torque vs. H.P., whats better ?
10-30-2008, 12:49 PM
#61
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10-30-2008, 02:10 PM
#62
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I dunno if I would be happy with 4:10's or not....guess I will have to find somebody at the next corvette function and see if I can't go for a ride or better yet, drive their car for a block or two just to see what its like.
10-30-2008, 02:53 PM
#63
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In theory if you go from a 3:42 to a 3.80 gear and also modify the engine to move the torque curve up in rpm's about 11% you have made a good improvement. This would maintain the same speed in each gear and yet get more torque to the ground in each gear.
But then, that would likely hurt lower rpm torque and hurt when you try accelerating when the rpm's are low.
Peter
But then, that would likely hurt lower rpm torque and hurt when you try accelerating when the rpm's are low.
Peter
10-30-2008, 03:12 PM
#64
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In theory if you go from a 3:42 to a 3.80 gear and also modify the engine to move the torque curve up in rpm's about 11% you have made a good improvement. This would maintain the same speed in each gear and yet get more torque to the ground in each gear.
But then, that would likely hurt lower rpm torque and hurt when you try accelerating when the rpm's are low.
Peter
But then, that would likely hurt lower rpm torque and hurt when you try accelerating when the rpm's are low.
Peter
I guess there is no substitute for bigger displacement?
10-30-2008, 03:42 PM
#66
I think this might be an analogy, yes or no ?
10-30-2008, 05:19 PM
#67
Drifting
OK you quys are speaking in somewhat advanced/thick terminology.
When we were kids:
Balsa wood airplane with the rubber band propeller = torque
Balsa wood airplane with *** .049 = H.P.
Thrust = the action of actual propulsion, for either plane.
Like this or ?
When we were kids:
Balsa wood airplane with the rubber band propeller = torque
Balsa wood airplane with *** .049 = H.P.
Thrust = the action of actual propulsion, for either plane.
Like this or ?
Seems like a simple question, but unless you look at all the things going on it will be confusing.
Torque is the only real measurement of power. It is how much power your engine is making at any particular instant. Dyno's can only measure Torque.
HP is a way of stating how much 'work' is done, i.e. the amount of power generated over a time period. Sort of an accumulation of torque. Not that straight forward, but in a very simplistic view it is pretty much what is happening. The calculation is HP = (torque * RPMs)/5252. This means that even though the engine power is not at its peak, the total accumulation of that power will be higher when the RPMs are high. And the accumulation of that power is what accelerates you and keeps you at speed, both of which are time dependant.
Just looking at the max numbers is not the best way to determine how the engine performs. You need to look at a dyno graph to tell how the engine really behaves. However, it does give some clues to how it will behave. Higher torque rating means that the torque drops off as the engine speed increases, so you loose power as the rpms go up. Higher HP means that the engine maintains power in the higher rpms.
An engine that makes more torque than HP. It would more than likely be a great ‘street warrior’, it can go fast off the line and is a lot of fun in relatively short distances, like a few blocks.
An engine that makes more HP may not have as much torque down low, but it usually will. What it does mean is that it maintains its power as the RPMs climb. Better for road racing and drag racing where the distances are longer and the speeds are much greater. But it starts getting really fuzzy after that about what is better where…
04-03-2012, 02:41 AM
#68
Team Owner
04-03-2012, 06:56 AM
#69
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tq curve crosses HP curve at 5700 = Bonus Dyno Operator. the dyno operator is fudging to give the car owner BIGGER numbers then they really have.
5252 is the constant, where tq=hp
Let's put this all together. We need to get to horsepower, which is 550 foot-pounds per second, using torque (pound-feet) and engine speed (RPM). If we divide the 550 foot-pounds by the 0.10472 radians per second (engine speed), we get 550/0.10472, which equals 5,252.
So if you multiply torque (in pound-feet) by engine speed (in RPM) and divide the product by 5,252, RPM is converted to "radians per second" and you can get from torque to horsepower -- from "pound-feet" to "foot-pounds per second."
04-11-2012, 02:58 AM
#70
Team Owner
Thread back from the dead??
tq curve crosses HP curve at 5700 = Bonus Dyno Operator. the dyno operator is fudging to give the car owner BIGGER numbers then they really have.
5252 is the constant, where tq=hp
Let's put this all together. We need to get to horsepower, which is 550 foot-pounds per second, using torque (pound-feet) and engine speed (RPM). If we divide the 550 foot-pounds by the 0.10472 radians per second (engine speed), we get 550/0.10472, which equals 5,252.
