On a longer manifold with a high rpm the exhaust is already closed before the wave is comming back, the a lot of fresh fuel is lost in the exhaust giving less in the engine and so a less powerfull combustion.

Also read on the bottom of the page: Manifoldsi for 3,5cc on-road Engines - NOVA | Novarossi World - NOVAROSSI WORLD

I'm not sure where you got that book, but I would return it! :lol:

When the length is too short you get a power surge in the bottom end due to the puls returning too soon pushing the mixture back down the transfers. Even if you don't get erratic behavior, you might still see the buildup of carbon at the transfer ports on the sleeve.
If it's excessively long you will notice how the engine just falls flat on its nose at the top end, the power just drops of a cliff due to not getting the needed mixture to sustain power.

Oh here we go again..... :rolleyes:

And he calls himself a pro driver.......

oh ok u guys r so right!! thanks so much.....!!

Somehow I'm guessing we fell short of getting through... :lol:

next time u at the track run a tank with the long get best lap time, and run a tank with short and see the lap times, sometimes think outside the box. Didn't daddy ever say son don't believe everything u read... let me know maybe its just my car maybe its the demons did it!!!:D:D:D

I contemplate on most everything I read, to be able to take things further then the book I'm reading. That's a reason why I see some things differently then other people working with engines.
Please, give me the name of the book you read, if you don't mind.

I’d like to know what book it is too. It’s got some silly writings in it that I’d like to get a look see at. When it comes to 2-strokes, it’s all about length, shape, and volume of the exhaust system. Together it makes an engine run poorly, okay, greatly, or superbly.

Ask the boat guys how they tune their engines’ exhausts for high rpm.

Lap times will depend on layout of track...on a flowing top end track your times will be much slower...just listening to rpms down the straight and you will know that long limits rpm.

and exactly my point I didn't want to get into names but u be very surprised to see a top us drivers running it the other way around again try it see your times.

u ok? lol lap times depend on layout ? don't make a difference what the track is we are not comparing lap times from different tracks u comparing your times on the same track hello!!! wake up!!!

at least u keep an open mind and are willing to try, u don't need a book very simple try it both ways compare times period...

Ralph could be right if you do not know how to set the gearing and are way off.

Yes, I try to always keep an open mind, draw conclusions and try to get the big picture. But I would still like to read what you have read, do you at least have a name on the book?