How much HP do you have??

[AL427SBF]

Originally Posted by scootter

Nice dyno chart, pull from 2K up on a 500 HP motor, that's how a dyno run should be done.

[Gary(SF)]

Originally Posted by Slick61

The side pipes are lossy...

Did not know that. Were the race engineers of the day unaware also? Or does this only apply to "streetable" baffled side pipes that keep the noise within somewhat acceptable limits?

[WardL]

TT, I should have said something like: IMO, more people know their flywheel/engine HP than their rear wheel HP because they bought or built a engine with an advertised/expected HP. You have to go one step further with a dyno to get the RWHP.

Since CC is not where "normal people" ): talk about cars..... maybe a better poll would be what percent of Cobra owners have had a dyno? I've had a dyno and don't know where it is right now, but sure I have more than 500 HP somewhere in there like every other Cobra on this site. )

When I am showing my Cobra to someone, no one has asked me what the rear wheel HP is.

[Varmit]

Rwhp: 535

[Robert McLinden]

I have 2 "HP", one a desktop and one a laptop.

[Tommy]

I've long been of the opinion that the only numbers that matter are lap time and elapsed time. Peak horsepower only matters as you approach your maximum speed in top gear, and I suspect only a few here have ever seen that. The rest of the time peak horsepower numbers are only good for bragging rights and some people have been known to exaggerate about such things.

[twin turbo]

Originally Posted by Tommy

Peak horsepower only matters as you approach your maximum speed in top gear, and I suspect only a few here have ever seen that.

What about acceleration thru the gears?

[joyridin']

Kind of funny story...I was at a shop this week talking to a guy that is heavily into cars. He has a 1973 corvette with a 650 hp EFI big block Chevy engine in it with a Richmond 5 speed and 3.73 gears.

Last year, he wanted to go a little faster, so they took out the solid lifter cam and put a roller in it. The cam they put in was pretty radical from what he said. They took it for a ride and both were amazed at the new found power. He took it to his buddy's shop and threw it on a dyno to fine tune it. They ran it and found out it had 100 LESS horsepower than before! The old man that used to own the shop (he retired and gave it to his son) came over and said #3 spark plug was arcing. Lo' and behold, he was right. They fixed the wire and added 150 hp (50 over what it originally was).

Sometimes a lot of sound and cool parts do not equate to actual horsepower. He was laughing when he told me this story but he swears that the car FELT like it had tons more power after the new cam was installed all the way up till they saw the numbers on the dyno. The dyno stated different.

[joyridin']

Double post. My keyboard has been going a little nuts lately.

[henrik]

Originally Posted by undy

Not enough but more than I need

Ditto

Roush 427 with EFI and some fine tuning to improve the output... but still not enough

[Ken Oikawa]

Originally Posted by undy

Not enough but more than I need

ditto.....

[Tommy]

Originally Posted by twin turbo

What about acceleration thru the gears?

Lots of people tend to think of horsepower as the UMMMPH that makes cars go. Therefore, they conclude that more horsepower results in quicker acceleration as well as higher top speed. And in casual conversation that's probably a good enough understanding. But technically, its an engine's torque that determines its rate of acceleration. Its possible (and sometimes desirable) to build two engines that produce similar amounts of torque, but at different points in the RPM range. The engine that produced its optimum torque higher in the RPM range would produce more power (horsepower), but it wouldn't necessarily be capable of accelerating more quickly. It would, however, be capable of pushing the same car to a higher theoretical top speed.

[CzyCobra]

Roush 427 SR w/510hp to the crank.... I plan on upgrading the heads, cam and intake.

Is it possible to take the baffles out of the side pipes, I did this on my ducati and it gained a few hp?

[Snake2998]

Originally Posted by Tommy

Lots of people tend to think of horsepower as the UMMMPH that makes cars go. Therefore, they conclude that more horsepower results in quicker acceleration as well as higher top speed. And in casual conversation that's probably a good enough understanding. But technically, its an engine's torque that determines its rate of acceleration. Its possible (and sometimes desirable) to build two engines that produce similar amounts of torque, but at different points in the RPM range. The engine that produced its optimum torque higher in the RPM range would produce more power (horsepower), but it wouldn't necessarily be capable of accelerating more quickly. It would, however, be capable of pushing the same car to a higher theoretical top speed.

That's actually wrong - it's horsepower or using another name for it "Rate of Work" that makes a vehicle accelerate quickly.

If you don't agree think of it this way - two identical cars geared for their rev range but with Identical torque - one a stump puller making peak torque at say 3000 revs hitting the limits of it's usable rev range at say 4500 rpm and the other making peak torque at say 5000 revs and peak horsepower at say 6000 revs racing down the drag strip. Which do you think will win. You're wrong if you think it's the stump puller - if you don't agree try feeding the figures into a drag simulator and you will see why horsepower matters.

[Tommy]

Snake2998,
We may have to agree to disagree on this one. ... In my comments to twinturbo I was speaking of instantaneous acceleration rather than a race in which acceleration is one of several factors that determines the winner. A drag race is partly about the torque required for acceleration, but also about the power required to push the car against the ever increasing wind resistance. .... I would argue that if you were racing from 30 to 70 MPH you should choose the engine with greater torque regardless of its horsepower. But if you are racing from 70 to 150 MPH, choose the engine with the greater horsepower. ... Newton's 2nd Law of Motion says that the acceleration of an object is proportional to the force applied to it. And the force applied to a car by its engine is torque, not power.

[mtrain2000]

HP, IS TQ over a period of time........

Now having said that, my 428FE engine has a mountain of TQ, but not a high hp peak, BUT that TQ drawn out with the help of the TKO600, 5 speed makes it a pretty lively vehicle.

Now the 540FE tunnelport engine that I have in my 67 Mustang fastback has even MORE TQ, with its 4.5" stroke, but sadly I've yet to get a chance to try it out.........One thing I can say is that the FE engine was different than most all other Ford engines I have ever built, and the most costly.