diy exhaust project
10-17-2015, 05:16 PM
#31
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Kindof - if only one side is running. 
Net volume of air is the same, the x pipe in my design is strickly to mix the sides for a better sound - no claim or intention to increase HP EXCEPT the end plan is to use 3" pipes dowstream from the turbo - and i am 1/2 way there. That increase in diameter will make a difference. This winter is about taking the system from the reducers and bring it to 3" all the way out. The big challenge is the i want a quiet and loud mode, and have the butterfly valves ready to go. Weld on!
Net volume of air is the same, the x pipe in my design is strickly to mix the sides for a better sound - no claim or intention to increase HP EXCEPT the end plan is to use 3" pipes dowstream from the turbo - and i am 1/2 way there. That increase in diameter will make a difference. This winter is about taking the system from the reducers and bring it to 3" all the way out. The big challenge is the i want a quiet and loud mode, and have the butterfly valves ready to go. Weld on!FlatSix your system looks good and clean!
Boosted - there's lots of controversy regarding x pipe/h pipe/prochamber etc as to any benefits.. A lot of current cars do use a merging type system though. I thought at the least, you will have 2 outlets to potentially decrease the back pressure (past the merge) vs 1, so especially if you are going to keep the mufflers, one bank now has 2 mufflers and 2 pipes to exit from, which should decrease the back pressure. Decreasing back pressure may not be as useful for NA cars but theoretically not a bad thing for turbos.
My reasoning anyways.
Boosted - there's lots of controversy regarding x pipe/h pipe/prochamber etc as to any benefits.. A lot of current cars do use a merging type system though. I thought at the least, you will have 2 outlets to potentially decrease the back pressure (past the merge) vs 1, so especially if you are going to keep the mufflers, one bank now has 2 mufflers and 2 pipes to exit from, which should decrease the back pressure. Decreasing back pressure may not be as useful for NA cars but theoretically not a bad thing for turbos.
My reasoning anyways.
10-17-2015, 07:03 PM
#32
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10-18-2015, 10:49 PM
#33
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Got a little more done this weekend.
Have everything fitted to my liking. I can weld okay when it's a straightforward joint but have difficulty with corners and angles, especially when the angles are such that I can't fit the torch in ... I have to be more careful with the order I'm putting things together to avoid tight spots. Also have to not get lazy and clean welds prior to laying another bead, welds don't look pretty in some areas as the weld pool doesn't come together very well if not cleaned (same as aluminum although not as bad).
Made heat shields for the driver's side turbo, need to make the shield for the other side yet. Then onto trying to make parts for the heater ducts, not much room there.
Managed to fit things so it is not the lowest part of the car!
Have everything fitted to my liking. I can weld okay when it's a straightforward joint but have difficulty with corners and angles, especially when the angles are such that I can't fit the torch in ... I have to be more careful with the order I'm putting things together to avoid tight spots. Also have to not get lazy and clean welds prior to laying another bead, welds don't look pretty in some areas as the weld pool doesn't come together very well if not cleaned (same as aluminum although not as bad).
Made heat shields for the driver's side turbo, need to make the shield for the other side yet. Then onto trying to make parts for the heater ducts, not much room there.
Managed to fit things so it is not the lowest part of the car!
10-19-2015, 02:25 AM
#34
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If the pipes are equal length on both sides to where they join, then ideally the two sides will be out of phase due to the alternate banks of the engine taking turns at ignition, and thus you get a much even engine sound. Scavenging effects are much harder to calculate, it depends on lots of dynamics and design of how the flows are combined, so I think it's more of an art than science. Really hard to measure the impact of scavenging too.
Then again, I could be wrong . ...
Cheers,
Mike
10-19-2015, 02:56 PM
#35
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I was thinking of each cylinder firing as a individual event so one cylinder firing has two exhausts to exit but you're probably correct, especially with the turbos and it's just continuous flow with some pulses that are attenuated with the turbos.
I guess I should fire it up before putting the bumper etc back together to see how it sounds..
I guess I should fire it up before putting the bumper etc back together to see how it sounds..
10-21-2015, 01:44 AM
#37
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no exhaust tips yet, enclosed garage. sounds okay, little loud, deep throaty, has lost the motorboat sound completely. I'd say not as loud as muffler bypasses. Will have to see how it sounds outside and with fly by.
(pls ignore the mess!)
(pls ignore the mess!)
10-21-2015, 03:04 AM
#40
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I think it would be interesting if I came over with my car and we can compare the tones - from the video, yours does not sound as deep but there is so much variability in recording equipment that its too hard to tell.
How about this weekend?
Cheers,
Mike
How about this weekend?
Cheers,
Mike
10-22-2015, 12:21 AM
#42
Nordschleife Master
Sounds great ... well done!
10-22-2015, 02:34 AM
#43
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10-22-2015, 07:44 AM
#44
Drifting
Originally Posted by Basal Skull
Unfortunately, working this weekend. Next weekend is possible though!
I'll jump in on that if you guys do meet up. Would like to hear the comparison too.
