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Supercharged Kawasaki? Now supercharged NC!!

buckshot said:
Longer stroke doesn't necessarily mean longer rods. The stroke is set by the distance from the center of the crank pin to the center axis of the crank shaft. If you were building up a hot V8 for a car and wanted to install a stroker crank, one of your options to make it all work would be shorter than stock rods. Otherwise the pistons would smash into the head and getting it to run right would be a real bugger.
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I see said the blind man. Thanks for the explanation. Maybe Mazda just made crappy rods forever biasing me. LOL
 
Manufactures switch stuff up like that on a regular basis, different metallurgy or manufacturing processes. They could have gone from forged rods to powdered metal rods or something like that. When it comes to Mazdas though, I prefer mine without pistons or rods :cool::p bbrraaaappppppp!
 
Longer stroke doesn't necessarily mean longer rods. The stroke is set by the distance from the center of the crank pin to the center axis of the crank shaft.
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Correct! :D
Many many years ago I remember a guy who fancied himself as a bit of a 'Tuner'
His plan was to fit a longer Conrod into his Lambretta Scooter to increase the Stroke!
All it did was make the engine a little bit longer! :rolleyes:

Andy
 
buckshot said:
Solid theory, but now you're dealing with having a pressure vessel on board the bike. Given that motorcycles are prone to falling over, in order to keep insurance companies and law makers happy it would likely have to be one hell of a robust tank. And that means heavy. You may even have to ride around with some sort of safety label on yourself, like "I'm riding a bomb" or something. But I guess if everybody thought you might randomly explode, they might keep their distance a little more, and riding could be a little safer...
Also, when said compressor is filling up the tank, then engine would probably be quite the dog. As the tank pressure rises, so would resistance on the engine.
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I was thinking something like a composite SCBA container (under 10 lbs.). If you don't mount it on the side of the bike or where it would easily get damaged, it should be plenty safe. The heaviest part would be a compressor capable of filling the tank to the pressure you would need in order to get the PSI out you want for the length of time you want. Additionally, you would have the plumbing, valve, regulator and solenoid weight, but I wouldn't think these components would be more than a few pounds total. A compressor shouldn't make much of an impact on the engine, as it would be electric and only take a few horsepower at most. Something designed for the specific application could be integrated into the bike without looking like an after-thought. Oh well, it would never happen.
 
I ride my NC70X-DCT a certain way and having maybe double the hp would do nothing for me whatsoever except cost me much more for gas, maintenance, and the loss of all that Frunk space.
All negatives and zero positives for me personally.:rolleyes:
Besides, the article only referred to the NC750, not the 700
 
Isn't the supercharge boast level related to the engine's rpm? Honda marketing had highlighted that the NC700/750 engine delivers relatively high torque while at low rpm. This apparently is a true merit of its engine, and appreciated when the rider pulls away from a stop without needing to over-rev the engine. But wouldn't this proposed supercharged version still not offer much increase in torque until the engine had rev'ed to the mid or even the upper range?
 
Skeleton said:
Isn't the supercharge boast level related to the engine's rpm? Honda marketing had highlighted that the NC700/750 engine delivers relatively high torque while at low rpm. This apparently is a true merit of its engine, and appreciated when the rider pulls away from a stop without needing to over-rev the engine. But wouldn't this proposed supercharged version still not offer much increase in torque until the engine had rev'ed to the mid or even the upper range?
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Depends on how the supercharger is set up. If it's anything like how the Kawi is set up, it may incorporate a two speed transmission of sorts for the charger. At lower engine RPM, the compressor would be driven faster to create boost early, then as the engine RPM rises it "downshifts" the charger to keep it working in its efficiency range/not over-boost the engine.
But that would be an all-out power set up, which is what the H2R was built for.
I don't see Honda going that way with a boosted NC. It already has great torque down low and at cruising RPM, so boosting it there wouldn't be needed and just burn more fuel. If Honda built it to start generating boost at around 3500rpm you'd still get all the good fuel economy the engine provides just cruising around, but then when you stretch its legs some it will get up and go like I think a lot of people would like.
 
You wouldn't get the same MPG just cruising around, though. A Supercharger (and to a lesser extent, a turbocharger) has a constant parasitic drain on the engine. For a supercharger, it's the power needed to turn the belt. For a turbo, it's the backpressure in the exhaust and the intake restriction when the intake manifold is in vacuum. If I've noticed anything on the NC700X, it's that every little thing has a large impact on fuel economy. Without knowing the specs on the supercharger or any other modifications they might make, I would guess the overall MPG would drop anywhere from 5-10 MPG depending on how and where you ride. Now, assuming they lose 5-10 MPG and nearly double the power output. The costs will also increase and it's now almost a direct competitor to the V-strom and just about everything else in the class without the benefit of better gas mileage or having a 19 inch front wheel for the dirt. I suppose it makes sense for a limited edition Engineering exercise and to help draw attention to the model, but as a standalone model, it doesn't seem to make a lot of financial sense. Those of us who love the NC's layout and other features but who want a bit more power, though, would love it.
 
Wonder if Honda will turbocharge the NC?

Just thinking out loud. Seems like it would be ideal for turbo charging. Lower the compression ratio a bit and put in stiffer valve springs for a 2000 RPM rise in the red line. This would add about 20 HP and about 20 ft lbs of torque and would probably get great cruising gas mileage. Wouldn't take much boost to accomplish this, maybe just a couple of lbs of boost.
 
Nope, it would raise the price out its target price market or price point. No matter if it was turbo charged, people would go 'what, you want how much for a 670cc motorcycle???'
 
It would take more than "stiffer valve springs" to raise the red line by 2000 RPM. It they wanted it to have the normal Honda durability, most of the engine parts would have to be redesigned for such a change.

And as the previous poster asked "Why?" It's a lot easier to buy a CBR600RR if you want a faster bike.
 
Moderator note: Merged similar threads on turbocharging/supercharging.
 
C/R of the NC is a mild 10.7:1. Honda engines last forever, mostly because of their mild state of tune and perfectly balanced crankshafts.........smooth equals longevity. Do you hear that HD? Increasing the C/R will give more power and fuel economy, but the tradeoff is shorter engine life.
My Accord Hybrid has a 13:1 C/R, which is high. No other Honda is that high. My F800 was 12:1 and advertised at 64 MPG. I called its Rotax an angry motor; a very sweet ride.

I would think Honda would bump up the C/R before adding the weight and complexity of turbo. As mentioned, this is no sport bike and I don't see them changing the engine, except what they've already done...going to 750cc.
 
All the components of the engine have to work together so raising the compression ratio is rarely, if ever, done alone. The compression ratio is usually raised because torque was lost at certain engine speeds when they changed to a camshaft with more overlap or larger throttle bodies.

NOTE: the normal way of calculating compression ratio is the volume difference from BDC to TDC. Nowhere in that equation do they consider valve overlap so what may appear to be a very high compression ratio for a certain engine may not be nearly as radical because the intake valve is being held open for much longer than normal.
 
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