Thumper Club Forum

Club House => Chatter => Topic started by: Propellor on June 27, 2015, 08:26:05 AM

Title: Intake pulse tuning
Post by: Propellor on June 27, 2015, 08:26:05 AM

Came across this article. Makes interesting reading.

http://www.autozine.org/technical_school/engine/Intake_exhaust.html

Title: Re: Intake pulse tuning
Post by: JOOLZ on June 27, 2015, 09:04:18 AM

Interesting article, I use a tuned intake in my XBR 31 cm from valve face to intake trumpet

Title: Re: Intake pulse tuning
Post by: Propellor on June 27, 2015, 02:58:26 PM

Quote from: JOOLZ on June 27, 2015, 09:04:18 AM

Interesting article, I use a tuned intake in my XBR 31 cm from valve face to intake trumpet

What rpm does it chime in?

Another thing I learned recently, is that a velocity stack intake shape, in section, is an ellipse. For some reason I had it in my head it was parabolic. There you go.  ???

Title: Re: Intake pulse tuning
Post by: JOOLZ on June 27, 2015, 06:54:03 PM

 The runner is designed to work at between 5700-6400, although there is a 4th harmonic at 7300 but I try not to rev it that hard

Title: Re: Intake pulse tuning
Post by: guest564 on July 02, 2015, 08:39:30 PM

I tried some different intake lengths on my XBR600 with the HRC cam on a dyno and found that the shortest possible intake worked best. I would rev it to 8k with a lightened flywheel, it would pull higher but the power was tailing off so there wasn't any point.

Title: Re: Intake pulse tuning
Post by: CrazyFrog on July 03, 2015, 01:09:49 PM

Very interesting. Same principle as two stroke tuned pipes really.....