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G11 Headers.

Charlie J

Charlie J

Cruisin' Guzzisti
Joined
Jun 19, 2009
Messages
162
Location
Taree, Australia
Why are the header pipes different lengths? Surely this is not a case of form over function? Wont this stop them from working "together"? The double walled pipes look all lovely and shiny (until they get "Liver Spot")and would keep exhaust gas hot for better flow,but how much heat do they return to the head? Would a pipe to head clamp with more surface area be better? If I was to fit a conventional 2 into 1set of headers of equal length(header either side of sump) what do you reckon would happen to the torque/H.P. curves? Does it not really matter on a "Road Bike"?
Why do my posts here have a different icon to the rest? is this some sort of "Idiot Alert"
Curiosity, what a wonderful thing! I am buying Todds ECU reflash,PCV and A/T next week which will see me broke for a while but I still may have more money than sense!
 
Charlie J said:
Why do my posts here have a different icon to the rest? is this some sort of "Idiot Alert"
Click to expand...

I believe it indicates the topics you have posted on, for you only. Try replying to another post and watch the icon change.
 
Every Guzzi has headers of different lengths. It is necessary to get even at the crossover. If you look at the bike from above, you will see that one cylinder is further forward than the other. Also that small difference in length makes little to no difference in street use. Pipe length isn't as critical on a 4 stroke as it is on a 2 stroke.
 
hmnmmm . . . I actually got a few more of the "liver spots" but on just the left header. It had a few before but I installed the ECU upgrade and a bunch more appeared. However the bike runs better and the "pop" on deceleration with the GT-Rx pipe is gone :)

I don't have the PCV or the Autotune . . . maybe those items would make a difference. I'm not concerned or really care all that much to be honest. It is just cosmetic after all.
 
What I would like to know is why is the L.H.S. 90 mm (roughly 3 1/2 ") shorter than the right? Wont this make the pipes "scavenge" at different rpms and Id have thought this would affect vacum. Although Ive been told Im being anal about my vacum issues and we should move on from "Tuning for Speed"but I cant see why you would deliberately put a relatively straight pipe whith a curvy one,surely they cant have the same flow rates?
 
Charlie J said:
What I would like to know is why is the L.H.S. 90 mm (roughly 3 1/2 ") shorter than the right? Wont this make the pipes "scavenge" at different rpms and Id have thought this would affect vacum. Although Ive been told Im being anal about my vacum issues and we should move on from "Tuning for Speed"but I cant see why you would deliberately put a relatively straight pipe whith a curvy one,surely they cant have the same flow rates?
Click to expand...

It is called form over function. Design team won that one, not the engineers. Get over it and ride the bike.
 
There is a difference in timing between the firing of cylinder one and two then the timing between cylinder two and one, so there is no symmetry to be maintained.
 
GuzziMoto said:
There is a difference in timing between the firing of cylinder one and two then the timing between cylinder two and one, so there is no symmetry to be maintained.
Click to expand...
Having equal length headers means NOTHING when the timing between the two cylinders is not equal.
There is undoubtedly an optimum header length for each cylinder with a 90 degree v twin but it is likely not the same length for each cylinder.
But there are ALWAYS other factors in how an exhaust system is made for a production bike, and production costs, looks, and how well it fits, usually come before maximum performance.
I would love to fit a proper merge collector on my Griso, but what it costs and making it fit are likely large hurdles and what I will get out of it probably is not a huge improvement. But maybe someday I will get around to it. Or more likely I will fit one up to my Daytona.
 
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