Why are the Vincent Egli Headers/down pipes swaged out to a larger diameter? Just asking as to what is wrong with the standard pipe sizes? The exhaust hole size in the head is still standard Vincent size, this is then adapted to a larger 2"? pipe, as the gas leaving the cylinder head is still restricted at source it hardly seems worth the bother ...... or am I wrong?
PT: Exhaust Egli Headers/down pipes
- Thread starter tom wilson
- Start date
Simply for looks........old school pre war type mentality i feel........Everyone thought that by having large pipes that this would help the exhaust gases exit better, but it is incorrect.......smaller pipes increase the gas flow and this causes better scavenging, thus aiding the incoming intake charge. One big downside to the Vincent head is the shape of the exhaust port......it is too big......Having said that, most of these earlier designs were very similar.......So not just a Vincent thing. Larger bore pipes would be better on a larger capacity engine, say 1200 cc plus........
Thanks for the reply Greg. That was also my thinking, it seems a lot of effort just for looks or at best a tiny increase in power.
our pipes on the Goodwood racer are bigger but for a very good reason, who wants too fiddle with that fine thread exhaust nut with the tannoy announcing the next race? fitting those stubs was a great idea
The next road Comet I do will have a copy system
Incidentally a bigger pipe will alter where your power curve will go the Vincent is best against opposition in the mid range
The next road Comet I do will have a copy system
Incidentally a bigger pipe will alter where your power curve will go the Vincent is best against opposition in the mid range
Large bore for flat out high speed work and smaller bore for track work.
I suspect that larger than stock pipes on a road going 998 are probably detrimental to midrange at least.
One would have to do some testing to be sure.
I have tested with my stock 850 Norton Commando. The stock headers on that bike are quite skinny, only 1 3/8".
I tried a set of "big bore" 1.5" headers on the bike. It went measurably slower on dyno hill. Tried up and down on mj size, no improvement. Put the skinny pipes back on, the speed came back.
Having said that, I did use 2" pipes on the 1360. I'm really not sure that they needed to be that large, but they do look good on there!
Glen
One would have to do some testing to be sure.
I have tested with my stock 850 Norton Commando. The stock headers on that bike are quite skinny, only 1 3/8".
I tried a set of "big bore" 1.5" headers on the bike. It went measurably slower on dyno hill. Tried up and down on mj size, no improvement. Put the skinny pipes back on, the speed came back.
Having said that, I did use 2" pipes on the 1360. I'm really not sure that they needed to be that large, but they do look good on there!
Glen
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I hill tested 9 exhaust systems on the Commando. One thing for sure, unless they are abysmal (super quiet stock black caps) the seat of pants dyno is extremely inaccurate.
The Dunstall 2into 1 into 2 system claimed to be " scientifically designed to add 20% more power, no other changes necessary"
It certainly sounded more powerful and it also felt very good on acceleration. Sadly it netted about 5 kmh less than open peashooters at top of hill, every time.
The hill doesn't lie.
Glen
The Dunstall 2into 1 into 2 system claimed to be " scientifically designed to add 20% more power, no other changes necessary"
It certainly sounded more powerful and it also felt very good on acceleration. Sadly it netted about 5 kmh less than open peashooters at top of hill, every time.
The hill doesn't lie.
Glen