drag racing technique question

[toph99]

i am curious, to get the best quarter mile time do you want to shift at your peak horsepower or at the redline? what will give you better times, 0-60, 1/4 mile etc.
i suppose it has something to do with how quickly the power drops off after the peak right?


also, who would win(best guess)
95 honda accord (2.2L I4 i think)
2001 taurus (3.0L V6, 155hp, 185 ft-lb's)
both are automatics

 

[StageLeft]

Depends on the vehicle If you don't know any better go to redline but if you have a chance to do a bunch of runs you may very well find that shifting before redline keeps your times down.

 

[Viper GTS]

According to Edmunds:

1995 Accord DX coupe:

Weight: 2822 lbs
HP: 130
Torque: 139

HP/weight ratio: 0.0461
Torque/weight ratio: 0.0493

2001 Taurus LX Sedan:

Weight: 3354
HP: 155
Torque: 185

HP/weight ratio: 0.0462
Torque/weight ratio: 0.0552

The Taurus has both a better hp/weight & torque/weight ratios, so I'm guessing the Taurus would be a little quicker. If the Accord is a sedan the gap would increase slightly (LX sedan is 50 lbs heavier than the LX coupe).

Viper GTS

 

[toph99]

<< According to Edmunds:

1995 Accord DX coupe:

Weight: 2822 lbs
HP: 130
Torque: 139

HP/weight ratio: 0.0461
Torque/weight ratio: 0.0493

2001 Taurus LX Sedan:

Weight: 3354
HP: 155
Torque: 185

HP/weight ratio: 0.0462
Torque/weight ratio: 0.0552

The Taurus has both a better hp/weight & torque/weight ratios, so I'm guessing the Taurus would be a little quicker. If the Accord is a sedan the gap would increase slightly (LX sedan is 50 lbs heavier than the LX coupe).

Viper GTS >>



wow, thanks for the info i guess it'll be close, can't wait to try it

oh, and where on edmunds' site do you find the stats? it's a taurus SE and the accord is a 4 door.

 

[teriba]

lol, you are asking about shift points and then you say they are both automatic. You got some problems kid.

Back to the original questions though, it all depends on the shape of the curve. You want to have the highest average horsepower, which means going a little above the peak so that post-shift you will be a little below the peak. It should be equal above and below the peak.

 

[toph99]

<< lol, you are asking about shift points and then you say they are both automatic. You got some problems kid.

>>



i was just asking in general the two questions are totally unrelated

 

[Viper GTS]

Look up the vehicle, then click on the "Specs & Safety" tab.

They list the HP & torque, as well as the weight. The ratios you have to do yourself.

Viper GTS

 

[Jzero]

I'm no mechanic, but I thought it was possible to program an automatic transmission to shift at certain points. I imagine this requires the use of some ridiculously expensive computer to interface the car's computer, but I thought it could be done.
In fact, most cars with automatics are configured to shift smoothly, but many pro racers use automatics configured to shift at maximum power....

 

[toph99]

<< Look up the vehicle, then click on the "Specs & Safety" tab.

They list the HP & torque, as well as the weight. The ratios you have to do yourself.

Viper GTS >>



wonderful, thanks

 

[toph99]

<< I'm no mechanic, but I thought it was possible to program an automatic transmission to shift at certain points. I imagine this requires the use of some ridiculously expensive computer to interface the car's computer, but I thought it could be done. >>



most automatics will let you keep it in first as long as you want, some cars(like the 2000 alero) let you choose when you want to shift, it gives you 1st 2nd and 3rd gear choices, though you always have to start in first.

 

[Big Bwana]

<< The Taurus has both a better hp/weight & torque/weight ratios, so I'm guessing the Taurus would be a little quicker. If the Accord is a sedan the gap would increase slightly (LX sedan is 50 lbs heavier than the LX coupe). >>



ooh, careful there...hp-to-weight ratios are a good place to start, but there are lots of other factors like unsprung weight, final drive ratios, aerodynamics, etc that will GREATLY affect acceleration.

The ford may have the advantage in the hp to weight catagory, but if the honda's got a lighter flywheel, lighter wheels, higher (or more suited) FD ratio, proper gearing, and a more aerodynamic body, it can and will pull ahead of the ford.

