Where should I shift to get the quickest straight line performance?
98 240sx5 SpeedBone stock
Shift Points
some people stand by the idea that you shift at the optimum point of your car ( whatever that may be)
but unless you have a close-ratio transmittion, most stock cars will drop you all the way back to ground zero when you shift. And you want to be as close to the optimum point as possible.
reving 400-500 past your optimum point takes fractions of a second, but when you switch gears the fact that you are now closer to your optimum point will result in a faster next gear.
also depends how you shift, practice shifting lightning fast, the longer you take to clutch/release switch the farther off the rpm will drop.
try switching gears by simply tapping on the clutch without ocmpletly pushing through and just move that gear as fast as you humanly can. I do this all the time when i'm in the mood and i dont hear any noise from the clutch, so it aint grinding, and thats a plus.
but unless you have a close-ratio transmittion, most stock cars will drop you all the way back to ground zero when you shift. And you want to be as close to the optimum point as possible.
reving 400-500 past your optimum point takes fractions of a second, but when you switch gears the fact that you are now closer to your optimum point will result in a faster next gear.
also depends how you shift, practice shifting lightning fast, the longer you take to clutch/release switch the farther off the rpm will drop.
try switching gears by simply tapping on the clutch without ocmpletly pushing through and just move that gear as fast as you humanly can. I do this all the time when i'm in the mood and i dont hear any noise from the clutch, so it aint grinding, and thats a plus.
true.In a manual car, my foot never comes up from the floor on the gas.It's all about speed, and that only comes with practice.Truthfully, every car is different, and some people have things that just work better for them 
I suggest trying everything you can think of, and finding what the Butt Dyno says is right
I suggest trying everything you can think of, and finding what the Butt Dyno says is right
I've noticed with my s14 that i can shift right as close to the redline as possible and it actually seems to help....the main reason i say that is because with bad tires on my car i can easily spin 1st and 2nd, but occasionally when i floor it i can keep it hooked up for most of first until 5500 or so then the tires break loose, it just seems to get a ton of extra power up there...that's a dohc motor, granted, but at least on my car the power curve seems to be a bit higher. (This isnt recomended btw, one time i bounced off the limiter doing this...7k rpms or so probably not a good thing)ast
You must have bad tires astron.
I use a pair of Falcon Ziex 205/60/R15s in the back of my 1991 240SX w/ about 33% tread left on them at about 35psi w/o LSD. Any good road will allow me to give it full throttle and sidestep the clutch at around 5000 RPMs without excessive wheelspin. The tachometer hovers around 4500-5000 for about 1.5-2 seconds and then accenesds quickly to 7K when I put down a little more rubber but not muchwith my ACT clutch. Through the launch and the wheelspin I experience into 2nd the rear is sqirming a bit which tells me I'm getting both tires to put down the power most all of the time. I recorded a 2.1 60 ft time without the ACT a while back. I'll update sometime soon.
I use a pair of Falcon Ziex 205/60/R15s in the back of my 1991 240SX w/ about 33% tread left on them at about 35psi w/o LSD. Any good road will allow me to give it full throttle and sidestep the clutch at around 5000 RPMs without excessive wheelspin. The tachometer hovers around 4500-5000 for about 1.5-2 seconds and then accenesds quickly to 7K when I put down a little more rubber but not muchwith my ACT clutch. Through the launch and the wheelspin I experience into 2nd the rear is sqirming a bit which tells me I'm getting both tires to put down the power most all of the time. I recorded a 2.1 60 ft time without the ACT a while back. I'll update sometime soon.
The shift point will really depend on what gear you are in.
I don't have a dyno chart for a stock S14 to give you exact points (if you send me one, or post one, I'll figure them out).
But based on what I'm guessing as a stock-ish curve, I'd say:
1->2 and 2->3, shift right at redline3->4 shift at 62004->5 shift at 6000.
joe
I don't have a dyno chart for a stock S14 to give you exact points (if you send me one, or post one, I'll figure them out).
But based on what I'm guessing as a stock-ish curve, I'd say:
1->2 and 2->3, shift right at redline3->4 shift at 62004->5 shift at 6000.
joe
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jam149 wrote:The shift point will really depend on what gear you are in.
I don't have a dyno chart for a stock S14 to give you exact points (if you send me one, or post one, I'll figure them out).
