal, with the radials.

The thing is traction is hardly equal comparing a DR to a real slick. You can launch much harder with a true slick or even ET Street than any DR.

Now if you took regular old street radials, and compared them with slicks..
If the car with the radials was severly traction limited, there is a chance that the car might trap higher with the slicks since there might be more hp applied. (I.E. the guy with the radials might not keep his foot in it)

This was definitely the case with my measely 294/297rw SAE (stock longblock example above).

But radials will generally trap slightly higher than slicks because of rolling resistance. Sorry guys this is fact.:shrug:

LOL that's just it. The immeasurable loss of speed due to the minutely increased rolling resistance of a slick is EASILY overcome by a harder launch. Remember, if you're slipping the clutch (like you have to with a street radial) you're not putting down anywhere near the kind of power you can with a dump on slicks. Putting power down during the most critical part of the race is huge.

And to all of you who dont know to put extra air in their front tires at the drag strip...oke:

Been there done that. What do you really think you're saving 40 vs. 50psi? .01-.001 second? Not worth the hassle IMO.

One thing is for certain though.. This is defiantely not worth debating anymore..
So you guys win!

Agreed. Everyone can make up their own mind, I'm done on this one too. op:

 

[ON D BIT]

ON D BIT
Do you have any idea what you are talking about? Any at all????

the question was about rolling resistance. was it not? the question was about trap speed with radials and sticky tires. was it not?


i just took a proven drag racer who knows how to adjust driving technique to compensate for the different conditions he now has. by the way the different driving conditions are radials vs drag radials, in case you did not follow.

the comments before us was, with sticky tires you will lose mph on your trap speed. the reason for this phenomenon was varied.
you dont have the time to match speed.
you have to much rolling resistance to overcome to match speed.

both of these comments were null in void. they are not true.:read: you should not lose trap speed when you change to a stickier tire.

regardless of what tires(type) you have on your car you should not lose trap speed. as demonstrated by fourcam and ranger.

fourcam - trapped faster with et drags over the d/r.
ranger - the same trap speed with d/r over normal radials.

so if rolling resistance is such a huge factor in drag racing, why dont we see it in these examples? we dont see it, because it is not a factor!

Of course hes going to trap higher with CAI vs being stock.

the whole point of this discussion was to show that running slicks would slow trap speed. if that is the case where is the slower trap speed?
your right, 02 z is not a fair comparison. but really what is an intake? is it worth 3mph on the track? how bout 5mph? or 10mph?
i kept the 02 z in the equation to show further evidence that trap speed does not diminish with sticky tires. do you really believe that a intake is worth more than the more than 3mph at the end of the 1320?

 

[Purvis]

On D Bit:
Just curious but do you have any real world expereince with this?? Have you actually gone to the track for days on end and run your car with radials vs Slicks?
Let me guess.. You dont race at Drag strips very often?

FYI:
Fourcam's experience is not the norm.. People usually lose a little mph when running slicks. Rolling resistance is not the only reason why you lose mph. But it is part of it.
But you can chose to believe what you want. ;-)

As stated before, rolling resistance is definately a factor in Drag racing.. Again, this is why people run Skinnies! :read: (and for lightness)

Fourcam has chosen to make a statement that goes against the grain of generally excepted drag racing knowledge, based on his own experience. I can atleast respect that, since he is talking from his own personal experience..

What I don't respect is you going on and on about a bunch of illogical nonsense, preaching to everyone as if "you know". LOL:dw:

Lets just drop this and get back to the original topic.. Shall we?:sleeping:

 

[experiment626]

On D Bit:
Just curious but do you have any real world expereince with this?? Have you actually gone to the track for days on end and run your car with radials vs Slicks?
Let me guess.. You dont race at Drag strips very often?

FYI:
Fourcam's experience is not the norm.. People usually lose a little mph when running slicks. Rolling resistance is not the only reason why you lose mph. But it is part of it.
But you can chose to believe what you want. ;-)

As stated before, rolling resistance is definately a factor in Drag racing.. Again, this is why people run Skinnies! :read: (and for lightness)

Fourcam has chosen to make a statement that goes against the grain of generally excepted drag racing knowledge, based on his own experience. I can atleast respect that, since he is talking from his own personal experience..

