why does everyone want to spin the coyote up to 8000 plus?

[Dino Dino Bambino]

Interesting to note that the distance the piston travels up + down in one minute is virtually identical between a F1 car and nascar.

It comes down to mean piston speed. The highest revving engines can reach a mean piston speed of ~5000ft/min. F1 engines are able to live at 20k rpm by having an incredibly short stroke.
The Coyote engine has a stroke length of 3.65" and it would reach a mean piston speed of 5000ft/min at 8200rpm. Ford built the Coyote to survive up to 7500rpm so it would require some modifications (forged rods/pistons, HV oil pump with billet gears, cam phaser limiters or lockouts, upgraded valve springs) to safely rev 700rpm higher.

 

[JEWC_Motorsports]

If you had 1000 ft lbs of tq...but only 400 hp, your rpm at 1000 ft lbs of tq would be through the floor.

Really, hmmmmm. My truck is 300 hp and 1100 ft tq and never goes past 2200 rpm.

 

[stevbd]

Just my basic understanding: Torque is a measure of force, or ability to do work. HP is a measure of how quickly that force can be applied, or how quickly the work can be done. So to pull a trailer you want torque. To accelerate a car you want HP. Lots of complicating factors with gearing etc.

Both torque and hp drop off quickly in a stock Coyote after ~6800 rpm, so no need to rev to the moon.

Separately, I've heard it described that understeer is when the front of your car hits the wall, oversteer is when the back hits the wall, hp is how fast you hit the wall, and torque is how far you push the wall.

 

[Juice]

Zombie 222 mustang. Stupid fast, can smoke tires practically forever. 1800 lb/ft of torque. Hmmmmm

 

[JEWC_Motorsports]

People clearly do not understand how diesel engines work. I will take a drag car with 1000 ft tq every day over 1000 hp and no torque.

This may make some cry.....

 

[eighty6gt]

POWER - DEFINITION
Power is a measure of the work done per unit time.

You cannot measure work using torque units. Torque is a force unit.

 

[Norm Peterson]

You cut a slice of the peak on the hp graph and shift on either side of it to maximize area underneath. Nothing to do with torque.

Well, it does, sort of. It always goes back to torque x gearing even though the HP plot makes for better understanding.

8000+ rpm is looking at mean piston speeds in the 5000 fpm neighborhood. That's a whole lot for a street engine, up where mechanical limits start becoming a more serious consideration than the shape of the power and torque curves.


Norm

 

[tjm73]

My view is torque is ALWAYS more important. Followed immediately by the RPM at which it is made. Horsepower is horseshit, IMO. Torque is a real measured force. Horsepower is a calculated result of that force over time. Without the force or the time, horsepower cannot exist.

 

[eighty6gt]

prove god exists!

 

[Norm Peterson]

Really, hmmmmm. My truck is 300 hp and 1100 ft tq and never goes past 2200 rpm.

"Through the floor" for a Coyote, though.


Norm

 

[Norm Peterson]

My view is torque is ALWAYS more important. Followed immediately by the RPM at which it is made. Horsepower is horseshit, IMO. Torque is a real measured force. Horsepower is a calculated result of that force over time. Without the force or the time, horsepower cannot exist.

How many people have ever rearranged the units of HP - ft*lbf/sec which is torque per unit time - around to lbf * [ft/sec] which would be the units associated with traction force at some given speed such as your trap speed. Traction force of course being engine torque times gearing and divided by drive tire radius.


These discussions might never happen if some factory-based drag racers back around 1960 (Ramchargers?) hadn't done some curve-fitting of dragstrip results against HP and car weight. HP to weight is better at predicting trap speed than ET . . .


Norm

 

[Dino Dino Bambino]

So to pull a trailer you want torque. To accelerate a car you want HP. Lots of complicating factors with gearing etc.

To accelerate a car, or indeed any vehicle, you need torque.

Acceleration ∝ (Torque x Overall Gear Ratio)/(Weight x Tire Diameter)

If the engine doesn't produce much torque, you can compensate by increasing the multiplication of that torque to the wheels with higher ratio axle and transmission gears. You can also use smaller diameter tires.
It's advantageous to have an engine that produces a high amount of torque over the widest possible rpm range. This allows you to sustain strong acceleration over a wide road speed range. An engine that produces a high amount of torque at higher rpm will also have a higher HP output and give the vehicle a higher top speed.

 

[Dino Dino Bambino]

all of dino's talk about torque hurts my head worse than his opinions on the orange menace

Yeah, my torque talk must be making your head spin at 8600rpm.

