There is a little bit more to it than just notching a hole in 90 degree elbows as you want to premote cross over and a scavenging effect not just the gas being exposed to the other side.
The cut on this design needs to be done so the merge
becomes slightly smaller to create the scavenging effect. Try to keep the entry angle at about 40 degrees or under, the exit is not as important.
This is 3" pipe, the cut is 200mm long. Also a shorter longer opening is better than a tall short opening.
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You will see on some mass produced x pipes how they get very hot and burn that's because they are not flowing well.
I am definitely not an exhaust expert,I just spent a lot of time on long boring night shifts talking to a guy named ken who used to work for a motorcycle exhaust manufacturer he also done development for Aussie super car teams he ended up buying the MC exhaust business in the end he also used to talk regularly to an ex formula 1 engineer by the name of Valintine
Here are a few things to think about when working on your pipes according to ken.
There is such a thing as too big, you need a certain amount of gas flow speed to enable siphon effect, also to avoid back eddies in gas flow thru mufflers and bends. Sounds fair
As the gas flows away from engine it cools maintaining gas pressure flow rates can mean that pipe diameter getting smaller can Sometimes be a good thing. Gas flow rate, volume of gas and temperature all interconnect so it is about designing complete systems . Too much tricky math involved for me to get into that whole thing.
Anyway the xpipe shown is a sound design hope it helps
The cut on this design needs to be done so the merge
becomes slightly smaller to create the scavenging effect. Try to keep the entry angle at about 40 degrees or under, the exit is not as important.
This is 3" pipe, the cut is 200mm long. Also a shorter longer opening is better than a tall short opening.
You will see on some mass produced x pipes how they get very hot and burn that's because they are not flowing well.
I am definitely not an exhaust expert,I just spent a lot of time on long boring night shifts talking to a guy named ken who used to work for a motorcycle exhaust manufacturer he also done development for Aussie super car teams he ended up buying the MC exhaust business in the end he also used to talk regularly to an ex formula 1 engineer by the name of Valintine
Here are a few things to think about when working on your pipes according to ken.
There is such a thing as too big, you need a certain amount of gas flow speed to enable siphon effect, also to avoid back eddies in gas flow thru mufflers and bends. Sounds fair
As the gas flows away from engine it cools maintaining gas pressure flow rates can mean that pipe diameter getting smaller can Sometimes be a good thing. Gas flow rate, volume of gas and temperature all interconnect so it is about designing complete systems . Too much tricky math involved for me to get into that whole thing.
Anyway the xpipe shown is a sound design hope it helps
