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.

Hello,

I have a 2019 vespa gts 300 hpe.
Read about the air box mod.

The airbox i have is the same as the older model except for the longer hose. Not sure why they made this hose longer, cant see why this would be better.

Think im going to do the V on the box inlet, also tempting to do something about that long hose.

Foto

It looks like air flow could be improved by cutting off some of that pipe, but don't be fooled. I tried that on my filter and the result was disastrous. That is a tuned length for induction pulses, and cutting it might have the wrong result.

Please experiment and let us know the results, but if you attack that pipe, be prepared to buy replacement. Just opening up the snorkel might be all you can mod out of that filter. The Malossi red filter element also helps, but I didn't like the induction noise that came with it. If you get really serious about it, consider replacing the whole filter with a K&N one.

Did only the box inlet, didnt had a spare pipe so left that alone, maybe in the future, but i also think vespa probaly had a reason to make the pipe longer.

Just ride 20km and im not unhappy.
Its not really faster looking at the 0-60 time, from the start is feels faster and the gas response feels better. It makes a bit more noise but that i like. It feels like the bike is happier now and can breath normal😜

That is about how much mine is cut away. Some guys drill holes all along the snorkel. Depends on how likely you are to get water splashed up there. I avoid riding in the rain if at all possible. Have a car for that!

Maybe the snorkel is also to keep gravel out. If you only ride on smooth dry roads I guess the snorkel is not needed at all.

Very soon going to adjust the inducation pipe. First going to cut to the halve of the airbox and later then might all of it. The boxvolume is now made less becouse of the longer induction pipe(not even half of the airbox is used). This could be for noise reduction or it really has a reason and cutting it, is going to make things worse, we will see. If not okey i just fit a new one.

Well today i have modded the pipe.
I had the idea to first cut half of it, test it and then all of it.

So i cut halve of it as seen on the foto and tested it. Make sure the pipe and the box is clean after.

I have not experienced any negatives. Its makes a bit more noise and on full trottle is feels more aggresive/powerfull.

If i had to chose for this or orginal i would chose this.

Maybe in the future i will do the whole pipe, but this is fine for now and maybe all of it is too much.

Foto

Picture is upside down