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. |
![]() Sun Aug 19, 2018 9:20 pm
Hooked
GTS 250
Joined: 26 Apr 2008
Posts: 307 Location: California |
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jerryd wrote: 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. |
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. ![]() |
![]() Mon Mar 29, 2021 4:49 pm
Ossessionato
GTS300 Super 2015 Blue, GTS300 Super 2018 White
Joined: 01 Nov 2005
Posts: 3059 Location: Sydney, Australia |
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Ossessionato
![]() GTS300 Super 2015 Blue, GTS300 Super 2018 White
Joined: 01 Nov 2005
Posts: 3059 Location: Sydney, Australia |
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😜 ![]() |
![]() Tue Mar 30, 2021 1:27 pm
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GTS300 Super 2015 Blue, GTS300 Super 2018 White
Joined: 01 Nov 2005
Posts: 3059 Location: Sydney, Australia |
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Ossessionato
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Posts: 3059 Location: Sydney, Australia |
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.
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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. ![]() |
![]() Thu May 27, 2021 2:45 pm
Hooked
GTS 250
Joined: 26 Apr 2008
Posts: 307 Location: California |
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Robert12345 wrote: 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. |
![]() Thu May 27, 2021 5:18 pm
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GTS300 Super 2015 Blue, GTS300 Super 2018 White
Joined: 01 Nov 2005
Posts: 3059 Location: Sydney, Australia |
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Ossessionato
![]() GTS300 Super 2015 Blue, GTS300 Super 2018 White
Joined: 01 Nov 2005
Posts: 3059 Location: Sydney, Australia |
![]() Thu Jul 08, 2021 1:32 am
Molto Verboso
2019 Supertech (EURO3/APAC)
Joined: 17 Nov 2020
Posts: 1391 Location: Batmania aka Melbourne, Australia |
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Molto Verboso
![]() 2019 Supertech (EURO3/APAC)
Joined: 17 Nov 2020
Posts: 1391 Location: Batmania aka Melbourne, Australia |
Robert12345 wrote: 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. ![]() with air filter in place ![]() behind the air filter (and zoomed in a bit) |
I would not recommend cutting the pipe like seen above. flow into any pipe can be increased significantly by adding a velocity stack on the entrance. thus eliminating the velocity stack as seen here was not a good idea. when the sound of intake is changed it can be misleading to whether or not there was a performance increase.
interesting there are two completely different box designs Last edited by jerryd on Thu Jul 08, 2021 3:23 am; edited 1 time in total |
![]() Thu Jul 08, 2021 2:54 am
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Posts: 3059 Location: Sydney, Australia |
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Posts: 3059 Location: Sydney, Australia |
Steelbytes, that filter does not look at all conducive to good air flow. Robert12345's mod looks good, and I have ordered the longer induction pipe to try it. But if it increases air flow much I may have to fit a larger injector, or install my Malossi Force-Master and set the mixture richer.
In my old-type filter box the induction pipe extends almost all the way to the outer box lid, with just a small gap for air to enter it. And the inside of the lid has a raised pattern on it which will also create turbulence. |
![]() Thu Jul 08, 2021 2:06 pm
Molto Verboso
2019 Supertech (EURO3/APAC)
Joined: 17 Nov 2020
Posts: 1391 Location: Batmania aka Melbourne, Australia |
|
Molto Verboso
![]() 2019 Supertech (EURO3/APAC)
Joined: 17 Nov 2020
Posts: 1391 Location: Batmania aka Melbourne, Australia |
![]() Thu Jul 08, 2021 2:12 pm
Molto Verboso
2019 Supertech (EURO3/APAC)
Joined: 17 Nov 2020
Posts: 1391 Location: Batmania aka Melbourne, Australia |
|
Molto Verboso
![]() 2019 Supertech (EURO3/APAC)
Joined: 17 Nov 2020
Posts: 1391 Location: Batmania aka Melbourne, Australia |
Mike Holland wrote: Steelbytes, that filter does not look at all conducive to good air flow. It was getting dirty very quickly because of some poor piaggio design where the air inlet would suck some air from the engine bay which of course is dusty on gravel roads. Had to use some foam to seal a gap before it would suck from the correct place which is under the front of the seat where the helmet pegs are |
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