How much does 60' affect MPH??
07-07-2004, 06:14 AM
#1
How much does 60' affect MPH?? I know it has alot of affect on your ET, but does a poor 60' hurt your MPH very much? Basically, here is what I'm dealing with. My clutch is slipping really bad off the line. I'm sure it slips well past the 60' mark, but I don't know how far past. I can't cut a 60' better that 2.0X. Prior to the clutch starting to slip, I used to cut 1.85s NA. I was running 7.9 @ 91 in the 1/8th, but I didn't get a 1/4 time due to high winds at the track. Now, with the slipping clutch, I'm down to 8.3 @ 88mph in the 1/8th and 12.7 @ 114mph in the quarter. Since I'm losing 4 tenths in the 1/8th, I'm guessing I'm losing about 6-7 tenths or so in the 1/4. What do you think? How much ET am I losing? How much MPH am I losing? Thanks for any help.
07-07-2004, 06:39 AM
#2
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Usually when a clutch gets to a point of "audible" slippage it has been in a performance limiting factor for a while.
Im dealing with the same thing with my cobra, My car will make good dyno pulls, but when I throw the sticky's on it best I can get in low 1.7's and the clutch will slip more and more on each shift, everyday driving it is fine on street tires. I know im not a ls1 by anymeans, just thought I would share. I think I am giving up close to 2-3mph on the big end and at least 2 tenths.
My buddy was also at the track this weekend with his H/C 100 shot 02 Vert SS and his spec3 took a dump and got soft, he went from 60ft mid 1.5's to 1.7's in a hurry and the car was hurt everywhere else as well, I will get some specifics from him but it was not pretty.
Good Luck.
Im dealing with the same thing with my cobra, My car will make good dyno pulls, but when I throw the sticky's on it best I can get in low 1.7's and the clutch will slip more and more on each shift, everyday driving it is fine on street tires. I know im not a ls1 by anymeans, just thought I would share. I think I am giving up close to 2-3mph on the big end and at least 2 tenths.
My buddy was also at the track this weekend with his H/C 100 shot 02 Vert SS and his spec3 took a dump and got soft, he went from 60ft mid 1.5's to 1.7's in a hurry and the car was hurt everywhere else as well, I will get some specifics from him but it was not pretty.
Good Luck.
07-07-2004, 10:30 AM
#3
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I hear a lot of people say that a good 60' lowers your MPH. But in my IROC, the opposite was true. I could run 1.71-3 60's and get 12.1-3 @ 111-ish mph. If I hit the throttle too hard and got a 1.9 60', it'd run 12.7-9's @ 107-ish. Only took the T/A to the track once so far and it was getting 2.3-2.5 60's on the stock 245 RS-A's 
07-07-2004, 09:08 PM
#5
its not the actual sixty foot time that will effect mph per say.
its really more HOW you get that sixty foot..i.e- is the car spinning really bad, bogging real bad, or dead hooking nicely.
myself and most others that race alot here will tell you a nice dead hook will result in the best mph. the theory that a bunch of spin will create more MPH is pretty bunk. if you think about it if you are spinning you are just not gaining ground and wasting rpm band, the car will mph less.
to be fair. a mild spin will create more mph than a real bad bog, its always better to keep the car up in the rpm band rather than let if fall and make the car have to fight its way back into the power band.
broke7's comments can apply to my last comments about spin vs bog. a badly slipping clutch will have some similar effects on the car through the sixty foot and the power band as well.
its really more HOW you get that sixty foot..i.e- is the car spinning really bad, bogging real bad, or dead hooking nicely.
myself and most others that race alot here will tell you a nice dead hook will result in the best mph. the theory that a bunch of spin will create more MPH is pretty bunk. if you think about it if you are spinning you are just not gaining ground and wasting rpm band, the car will mph less.
to be fair. a mild spin will create more mph than a real bad bog, its always better to keep the car up in the rpm band rather than let if fall and make the car have to fight its way back into the power band.
broke7's comments can apply to my last comments about spin vs bog. a badly slipping clutch will have some similar effects on the car through the sixty foot and the power band as well.
07-08-2004, 10:42 AM
#6
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Seems that no matter what my 60' is, if it's an otherwise clean run my MPH stays pretty much the same. I've run the same MPH on a 2.0 as a 1.6 on the same day more than once. BUT, if I'm spinning through second gear as well, it will affect the MPH.
Why? 60' at the end of the pass doesn't allow you much acceleration, hence if you shortened the dragstrip by 60' your MPH wouldn't change much.
Why? 60' at the end of the pass doesn't allow you much acceleration, hence if you shortened the dragstrip by 60' your MPH wouldn't change much.
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07-09-2004, 02:07 AM
#9
Originally Posted by McRat
Seems that no matter what my 60' is, if it's an otherwise clean run my MPH stays pretty much the same. I've run the same MPH on a 2.0 as a 1.6 on the same day more than once. BUT, if I'm spinning through second gear as well, it will affect the MPH.
I can smoke the tires for 60', shift early and still end up within 1 mph of a good hook, nice shift run.
Differnce is quickness(e.t), not top speed.
Once I saw what my consistent mph was I tried to get my e.t. to match up.
112 mph over and over at 12.6-13.1 until I got a few 12.3x runs and figured that was about it!
My e.t. improvements all showed in the 60' on my timeslips.
07-09-2004, 01:56 PM
#11
Originally Posted by NJSPDER
it woudln't really matter to me what my mph did if i get better 60ft times. et is what wins races, not trap speeds.
later
tim
later
tim
