mikeg8r

iTrader: (2)

Chalk it up to marketing. What sounds better, a 287hp engine or 300hp engine?

The wikipedia articles are right on.
so by flattening the torque curve they were able to get from
287 hp @ 6,200 rpm to 300 hp @ 6,400 rpm
remove a little torque from here, give a little more torque there.

Bottom line is tho, you can't get something from nothing. From the same engine, you might be a little quicker at earlier but you'll be slower later. In the end I think it will equal out.

mikeg8r

iTrader: (2)

You are and are not correct. I think (and I am not a mathamatician) you want to look at the AREA within the hp and torque curves. Since
power = torque x angluar momentum
power does increase when torque increases, BUT it is possible to LOWER the PEAK power while at the same time INCREASING PEAK torque and vice versa. This is because the area under the curves is the same and that is the true measure of overall power and torque.

I can't belive i'm saying this but ROAST is RIGHT () when he says (paraphrasing) peak power or torque is sort of meaningless without looking at the whole curve.

edit: i love these discussions we've been having about physics lately. let's keep it up

roast

iTrader: (2)

Awwww cmon now. Why would you say that.

bailey bill

I'll skip any further semantics debate over teh terms direct, proportional, etc.

I'll simply repeat the significant fact:

"At any point along the RPM axis, an increase of 5% in torque will yeild a 5% increase in HP, an increase of 10% will yeild an increase of 10% in HP, etc."


Again, note my exact words:

"At any point along the RPM axis ...

If you want to demonstrate the effect of changin one variable (torque), you MUST hold the other (RPM) constant.

Torque and HP are always expressed in relationship (are you OK with the term "relationship"?) to a single point on the RPM axis.The standard notation for automotive power curves is A hp @ X RPM, and B torque @ Y RPM where X and Y are points on the horizontal (RPM) axis. My '06Z has 300 HP @ 6400 RPM, and 260 ft/lbs torque @ 4800

To be sure, neither of these data points (for any car) gives a real indication of overall performance. The best indicator is "area under the curve". Unfortuantely there is no quick shorthand like "300@6400" to describe "area under the curve".



Probably not.

bailey bill

Mike-

If you read my post about the perfromance of my MR2 turbo, and my post just above, it should be apparent that I understand the concept of "area under the curve". The MR2 reached peak torque (200) at 3200 RPM, and the curve was nearly flat to about 5200. That makes for a big area under the curve. And it makes for a lot more real perfromance than you would normally expect from a car with "just" 200 HP and 200 ft/lbs. That's real world example of why the 2 data points (HP@X RPM, torque@Y RPM) don't accurately describe performance capability.

But the relationship between torque and horsepower is clearly defined by the formula. At any given RPM, 1) You cannot increase HP with out increasing torque, and 2) the percentage change in HP will be the same as percentage change in torque. (When I got my mechanical engineering degree, that was called a proportional relationship. But that was back in the 60's. Maybe its changed?)

The formula, HP = (Torque X HP)/5252. You can only substitute one value for torque, and one value for RPM. Each point on the RPM axis must be associated with a corresponding value on the torque curve. You can only calculate HP by referencing a specific point on the RPM axis.

bill

jungle

Torque is king on the street, horsepower is king on the track. I'll take as much as I can get of both, but a torque monster is easier to drive and takes fewer shifts to cover the ground.
That said there isn't a huge difference between the two Z engines. Somebody drop a Chevy 502 into one and we'll compare notes.

bailey bill

An oversimplification, but essentially a correct statement.

deluzrider

i would rather have hp. i have the 06 and i wouldnt trade an 05 on any day

mikeg8r

iTrader: (2)

Sorry bill, i think that must be a typo, i'm not a mechanical engineer, but I did study physics and according to that wikipedia article

not sure where you got: hp = (torque x hp) / 5252.

Anyway, I think, as is often the case, the issue comes from a misunderstanding. And your right, for some reason I missed your MR2 post, I apologize for that.