BB

 

[Cyberian]

<< ooh, careful there...hp-to-weight ratios are a good place to start, but there are lots of other factors like unsprung weight, final drive ratios, aerodynamics, etc that will GREATLY affect acceleration.
>>

Is unsprung weight really a factor in straight line performance?

 

[Big Bwana]

of course unsprung weight includes everything that is not supported by the suspension which includes tires and wheels. the heavier the tires and wheels, the more rotational mass the engine will have to move.

BB

 

[Phuz]

I'd put money on the Accord.

 

[ISAslot]

Well, if Billy Bob Bubba is driving the honda, and Twiggy is driving the taurus, I'd bet on the taurus. Then again, maybe Twiggy is a sucky driver... n/m

 

[Big Bwana]

since both cars have auto trannys, all they'd have to do is mash the correct pedal down and hold the wheel straight

BB

 

[ZeroBurn]

the techniques vary by car. it's mainly up to you as the driver how to handle it, there's no golden rule.

your maximum power is at redline, right after you hit that point you lose power the longer you stay in gear. you have 2 options, you can shift at redline where you get the max power, but once you hit the next gear you're going to fall out of your top power. the other school will tell you to wait until after redline, just before the fuel cut, that way you'll fall right back into your max power when you shift. experiment with both. a good launch can make up for the difference though, make sure you work on that.

as for who would win, i would put my money on the accord. it's not as torquey or has as much power, but i'm betting that it's lighter and quicker. it would at least take em from the line. heh, i'd say it was up to driver but they're both autos, wtf ;P

good luck, drive safe

 

[notfred]

What the hell kind of crappy drag race is a Taurus vs. an Accord?

As far as shift points - you want to shift a little past peak. you want to keep as much power for as much time as possible, the best shift point will vary from car to car. I shift my Mustang at 5500.

 

[notfred]

<< the techniques vary by car. it's mainly up to you as the driver how to handle it, there's no golden rule.

your maximum power is at redline, right after you hit that point you lose power the longer you stay in gear. you have 2 options, you can shift at redline where you get the max power, but once you hit the next gear you're going to fall out of your top power. the other school will tell you to wait until after redline, just before the fuel cut, that way you'll fall right back into your max power when you shift. experiment with both. a good launch can make up for the difference though, make sure you work on that.

as for who would win, i would put my money on the accord. it's not as torquey or has as much power, but i'm betting that it's lighter and quicker. it would at least take em from the line. heh, i'd say it was up to driver but they're both autos, wtf ;P

good luck, drive safe >>




That's not true. The redline is where you start to risk breaking something. It has NOTHING to do with the amount of power being produced. Pushing the car past redline (I'm talknig about a stock car) will usually be pushing you out of the power band, and is definitely not good for the car.

Mustangs redline at about 6000 rpm (depending on the model). Most of them make max power around 5000.

 

[CraigRT]

<< your maximum power is at redline, >>



certainly was not on my old car... it was a torquey engine with alot less HP than torque. max power came around 4K with a 6K RPM redline.

 

[toph99]

<< What the hell kind of crappy drag race is a Taurus vs. an Accord?
>>


it's called poor highschool student racing parents cars

 

[Viper GTS]

<< it's called poor highschool student racing parents cars >>



I hope you poor highschool students can afford the cost of a new transmission after you blow it out on the dragstrip.

Racing mommy & daddy's cars is a no-no.

Viper GTS <-- Can kinda relate, did a fair amount of 85+ mph driving in a Taurus that didn't belong to him

 

[thomsbrain]

Almost all cars make their max HP below the redline. Even Honda's, which have the power way up in the curve. My girlfriends's Jetta doesn't pull after about 4500 RPM, although it redlines at 6500. My Accord seems to pull faster and faster the quicker the engine spins, though. Even with that, it stops pulling before the redline.

Regardless, we are only interested in torque here, HP isn't going to be much of an isssue.

 

[toph99]

<<

I hope you poor highschool students can afford the cost of a new transmission after you blow it out on the dragstrip.

>>


transmission will be fune, i'm not going to launch it i don't have a death wish(my father would kill me)

 

[notfred]

<<

<<

I hope you poor highschool students can afford the cost of a new transmission after you blow it out on the dragstrip.

>>


transmission will be fune, i'm not going to launch it i don't have a death wish(my father would kill me) >>



"Hey dad, I had some car trouble, think you could come pick me up? I'm at... uh... the racetrack...."