IX Brochure, HP/TQ Curve Question
 

I'm going to buy a IX soon and was looking thru the brochure. On the HP/TQ curve I noticed that they don't cross at ~5250 RPM but instead cross at ~3500.

If by definition: HP=(TQ*RPM)/5252, then they have to cross at 5252. Don't they? Since a brake dyno measures torque and then they convert to HP using the formula, I don't understand this. Every curve I've ever seen cross at ~5250 except this one. Does Mitsubishi believe in ponies and not horses?

Someone please explain what I'm missing here

Haven't seen the brochure, but could they have the curves on different scales so that where they "cross" is not keyed to the same RPM value?

the RPM scale is the same: 1000-7000.
I couldn't find where you could download the US brochure, but here is the UK one. The power curves are in there and you can see where they cross.

http://www.mitsubishi-cars.co.uk/evo..._download.asp#

WTF the dealer I got my IX at said they didnt make brochures?

that just can't be right... the dyno must be distorted when they resized it to fit the brochure

I requested one online and then got one at my local (tiny) dealer. After I got one from the dlr I got the other in the mail a few days later. They've been out for at least a month as I got mine that long ago.

On the dyno charts, I dug out the brochure on my 92 Talon they cross at 3000RPM. Strange.

Why does it matter? It's not a realy dyno graph anyway. They list the IX at 286/296 or whatever, but it dyno's 270/270 on a Dynojet, which indicates that Mitsu's published numbers are way off. I don't even know what that graph in the brochure is trying to say. It's in different units of measurement than we use, and the torque is wayyyyyyy lower than the HP, which isn't normal either.

my guess is the difference is due to the graph showing KW instead of HP units on the left axis.

That's only true if power is measured in units of horsepower and torque is measured in units of foot-pounds. Power and torque are different quantities entirely. Whether measurements happen to have the same numerical value depends on which units you use.

Dave

note the increments are different on left and rightt!!!!!! im looking at the brochure right now. that will make them cross at a different spot.

that's it! at 100 they are the same, then the scale changes. Good eye. If you look at ~5200 RPM the HP and TQ are both ~260. now I'm happy :D

It doesn't matter, I was just curious. I believe the chart is flywheel HP/TQ so it is obviously going to be different than wheel results.

djh: The US brochure uses HP and LB-FT, the "correct" units. If the "y" scales were equal they would cross at 5252 because of the reasons listed in my first post.

My guess is that because the units are in Newton-Meters and Kilowatt-hours, the curve crosses at a different point. I don't have time to review the derivation of horsepower from torque, but changing the units could affect this, since they are graphed on the same X axis but on different Y axes.

Yeah, what is it with the rest of the world?

But if you were to plot power in kilowatts and torque in newton-meters on the same scale you'd find the curves cross at ~9549 RPM.

By definition:
1 kilowatt = 1000 newton-meters/second
1 horsepower = 550 foot-pounds/second
1 RPM = 2 Pi/60 radians/second

Play around with those numbers and units and you'll see where the magic 5252 and 9549 come from. Oh, radians are actually "dimensionless units" so you can just drop them when they get in the way.

Dave

I guess I shouldn't have posted the EU brochure because that further confused things. My bad.
Yes, I am a ME, I understand where the units come from. Thanks for the reply though.
Oh, and I meant "correct" per my example. I agree metric is much better.