The Maxima (any year) and Aerodynamics
03-10-2002, 03:00 PM
#41
Originally posted by Dave B
Ummmm....not really. Acceleration is related to torque. The longer the motor can sustain torque, the longer the motor will accelerate in each gear. These are crudely simple examples, but they do show that torque is what is truely responsible for acceleration (HP just a measurement determined from peak torque).
Examples:
Take a GM Vortec turbo diesel. It puts out 300hp and 520ft/lb tq. Big numbers, yes, but the torque starts out right off idle (1100rpms) and then falls off hard after 3300rpms. The HP curve peaks quickly and falls off fast by 3800rpms. What ends up happening is the truck accelerates hard right off the line, but quickly runs out of gear. Therefore the truck has very short powerbands which necessitates lots of shifting to stay in the power and ultimately no topend acceleration.
Now take the 4th gen Maxima. The curve torque stays relatively flat (within 10fwtq +/-) from 2000rpms all the way to 5800rpms. What this means in that the powerband is far more linear, useable, and lasts much longer than the diesel's.
By simply looking at the peak power (tq vs hp) you can roughly determine how the motor is going to accelerate (not factoring in vehicle weight and gearing). A car that posts 350hp/350tq (C5 Vette) means it has a extremely linear power delivery, flat torque, "power everywhere" and excellent topend performance. Now take a car that posts 240hp/280tq (Grand Prix GTP) means it is strong off the line and in the lower revs, but can't sustain strong acceleration up top. Finally take a car that posts 240hp and 130tq (Honda S2000) means this car is lethargic off the line, very weak in the low revs (no torque), but once the torque curve begins to rise then level out and the hp begins to build, the car accelerates very strongly and can run hard up top has long it can stay in the power band.
Dave
Ummmm....not really. Acceleration is related to torque. The longer the motor can sustain torque, the longer the motor will accelerate in each gear. These are crudely simple examples, but they do show that torque is what is truely responsible for acceleration (HP just a measurement determined from peak torque).
Examples:
Take a GM Vortec turbo diesel. It puts out 300hp and 520ft/lb tq. Big numbers, yes, but the torque starts out right off idle (1100rpms) and then falls off hard after 3300rpms. The HP curve peaks quickly and falls off fast by 3800rpms. What ends up happening is the truck accelerates hard right off the line, but quickly runs out of gear. Therefore the truck has very short powerbands which necessitates lots of shifting to stay in the power and ultimately no topend acceleration.
Now take the 4th gen Maxima. The curve torque stays relatively flat (within 10fwtq +/-) from 2000rpms all the way to 5800rpms. What this means in that the powerband is far more linear, useable, and lasts much longer than the diesel's.
By simply looking at the peak power (tq vs hp) you can roughly determine how the motor is going to accelerate (not factoring in vehicle weight and gearing). A car that posts 350hp/350tq (C5 Vette) means it has a extremely linear power delivery, flat torque, "power everywhere" and excellent topend performance. Now take a car that posts 240hp/280tq (Grand Prix GTP) means it is strong off the line and in the lower revs, but can't sustain strong acceleration up top. Finally take a car that posts 240hp and 130tq (Honda S2000) means this car is lethargic off the line, very weak in the low revs (no torque), but once the torque curve begins to rise then level out and the hp begins to build, the car accelerates very strongly and can run hard up top has long it can stay in the power band.
Dave
03-10-2002, 03:32 PM
#44
Not DAVEB the parts guy
Join Date: Aug 2000
Posts: 8,555
Originally posted by dmbmaxima88
and you need drag radials or different tires or VHT in a can or something
and you need drag radials or different tires or VHT in a can or something
03-10-2002, 03:34 PM
#45
Senior Member
Join Date: Oct 2000
Posts: 866
Drafting works at all speeds... Ever seen a flight of migrating geese? There's a reason they fly in a V. In fact, if one goose gets sick or tired, and has to pull out of the formation to rest, almost always more than one goose will pull out with it. Why? Because one goose, alone, is unable to overtake the formation. Only two or more geese, flying in formation, are able to catch up with their flight. Interesting, huh?
