Have you run the bias ply ET streets in a comparable size that you could give a comparison to?

1.7's are nice and i'm sure they'll come down some. Are they floaty at all at 16psi? Do you plan to drop tire pressures at all?
What rpm do you launch at? Do you get wheel hop at all? I know the regular et streets have only ever wheel hopped on me once.

 

these are et streets...NOT radials. Wheel hop really isnt an issue with a solid axle sn95 stang. No sway on them, and i plan on running them at 13psi or so when i get some gear in the car

 

My bad, I misread your post. when you mentioned the 15 inch et radial I assumed you had the same tire but in 17's.
What were your et's with the 1.7 60fts?

 

I bet he ran 16s.....

 

Because the slicks are also spinning.

Think of it this way.....if you put your car in 5th......rev the engine up......and drop the clutch......what happens? On a good clutch the RPMs will drop immediately.

The situation you are describing......the clutch would be glazed from launching in only a few passes.....and we all know that is not the case.

Regardless.....I'm tired of typing essays on this. You can have your opinion and i'll have mine.

 

wow what would u need to pull that those kind of #'s NA

 

well, my ets werent good at all...i was only running 13.3@100. Somehow i lost 3-4mph and all of it after the 1/8th compared to my runs before on street tires. I need more gear, only 5k. I am looking at some 4.30s

 

I'm not talking about the slicks spinning...on every good launch I've had on slicks there is ZERO spin. And the force put on the drivetrain in 5th by dumping the clutch while the car is moving is hardly comparable to getting 3000+lbs moving from a dead stop. My clutch is great...but it still slips when it has to get 3000lbs moving to meet up with 5000+rpms of engine speed....if it didn't..things would break.

Why do you say that?? Clutches glaze from excessive heat, and slipping for a half second on a a launch isn't going to create excessive heat. Back when I was stock...I rode the clutch really bad on a launch...and burned the crap out of it through first, second and third gear...and it stunk like a$$...when I pulled my stock clutch out of my car it looked almost brand new. It takes A LOT of burning the **** out of a clutch to glaze it.

In fact...the clutch probably heats up more on a street tire, slip/dump launch....

It's not about opinion...it's about what actually HAPPENS when you dump the clutch and don't break traction...

 

You would be surprised at how much slicks really spin...

So how did you burn the **** out of your clutch yet it looked great when you pulled it out?

 

I know when my tires are spinning and when they hook...same with my DRs...when I come out of the hole I have ZERO spin...if I do spin my 60's SUCK...just like if I bog.

I only burned the **** out of it once...but it was for 3 consecutive gears and it STUNK. My point is...the short slipping that occurs from the time you dump the clutch to the time the car gets moving and the speed of the car matches the revs is nowhere near long enough to burn out a clutch.

My point was it takes A LOT of abuse to glaze the clutch...it's just like brakes...you have to use them wrong a lot to glaze rotors..not for a half a second for 10 runs in a day.

 

One point a few folks are missing here is they look at what they are trapping now and assume they have enough ommph for an entry in 12's based on that trap MPH and simply adding more traction, but it does not always work that easy.

Once you up your traction/improve 60 ft you more often than not see a decrease in trap MPH but your ET improves.

Example if you're trapping 105 with a 13.5 ET with an average say 60 ft of 2.0 and you get some sticky tires, you now see a 1.8 60 ft, your ET drops to around 13.2ish and your MPH 103-104. So you usually need a few more MPH up front if you're claculating on running lower ET based on current MPH trap + additional traction. Not always the case but quite often it is, especially if you're going from a spinning launch to a dead hook.

 

wow... 3.9's on the auto! glad to see someone finally tried that.

 

I ran 11.95@119mph with a 1.90 60'
two passes later I ran 11.72@120mph with a 1.73 60'

Same power, same tires and wheels.

I have NEVER seen an average correlation between better 60's and lower mph when I've taken multiple cars that I've owned to the track. In fact... my best 60' of the day usually ends up being one of my best traps too.

I know where this theory stemmed from though. If you go from running a radial street tire to a bias ply drag slick you'll see a drop in MPH from the bias ply tires at very low tire pressures. Has nothing to do with the 60' you pull.

 

I've seen it many times. The difference is not so much a 60FT variance but whether or not you're spinning significantly off the line.

A 2.1~ more often than not has some good spin, getting it down to a 1.9 more often than not removes a good deal of spinning. Generally if you spin off the line you end up seeing slightly inflated trap MPH.

 

Ok...I'll bite....on another run I spun my *** off to a 2.0 60' and a 12.1@118mph....

It makes no sense that you'd achieve a higher trap speed with the same amount of power when you have LESS track to accelerate on after spinning your butt off wasting time and track.

In your first post...the 60' seemed like a pretty big factor...now you're saying it's not that important?

 

Looking through several groups of my old timeslips I've found probably a 50/50 ratio of slips where the MPH gained when the 60 ft went poor enough to obviously have been spinning off the line. So.... I guess it's a tossup if what I looked at ended up as a 50/50 chance. I thought it occured more often but once I really looked at quite a few slips I guess not.

 

If you weave and do not stay straight, your trap will rise also.

 

 

I really hope you're kidding.

 

No, i'm not. Weaving does increase trap. But, it lowers time also.
If you are weaving, you are increasing the amount of time on the track and the length. Therefor, you increase the trap.