Terry makes some good points. My tendency is to keep things simple and brief. I know I can always rely on you folks to extract the balance of my thoughts :-) Maybe I should have said the constant throttle flow will achieve stasis. So, how about a CV airbox inlet ? I suppose I'll add that to my project list. Mike Oberle /1990 Shiny-Black MonkeyMax VMOA #1355 / AIM - "Injuhneer" -----Original Message----- From: V-Max [mailto:[EMAIL PROTECTED]] Sent: Thursday, November 02, 2000 3:58 PM To: [EMAIL PROTECTED] Subject: V-Max V1 #1018 ---------------------------------------------------------------------- Date: Thu, 2 Nov 2000 08:36:09 -0800 (PST) From: Max Rider <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Subject: RE: [Vmax] Air box mods Message-ID: <[EMAIL PROTECTED]> The box on the Max is 7 liters, not bad but ideal would be 12. CV carbs like to operate in still air. I agree that a larger box helps respond to an initial gulp of air that the engine needs when the throttle is whacked open. However, the pressure will not equalize if you maintain full throttle. The airbox openings are too small for top end performance. As a rule of thumb for high end performance you want an opening at least equal to the area sum of all the carbs openings. Sportbike did a ram air test on a a number of sportbikes awhile back and used a non ram air zrx1100 as a benchmark. They found that the zrx1100 (which has an airbox set-up similar in size to the Max) went into a negative 25mb pressure under full throttle. This means there was a vacuum in the airbox resisting flow into the engine. This equates to a loss of 3+ horsepower. My own tests on a homemade flowbench confirmed the restriction of the airbox...dyno tests show the biggest difference. Roy Richards jumped 6 hp by dumping the airbox and going to individual filters. The same result with open filters may not be the same at high speed because the disrupted airflow under the dummy cover but it does illustrate that the Max likes to breathe... The problem with opening up the airbox is that it upsets the pressure differential that the carb slides rely on to open. The lower the vacuum the harder it is to raise and properly control the slide rate. The ideal airbox would have small openings at low rpms to enable the carb slides to rise quickly and then have a flapper open at high rpms to better feed the engine. Several current bikes have this... cheers, Terry ............................................. To unsubscribe go to http://www.sayegh.org/unsubscribe.htm .............................................
