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Exhaust bung - effect on performance

SmegHead

SmegHead

Messages
124
Has anyone done any back to back dyno runs with an exhaust that has a tip baffle\bung\db killer are whatever you want to call it, fitted and then removed?
I'd be interested in seeing what the difference was with the thing fitted on these engines, the majority of info I can find is about bikes where these are extremely common.

The assumption here is that people have mapped for baffle-out and then throw the bung in when needed.

Cheers
 
Cheers. The bung I have is the usual type and came with the exhaust (tdi 3"). The one in the link might be better but it looks bloody terrible :)
It's in for a remap next week so I'll see if I can get a final run done with it fitted for comparison.
 
Doesn’t look pretty, but it’s far less restrictive and better at sound suppression. No one cares what the car looks like on track, only how fast you’re going.


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SmegHead said:
Cheers. The bung I have is the usual type and came with the exhaust (tdi 3"). The one in the link might be better but it looks bloody terrible :)
It's in for a remap next week so I'll see if I can get a final run done with it fitted for comparison.
Click to expand...
I have the same exhaust so would be keen to see your results. On a recent track day I did 94 (I think) without silencer and 88 with. Which is good as its just below the limit for Thruxton.

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All I know is the Spoon N1 I've got sounds like a jet with the silencer bung in, changed the reading from 106db down to 98db on a static sound test, limit was 105db which is what it made in the morning, before the manifold needed welding back together :rolleyes:. No idea about power but as above I'd think it restricts it somewhat.
 
Last edited by a moderator:
Lewisgame said:
Doesn’t look pretty, but it’s far less restrictive and better at sound suppression. No one cares what the car looks like on track, only how fast you’re going.


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Click to expand...

True, though I may be tempted to 'bung' it in (groan) on the road too if the mood takes me. Having what looks somewhat like a steampunk enema up the cars chuff isn't ideal.

It's not over the top loud now but if it only drops a few bhp and doesn't cause it to run too rich in open loop then I may let it stay in. I can then take it out for absolute max performance, as the car's boosted having it slightly richer isn't such a bad thing. Rather that than map it with the baffle in then it runs lean without.

I thought about using dual maps if there is a big difference in output but I won't have that option as the second map is going to be used for water meth tables (at least I assume this is how this is done, haven't confirmed that detail yet; a long list of detail stuff to ask when I drop it off).

Anyway I'll update when it's been sorted, hopefully with multiple dyno runs. Ideally I'll have readouts for as the car was with a 2.5" Teg pipe, then with the 3" pre remap, then 3" mapped, the same with baffle, then a meth kit run. This all depends on time constraints on the dyno though the only additional thing above a normal session will be the bung run so hopefully a goer.
 
I could feel the restriction on mine (3" solid fabs system with generic 3" DB trap). Especially at high RPM. Better than being kicked off a trackday though
 
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