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View Full Version : Got a queston regarding 1/4 mile times


98-LS1
09-01-2006, 06:21 AM
I recently ran a 12.7 at 105.6 mph at Bristol in my automatic 1998 Z-28, well, I called a buddy of mine up that has a 1998 SS with the T-56 and equal mods. He ran a 12.7 at 113 mph. I can't figure out why my MPH is so slow but the time is good? I'm below a 2.0 on the .60 with a reaction time of .633
Is the lack of a stall converter killing me or is it my gearing? It's the stock 3.23's out back, I'm stumped on this one!

98-LS1
09-01-2006, 06:25 AM
BTW I was running on Nitto 555's too, my first time below 13.0 and hit a 12.7

I'm still not believing it.

FastTaz
09-01-2006, 06:53 AM
BTW I was running on Nitto 555's too, my first time below 13.0 and hit a 12.7

I'm still not believing it.

your second faster than me @ same speed,6 speed, 3.42s, pure stock,no mods
original good years

98-LS1
09-01-2006, 09:35 AM
your second faster than me @ same speed,6 speed, 3.42s, pure stock,no mods
original good years


Dang, your cars strong as hell then! I can't figure this out, it pulls hard from down low to up top. what's the trick to get the MPH time up? I need a stall converter so I can come out of the hole harder for one but would that really help? Guess the automatic really does kill performance then, for one this car needs a tune desperately.

ForceFed
09-04-2006, 09:41 AM
I recently ran a 12.7 at 105.6 mph at Bristol in my automatic 1998 Z-28, well, I called a buddy of mine up that has a 1998 SS with the T-56 and equal mods. He ran a 12.7 at 113 mph. I can't figure out why my MPH is so slow but the time is good? I'm below a 2.0 on the .60 with a reaction time of .633
Is the lack of a stall converter killing me or is it my gearing? It's the stock 3.23's out back, I'm stumped on this one!

Its probably because you have an auto and hes got a 6 speed. Typically speaking, most autos will lose a little more power through an auto tranny vs a manual transmission if you are comparing identical power output. Call your buddy up and compare 1/8th mi trap speeds and final trap speeds. I bet your buddy picked up more mph on the back half of the track.

Ed Blown Vert
09-04-2006, 09:43 AM
A M6 will almost always have a higher MPH because they can transfer more HP to the ground.

Get a converter and sticky tires installed. Then get those ET's down.

AKIRA
09-04-2006, 09:54 AM
A M6 will almost always have a higher MPH because they can transfer more HP to the ground.

Get a converter and sticky tires installed. Then get those ET's down.

Bingo.

Just for shits and giggles, see if you can race him from a roll. Chances are, hell win. But from a complete stop, you will win. (if hes not good at launching)

GA Country Boy
09-04-2006, 12:21 PM
It's difficult to compare two cars unless you know everything about them, but the most obvious difference is the differential ratios. You're running a 3:23 and your friend running a six speed likely has a 3:42. So apart from him possibly having a stall and different tires, you're going to show a different acceleration curve because you're going to be at different points of your power bands. If you
want to improve your ET's, you would be much better off changing to a lower ratio like a 3:42 or 3:73. The 3:42's are the easiest (and cheapest) to find used since they are standard on six speeds and will give a lot more performance while still being very streetable. A 3:73 @ 70MPH will produce about 2,300 RPM, a 3:42 about 2,100 and now you're around 1,992 RPM,but your ET's will probably improve somewhere around 3-4 tenths.

98-LS1
09-04-2006, 01:11 PM
Thanks for the help! I guess 3.42 gears and a stall would help out that ET alot then. We have raced from a roll several times and he walks me so I can definately see how that affects my ET on the 1/4. I was impressed with the times though, old car runs strong as hell being almost eight years old. Thanks again,


98- LS1

Forcedinductiontech
09-04-2006, 02:12 PM
Also...a car that spins out of the hole will almost always mph faster. I bet that if he hooked...he would probaly e/t a tenth or lower than yours and his mph would drop.