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T25 Watercooled exhaust system question
Posted: 22 Mar 2006, 13:11
by ghost123uk
Now I am still new to all this, with my new tin top camper, but fo years I have attended many VW shows with my Scirocco and some camper van friends.
Question 1 = Why do all camper vans with standard exhausts sound like the exhaust is blowing, and they are only running on 3 cylinders
Question 2 = Suggestions for a nicer exhaust system ?
Posted: 22 Mar 2006, 13:20
by skell
Q1) 'cos they're blowing and dropping a cylinder....
Posted: 22 Mar 2006, 13:24
by Cate
Some people like the gravelly low-note of a blowing exhaust type noise!
You could get a nice stainless steel exhaust, JP Exhausts, they are nice!
Posted: 22 Mar 2006, 13:31
by ghost123uk
Posted: 22 Mar 2006, 14:46
by shepster

Can't answer the first one other than they all seem to sound like that, i've got a stainless backbox from 'Bluebird customs' which sounds quite nice (not quiet though if that's what your looking for) but i think they're only for early w/c motors.
Posted: 22 Mar 2006, 15:05
by ghost123uk
shepster wrote:
Can't answer the first one other than they all seem to sound like that, i've got a stainless backbox from 'Bluebird customs' which sounds quite nice (not quiet though if that's what your looking for) but i think they're only for early w/c motors.
Thats the kind of thing I was thinking of
Though I wouldn't want it too noisy, I will wait till the next show ( Oswestry ) and have a look and listen around.
Does your system make a more normal engine sound or does it still
sound like the exhaust is blowing, and only running on 3 cylinders

Posted: 22 Mar 2006, 15:25
by shepster
I'll be going there myself so feel free to come over and have a listen.
Posted: 22 Mar 2006, 18:20
by geof914
You mean that lovely noise of a v-dub flat 4. Surely that's music to the ears!
Posted: 22 Mar 2006, 21:39
by "WEAZLECHIN"
yeah, the only reason they sound like that is the engine configuration, flat four. subarus sound distictive too, flat four. as do porsche 911 flat 6. some do sound pants dont they? its a pity they werent all V6 or v8, beautiful !!
Posted: 22 Mar 2006, 23:37
by ghost123uk
It's not that I have anything against a flat four "boxer" sound, I think it is just the silencer system that I don't like the sound of !
So, Steve from Gasure tells me a manifold balance pipe and a "bug-pack" silencer makes a much nicer sound and works better too...
Will be looking for this set-up then

( I think

)
Posted: 23 Mar 2006, 10:26
by Pickles
Can you explain the manifold balance pipe.
Is this for the early systems were the two cylinder banks are kept seperate only joining at the silencer box.
The later pipework joins at the cast knuckle to the rear.
I am after a better system I have thought of using the late pipe work and swapping the existing silencer for a performance one.
I have been unable to obtain flow figures for uk silencers.
In the USA the flow figures are available the best ones are as recommended by David Vizard are sonic turbo 2.5" flow 385cfm
dynomax 2.5" flow 375cfm
http://www.a-1performance.com/
Posted: 23 Mar 2006, 10:46
by ghost123uk
Well although I am a fairly competent amateur mechanic I am new to these flat fours.
From what I gather, the balance pipe joins the 2 flanges (having 2 exhaust down-pipes each) that would normally go on the front of the silencer.
A more normal “inline"| silencer is then used.
This set-up apparently gives better scavenging ( summat these motors seem sadly lacking in ) and produce a nicer, not too loud sound
As for flow figures, I reckon if you look at gas flow, both in and out on this set-up, the last thing to worry about is the silencer, I mean take a look at the air inlet to the carb and the overall in / out porting arrangement Aaaarrrhg
Mind you it does make me smile when you see a 2Ltr VW with a 1"| tail pipe and a Lil Saxo with a 4"| bore one
Oh and btw, I am told that some of the sporty twin t/pipe offerings are very poorly made.
Posted: 23 Mar 2006, 19:05
by skell
Actually mine was blowing and dropping a cylinder for a while and sounded ok, then rebuilt lump and cheap n cheerful (early) exhaust sounds horrible, think it nees to age a bit to sound less tinny.
Posted: 24 Mar 2006, 09:54
by ghost123uk
Aye, I got a Jetex system for my GTX Scirocco that sounded far too resonant and loud for the first month or 2.
Then it calmed down.
Then it broke.
Jetex service stinks
Back to a standard system on that car now
