Best shift points on 1/4 mile drag

[GreyKnight]

I heard the best shift points are determined by where the torque and hp curves meet on a graph.

Anyone out there with a stock GTS (mine is a 00') have any recommendations on the shift points from 1st to 4th on a 1/4 mile? I think 4th may not even be used.

Thanks!

 

[uvbnbit]

I'd say 5500-5800rpms. You're right, I don't think you'll need 4th gear if it's a stock rear gear.

 

[Tagoo]

I disagree. You want to accelerate all the way to the end of the quarter. If you don't grab 4th you will find that you are at or near redline for the last 100 or 150 feet. Your HP drops up at redline and you stop gaining speed. I've tried it both ways many times. I always get better times when I grab 4th. I have a mostly stock GTS. Made dozens of runs. I'm at 2700 ft elevation. If you are lower you will likely make more power than me. All else being equal, the more power you make, the more likely you are to run into redline before the end of the quarter. My opinion anyway
Joel

 

[Canyon707]

I have my G-Tech red shift light set for 5500. I have a fairly stock Viper Corsa, TB, DC Tune. running 3:73 gears. Its the best place on the curve to shift up. I have to use 4th gear with 3:73 gears. With 3:55 I am right at top of 3rd still looking hard at 4th gear at the end of a 1/4. I ran 12 sec 116mph but, I was light on the new MT Drag Radials. Trying to get the feel of these tires without breaking anything. So far I like them but want to explore some differen tire pressures. Going to 12 lbs for the next Wed night drags. The last couple Wed. have been rained out. I think with 3:07 gears you could stay in 3rd but, I never tried it. I think the perfect gear might be around 3:45.

 

[plumcrazy]

when mine was stock i had to shift to 4th at the end of the 1/4.

i would assume it will hurt your MPH if not

 

[TexasPettey]

6K Redline in a Gen1 in 3rd gear puts me right around 110MPH with a stock rear end.

If you have a dyno sheet, you can pick the optimum shift points by multiplying the torque by the final ratio. You'll want to account a bit for reaction time, so that you are shifting at that point.

If you have an iPhone, download the accelerometer app and do some trials.

 

[BOTTLEFED]

I heard the best shift points are determined by where the torque and hp curves meet on a graph.

Anyone out there with a stock GTS (mine is a 00') have any recommendations on the shift points from 1st to 4th on a 1/4 mile? I think 4th may not even be used.

Thanks!

the problem with your theory on shifting where the TQ and HP graphs meet is that every car's graph is going to meet at 5252rpm - that is part of the equation for finding horsepower from lb/ft of torque
so if what you heard is right, then every car's optimum shift point would be at 5252rpms

the optimum shift point is going to depend more on your setup and conditions

 

[GreyKnight]

I agree its going to be different depending on conditions and modifications. I was just curious on a stock setup as I heard that top torque peaks at 3700 rpm? versus HP, which peaks much later in the rpm. That started me thinking on what the optimal shift points are.

 

[ShadowLight]

The other thing to consider is that you want to remain in that "sweet spot" so you'll want to exceed it so when you shift, you dip down right back in to it.

 

[BigBadViper]

I end up in 4th every time.

 

[sdaddy]

Ran 11.997 @ 120.66 at Gainesville Raceway a few weeks back in my 96 GTS. Stayed in third and hit the rev limiter right at the end. My car has the stock 3.07 rear end and seems to hit the rev limiter somewhere between 117 and 118. I was surprised to get over 120 in third.

 

[Batboy]

My first time down the track I thought I could make it without 4th and hit the rev limiter about 100 feet from the end (hard to tell distance). I have used fourth every time since. If you don't make it to fourth then you didn't get a good time.

 

[GTS Bruce]

god you guys are S_L_O_W

 

[BigBadViper]

god you guys are S_L_O_W

mine topped out at about 157 in 4th in the quarter on pump gas.