Anyone got some KZ\ICC Dyno Charts?

Joe Ricard · Posted: Mon Oct 22, 2012 12:44 pm Post subject:

Pretty spiffy graph with the vertical numbers missing.
My Vortex RVS was supposed to make 42 HP when new.

I see the chart for the Honda claiming the same.

So what are the KZ's making nowadays.
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Arrow AX-8/ Rotax Sr.

Tim Salvino · Joined: 20 Nov 2010 Posts: 257

Joe Ricard · Posted: Mon Oct 22, 2012 1:10 pm Post subject:

Yea, I know. Would like to put them all up on the same dyno someday.
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Arrow AX-8/ Rotax Sr.

Steve Buckner · Joined: 22 Apr 2003 Posts: 839

Mike Goebel · Posted: Mon Oct 22, 2012 7:33 pm Post subject:

To get the shift point right one must graph velocity vs HORSE POWER for all gears and find where the HORSE POWER curves cross. Then back calcutate RPM.

Lets say at 26MPH you see the curves for 1st to 2nd cross, just find out what RPM the engine is at 26MPH and you have your shift point.

Don't try to shoot holes in this method, it is PERFECT!!!

Mike G.
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Jim McMahon · Posted: Mon Oct 22, 2012 7:45 pm Post subject:

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Jason Berry · Advertiser Joined: 29 Dec 2001 Posts: 294

Tom Barth · Posted: Sun Oct 28, 2012 6:21 am Post subject:

In my humble opinion, the properly set up KZ has only one power band. It is in the design and no amount 'tuning' will change it! This assumes that the timing and carburetion is correct.

If maximum performance is desired then adherence to the homologation specs is very important i.e. port timing and any other spec that is flexible.
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Power is good...more power is better... too much power is just right!

al nunley · Joined: 13 Nov 2006 Posts: 3030

al nunley · Joined: 13 Nov 2006 Posts: 3030

[quote="Mike Goebel"]To get the shift point right one must graph velocity vs HORSE POWER for all gears and find where the HORSE POWER curves cross. Then back calcutate RPM.
Interesting, but I think you might be forgetting something; HP is a calculation, torque is what get’s the job done. All you get to the rear axle is torque, (there is no HP going thru the transmission, only torque.) you then multiply that by the axle RPM, then divide that total by 5252.1 and you get HP.
Not that HP isn’t important, it is, but it’s HP at the axle that’s important, not at the engine, and it is different.
Think of this, let’s say the engine is turning 11,500 RPM, near peak HP, but you’re in third gear, with a ratio of, lets say, just for this discussion, 3-1. And lets say that the axle is turning, (again, just for discussion) 1500 RPM. Again, just for discussion, at that RPM the engine is producing 20ft lbs of torque. So the engine is producing 11,500 X 20 / 5252.1 = 43.79 HP. The torque is multiplied by 3, so the axle is seeing 60lbs of torque. 1500 X 60 / 5252.1 = 17.14HP
Now let’s use the engine RPM at peak torque, let‘s say 30ft lbs at 10,500. Thru the 3-1 ratio means 90ft lbs. at the axle. 1500 X 90 / 5252.1 = 25.7 HP at the rear axle
Just numbers I dreamed up, but use the real numbers and you’ll find pretty much the same thing, or close.
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If the data does not support the theory, get a new theory. (Al Nunley)
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Jim McMahon · Posted: Mon Oct 29, 2012 7:34 am Post subject:

Mike Goebel · Posted: Mon Oct 29, 2012 6:27 pm Post subject:

HP at engine = HP at rear wheels minus some frictional losses.

Assume single gear kart

Example

Engine
12,000 RPM and 30HP
Torque = 30HP*5252/12,000RPM = 13.13 ft-lb at the engine

Rear axle ratio = 1/3
Rear axle is turning 1/3 speed so....
Axle speed is 4,000 RPM
Rear Axle see 3 times the torque (see where this is going??)

Wait you ask if you increase torque by 3 but reduce speed by 3 then you have no change in HP Shocked

Power is conserved minus friction losses. THIS IS THE LAW.

What law you ask??? the law of conservation of energy.

Click here ---> THE LAW

Mike G.

Any mathematical mistakes are trival!!
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Brian Degulis · Posted: Fri Nov 02, 2012 5:00 am Post subject:

Mike Goebel · Posted: Fri Nov 02, 2012 6:27 am Post subject:

Plot HP vs MPH. Once you do that you will see where the curves cross. Find that point and back calcuate RPM. It's a kinda back and forth calc.

Since you have RPM you can find HP from the dyno curve (verticle axis) and you can calculate Speed (horzontal axis) from gear ratios.

Mike G.
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Brian Degulis · Posted: Fri Nov 02, 2012 11:24 am Post subject:

OK I got it. That makes a lot of sense becuase if you go soley by the power curve your not factoring in the ratio from transmission to axle wheel diameter and momentem. On the other hand is it really possible to apply this in reall world driving? You'd have to be pretty focused on the tach.

Brian