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Discussion Starter · #1 ·
Is it feasible?

Having a dino run soon.

For not a lot of money ,Black & Deckers finest blasts up to 260mph.
 

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The only way to be sure it to do a high speed road run with a pressure sensor just in the intake of the fairing. If your leaf blower can duplicate this then yes.
 

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It depends if you want the blower for cooling or ram air. To be honest with a supercharged engine ram air isn't a big factor, unlike temperature. Just ensure that the dyno' room is not a closed cell.

The stock exhaust's steel headers on my H2 were cherry red when I first dyno'd it in 2015 and that was with a huge fan in front of the bike.
 

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Discussion Starter · #6 ·
This would be specifically to record or debunk any ram air effect.

Back to back pulls.One with and one without the leaf blower.

Thought I'd try it as bike on dyno for sc3 gears and new filter fettling.

Debating removing the front intake grill as its an airflow restriction?
I'm aware of its purpose.
 

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99.9% sure you'd be wasting your time. The holes in the air tube next to the forks will bleed positive pressure from forming in the rest of the tube. Block the holes and maybe there will be something there to find. the best test would be to put a sensor/logger in there and actually drive it fast with the holes plugged. You may only get +.1 atmospheric additional pressure but it is not nothing.

I don't think it is a true statement that ram air wont help much. If you think of the SC compressor as a pressure amplifier then a small change at the front end means a bigger change at the back end. Also the higher pressure at the front means its less likely the compressor would stall ...so more positive pressure in the air intake tube MAY help if there is any stall from SC gear upgrades or enlarged compressor wheels at top rpm's. If I was in the racing game this is an area I would look into.
 

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Discussion Starter · #8 ·
Thanks.
I'll have a dyno run done with and without taped holes.
Likewise with and without the blower with taped and untaped holes.

Will report back.
 

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Kawiguy454, I don't think the supercharger multiplies pressure, it merely increases the input pressure by a fixed amount. Add the inlet pressure to the boost value, don't multiply it. This answer will vary too because as the input tube pressure varies the air density varies with it and the efficiency of the compressor changes.
 

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Very generally If you can eek out any additional ram air pressure on the inlet side it will be stepped up in the compressor for a net performance positive. some carefully thought out tests should disclose the measurable benefits.

I've posted before, IMO the 6 X 1" holes are there in case a plastic bag manages to cover the intake at speed. Secondarily shunting the inlet to atmospheric pressure simplifies fueling concerns. A search for "ram air pressure vs speed" yields some interesting results.

... for NA engines.
https://www.sportrider.com/ram-air-test#page-12
...Plotting pressure vs. speed gives a graph that has theoretical pressure rising with the square of speed, and this is why ram air has much more effect at greater speeds. For a speed of 150 mph, the resulting maximum theoretical pressure would be about 27mb (approximately .4 psi).

..SC dragsters
https://www.enginelabs.com/engine-tech/engine/high-speed-engine-tuning-factoring-ram-air/
 

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What you don't want is the impeller blades scavenging for air. That's when there is a pressure drop across the blades where some reverse flow can take place to fill the low pressure void. The issue can be picked up as a very low sound emissions that can be below hearing range. This also creates damage by collapsing areas of air containing moisture as all air does to some degree. KHI engineers are very smart, knowing that some moisture can become super heated and in the wrong place very destructive. Just making the impeller spin faster doesn't equate to a linear increase in boost. I may sound a bit technical but a multi billion dollar company doesn't take a guess at the operating parameters of the engine or supercharger combined. So much for a lot of horse power mods for the older models, same exhaust for the 2019 model..... Seems we are doing a hit and miss job trying to duplicate KHI's R&D department. They already know the TBF vs HP and we are just guessing.
 
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