So if you multiply torque (in pound-feet) by engine speed (in RPM) and divide the product by 5,252, RPM is converted to "radians per second" and you can get from torque to horsepower -- from "pound-feet" to "foot-pounds per second."
tq curve crosses HP curve at 5700 = Bonus Dyno Operator. the dyno operator is fudging to give the car owner BIGGER numbers then they really have.
5252 is the constant, where tq=hp
Let's put this all together. We need to get to horsepower, which is 550 foot-pounds per second, using torque (pound-feet) and engine speed (RPM). If we divide the 550 foot-pounds by the 0.10472 radians per second (engine speed), we get 550/0.10472, which equals 5,252.
So if you multiply torque (in pound-feet) by engine speed (in RPM) and divide the product by 5,252, RPM is converted to "radians per second" and you can get from torque to horsepower -- from "pound-feet" to "foot-pounds per second."
04-11-2012, 05:04 AM
#71
Drifting
There is no simple answer. It depends how YOU want to use the car. For drag racing, peak RWHP is king since you're always in the upper RPM. For overall driving, autocross and road racing, you would want a power curve that enables you to merge and come out of corners without having to rev the engine sky high or wait to make poer.
This is my dyno graph. I make 380 RWT at 2200RPM and 400RWT from 3k up. Tip is is insane and I can roast the tires from just off idle. The average power is usable and a blast to drive.
This is my dyno graph. I make 380 RWT at 2200RPM and 400RWT from 3k up. Tip is is insane and I can roast the tires from just off idle. The average power is usable and a blast to drive.
I agree with WKMCD. I wanted Torque for DD and passing and could care less about winding the car out or taking it to the track. Still had a little belt slip on that graph but Torque was more important to me than HP and I seen someone post about the cam. I ordered the cam from comp for that reason.. Just my views but if your not going to track it or drag race it Torque is more fun to play with on the street. 500 wtq @2250 rpms and 557 at 3600 rpms. Thats a passing gear. Ended up with 493whp and with the 3.90s in the rear she is fun to play with on the street. For drag racing> WHP without a doubt. I'm spinning 7800 with a 498ci in the rail but thats not the street.
My big rig only has 485hp but it has 2150 pounds of torque. Hauls 10 cars like theres nothing on her at 1500 rpms. For the street and a DD > Heres a vote for torque...
Last edited by liveaboard74; 04-11-2012 at 06:08 AM.
04-11-2012, 07:49 AM
#72
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Those Diesel Audi TDI and Peugot ALMS race cars have well over 600 lb ft of torque, and they accelerate out of corners like rocket ships.
Think I read some place they can do a 1/4 mile from 0-200-0 ( and Stop ) in under 10 sec, if the drivers guts are not mushed doto the g-forces on his body.
Think I read some place they can do a 1/4 mile from 0-200-0 ( and Stop ) in under 10 sec, if the drivers guts are not mushed doto the g-forces on his body.
04-11-2012, 07:56 AM
#73
Race Director
I agree with WKMCD. I wanted Torque for DD and passing and could care less about winding the car out or taking it to the track. Still had a little belt slip on that graph but Torque was more important to me than HP and I seen someone post about the cam. I ordered the cam from comp for that reason.. Just my views but if your not going to track it or drag race it Torque is more fun to play with on the street. 500 wtq @2250 rpms and 557 at 3600 rpms. Thats a passing gear. Ended up with 493whp and with the 3.90s in the rear she is fun to play with on the street. For drag racing> WHP without a doubt. I'm spinning 7800 with a 498ci in the rail but thats not the street.
My big rig only has 485hp but it has 2150 pounds of torque. Hauls 10 cars like theres nothing on her at 1500 rpms. For the street and a DD > Heres a vote for torque...
WOW - a lot has changed since those graphs. Same thought just much more of everything. Over 400 Ft/Lbs of torque just off idle is stupid fun.
04-11-2012, 01:45 PM
#75
Race Director
05-15-2012, 01:34 PM
#77
Team Owner
Response on another forum about the 5250 rpm cross. (Not mt dyno it was one posted)
Said dyno:
Said dyno:
Actually your HP and Torque are the same at 5252rpm, both are about 225. There is nothing wrong with your chart or the dyno, it is just the way the graph is scaled.
If you look at your HP & TQ scales they are different. Some dynos automatically change the scaling to make the graph easier to read with the peak hp and tq in the same area of the chart. On the chart above if both sides were scaled from 50-275 the HP and TQ lines would cross at 5252rpm.
If you look at your HP & TQ scales they are different. Some dynos automatically change the scaling to make the graph easier to read with the peak hp and tq in the same area of the chart. On the chart above if both sides were scaled from 50-275 the HP and TQ lines would cross at 5252rpm.
