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how to silence a bug?
jsheppard64 - May 13th, 2009 at 12:22 AM

hi
After having various tone and flavours of exhaust systems. I decided to make a quiet system which has 2 res and a glasspack Lukey muff 1 3/4" that makes it heaps quieter on the outside and the inside of the car.
but driving at 80km/h it still gets noisy from the engine with the windows sp and all. i had sound deadening mat on the parcel tray and under the rear seats. still i can distinctly hear the inlet noise and i think it may have come from the rear vents.
I want it to be as quiet as most modern car in the cabin.
is that too much to ask for?

my question is : is the rear vent go to the outer vent and also engine?
(you know that vent on a superbug rear window there are 3 vents on each side) (and there are vents above the rear guards)

and also what was that foam they use as fillers? and if i can get them at general auto shops


68AutoBug - May 13th, 2009 at 02:26 AM

Its hard to believe that a beetle could be as quiet as a normal.. modern day car...

I have two straight thru pipes coming from My VW muffler
and it s very loud...
I also have two large tapered muffled tail pipes I use when going long distances..
it does make a difference..

I'll have to check one day and see if there is any performance difference...

I will admit that a normal VW muffler with the two small muffled peashooter exhausts is very quiet for a beetle..

I have used heaps of PVA yoga mats everywhere on My beetle.. and also that spray foam you are talking about..
I have also used it above the gearbox and around the engine bay... under the carpet.. over the roof..
inside the doors and back panels..

My Son always says that he would like his beetle to be as quiet as Mine...
He often uses earplugs... so cannot hear the phone etc..
so a stereo system would be out of the question...

My Next soundproofing move, is to add a shelf behind the rear seat with lots of PVA foam...
Maybe that will make a BIG difference,

Best to cover up those flow thru ventilation vents on the outside, as rust usually starts in there...
spray a lot of fish oil in them... let dry for a week...
and then fill them in...

I did buy some excellent soundproofing materialfrom jaycar
If I had used it in My beetle, My beetle would have been many kilos heavier... something I don't want..
cheers

LEE

http://community.webshots.com/user/vw68autobug 


Joel - May 13th, 2009 at 04:39 PM

Quote:
Originally posted by jsheppard64
still i can distinctly hear the inlet noise and i think it may have come from the rear vents.


ur kidding right....
its cos of that whopping big boy racer pod filter u got on, its doing nothing for filter just making lots of noise
if u want quiet then get or make an adapter to fit a stock oil bath on that weber

http://c3.ac-images.myspacecdn.com/images02/43/l_91d1cdef9f3a45d297f313f92d6486d2.jpg

Quote:
Originally posted by 68AutoBug
Its hard to believe that a beetle could be as quiet as a normal.. modern day car...



its really not that hard
mine back when it had a stock carb, oil bath filter and thunderbird quiet pack is as quiet inside as most modern cars
but i also have low profile falken tyres and spent alot more on sound insulation than most people would

a blower and hotdog on a 1776 with a straightcut gear'd mild cam kinda killed that one tho :crazy:


grumble - May 13th, 2009 at 09:19 PM

Induction noise is a blight on all of those who think a big cool filter is the ducks nuts,I have driven a lot of cars with various types of filters and the only thing that you hear in the car is the suction over the top of the stereo.Joel is right if you want a quiet car get a decent air filter to drown the noise.


VWCOOL - May 13th, 2009 at 10:02 PM

...and move your fuel filter to 'before' the fuel pump to reduce the risk of burning your car to the ground


jsheppard64 - May 14th, 2009 at 12:14 AM

i don't have pod filter anymore. it kills the car on a wet day now it's just a paper element filters from auto pro for 32/36.
even so pod was quieter than the new paper filter.
that pod is quieter than the proper filter. it was meant to be a tempolary solution until i find a right filter with the right cost.

It's not a big boy racer pod it's a thrown away usable part that i had a hole now patched with silicone.

i made it like that because i'm cheap since my mate just gave me that pod since he stuffed it. so that air box ended up costing me a welding rod. and i had to squeeze every dollars i can save. my part time job doesn't pay much bein 17 and all
i mean last month i had to trouble my parents for my rego
and u kno how there are always parts need replacing on the car just can't seems to keep up with it.

last week the reverse decided to not work as it turns out that the locking bolt that hold the reverse shaft from moving out of place. the bolt hole didn't have any thread in it. and the hole is now bigger than M8
anyway i fixed the bastard

as for the filter it's under the tank
that is way old pic by the way

i resolved to stuffing some clean rag under the seat which helps a bit but it seems that the sounds seems to come thru the vents


68AutoBug - May 14th, 2009 at 12:53 AM

One thing I have noticed is My torsion bar 68 beetle doesn't get any tyre noise from the road like in many cars.
I don't get any road noise at all... on any bitumen type road.. where in others, there are quiet roads and ther are very noisy roads....

