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What affects acceleration in the last 660ft?

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Old 10-29-2007, 11:18 AM
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Default What affects acceleration in the last 660ft?

So I hit the track this weekend looking to fine tune my new suspension components.
I managed to pull a 1.588 60ft (which was an improvement over my previous 1.70).
Timeslip-> http://s38.photobucket.com/albums/e1...102707-004.jpg

I even got one of the wheels off the ground this time out.
Pics ->http://erikandersondesigns.com/image...801/index.html

The first half of my run looks like it's destined for 11.xxx's but I find myself
only picking up 22mph in the second half.
I'm ending up with a collection 12.0xx timeslips.

- I've tried enabling and disabling TCC lockup and it made very little difference.

The car is just a little under stock weight (FG hood, !rear seats, !front swaybar !front BS, !spare and jack, QA1s, skinnies)
This car is my DD, so I don't gut it completely.
I do however remove some items for racing and reinstall for DDing.

The car is a 93 Firehawk with LE1HL cam, LE2 heads and a Yank SS4000.
She puts down about 380-390 to the wheels and I shift at 6375rpm (stock bottom end).
I run on MT ET DRs on 15" prostars.
(complete mods list on cardomain site - http://www.cardomain.com/ride/2297151)

I'm going to do some datalogging this weekend at the MidWest shootout.
I was hoping to make some improvements before then.
Old 10-29-2007, 12:32 PM
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..... I can't find any data regarding rear-tire height, or rear-gearing, in your info-list:
is it possible the car isn't at maximum RPM at the finish-line, traveling 111+ MPH?


EDIT: I just saw you have 3.73s..... what is the trap-RPM, and/or rear tire-height?
Old 10-29-2007, 05:56 PM
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Power & aerodynamics.
Old 10-29-2007, 06:42 PM
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Horsepower...
Old 10-29-2007, 06:49 PM
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Identical to me, as well. My 1/8th mph is 89.05 and the car traps at 12.214 with only a 22mph gain at the end after the 1/8th. 60' is 1.707, but, it's only 2nd time I have been to the track ... first time was on Nitto's ... last time was on 315 M/T's. Thinking of moving my shift points up to 6750. Frustrating to say the least.
Old 10-29-2007, 06:59 PM
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wow, the car is launching HARD james.... now just add a 150 shot on top
Old 10-29-2007, 07:08 PM
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could be a tranny or converter issue. Its not gonna pull good if the tranny is slipping or your blowing through the converter. You shouldn't be blowing through the converter at your power level unless its junk. Might try to find out how bad its slipping in third gear
Old 10-29-2007, 07:13 PM
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To be honest, I really don't see a problem. I run similar times and I gain 24 mph on the big end. My car leaves good & hard and accelerates continuously until it hits the stripe. The faster you go, the slower you will accelerate.
Old 10-29-2007, 07:32 PM
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Yeah, just from my experience a 22mph gain is pretty normal.
Old 10-29-2007, 07:43 PM
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22-24 mph is normal with an auto. depends on how efficient your converter is. the bigger the converer, generally, the less efficient it is.
Old 10-29-2007, 07:55 PM
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Originally Posted by Tiago
wow, the car is launching HARD james.... now just add a 150 shot on top
LOL .. I think I need may a new rear end first T.
But a N20 install is certainly on my list.
I was hoping to get into the 11s N/A this year and look at juicing for next season.
Gonna need a cage too LOL

Originally Posted by gator's 99TA
22-24 mph is normal with an auto. depends on how efficient your converter is. the bigger the converer, generally, the less efficient it is.
The more timeslips I look at the more that seems the case gator.
I need to figure out what the local club guys are doing that I am not.
They're cutting 1.5x and pulling mid 11s N/A.
Old 10-29-2007, 10:51 PM
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Horse power, ride hight, aerodynamics of the body, wind speed, gearing, clutch or torque converter slippage, tire growth, rotating mass drive train, weight of tires, weight of car to name a few.

Last edited by chrismorales75; 10-30-2007 at 11:10 AM.
Old 11-03-2007, 10:26 PM
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I made 10 passes today at KCIR (~ -100 DA)
My best run was 11.89@113mph with a 1.63 60ft.

Not bad for a full weight car and a full weight driver LOL

So I'm very happy to be in the 11s (finally) and I got plenty of wheels-up launches.
I'm sad to see another racing season come to an end.

I'll be back next year looking for mid-11s N/A
I think it's time to look at a stronger rotating assembly and rear end.
(Which will no doubt lead to a bigger cam and new tune)
I'm thinking a built tranny would be a good idea as well.




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