Suzuki Quadracer HQ

LT250R Quadracer => LT250R - Engine => Topic started by: James Dandy on September 21, 2013, 09:34:36 pm

Title: Re: Dead end exhaust port?
Post by: James Dandy on September 22, 2013, 05:57:24 pm

Thanks motorgeek. Your the real  (Y) deal dude. Great explanation. I truly understand now. I'm just gonna match the 2 cases right there, and match the ports. Should help the resonation, which if I understand correctly, helps to draw the fresh fuel/air in to the cylinder.

Title: Re: Dead end exhaust port?
Post by: MotorGeek - Jerry Hall on September 22, 2013, 01:40:11 pm

The natural frequency of a Helmholtz resonator depends upon the volume of the flask and the diameter and length of the tube attached to the flask.

A tuned two stroke pipe is a sophisticated Helmholtz Resonator.  The exhaust port and the first section of the pipe (head pipe) where the angles are small, can be compared to the tube attached to the flask of a Helmholtz Resonator.

Suzuki's power valve system on the LTs adds volume to the head pipe and the exhaust port.  Adding length and or volume to a Helmholtz resonator lowers the natural frequency.  Lowering the natural frequency of the tuned pipe is the same thing as tuning the pipe to be in tune at a lower RPM. 

Suzuki's power valve system essentially fools the engine into thinking that there are two different pipes.  The engine runs on the pipe that is tuned for low end up to about 5500 to 6000 RPM and then is quickly switched to the pipe that is tuned for good power above 6000 RPM

Title: Re: Dead end exhaust port?
Post by: Dezsled on September 22, 2013, 08:18:31 am

How the qualitative explanation works in relation to the Quadracer engine

Goes right over my head whooooosh

Title: Re: Dead end exhaust port?
Post by: James Dandy on September 22, 2013, 08:13:26 am

Haha! I knew youd figure it out motorgeek! Helmholtz resonator! Who the he'll is helmholtz? Should I polish this resonator up? I'm guessing it needs to be smooth for the soundwaves and whatnot??

Title: Re: Dead end exhaust port?
Post by: Rider414 on September 22, 2013, 08:09:09 am

Helmholtz resonator!!

 (Y)

Title: Re: Dead end exhaust port?
Post by: MotorGeek - Jerry Hall on September 22, 2013, 07:48:54 am

Quote from: James Dandy on September 22, 2013, 07:34:12 am

I just can't figure out how it would do anything since when it comes out of the case, and towards the powervalve, it just runs into a dead end, that is unless somebody at the factory forgot to machine mine.
I wonder what would happen if I opened the dead end  up into the exhaust valve body?

It is the tank for the Helmholtz resonator better known as part of the power valve tank.  DO NOT grind it to connect it to the exhaust port, otherwise your engine will behave like the power valve is open all of the time.

Title: Re: Dead end exhaust port?
Post by: James Dandy on September 22, 2013, 07:34:12 am

I just can't figure out how it would do anything since when it comes out of the case, and towards the powervalve, it just runs into a dead end, that is unless somebody at the factory forgot to machine mine.
I wonder what would happen if I opened the dead end  up into the exhaust valve body?

Title: Re: Dead end exhaust port?
Post by: Dezsled on September 21, 2013, 11:31:30 pm

That cavity is what the power valve uses to enhance the lower rpm power transition of the powerband into the mid range/top end

Title: Re: Dead end exhaust port?
Post by: James Dandy on September 21, 2013, 11:00:42 pm

Come on guys! Somebody has to know something about this mystery port!

Title: Dead end exhaust port?
Post by: James Dandy on September 21, 2013, 09:34:36 pm

http://i.imgur.com/NCJI3hO.jpg
I still can't place images in the right spot, but hopefully you all can see this.
What was this port for?
Could there have been plans for a 3way exhaust valve?
Does anybody know if suzuki's factory race engines had any special work done to this area?