gr8ging
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| posted on 16/4/08 at 05:41 PM |
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air box volume
Does the volume of air in your air box make a difference to the running/bhp of the engine?
I can't fit the original air box off of my zx9 so was looking to make a box and have a remote filter. Done a search on here and seen some good
systems you guys have made. But just wondered if the Volume of air is a consideration?
Cheers
Weaseling out of things is what separates us from the animals.... except the weasel.
You couldn't fool your own mother on the foolingest day of your life with an electrified fooling machine!
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DIY Si
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| posted on 16/4/08 at 05:58 PM |
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yes, it is vital! As is the distance of the far side of the box from the carb openings. Have a search, or U2U Smart51, his thread mas most of the best
advice in it.
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smart51
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| posted on 16/4/08 at 09:35 PM |
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Volume has several effects. One is the RPM at which the air box resonates. It is the volume, length of inlet port and diameter of inlet port that
affect the speed.
Another is the size of the resonant effect. At your chosen RPM, the airbox forces air into the cylinders giving a bit more torque. Small boxes have
more effect. The down side is that at 2/3s that engine speed, you get less air in your cylinders.
The third effect is the restriction in breathing. Big air boxes are better as a single gulp of air into the engine reduces the pressure in the box
less. Of course, if you have a big enough inlet then your air pressure recovers before the next cylinder opens.
I found that the R1 air box was quite restrictive. Back to back tests showed that an inlet port area equal to 3 times the area of a single throttle
body or carb had no noticeable restriction in airflow but a smaller pipe needed a smaller main jet to run right.
Interestingly, above the resonant RPM, the inlet port becomes "accoustically opaque" in theory, blocking some of the induction roar.
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