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H2R world record

Sun Jul 03, 2016 2:35 pm

Now that the H2R has set a record or two:
http://motorbikewriter.com/kawasaki-h2r-reaches-400kmh/
it's probably worth thinking about some of the the engineering behind it.

If that bike was making about 240kW (presumably at the crank), that is a lot of heat to get rid of, but not all the heat made makes the crank turn. Only about 1/3rd of the heat made creates the mechanical power we want.
If we are generous and say that 40% of the heat made creates H2R crank power, that means the H2R is shedding (240 X 1/0.4)kW, or 600kW of heat out the exhaust and radiators and off the power unit surfaces.
A typical little fan heater at home makes about 2.4kW of heat at full blast. The H2R would be making total of about 600/2.4 or 250 fan heaters worth of heat. Imagine what that would do to your electricity bill.
Assuming half of the heat is going out the exhaust pipe, that leaves the cooling systems to deal with about 125 fan heaters or 300kW worth of heat.
That is a lot of heat for a compact cooling system to deal with. Imagine the size of the radiator a 240kW car would have.

I have to wonder whether the H2R cooling systems are capable of sustaining full power indefinitely. I guess we would have to set up a dyno inside a potent wind tunnel to really test it, not that there are many places you could actually ride one at full blast for long anyway.

Re: H2R world record

Mon Jul 04, 2016 10:57 pm

Well mine is standard H2 with slip on and I can tell you there is a shit load of heat coming out of that pipe, left idling in the dark the headers start glowing.Around town on a warm day the cooling system seems to work fine and surprisingly there is not an unbearable amount of heat coming up from the engine when sitting at the lights.

Re: H2R world record

Tue Jul 05, 2016 6:30 pm

z900/zx9 wrote:left idling in the dark the headers start glowing

Titanium?

Re: H2R world record

Fri Jul 08, 2016 7:40 pm

Here is a guide comparing different bikes on the same dyno,looks like the H2 has it in spades
Attachments
h2 dyno comp.JPG
h2 dyno comp.JPG (67.94 KiB) Viewed 6767 times

Re: H2R world record

Sat Jul 09, 2016 12:47 pm

The H2 certainly has top end in spades.
I think people who are familiar with dyno sheets would also be impressed with the straightness and smoothness of the H2's graph.
That suggests the power would be predictable and relatively controllable. A credit to the the developers.
By virtue of the forced induction, I guess the H2 can run milder cam timing than a naturally aspirated engine, making resonance tuning a bit less critical.
I see the line gets a bit jumpy at the top end. Is there a bit of tuning to do to suit the Akro? Or was it a traction issue?

Re: H2R world record

Sat Jul 16, 2016 9:03 pm

z900/zx9 wrote:left idling in the dark the headers start glowing.

I've been thinking about this. Maybe I think too much, but I think it is better to over-think something than to under-think it (oops, there I go again...).
I don't ever recall seeing a bike or car doing that. Then again I don't run them in the dark much. It can't be good for the exhaust valves.
Sure I can remember pics of a Hemi 6 with glowing extractors, or a video of a turbo'd Ford straight-6 with the manifold glowing right down to the turbo, but those were power runs on a dyno, not idling.
If I saw a car or bike with headers that started to glow in the dark at idle, my first thought would be the ignition timing was way retarded somehow, maybe for emissions reasons.

Cutaway pics of the cylinder head like this one:
Image
do show a fairly short exhaust port which I guess helps reduce the heat the cooling system has to deal with since in just about any 4-stroke water cooled engine the intake ports are water heated and the exhaust ports are water cooled.
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