unequal length runner exh mani

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frank

frank

Club Member
cheers guy,s, the conclusion on the volume needed measures about 300cc (29mm bore x 45cm length)
and there seems to be more of a burble under boost conditions, perhaps as a result of the increased pressure in the exh mani when boosting, resulting in a greater volume differential (20+ psi apparently)
so according to that, the volume will need to be increased?doubled for an N/A manifold ! (i might need test out an expansion chamber design)
 
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frank

frank

Club Member
the 1st N/A mani had too much volume :( nice growl, but not much burble
so we have used some s/s flexi (that i can alter the length of) here,s half a meter of it (you can hear it blow off the joint on the final backfire :D)

PB170068.JPG



 

h701micra

Deactivated Account
Sounds good, nice work Frank :)

Reminds me of those fake dump valves :/... sounds like the real thing but its not

In no way detracts credit from your work :)
 
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frank

frank

Club Member
its given me the chance to cut the loop pipe from the TD04 mani, and do a neater s/steel one instead,
the loop took 300ml of water to fill, and i guess the flexi will be nearer to 500ml/500cc (so we,re not there yet in terms of "sound" :) )
damn cyl # 2 flange has been leaking too eh ! and thats with new factory gaskets fitted, gonna have to copper "O" ring them for boosting i think

PB180096.JPG
 
From looking at this, if I were to get 2 U sections of 1" diameter piping, then this would be easy to replicate? You can weld to the OEM manifold also, which looks pretty awesome.

I like this idea a lot!!!
 
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frank

frank

Club Member
1 stage further with the unequal length mani experimentation now :) the burble one lets the exhaust pulses out in pairs, here is the big-bang version, all 4 pulses exiting together (in theory)

P3230709.JPG
 
1 stage further with the unequal length mani experimentation now :) the burble one lets the exhaust pulses out in pairs, here is the big-bang version, all 4 pulses exiting together (in theory)

View attachment 29278
And there I was thinking you had gone to ground for a while... then you emerge with this!!
Amazing :cool:

But this is lacking one thing..... A video!!!
 
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frank

frank

Club Member
project aborted, sounds cack :( so we,re back to the single loop one ^


 

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Guy

Has gone over to the oily side...
Club Member
Great to see you're still being a mad scientist there Frank :). I read recently that putting a fancy exhaust on a turbo diesel is pointless because the exhaust turbine in the turbo absorbs so much of the energy in the exhaust you'll never get a loud, cool sounding exhaust note.
 

Guy

Has gone over to the oily side...
Club Member
Ha, ha, I had a custom stainless on the 160SR and it sounded proper rude bwoy!
 
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