03-10-2002, 03:36 PM
#46
Originally posted by Dave B
Hey, go ring a bell or something "Mister 14.3 bonestock 2k2, first time at the track racing a stick, I'm a lucky a$$"
Hey, go ring a bell or something "Mister 14.3 bonestock 2k2, first time at the track racing a stick, I'm a lucky a$$"
03-10-2002, 04:19 PM
#47
Supporting Maxima.org Member
Thread Starter
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Join Date: Apr 2001
Location: FV, NC
Posts: 14,287
Originally posted by bullseye
Drafting works at all speeds... Ever seen a flight of migrating geese? There's a reason they fly in a V. In fact, if one goose gets sick or tired, and has to pull out of the formation to rest, almost always more than one goose will pull out with it. Why? Because one goose, alone, is unable to overtake the formation. Only two or more geese, flying in formation, are able to catch up with their flight. Interesting, huh?
Drafting works at all speeds... Ever seen a flight of migrating geese? There's a reason they fly in a V. In fact, if one goose gets sick or tired, and has to pull out of the formation to rest, almost always more than one goose will pull out with it. Why? Because one goose, alone, is unable to overtake the formation. Only two or more geese, flying in formation, are able to catch up with their flight. Interesting, huh?
03-11-2002, 09:56 PM
#48
Senior Member
Join Date: Jan 2001
Posts: 1,816
Originally posted by Badaxxima
Deezo, Chinkzilla- You guys are confusing torque with low-end power. A car accelerates to match it's torque curve, when people talk about helping top-end power, they are actually referring to the torque curve at higher RPM. F=MA, Force = Mass X Acceleration. Torque is force (multiplied by a lever or numerical gear ratio); divide that my the mass of the car (weight divided by acceleration of gravity) and you get an object's rate of acceleration. Torque is NOT work. Yes it has the same units, but you can produce torque without doing any real work. You can try to loosen a bolt for hours, but if it doesn't move, you haven't done any work (force X distance applied). Acceleration is created ONLY by torque. Horsepower is a convoluted way of looking at torque. Torque is created every rotation. Horsepower at any RPM is torque X any given RPM / 5252. Horsepower is a measure of how often an engine can create torque. When you increase peak hp, you are actually boosting the top-end torque curve. If you don't believe me: Torque vs. HP
Deezo, Chinkzilla- You guys are confusing torque with low-end power. A car accelerates to match it's torque curve, when people talk about helping top-end power, they are actually referring to the torque curve at higher RPM. F=MA, Force = Mass X Acceleration. Torque is force (multiplied by a lever or numerical gear ratio); divide that my the mass of the car (weight divided by acceleration of gravity) and you get an object's rate of acceleration. Torque is NOT work. Yes it has the same units, but you can produce torque without doing any real work. You can try to loosen a bolt for hours, but if it doesn't move, you haven't done any work (force X distance applied). Acceleration is created ONLY by torque. Horsepower is a convoluted way of looking at torque. Torque is created every rotation. Horsepower at any RPM is torque X any given RPM / 5252. Horsepower is a measure of how often an engine can create torque. When you increase peak hp, you are actually boosting the top-end torque curve. If you don't believe me: Torque vs. HP
Example, you are standing on a bathroom scale. You're not moving. Torque is not work done, it's work applied. Assuming that the area of contact on the bottom of your feet is equal to 1 sq foot, and you weigh 160 lbs. Effectively you are exerting a FORCE of 160 lbs over 1 sq foot. Now if you were to remove the scale, and the floor of your bathroom. You would now be doing work falling through the floor and moving which could probably be related to horsepower through some crazy conversion. Now, apply drag of air towards your falling motion, and your "work done" or D/T or Distance over Time is effectively reduced. Torque remains the same, because force applied is constant.
My example may be off, but I do not assume that torque is low end acceleration, nor do I think that it only has an affect at lower speeds. I've read that link you posted and that in fact was where I got my original information. Thanks =)
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