That being said, I was commenting on an earlier post, in which hp is always proportional to torque. Which is true ONLY at the same RPM (which you later clarified). And in fact they are directly proportional as you say. a 1% increase in torque would equal 1% increase in hp. At varying RPMs though, torque can fall while hp rises, which is often the case when you look at a dyno chart. But I have a feeling you already know that so I'm not going to argue with you about it, we're on the same page. Like I said, I think it was just a misunderstanding. No harm, no foul

And you are right, the most important thing is do you have the torque when you need it.

mikeg8r

iTrader: (2)

then perhaps you want want of these: http://www.deere.com/servlet/ProdCat...R&pNbr=9620TRW

That's what would make the Z better, 18 foward speeds and 6 reverse speeds and max torque at 1800 RPM

bailey bill

From any basic mechanical or physics text.

Or by googling "horsepower torque "

Its the standard formula for (mechanical) horsepower


http://vettenet.org/torquehp.html

http://auto.howstuffworks.com/question622.htm

http://www.largiader.com/articles/torque.html

http://www.innovatemotorsports.com/f...hp/t-3350.html

http://en.wikipedia.org/wiki/Horsepower

Julian@MRC

iTrader: (28)

TQ is in fashion..Did'nt you get the memo??

tekk

the torque gained at lower rpms is so great that it improves the performacne of the car at lower rpms, in daily driving conditions.

in racing though, you want as much hp as you can, under the power curve.

Hydrazine

iTrader: (53)

In a recent track event at Pahrump (just outside of Las Vegas) I did some data logging of engine vitals using the Cipher data logger.

The purpose of the test was (predominantly) to data log throttle position and engine RPM while on the track. Knowing this information would give insight on the real world effect of MREV2 while on the track.
The first thing to find is the average RPM while on the track.
The second thing to find is the throttle position so all RPM data could be sorted based on throttle position.

By sorting to throttle position it was possible to find the average RPM at a range of throttle positions. All RPM’s at a throttle position less than 95% were discarded from the data set to help focus on average RPM while at very high engine loads.

There is no point in analyzing or comparing performance data at less than 95% of full throttle because stock or modified engines are both equally capable of the same power output at less than 95% of full throttle.

Any difference of “modified Vs stock” is revealed at full throttle or very close to full throttle.

When the data was sorted to 95+% of full throttle, I found the “average” track RPM to be ~5600 RPM.
There is of course WOT RPM’s above and below 5600 RPM but the average is the best unit of measure to compare by.

Since the average track RPM is ~5600, you will be able to find an average HP utilized on the track based on your power level on your dyno plot power curve.

Every dyno machine has different absolute numbers but if you look at the pre/post dyno installations of MREV2 and spacer, you can see how much of a power change is seen on the track by comparing the modified and stock plots.

There is approximatly a 12HP gain at 5600 RPM with the MREV2 and spacer. So this means you have 12 more average HP while tracking.


Although this is a technical analysis demonstrating the MREV2 and spacer provides more power on the track, it doesn’t take a rocket scientist to see which power curve will make more power on the track, auto X or street.

You only need to see the independant dyno plots below for an obvious answer.
These dyno plots are two recent independent REVUP pre/post dyno tests of MREV2 and spacer Vs baseline.


Tony

dvo

iTrader: (26)

non-revup vs. revup
287hp -----> 300hp
274ft/lb ---->260ft/lb

is that right? i think that those are the numbers

roast

iTrader: (2)

You messed the equation up, yet again.

bailey bill

Yup.

But if you clidked on any of the links I posted, you found the correct HP = (torque X RPM)/5252

Fluid1

iTrader: (19)

Bump to further discussion.

Which would you people rather have, for a DD that is a heavy autox'er?

300 or 287.

JCZ33

TQ = the force that moves mass
HP = the force that creates speed

TQ give you your E.T.
HP give you your trap speed