Modern Vespa

Thank you for the information Mike.

Additionally, I ground down the wquare pieces that probably disrupts smooth flow of air. Nice mod.

I read through this whole thread. my first thought is I wish I hadnt chucked spare airbox I had for my project 300. my second thought is changing the shape of the U in the divider is likely doing nothing. its simply not a restriction there. all the extra flow is coming from reducing the pressure drop across the rectangular channel. the biggest improvement would be seen by cutting it open nearer the entrance. as opposed to the v mod near the tail end.

I am also pretty certain the ECU is not capable of correcting for the extra airflow. the 02 sensor feedback can only correct for idle and light cruise conditions. 02 feedback is ignored during acceleration. the change here is likely just not big enough to cause a huge a/f swing.

I think I will mod mine by making the whole channel bigger with rounded edges at entrance and exit. this should maintain its original design which is to distribute air to the filter evenly by dumping air at top of box. and second to insulate my larger channel with sound deadener . I will snap pics and report my results.

You might like this thread: http://www.apriliaforum.com/forums/showthread.php?243793-Project-Vespa-300-SUPER-(should-end-up-living-up-that-name)

I was putting off modding my box. Since installed this new exhaust and maybe before I have been battling detonation WOT. A few days ago I installed a 170cc injector to replace the factory 158cc. It was immediately noticeable difference with the extra fuel. and it took several days of driving around till it felt as fast as it was. So I figure it was safe to lean it out some with the airbox mod. only to find I was running around with no dang filter. dont think I will be able to ad to seat of the pants difference.

My attention was on the channel only. and the entrance seemed like a bad design. Would like to talk to engineer on why they have that little lip that looks like all it will do is cause turbulence at the entrance. I used a heat gun first to bend it out of the way. then I ground the lip all the way around so the glue would have something to stick too. on the channel itself I heated the end and flared it. and cut a smallish relief hole. I think flow through channel is greatly improved. I will be ordering a malossi filter as I miss the airbox sound. was kinda depressing taking it for its first spin with a filter onboard. way to quiet.







and at same time this was done my friend was doing his beo 500 box. I was floored at how restrictive the intake snorkel is on this 460cc 39hp bike. it wouldnt pass a nickel. he got much more seat of the pants power.