the_midwesterner
NAXJA Forum User
- Location
- Evansville, IN
I forgot about this thread, so I figured I would update it.
I ended up doing my own mandrel bent exhaust and I am really glad I did. I ordered up 2 90s and 2 45/180 bends and had 1 of the 45/180 left over. I am very happy with how it came out and it wasn't necessarily hard, just time consuming and somewhat of a pain in the ass. I would say that a pneumatic pipe expander would make this job wayyyy easier. I used the autozone/oreilly's special mechanical expander to create the slip-over and it sucked. Ended up going through 4 expanders total to create the slip fit on 16ga 304 stainless tube.
To anyone thinking about doing it and you have the fab tools, then just do it!!! The most expensive item is the gas, since a new bottle is required. If you go to Gardena Welding Supply, they will let you borrow a bottle with a deposit that they will return to you when you bring it back and the only expense is the actual gas fill. I went with 98% Ar/2% Co2 for $36 on a 55 bottle. You can go with a tri-mix which is helium based but that is exponentially more expensive.
To both of these comments, you are correct, but we are comparing apples to oranges here. You guys are implying that creating a more turbulent environment for the expelled gasses won't make a difference at the primary, which is correct. The way this is different is that all of those changes occurred pre-collector. All of my changes would be post collector. I wanted the least amount of turbulence introduced into the exhaust post collector to have the highest possible laminar flow.
I agree that adding a more turbulent environment to already turbulent expelled gas is not ideal, but no huge difference is made unless the primary overall area is significantly reduced. I wanted to take advantage of the negative pressure created post collector after a cylinder expels on the exhaust stroke in which a scanvenging effect is created and hopefully maintain that speed up through the 2-1 merge collector further down the run of tubes. The way I am looking at it is that I spent all the money to cam an engine and purchased good flowing headers, I might as well do anything I can to make sure the engine breathes the best it possibly can.
I ended up doing my own mandrel bent exhaust and I am really glad I did. I ordered up 2 90s and 2 45/180 bends and had 1 of the 45/180 left over. I am very happy with how it came out and it wasn't necessarily hard, just time consuming and somewhat of a pain in the ass. I would say that a pneumatic pipe expander would make this job wayyyy easier. I used the autozone/oreilly's special mechanical expander to create the slip-over and it sucked. Ended up going through 4 expanders total to create the slip fit on 16ga 304 stainless tube.
To anyone thinking about doing it and you have the fab tools, then just do it!!! The most expensive item is the gas, since a new bottle is required. If you go to Gardena Welding Supply, they will let you borrow a bottle with a deposit that they will return to you when you bring it back and the only expense is the actual gas fill. I went with 98% Ar/2% Co2 for $36 on a 55 bottle. You can go with a tri-mix which is helium based but that is exponentially more expensive.
Or mandrel bent.....
To both of these comments, you are correct, but we are comparing apples to oranges here. You guys are implying that creating a more turbulent environment for the expelled gasses won't make a difference at the primary, which is correct. The way this is different is that all of those changes occurred pre-collector. All of my changes would be post collector. I wanted the least amount of turbulence introduced into the exhaust post collector to have the highest possible laminar flow.
I agree that adding a more turbulent environment to already turbulent expelled gas is not ideal, but no huge difference is made unless the primary overall area is significantly reduced. I wanted to take advantage of the negative pressure created post collector after a cylinder expels on the exhaust stroke in which a scanvenging effect is created and hopefully maintain that speed up through the 2-1 merge collector further down the run of tubes. The way I am looking at it is that I spent all the money to cam an engine and purchased good flowing headers, I might as well do anything I can to make sure the engine breathes the best it possibly can.
