Cheap Horsepower-Ram air

[Mike Fahrion]

There have been a couple good articles about ram air in the bike 
rags - most by Kevin Cameron.  Kawasaki first put ram air on the zx11 
in 90(?).  I think this was the first on a production bike.  Since 
this time it has been adopted by most (or all) of the japanese bike 
mfgs in their sport bike class.  

Note you must pressurize the fuel supply to the same pressure as the 
airbox or you'll just lean out as you go faster.  

There are definately small gains to be had, although only 
significant at triple digit speeds, the main benefit though is the 
cool air supply.  I wish I could remember Keven C's theoretical power 
gain discussion.  All that I remember was that it wasn't all that 
great, immeasurable at highway speeds, sigficant at 
superbike/racing speeds.  On the zx11 speculation is that its good 
for a couple mph at the top end (176 mph top speed).  I think this is 
the main reason its found on today's sportbikes - that top end speed 
number, though not used directly by the mfg's, is a big part of their 
marketing.

If anyone is interested in Kevin C's article let me know and I can 
put some effort into digging it out of my big box of articles.

A friend tried to add it to his Suzuki RG500 (4cyl, 2 stroke 500cc) 
but had trouble achieving a good pressure balance between the air and 
fuel supply, was leaning out at high speeds, dangerous thing on a 2 
stroke.

-mike
mfahrion at bb-elec.com

> I have been following the various threads on free/cheap horsepower.
> This has got me thinking about ram air induction and cold air induction.
> Now looking at cars like my wifes Audi, where the radiator only takes
> up about half of the grill opening, one could build a 'funnel' to cover
> the rest of the grill for a ram air set up. Seems like this would 
> provide some free power, but mainly at higher car speeds.
> Now if you were to dyno an engine with this set up (like to set up a
> fuel map), could a dyno facility provide a pressurized air source to
> mimic ram air?