Do you find your Decat too loud?
29 January 2005, 12:53 AM
#61
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I have just put a Magnex decat downpipe on my Legacy tonight and to be honest i've yet to find any difference in sound appart from a bit more growl. It doesn't pop and bang as much (even though its lagged) which i dont get aswell?
It does pull alot smoother though!
Comper100
It does pull alot smoother though!
Comper100
29 January 2005, 07:46 PM
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31 January 2005, 09:43 AM
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This is on a '97 wagon.
Started off with H&S ce-cat down pipe, resonated Ninja centre and Standard H&S backbox - the one that used to be the Scoobysport backbox. That was too loud on WOT, made the inside of the car boom and it was quite boomy at about 3000 rpm on the motorway. Got Iain at H&S to make me a quiet backbox, the first try at this we went over the score with some silencing inside the tailpipe too, it was definately quiet, but as the car came on boost it went from Scooby throb to a jet like blowing noise - horrid. Spoke to Iain and we agreed to try it with a standard tail pipe. I sent the box back and they changed it for free, 2 day turnaround - superb service! It's now spot on, pretty quiet around town, fine on the motorway and a nice loud, but not overly harsh blat on WOT. I have also Dynamatted the boot floor and spare wheel well and have carpet underlay under the back seat, this, to be honest, made very little difference. My wife is perfectly happy and prefers the sound on the motorway to her own 1.2 clio, which sounds much quieter to me ! Had my 67 yr old Mum in the car for a gentle trip round town and she commented un-prompted that she liked the noise my car made !!
The backbox is much as the standard H&S one and looks identical externally, but with 2.25" perf pipe through instead of the standard boxes 2.5", this makes absolutely no detectable difference to performance but a noticable effect on the noise. I guess by the backbox the gasses have cooled and contracted, so the short 2.25" section isn't a restriction.
Out of interest, when I had the standard Uk centre cat back on with the rest of the system for the MOT it was quite noticable that it spooled slower, was less punchy and was noisier, both on gentle cruise - more boom, and on WOT - made the noise harder edged. It passes it's emissions no problem though!
Started off with H&S ce-cat down pipe, resonated Ninja centre and Standard H&S backbox - the one that used to be the Scoobysport backbox. That was too loud on WOT, made the inside of the car boom and it was quite boomy at about 3000 rpm on the motorway. Got Iain at H&S to make me a quiet backbox, the first try at this we went over the score with some silencing inside the tailpipe too, it was definately quiet, but as the car came on boost it went from Scooby throb to a jet like blowing noise - horrid. Spoke to Iain and we agreed to try it with a standard tail pipe. I sent the box back and they changed it for free, 2 day turnaround - superb service! It's now spot on, pretty quiet around town, fine on the motorway and a nice loud, but not overly harsh blat on WOT. I have also Dynamatted the boot floor and spare wheel well and have carpet underlay under the back seat, this, to be honest, made very little difference. My wife is perfectly happy and prefers the sound on the motorway to her own 1.2 clio, which sounds much quieter to me ! Had my 67 yr old Mum in the car for a gentle trip round town and she commented un-prompted that she liked the noise my car made !!
The backbox is much as the standard H&S one and looks identical externally, but with 2.25" perf pipe through instead of the standard boxes 2.5", this makes absolutely no detectable difference to performance but a noticable effect on the noise. I guess by the backbox the gasses have cooled and contracted, so the short 2.25" section isn't a restriction.
Out of interest, when I had the standard Uk centre cat back on with the rest of the system for the MOT it was quite noticable that it spooled slower, was less punchy and was noisier, both on gentle cruise - more boom, and on WOT - made the noise harder edged. It passes it's emissions no problem though!
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