One place engine noise does come from...
is thru My heater mufflers... well I actually took the plastic mufflers off and pulled all the asbestos out... then wasn't game to reuse them.. so I have used 50mm heater hose..
as soon as I turn the heater on...
in comes the noise... mechanical engine noise..

cheers

LEE


sander288 - May 14th, 2009 at 03:29 PM

DYNAMAT, it is the goods! there is varying degrees of thickness for it but look it up online the yanks use it for everything, even just go ask an audi specialist they will show you some and should have a test setup, the downside to this is that it is a bit expensive but I think for the modern car feel it's the only way to go...


Joel - May 14th, 2009 at 03:36 PM

Quote:
Originally posted by sander288
DYNAMAT, it is the goods!


ding ding ding we have a winner ;)
i worked in car audio and installed more of the stuff than i care to remember, it may have a big price tag but its worth every cent

JS, you willl be amazed how much quieter it will be if you fit the original oil bath
there are adapters out there but if you made the one for your pod filter then im sure u could make one for the oil bath


jsheppard64 - May 14th, 2009 at 04:10 PM

so a quick recap
- oil bath
- dynamat & heaps of padding
- foam

come to think of it maybe i should replace rear wheel bearings
and maybe door seals aswell?


Joel - May 14th, 2009 at 05:31 PM

if u can hear the wheel bearings then yah might be time :lol:


trickysimon - May 14th, 2009 at 06:13 PM

Hmmm better put my bearings on things to do list as well then :lol:


shaihulud - May 17th, 2009 at 10:26 AM

When they were brand new, Beetles were very quiet. Induction noise was almost absent, cross ply tyres were quieter than radials and the loudest noise was the exhaust, which could be almosy eliminated by closing the windows. I suppose that a good way to have a quiet Beetle is for it to be stock.


helbus - May 17th, 2009 at 11:57 AM

I was playing with the heater lever in the Beetle the other day and it was surprising how much noise come in through the heater. With the heater on, there was a myriad of ticking mechanical noises that were gone when the heater was off. The main noise is some airflow around the front quarter vent windows and lower frequency exhaust noise. I used German muffler and German tailpipes, not cheap ones, and that made a big difference to the chirping of the cheap exhaust.

Quote:
Originally posted by 68AutoBug
One thing I have noticed is My torsion bar 68 beetle doesn't get any tyre noise from the road like in many cars.
I don't get any road noise at all... on any bitumen type road.. where in others, there are quiet roads and ther are very noisy roads....

One place engine noise does come from...
is thru My heater mufflers... well I actually took the plastic mufflers off and pulled all the asbestos out... then wasn't game to reuse them.. so I have used 50mm heater hose..
as soon as I turn the heater on...
in comes the noise... mechanical engine noise..

cheers

LEE


kroozzn63 - May 17th, 2009 at 01:02 PM

seem bizarre u want to eliminate the sweet sound of the aircooled motor i remember hearing the ticking sound of the lack of oil belting up the highway and pulled over to find i almost lost all my oil "old cracked oil seal from siiting for a year or two" and if i didnt hear it it probally would have blown up and or siezed .
poured more oil in and made it home safe.


jsheppard64 - May 20th, 2009 at 08:00 PM

something similar happened to me. one friday i was going to school as usual picked up my mate and we went to school. the temp gauge went up to ~110 which was a bit much for a 10degree morning then the oil press went down to 10. and i was coming in the carpark, got out of the car and i was like HA! some previous person left a trail so they could find their way. I looked again turns out it was me. and the rocker cover wasn't done up right. the moral of the story is always carry a bottle of oil and rocker cover gasket. ofcourse there was a situation that i happened to have spare coil when my GT40 gave out


Joel - May 20th, 2009 at 08:54 PM

a GT40 dying.......never :lol:


matberry - May 20th, 2009 at 11:34 PM

Quote:
Originally posted by Joel
a GT40 dying.......never :lol:
...still:lol::lol::lol: