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-   -   Subaru beetle exhaust (https://www.volkszone.com/VZi/showthread.php?t=1587879)

StuF 23-07-2019 10:06 PM

Quote:

Originally Posted by Big Al (Post 16555487)
That looks a nice exhaust however I don't mean this as a criticism but if looking for maximum bhp it doesn't seem a very well gas flowed solution, much like an original bug box making the exhaust gas do an unmerged full 90 in there??
I'm no expert just saying what I'm seeing so possibly complete balls and he's the expert :lol:
I guess as mine is a turbo the ideal solution may be different as I just need the gas out easy as poss to minimal presume after the turbo. (And I know I'm turning mine 99 degrees but there are x2 3'' outlets!!). However merged bug headers are merged for a reason and the style like that are known for less performance advantages in the bug world are they not?
Maybe it's a toss-up between quiet and performance?

Al - its a fair point and something I did ask Mike about after he crafted the exhaust, apparently the headers do merge however it is done inside the large and wide back box which isnt as simple as it would appear. Think it is one of his secrets how he crafts the boxes - they aren't the usual baffle plates and wadding found in some systems.

Ive been out in a few EJ25 powered buses/bugs and mine is no slower or faster than any of the others however is much more civilised than any of the other options I sampled (Fellows, Custom, RJES and mixes in-between of longer/merged/unequal/equal length headers and so on)

Ive the ground clearance required and the wife is happy with the noise when cruising the motorway - even upto some silly (overtaking) speeds

Ill tag Mike in the thread and see if he has anything to add

Stu

Goldfeesh 24-07-2019 03:15 AM

Mine currently is a stock Subaru manifold (Will be shortened at some point) with a motorbike can on the back. Loud. Stupid. Hits the floor a lot. Makes long distances at speed an unpleasant experience. But cost under 20 quid and doesn't hurt the power because I'm basically using no silencer.

Big Al 24-07-2019 10:51 PM

Quote:

Originally Posted by StuF (Post 16555499)
Al - its a fair point and something I did ask Mike about after he crafted the exhaust, apparently the headers do merge however it is done inside the large and wide back box which isnt as simple as it would appear. Think it is one of his secrets how he crafts the boxes - they aren't the usual baffle plates and wadding found in some systems.

Ive been out in a few EJ25 powered buses/bugs and mine is no slower or faster than any of the others however is much more civilised than any of the other options I sampled (Fellows, Custom, RJES and mixes in-between of longer/merged/unequal/equal length headers and so on)

Ive the ground clearance required and the wife is happy with the noise when cruising the motorway - even upto some silly (overtaking) speeds

Ill tag Mike in the thread and see if he has anything to add

Stu

Ahh cunning! I like that :)

Big Al 24-07-2019 11:23 PM

Quote:

Originally Posted by Goldfeesh (Post 16555519)
Mine currently is a stock Subaru manifold (Will be shortened at some point) with a motorbike can on the back. Loud. Stupid. Hits the floor a lot. Makes long distances at speed an unpleasant experience. But cost under 20 quid and doesn't hurt the power because I'm basically using no silencer.

To be fair mine is turbo so the sound is already chopped up, fitted the biggest straight through back box I could find and it's still loud. Unless you playing with something the length of the muffler above or wanting to restrict flow I'm not sure you can do much about it. Again, just an assumption based on limited experience. The turbo mufflers etc on bugs are all very loud too and they are fair sized cans! My JMR low loss turbo style muffler cost me a pair of headlights and a paint job I think due to pissing someone off going to work at 6am in the bug, was no sneaking about :lol:

beelzedub 29-07-2019 10:17 PM

Hey guys its Mike from Vintage Volkshaus here. Thanks Stu for pointing me back in here, its been a long time :lol::lol:

basically as Stu said my headers actually extend into the silencer and merge inside.
i have had experience building exhausts for some of the worlds most expensive and prestige vehicles. i have also been involved with the developement of Jaguars f-type factory exhaust systems as an outside contractor.

all of my vw silencers incorporate a lot of techniques to enable the soundwaves to do all kinds of crazy stuff to help with noise whilest trying not to slow down the exhaust gases too much to aid flow.

the system fitted to Stu's bus was designed to look stock and behave well and having had on eof these on a rolling road found that it does it well.

funny how a lot of subaru conversion guys said one silencer will not work and will be too loud, not if you know what you are doing and actually build exhaust systems knowing the maths and science behind it.

yes in theory the turbo acts as a silencer (by choping it up):lol::lol:
i have sucessfully built a single box straight through on a turbo bus and it wasn't loud. it just depends on who builds it.

Big Al 15-08-2019 11:44 AM

Finally got mine extended. Sure it's not upto the reduced resonance, very sexily welded, definitely not hydrogen enbrittled, chopped up turbo muffled standards of others :p :lol: but I'm happy for a diy job :)

Can't wait to hear it under load, lots hope it doesn't fall off.

https://i.ibb.co/2F9CCgs/20190814-202748.jpg

Has anyone had any experiments adding perforated baffle to theirs much like a stock bug on the exit pipes. Doubt it would do much on mine, maybe reduce the low boom a little? Just curious?

StuF 15-08-2019 01:49 PM

Al - im sure that will sound great, please post a vid of it running when you get chance!! Those tips look epic

eugopnosaj 15-08-2019 04:56 PM

Question: I need to redo mine, but what have you done about the 2 lambda sensors that the ECU needs? I re-used the CAT and put one before, and one after as stock, and then used a S/S centre box (can't remember where it was from) as a back box, its loud doing 70mph but on idle its reasonably quiet.

Big Al 16-08-2019 12:05 PM

Well no took it for a run and it's supprisingly quieter, much quieter in the car. Maybe it's the reduced energy at exit as now spread through 2 pipes, I actually assumed woukd trumpet the sound and make it louder but wrong on that one. Also it's less boomy and low down. Could also help that I'm directing all the sound at the guy losing the race behind me :lol:

Big Al 16-08-2019 12:10 PM

Quote:

Originally Posted by eugopnosaj (Post 16559781)
Question: I need to redo mine, but what have you done about the 2 lambda sensors that the ECU needs? I re-used the CAT and put one before, and one after as stock, and then used a S/S centre box (can't remember where it was from) as a back box, its loud doing 70mph but on idle its reasonably quiet.

Unless I've cocked up I only have the one sensor. This is the one after the turbo. I fitted it same distance from the turbo as the stock downpipe. I don't have a back one at all.

Pic here of mine. Right or wrong :lol:
https://i.ibb.co/g7xrWD3/2013-07-18-...ps2864bc4b.jpg


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