What I don't respect is you going on and on about a bunch of illogical nonsense, preaching to everyone as if "you know". LOL:dw:

Lets just drop this and get back to the original topic.. Shall we?:sleeping:

I agree with you and also, a slick krinkles on the side wall where a radial don,t so theres is more rolling resist with a slick unlike a radial.
So there for, you will MPH slower then you will with a radial.And I do race at the track norwalk and milan so I got some knowledge on this also.;-)

 

[jtfx6552]

On D Bit:
Just curious but do you have any real world expereince with this?? Have you actually gone to the track for days on end and run your car with radials vs Slicks?
Let me guess.. You dont race at Drag strips very often?

FYI:
Fourcam's experience is not the norm.. People usually lose a little mph when running slicks. Rolling resistance is not the only reason why you lose mph. But it is part of it.
But you can chose to believe what you want. ;-)

As stated before, rolling resistance is definately a factor in Drag racing.. Again, this is why people run Skinnies! :read: (and for lightness)

Fourcam has chosen to make a statement that goes against the grain of generally excepted drag racing knowledge, based on his own experience. I can atleast respect that, since he is talking from his own personal experience..

What I don't respect is you going on and on about a bunch of illogical nonsense, preaching to everyone as if "you know". LOL:dw:

Lets just drop this and get back to the original topic.. Shall we?:sleeping:

+1

Quantifying exactly what goes on between different runs could fill volumes. I have spent many a night at the track trying to figure out why one et was better than another, how i got a better second half ET, with a bad 60 ft, how i got a better second half et with a worse 1/8 and worse 1/4 trap? Certain results can boggle the mind.

Anyway, some generalites from track experience, runs with moderate wheelspin (which is pretty much the norm on street tires) can result in a slightly "inflated" trap speed.

Runs with excessive wheelspin can result in lower trap speeds.

Runs on sticky tires, that result in a bog really hurt trap speed.

I suspect the car in this thread had a slightly inflated trap speed on the street tire run, due to some wheelspin, and a low trap speed on the sticky's due to a bog.

On a good non spin-non bog run, my guess is it would probably go somewhere in the middle, 113 ish.

These results will also be affected by several other factors, the tire height change from the street tire to the drag tire, and rolling resistance.

I don't think rolling resistance plays a huge part, but I think it does show up on the clocks.

 

[ON D BIT]

FYI:
Fourcam's experience is not the norm.. People usually lose a little mph when running slicks. Rolling resistance is not the only reason why you lose mph. But it is part of it.

i could care less what the norm is.

yes i agree with you and have said so, normal drag racers will lose mph when they switch to a stickier tire. this is based on different conditions that are now being presented.
also the same can be said from racing a unprepped tracked to racing a prepped track with vht on the exact same tires and car. they will lose trap speed based on inproper launch technique with new conditions. this example has nothing to do with rolling resistance.

this is beside the point. rolling resistance can be overcome with proper launch technique. this is all i have ever stated. i believe this is what fourcam is stating as well.
with propper launch technique given the individual circumstances at the track one will not lose trap speed regardless of the type of tire. as evidence from ranger and fourcam.

most people lose mph because of inpropper technique, not rolling resistance.
i am not saying rolling resistance does not play a part in drag racing. all i am saying is that the difference is rolling resistance between a spinning tire a 40lbs and a different tire at 20lbs is not statistically significant to the times, or the speed of the run.

track experience: little. i have run a few(less than 50) times and i feel i have a lot to learn behind the wheel, specially at launch. i have been learning about drag racing for the last 5 years, and am positive you have more experience in this realm.

 

[SVTkel]

Hey man. You wouldn't be talking about me would you?

Unless your name is Bert and you are pretending not to know about this website -LOL

My buddy (Bert) did say that there was a Gt500 and another Cobra at the Shootoput on Friday. Does your car have a pulley b/c my buddy said there was another Cobra with a pulley running at the same time. He said he made like 15 passes.

