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Quiet(ish) free-flowing backboxes

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Old 05 August 2002, 09:56 AM
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nom
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I'm looking for a reasonably quiet BB - but one which is free-flowing to a vaguely ScoobySport level. Shortlisted at the moment are the ScoobySport & TSL 'group N', but open to others. I think the TSL is a 'more mature' sound than the SS, but not sure if it's as free-flowing? I'm just not after a huge noise here...
It's to plug on the back of a decatted DP & hi-flow centre, by the way.
Any ideas?
Old 05 August 2002, 10:00 AM
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Pavlo
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Scoobysport "quiet" is what I got, sounds great, not too loud with standard resonated centre section.

Quiet enough for my 20month old daughter to fall asleep on the journey home yesterday, and I don't get a headache from driving. But I did add some sound proofing to the spare wheel well on my Legacy estate, just to take the edge off the noise.

FYI I also have a ss downpipe.

Paul

Old 05 August 2002, 10:19 AM
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nom
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Ta - I forgot about the 'quiet' SS! I also have great clods of soundproofing myself...
Any other ideas out there?
Old 05 August 2002, 12:18 PM
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GavinP
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If you want VERY quiet then Remus flows well but is quieter than the OE exhaiust (depending on your downpipe/centre obviously )

Thanks

Gavin
Old 05 August 2002, 12:34 PM
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nom
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Had (well, still have ) the Remus - on your advice!, but find it too restrictive now - similar to the PPP BB. Worked very well for the 'mid-power' type stuff, but I'm planning on stepping it up a notch now
Old 05 August 2002, 02:25 PM
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Tony_W
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I wanted exactly the same from a BB...low noise/no drone on cruise, but a bit more on low revs and with the foot planted..I tried 2 GGR exhausts, neither fitted, so went to TSL-Motorsport and bought the Gp N BB. It fitted first time and is spot on. The car feels smoother to drive as well (presume due to gas flow?). It sounds just right burbling at low revs and sounds spot on with the foot down. My kids sleep in the back on long journeys no probs, and I haven't had to adjust the stereo from previous settings....except to off to have a listen with the window down!!

Go for TSL....you won't be disappointed.

Tony
Old 05 August 2002, 02:31 PM
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nom
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Thanks very much for that, Tony! I think I'm going to go for the TSL
Old 06 August 2002, 06:58 AM
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dowser
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The problems start when you change anything in front of the backbox

I've got a quiet Scoobysport - with the td04 and oe manifold & centre it was perfect noise/flow wise.

However, with a new manifold, vf23 and straight through centre it is a *very* loud thing. At least if the Swiss police stop me they wont actually inspect the car, they'll just tell me "exhaust is blowing, get it fixed"

But....to make it quieter you have to introduce more back pressure. Life is sh*t..... Has anyone any experience of Australian HiTech mufflers? These are supposed to be quiet and flow well....

Richard
Old 06 August 2002, 07:37 AM
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AndrewC
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You don't want a quiet system, go for a full scoobysport, then when you drive past a fellow scooby owners house at 06:00 on a Sunday morning he will jump out of bed thinking his car is being stolen from his garage! Isn't that right Tony

Andrew...
Old 06 August 2002, 08:02 AM
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Tony_W
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Hi Andrew..

YES, almost gave me a heart attack that morning....
Old 06 August 2002, 08:42 AM
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Pavlo
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Dowser, get a resonated centre section, Scoobysport said they could do one special for my Legacy. I have a decat downpipe, no cat in the up-pipe etc and the noise is fine.

Paul
Old 06 August 2002, 12:24 PM
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dowser
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I'm actually going to refit a spare STi backbox and check the Scoobysport on a standard car - I'm really starting to think something's broken inside!

Richard

Old 06 August 2002, 04:44 PM
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Brun
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Magnex 3.5" looks the part and sounds the part. Costs £208.
Old 07 August 2002, 06:57 PM
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madou
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Dowser

Surely Swiss police are too busy hiding GATSO cameras in wheelie bins to trouble you :-)

( See this weeks Autocar )
Old 07 August 2002, 07:25 PM
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dowser
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If the gatso in wheelie bin is the photo doing the rounds of the internet, they're Aussie 'polizei'

There are perhaps 5 fixed camera's I'm aware of in CH - and there's a freephone number where you can dial for the location of any roaming ones (public gets free gifts for reporting one when they see it)...it's all very civilised

Swapped to the STi backbox last night - quiet as a mouse....and as strangled as a giraffe in a mangler.

Oh, and apologies to Scoobysport - the original gasket disintegrated as I removed the backbox, which I guess was causing the problem - will know in about 30 minutes (no ramp at home ).

Richard
Old 08 August 2002, 06:13 PM
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madou
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dowser

Apologies for the attack of belief in Autocar. I did notice one of the fixed cameras outside Basle on the central reservation, glad to hear there are so few

nom

Having standard manifold ported and gasflowed does reduce noise, especially on part throttle
Old 09 August 2002, 08:06 AM
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dowser
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I refitted the Scoobysport 'quiet' backbox - I'd dread hearing a normal one with manifold/big turbo....f*ck, it's loud. Still, it can beathe again

Richard
Old 09 August 2002, 06:08 PM
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raybotha
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I found the centre resonator makes a big difference to in-car sound . More flow = more power up top especially after 5500rpm . I found standard STI back box on 3" gave good part throttle response and bottom end torque . You feel you have too cane a free'er flowing car but it is very rewarding . Am surprised if you can't live with a Scooby quiet with centre resonator . No boom in cra .

Ray
Old 11 August 2002, 08:19 PM
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dowser
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Hey Nom - next time you're going to see the Basel speed camera, email me first...I live about 30km from there

Oh, and the tunnel between the camera and Basel also now contain camera's which are intermittently switched on in both directions - 10km/h over limit is OK.

Richard
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