hello

 

In the market there is a lot of box ehaust that can be use in gs engine.

 

i found this dyno with big box 1.0. My question is what would be the diference if i use BBT or even lth box or sip road?

 

http://blog.scooter-center.com/auf-dem-pruefstand-vespa-vn125-mit-bgm-pro-bigbox-teil-2/

 

i buy grand sport piston and i will have some work with porting in exhaust and inlet window.

 

my question is what is timing that gs cylinder will play good? exaust 165º? transfer 120º? inlet 150º?

 

greetings from portugal

I would guess there will be very little difference in performance. The dynos i have seen showed that BBT revved a little less than sip road and lth box. Lth box is made of thicker material than the others.

hi

 

my doubt is because gs engine is piston ported and the exhaust from largframe need to be extended near by manifold maybe +- 4cm.

 

regards