T25 Watercooled exhaust system question

Post by **ghost123uk** » 22 Mar 2006, 13:11

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 ?

Post by **skell** » 22 Mar 2006, 13:20

Q1) 'cos they're blowing and dropping a cylinder....

Post by **Cate** » 22 Mar 2006, 13:24

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!

Post by **ghost123uk** » 22 Mar 2006, 13:31

skell wrote:Q1) 'cos they're blowing and dropping a cylinder....

Post by **shepster** » 22 Mar 2006, 14:46

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.

Post by **ghost123uk** » 22 Mar 2006, 15:05

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

Post by **shepster** » 22 Mar 2006, 15:25

I'll be going there myself so feel free to come over and have a listen.

Post by **geof914** » 22 Mar 2006, 18:20

You mean that lovely noise of a v-dub flat 4. Surely that's music to the ears!

Post by **"WEAZLECHIN"** » 22 Mar 2006, 21:39

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 !!

Post by **ghost123uk** » 22 Mar 2006, 23:37

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

)

Post by **Pickles** » 23 Mar 2006, 10:26

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/

Post by **ghost123uk** » 23 Mar 2006, 10:46

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.

Post by **skell** » 23 Mar 2006, 19:05

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.

Post by **ghost123uk** » 24 Mar 2006, 09:54

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