Stock 1/4 Mile Launch and Shift Points

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Mar 2, 2007 | 03:45 AM

#26

swoope

Zoom-Freakin'-Zoom

iTrader: (5)

Joined: Jan 2004

Posts: 14,603

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From: orlando, fl

Quote:

Originally Posted by SouthFL

Just a few things to think about:

Reaction Time makes no difference in determining your ET and Trap Speed. RT makes no difference when you're simply going out to set a good time, but it does make a difference if you're actually racing your opponent. So, next time, worry less about the tree and your opponent, simply line up at the beam and launch when you're ready- the timer doesn't activate until the wheel clears the sensor.

60' makes a huge difference in your ET (60' measures the efficiency and magnitude of your launch- as little wheelspin as possible, traction and torque which propels the car forward from a dead stop all matter- the 60' is what kills drivetrains).
3.1 60' is an eternity.
(As a comparison, 2.0 is OK, below 2.0 is respectable for a street car, below 1.6 and you're talking about a car with a suspension setup modified to launch).

Nailing a good 60' brings down your ET significantly. Rule of thumb, every .1 taken off your 60' = .15 taken off your ET.

MPH usually is a measure of your car's capabilities (instead of your driving skills). Usually, no matter how poor your launch is, if your car runs well it will trap well if you bang through the gears quickly. Sometimes a poor launch with lots of wheelsping will actually give you a slightly better trap speed (yet, with a higher ET), than an efficient launch which nets you a great ET.

A great run will have a low 60', a low ET and a sold MPH trap.

Good luck!

this is very good...

and you will have better luck if you feather the clutch from ~ 4 to 5 k rpm..

beers

Mar 2, 2007 | 08:03 AM

#27

SirZyrion

Thread Starter

What's Your ISM?

iTrader: (1)

Joined: Jan 2007

Posts: 145

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From: Tempe, AZ

Quote:

Originally Posted by Dookie_Rx-8

only one run??

Haven't been around in a little bit. New job is killing my spare time.

Long story short, I started out with half a tank of gas, got bad directions for the Team Meet point to cruise to the track, headed to the track, got a call from the GF to bring back my son's car seat so she could bring the kids to the track, and then found out when I got back to my house that she left without it. My fuel light was on when i got to the track

Practiced "launching" frequently from stoplights (rev to 4k and drop of feather clutch and accelerate to 50mph of so, repeat at 4.5k at the next light, etc), and a 4.2-4.5k DROP seems to get me off the line quicker, but that's probably because I have a heavy foot when I drive straight. I'll be headed out to a few more track nights soon to get better stock times, and then I'll start saving for the mods.

Mar 2, 2007 | 08:49 AM

#28

gregor

Registered User

Joined: Feb 2007

Posts: 8

Likes: 0

From: NJ

Quote:

Originally Posted by SouthFL

^
I love the solid 1-2 shift of a T-56 tranny (stock tranny on LSX powered vehicles, Vipers, etc.).

Having driven quite a few Vipers I am here to report the first gen cars shifted like dump trucks, the second gen cars are slightly better. Shift quality has more to do with the linkage and less to do with the gearbox itself. back when I had older VWs I found they have pretty good strong gearboxes that can handle a fair amount of abuse but their shift mechanisms are crap as opposed to my Honda gearboxes that can't handle abuse/hamfisted shifting but have mechanisms that replicate the precise action of a rifle bolt.