But based on what I'm guessing as a stock-ish curve, I'd say:
1->2 and 2->3, shift right at redline3->4 shift at 62004->5 shift at 6000.
joe
I'd have to disagree with that. I'm not trying to disrespect or anything, but if you just took 5 mins of observing your car and tried shifting at where Aries says (6000-6200), you'd notice a big difference~! I used to shift at redline, but the synchros would lock up 2nd gear until I got to around 6000 rpm. That's also how I lost to a 90 240. (Mine's a 93) Go ahead, take the car out and shift at 6200, when I power shift right, I'd get a little nice fishtail wag to impress the galleries. I'm bone stock, but they dont know that, so they think: "Damn, he's got NOS~!" HEHEHEHEH Funny~!
Quote » I'd have to disagree with that. I'm not trying to disrespect or anything, but if you just took 5 mins of observing your car and tried shifting at where Aries says (6000-6200), you'd notice a big difference~! I used to shift at redline, but the synchros would lock up 2nd gear until I got to around 6000 rpm. That's also how I lost to a 90 240. (Mine's a 93) Go ahead, take the car out and shift at 6200, when I power shift right, I'd get a little nice fishtail wag to impress the galleries. I'm bone stock, but they dont know that, so they think: "Damn, he's got NOS~!" HEHEHEHEH Funny~![/quote]
Er, I run very good fluid in my transmission. I don't have problems shifting anywhere from 2k up through 7k.
The shift points I gave were if you want to get the most horsepower out of the car. In 1st -> 2nd shift, the HP curves do not cross - so run it to redline. Same for 2nd -> 3rd. The 3rd -> 4th curves do cross around 6250 or so, so that would be your shift point. The 4th->5th curves cross a little earlier, just over 6000 IIRC, so that is your shift point.
I can't help it if you can't shift! Maybe you shouldn't power shift, and save some wear on the trans.
(oh boy I can see this being a flame war already).
Listen, whatever. I'll graph the sucker out over the HP curve of a stock S14 if you want. The numbers tell the story, not powershifting.
joe (just a granny shifting not double clutching when I'm supposed to - oh wait, but I know how to double clutch alright....for a downshift)
Er, I run very good fluid in my transmission. I don't have problems shifting anywhere from 2k up through 7k.
The shift points I gave were if you want to get the most horsepower out of the car. In 1st -> 2nd shift, the HP curves do not cross - so run it to redline. Same for 2nd -> 3rd. The 3rd -> 4th curves do cross around 6250 or so, so that would be your shift point. The 4th->5th curves cross a little earlier, just over 6000 IIRC, so that is your shift point.
I can't help it if you can't shift! Maybe you shouldn't power shift, and save some wear on the trans.
(oh boy I can see this being a flame war already).
Listen, whatever. I'll graph the sucker out over the HP curve of a stock S14 if you want. The numbers tell the story, not powershifting.
joe (just a granny shifting not double clutching when I'm supposed to - oh wait, but I know how to double clutch alright....for a downshift)
all i had on my 240 was an injen cai. and i got the best times shifting right before i hit my revlimiter. maybe its cuz i have a 91 that it works for me but without the intake i did shift a little earlier. shifting at the redline did seem to help out alot just because it put me right at the beginning of my sweet spot in the next gear
Hey, I only thought I'd get flamed back!
Anyway, I'm saying that I've taken enough time to learn the fundamentals of my car that I dyno'd the car, graphed out the chart over the measured HP and torque curves, multiplied by trans ratios, final drive ratios and wheel sizes to determine the exact shift points that scientifically give you the absolute biggest area under the horsepower curve.
My car also sees about 2000 miles of on-track time a year. I think I know her pretty good!
That's all. No flames.
joe
Anyway, I'm saying that I've taken enough time to learn the fundamentals of my car that I dyno'd the car, graphed out the chart over the measured HP and torque curves, multiplied by trans ratios, final drive ratios and wheel sizes to determine the exact shift points that scientifically give you the absolute biggest area under the horsepower curve.
My car also sees about 2000 miles of on-track time a year. I think I know her pretty good!
That's all. No flames.
joe
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Shift points
I have to go with jam 149 on this one, just based on experience. i can tell the car takes longer to make it through the rpm gauge as i get into higher gears and so for the sake of speed shift a little sooner like 2 or 3 hundred rpms sooner each gear but run it to red line in first. Doing it this way i beat a 91 with headers, pulledeys, exhaust, cold air intake, and pulleys. all i had was my injen short ram, a shifter, and my exhauste on my 92. The only way to explain it was the driving.
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