 

[Fourcam330]

I agree with you and also, a slick krinkles on the side wall where a radial don,t so theres is more rolling resist with a slick unlike a radial.
So there for, you will MPH slower then you will with a radial.And I do race at the track norwalk and milan so I got some knowledge on this also.;-)

LOL the slick does not stay wrinkled the entire time. It unwrinkles itself during launch and whatever energy was stored goes back through the tire into the ground.

 

[dgussin1]

Nope, I believe he was referring to this one:

http://www.300cforums.com/forums/sr...1-50-mph-bone-stock.html?highlight=stock+12's

12.5@111, stock, great air at a great track. I think that given the same conditions, a well driven GT-500 could see low 12's, maybe better.

THE WEATHER WAS GREAT MID TO HIGH 40'S

umm, that is for sure negative DA at a sea level track...probably -1500 or more.

 

[Formula51]

In general, an ET Street has greater rolling resistance than a Drag Radial, which has greater rolling resistance than a Radial. This assumes tire pressure and contact patch to be the same across all three types of tires. In this case, the rubber compound (directly related to friction coefficient) and sidewall stiffness are the variables.

Now, does the difference significantly effect 1/4 mile times or trap speeds? I believe the answer is no. It may effect them, but not significantly. However, I cannot say this with certainty.

I admit that I did not read all the replies, so if this helps, great. If not, please ignore.

Qualifications: Mechanical Engineer

 

[ON D BIT]

In general, an ET Street has greater rolling resistance than a Drag Radial, which has greater rolling resistance than a Radial. This assumes tire pressure and contact patch to be the same across all three types of tires. In this case, the rubber compound (directly related to friction coefficient) and sidewall stiffness are the variables.

Now, does the difference significantly effect 1/4 mile times or trap speeds? I believe the answer is no. It may effect them, but not significantly. However, I cannot say this with certainty.

I admit that I did not read all the replies, so if this helps, great. If not, please ignore.

Qualifications: Mechanical Engineer

nice what you said is a lot clearer than anything i said.:rockon:

 

[MD03SVT]

Just to update the track elevation on my runs was 600' with a DA of 1200'.
I have been made aware of the fact that some GT 500's are pegging the maf at 4.7volts which could explain why she bogged at the top of 3rd gear.I will be heading to my home track this weekend to see what she can do in what is suppose to be bettere weather conditions.

 

[bad360rt]

THE WEATHER WAS GREAT MID TO HIGH 40'S

umm, that is for sure negative DA at a sea level track...probably -1500 or more.

Yup :-D That's why I love Atco in the fall. I'll be up there next month, and again Nov/Dec timeframe. Man I miss living 20 mins away from there

 

[Fourcam330]

Just to update the track elevation on my runs was 600' with a DA of 1200'.
I have been made aware of the fact that some GT 500's are pegging the maf at 4.7volts which could explain why she bogged at the top of 3rd gear.I will be heading to my home track this weekend to see what she can do in what is suppose to be bettere weather conditions.

What rpm were you launching at with the ET Streets? Did you feather/slip the clutch of just dump it? How much air in the tires, and did you do a nice long 7 second 2nd gear burnout to heat them up?
Sorry for all the questions, but all are important when optimizing your launch.

Thanks

 

[Formula51]

Why second gear for the burnout?

 

[experiment626]

heat tires better

Why second gear for the burnout?

You tires spin faster in second gear then 1st gear.So it will heat up better and you dont need massive rpms to do so.I do it all the time and get 1.44 60fts on motor with a 26x10.5 e.t street with a 6500 rpm launch.:rockon:

 

[Fourcam330]

You tires spin faster in second gear then 1st gear.So it will heat up better and you dont need massive rpms to do so.I do it all the time and get 1.44 60fts on motor with a 26x10.5 e.t street with a 6500 rpm launch.:rockon:

:beer:

 

[Formula51]

You tires spin faster in second gear then 1st gear.So it will heat up better and you dont need massive rpms to do so.I do it all the time and get 1.44 60fts on motor with a 26x10.5 e.t street with a 6500 rpm launch.:rockon:

Makes perfect sense. Thanks, I have never raced on slicks before.