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+--- Thread: standard silencer... how restrictive?? (/showthread.php?tid=11233)
standard silencer... how restrictive?? - Arron - 23-02-2013
I know chaps usually put mid boxes onto where the silencer should be but I'm just wondering how restrictive they really are as in , Turbo response. I don't consider my car laggy but is it really that restrictive?
I was considering getting the baffles smashed out of my silencer but will it be noticeably louder? I don't fancy an aftermarket back box as I don't want burble and I'd like to keep the 'whoosh' sound, so is it worth it?
Arron
RE: standard silencer... how restrictive?? - Just Sean - 23-02-2013
ive got pretty much straight through, and its still queit and throttle response is tonnes better. Do it mate. You wont regret it
RE: standard silencer... how restrictive?? - Piggy - 23-02-2013
pretty bad to be fair...
more flow, more go
RE: standard silencer... how restrictive?? - Oil-burner - 23-02-2013
Im totally straight through mate and it is pretty loud.
Id go double mid box shouldnt be too bad then
RE: standard silencer... how restrictive?? - Arron - 23-02-2013
Sean I was thinking an hollow silencer might hum on idle. What exhaust you got??
Oil burner would you say it dramatically sped up spool times or throttle response after you had it done
RE: standard silencer... how restrictive?? - Oil-burner - 23-02-2013
I did it in stages so cant really tell you over standard
But yeah its deffo better.
I personally wouldnt go 100% straight through again if im honest, its too noisy for a daily.
Infact i keep looking to go back to a modded standard system over my stainless tbh.
I loved it at first but it gets boring quickly. Although that might just be me getting old!
RE: standard silencer... how restrictive?? - Just Sean - 23-02-2013
Mines a powerflow. No cat. Just taken the baffles out the back box and I can't notice an exhaust note. But throttle response is deffiantly noticeably quicker
RE: standard silencer... how restrictive?? - Arron - 23-02-2013
Think I'm going to hollow out the standard silencer. Is there any easy way to do this without cutting the baffles out??
RE: standard silencer... how restrictive?? - Oil-burner - 23-02-2013
Do what I did mate, cut a flap in the top of the box, take all of the shit out then weld a piece of straight pipe through the empty box. Empty backboxes rattle and sound really tinny.
RE: standard silencer... how restrictive?? - Poodle - 24-02-2013
I've got a twin midbox exhaust, it's fairly quiet unless i'm thrashing it, ideal really.
RE: standard silencer... how restrictive?? - DeeTurbo - 24-02-2013
(24-02-2013, 09:58 PM)Poodle Wrote: I've got a twin midbox exhaust, it's fairly quiet unless i'm thrashing it, ideal really.
What, as in one in the original mid place and another replacing the rear or two mid boxes to replace the rear?
RE: standard silencer... how restrictive?? - Poodle - 24-02-2013
Decat --> original midbox --> midbox (replacing backbox)
You need to make up a hanger for it, but i just ripped the one off the old backbox and bent it into shape. Tack weld it in place and you're good to go.
RE: standard silencer... how restrictive?? - Toms306 - 24-02-2013
I've currently got no exhaust post cat (french pos rusted and snapped) and while its much louder and Mich less laggy, its also lost bottom end torque. Top end is much better, but bottom is noticably worse, do you guys get that with straight throughs or does the pipe give that bit of back pressure that seems necessary for low torque?
RE: standard silencer... how restrictive?? - Dum-Dum - 25-02-2013
Ive forgotten the exact figure but on a stage 2 car the scanguage indicated a 10-15bhp gain by swapping the oem back box for a straight through
RE: standard silencer... how restrictive?? - Poodle - 25-02-2013
(24-02-2013, 11:00 PM)Toms306 Wrote: I've currently got no exhaust post cat (french pos rusted and snapped) and while its much louder and Mich less laggy, its also lost bottom end torque. Top end is much better, but bottom is noticably worse, do you guys get that with straight throughs or does the pipe give that bit of back pressure that seems necessary for low torque?
You're confusing your exhausts mate, it's only NA engines that need backpressure.
RE: standard silencer... how restrictive?? - Toms306 - 25-02-2013
(25-02-2013, 07:27 AM)Poodle Wrote:(24-02-2013, 11:00 PM)Toms306 Wrote: I've currently got no exhaust post cat (french pos rusted and snapped) and while its much louder and Mich less laggy, its also lost bottom end torque. Top end is much better, but bottom is noticably worse, do you guys get that with straight throughs or does the pipe give that bit of back pressure that seems necessary for low torque?
You're confusing your exhausts mate, it's only NA engines that need backpressure.
Well thats what I thought - until my exhaust fell off. As said it's really noticeably worse bottom end BUT without restriction top end is better, so I'm thinking they do need some back pressure for low end.
It's odd though as I drove the Golf for a short while with no exhaust and there wasn't really any difference, wasnt even noisier, just whistled more, possibly to do with it being VNT though.
RE: standard silencer... how restrictive?? - Arron - 25-02-2013
Well I'm going to get the baffles taken out today so I'll keep you all updated. Tom that sounds weird, in theory your Turbo should have loved the reduced back pressure
Dum dum how accurate was the scan gauge, as in did you roll the car and then use the gauge, to see how far out it was
RE: standard silencer... how restrictive?? - Dum-Dum - 25-02-2013
the SG was about 15% out but ive forgotten the exact number anyway. I know it was 10-15bhp though.
lets put it like this, with a standard back box the clutch held, with a straight through it had some pretty impressive clutch slip.
RE: standard silencer... how restrictive?? - Poodle - 25-02-2013
Was that based on your bum dyno though Tom? Thing is, less exhaust restriction means sharper spool and bigger torque spike, makes off boost performance seem worse than it is.
RE: standard silencer... how restrictive?? - Arron - 25-02-2013
This guy who's doing it is an arse. I'm thinking this might be why my rr figure was a lil low, sounds like the difference with and without silencer will be like night and day
Also the rr I went to had a dyno day yesterday and some of the figures were way out, for example a v6 2.5 corsa b making 101bhp and 200 torque! And a Leon k1 with revo map and fmic making 231, the things 260 standard!! Should of been nearer 300.
RE: standard silencer... how restrictive?? - titch - 25-02-2013
I have a stage one mapped hdi and my back box had rusted out so i got a second hand scorpion one which was straight through.
Didn't really notice any difference in sound or performance had a tiny little bit more smoke if driving it hard.
RE: standard silencer... how restrictive?? - Toms306 - 25-02-2013
(25-02-2013, 11:07 AM)Poodle Wrote: Was that based on your bum dyno though Tom? Thing is, less exhaust restriction means sharper spool and bigger torque spike, makes off boost performance seem worse than it is.
Not dynod it no, but it struggles to overtake without a run up now, it doesn't just seem slower, it definitely is lol. But at 70 it pulls up to 100+ so much easier now.
RE: standard silencer... how restrictive?? - StefanUK - 25-02-2013
I have (Turbo ===================== not one box just a straight pipe and its only loud when putting your foot down. But my god its good