radial e.t mph vs slicks et mph ?

[charlloots]

basicly what i wanna know is will i lose mph if i switch from et streets to radials in the 1320 if the car runs 10.90 @ 121 with 28 in et streets the car should still run 120 maybe a 11.40 et with bfg radials not drag radials

 

[azgn]

your top speed should remain very close to what you run with the ET's....in fact, you "could" actually pick up mph with the radials and a slower et (more time on the track to build mph)

ASSuming you continue to make the same HP

 

[UNGN]

The "more time on track" argument really isn't supported by Newtonian Physics, unless the excess HP is stored in some way and then released during the run. The extra time is DUE to the lack of accelleration, where extra mph would require additional accelleration.

What can happen though, is a spinning tire acts like a slipping clutch, keeping the the engine in a higher horsepower portion of it's power band than it would be if the there was no slippage. (why a slipping clutch start is faster than just letting the clutch out)

 

[V6POWER]

The reverse of this would indicate that going from street tires to slicks would cause a decrease in mph because of less time on the track. Is this correct? For instance, 115 mph on street tires would equate to a slower mph on slicks.

 

[charlloots]

thanks guys also what kind of tire pressure would i run at the trackim tghinking 28psi or so i dont want to be pulling threw the traps

 

[TS6]

Radial tire pressure should be wherever you run it on the street. Unless were talking DR's here. Slicks I'd say run as much as you can and the car still hooks, but 28 will be too high. Start around 19-20, and you'll probably have to work your way down. Some people say don't go below 12 psi. Makes for a squirmy ride at the big end.

 

[Reginald West]

I tried this about eight months back.I drove my T to the track ran it on pump gas 16 psi with 275 15 BFGs on it. The first run was a whooping 14.95 at about 108mph with tires spinning all the way down the track. Went back to the pits bolted on a set of slicks pulled back on the track and ran 12.07 at 112 mph. Without major suspension work I don't see those street tires doing mush for you ET wise.

 

[strikeeagle]

Agree.

Going to the track on street tires is a complete waste of time and money.

The glaring exception is if you run in a gonzo street tire class. Those guys make all manner of tweaks to their cars to prevent them from going up in smoke - low stall converters, custom tranny and rear end gears, mystery cams and carbs, etc.

 

[wbrophy]

This is what I think happens in the real world. Lose et= due to wheel spin at start, Gain mph= due to less rolling resistance of a radial tire. Just that simple. Most people pick up 1 to 2 mph when they go to radials from what I have seen.

 

[Race Jace]

Originally posted by wbrophy
This is what I think happens in the real world. Lose et= due to wheel spin at start, Gain mph= due to less rolling resistance of a radial tire. Just that simple. Most people pick up 1 to 2 mph when they go to radials from what I have seen.

I second this.

 

[2 SLOW]

"More time on the track to build up speed"? Where do you come up with this stuff? So if I putt putt down to the eighth and then punch it I'll go faster in the quarter?

You don't need more time to go faster, you need more distance. You do know the rule that for every tenth quicker on your 60' time you will go .15 seconds quicker in the quarter, don't you?

If you spin your tires at the start why do you think your 60' time is longer? It's because you are going a slower mph at the 60' mark. That's why it took you longer to get there. Let's say with slicks your car goes 1.60 at the 60' mark. You are probably going say 45 mph. Now with radials you go 2.10 at the 60' mark and are going say 35 mph. Both times you still have the same 1260 feet to go to the finish. But with the slicks you are going 10 mph faster. You are going about that much faster all the rest of that 1260 feet than with radials. So how are you going to gain mph with the radials? That is why you gain .15 sec in the quarter for each .1 sec you go quicker in the first 60'.

Now there is no arguement whatsoever that a radial has less rolling resistance than a slick. If they could make a radial tire that had the traction of a slick there would be a rush to the tire store. If the run with the radial had the same 60' as the slick and therefore was going the same 45 mph at the 60' mark, then the radial probably would be going 1 or 2 mph faster at the finish. But not by losing that time and therefore mph at the beginning.

There are lots of times on the track and on the street that a car with less power wins because the other car spins his tires. Spinning tires don't win. Look what happens to top fuel and funny car when they spin tires.

 

[turbojimmy]

I'm sure the better 60' time with a slick far outweighs the rolling resistance of a slick. I have seen people's MPH drop when moving to a slick but never sat down to figure out why. Last time out I went to the track with a pair of DRs and a pair of slicks. In the same day I went from 12.2 to 11.9 (DR vs. slick) both with a 112 MPH trap.

Jim

 

[CopGn]

Jim can you list the tires and rim you ran on each run?

 

[turbojimmy]

Originally posted by CopGn
Jim can you list the tires and rim you ran on each run?

All the runs were on Draglites. DRs were 275/60-15s, slicks were 26x10.5 M&H Racemasters. Now that you've asked, I realized that the BFGs were 28" tall, the M&Hs are 26" tall. I guess not really an apples-to-apples comparison.

Jim

 

[ST. RACE]

What good is the same MPH if you go13.90 on the radials

 

[Race Jace]

One thing to look at that i have not tried, They do make radial slicks. They are supposed to be an advantage over regular slicks on super stock cars like Gallina's two cars. (not their 7 sec one) They claim that on a 12-11 sec car they are allot better. how much i don't know but I really think they would be a hot ticket for allot of the typical turbo regals out there. I have seen gallina's cars hang the hoops at least a foot off the ground with these tires on some 12.0 runs. they must work pretty good.

 

[charlloots]

Originally posted by Reginald West
I tried this about eight months back.I drove my T to the track ran it on pump gas 16 psi with 275 15 BFGs on it. The first run was a whooping 14.95 at about 108mph with tires spinning all the way down the track. Went back to the pits bolted on a set of slicks pulled back on the track and ran 12.07 at 112 mph. Without major suspension work I don't see those street tires doing mush for you ET wise.

how tall were the slicks were they 28 in that would explain the jump in mph

 

[Reginald West]

Yes they were 28 inch slicks. I have never had alot of luck with street tires but judging from the posts on this subject obviously some people know how to do it I have just never seen it done.


REG