 

[Dino Dino Bambino]

For comparison, the 5.2 Voodoo engine has a 3.66" stroke (almost identical to the Coyote) and a redline of 8250rpm. At that rpm the mean piston speed is 5033 ft/min which is right at the mechanical limit for that engine. Indeed ~5000 ft/min is the mechanical limit for the very best high revving engines, including F1 engines with a tiny 1.6" stroke and a 19000rpm rev limit.

 

[stevbd]

You guys are making my head hurt so I had to look it up.

According to wiki, the physics definition of "work" is force x. displacement (distance). HP is a measurement of power, or the RATE at which work is done. And "acceleration" is the rate of change of velocity.

Focusing just at the crank of engine, and leaving out different transmissions and final drive ratios, etc., HP is a measure of how fast (i.e., the rate) at which a motor can do "work." So yes, HP is a function of torque, but it also is a function of time. You could have a very big slow revving motor making a ton of torque doing a lot of "work," but which takes a lot of time to do that work. That motor, in isolation and without compensating with different trans gearing, etc., would be very useful for moving a big heavy object but if you were in a hurry it would not have much HP and would not accelerate very well.

Remember that MT article comparing an e90 M3 and the S197 coyote mustang back in 2011? The cars weigh about the same, make about the same hp, but the Mustang makes about 100 plus more lb/ft of torque. 0-60 times are identical. Comparison: 2011 Ford Mustang GT vs. 2011 BMW M3 Coupe (motortrend.com) If torque were king the Mustang should smoke the m3 in acceleration but it doesn't.

The usual performance metric for cars is pounds per HP, not pounds per lb/ft. of torque.

All that said I totally agree a broad and strong torque band is awesome for all the reasons stated.

 

[stevbd]

A little more apples to apples, the Boss Mustang is a little down on torque, a little up on HP, and accelerates a little faster than the same gen GT.

Track Tested: 2012 Ford Mustang Boss 302 vs. 2011 Ford Mustang GT (edmunds.com)

 

[Dino Dino Bambino]

Remember that MT article comparing an e90 M3 and the S197 coyote mustang back in 2011? The cars weigh about the same, make about the same hp, but the Mustang makes about 100 plus more lb/ft of torque. 0-60 times are identical. Comparison: 2011 Ford Mustang GT vs. 2011 BMW M3 Coupe (motortrend.com) If torque were king the Mustang should smoke the m3 in acceleration but it doesn't.

The usual performance metric for cars is pounds per HP, not pounds per lb/ft. of torque.

It depends on what performance parameters you're looking at. What you've stated above is absolutely correct. Pounds per HP does indeed determine standing start acceleration e.g. 0-60 to an extent but traction is also a significant factor. However both of the cars mentioned are RWD so the traction should be comparable.
Pounds per HP ratio is actually the most accurate predictor of 1/8 mile and 1/4 mile trap speed. I created a simple online calculator that'll estimate RWHP from vehicle weight and 1/4 mile trap speed. You can have hours of fun playing with it.

https://www.angelfire.com/my/fan/WHPCalculator.htm

You'll note that the BMW M3 has much shorter gearing to compensate for the 95lbft lower torque output (295 v 390) compared to the 2011 GT. In order for the M3 to complete a 4th gear 50-70mph WOT pull in the same time as the 2011 GT, it would require a 4th gear that's ~25% shorter geared than the GT's.

 

[eighty6gt]

The gearing does not compensate for the torque output.

The gearing allows for utilization of the HP production.

 

[Dino Dino Bambino]

The gearing does not compensate for the torque output.

The gearing allows for utilization of the HP production.

Let me put it a different way:

1. Shorter gearing (higher numerical overall gear ratio) DOES compensate for a lower engine torque output by increasing its multiplication to the wheels.

2. Shorter gearing allows you to take advantage of an engine's ability to rev higher.

These factors explain why a car such as the AP1 Honda S2000 (237hp @ 8300rpm, 153lbft @ 7500rpm, 9000rpm redline) has very short gearing for a 2L-engined car. With a stroke of 3.31", the AP1 engine has a mean piston speed of 4965 ft/min (near enough the magic 5000 number) at its 9000rpm redline.
The downside of such short gearing is that the Honda S2000 engine spins at a busy 3800rpm when cruising at 70mph in 6th gear.

 

[Juice]

My last example. 99 gsxr 750, and 91 yamaha vmax (1200 cc).
The gixxer is a little quicker in the 1/4. (About .4 and 10mph trap). Yet if I ride the 1200 for a while and then jump on the 750, it is an OMG this thing has no torque.
Then I ride the Hayabusa, and that makes both of them seem weak and lacking in the torque department.