pbee

115 db is very loud, you must have the large jap style h& s exhaust. and probably other induction mods.

If you want to keep your system try putting a resonator section in.

you could sell the H & S centre pipe on here and get a H & S version with a resonator or ask H & S to modify your exisiting one.

Matt P

I think you'll find the 74 dB(A) quoted above is for the 7.5m driveby test, which is NOT the same as waving a sound level meter around an exhaust pipe. In addition, your local friendly plod may not have used an "A-weighting", which adjusts the meter's readings to correlate to what the human ear hears. 115 dB(lin) at an exhaust outlet is (just about) believeable, 115 dB(A) is unlikely. As mentioned above, you would really know about it (115 dB(A)). The use of even basic SLMs is open to mistakes and coppers aren't generally likely to have been trained in their use. I'll bet it wasn't calibrated either

STI-R/A

The ******** copper put the damn thing right in the tailpipe while his fat colleague sat in my car revving it. I dont know if the machine was accurate or not but it was idling at 81db and then 115db @ 4000 rpm. Just spoke to h+s they will do me a bung for 35 squid. So for one night driving my car its cost me £65. At least ive got a few options now, either way its gonna cost me money. Sorry if im offending anyone here but i just think its pathetic that someone can get pulled for having a nice sounding car, i was surprised he didny do me for my wheels being too big! what a fud.

chrome

ask on 5ive-0.com - lots of coppers on there to advise wrt noise checks.. pretty sure its only DOT staff that are supposed to operate the equipment....

and yeah- definately get a bung.
my car is decatted, with an HKS hiper (unresonated centre!) and it is bloody loud with a stab at the throttle.. so just go easy in urban areas
works for me.

Stephen Pope

i too have a full de-cat afterburner at 115db - it is ridiculous!!! I drove down to blackpool at the weekend and next time i do that - i am taking ear plugs - seriously.

Matt P

If I were in your position I would be spending no more of my hard-earned and instead would be making a bee-line for the local cop-shop to ask Mr Plod exactly what he thought he was up to!! The closest he should have the meter is 0.5m at a 45deg angle to the outlet. And he should defintiely have a foam windshield on the end. And be using the A-weighting function. And it should be calibrated immediately prior to the test. If, and only if, he has done all of this correctly, I might start to accept the results. Unfortunately I don't know what the limit is for the 0.5m / 45deg test but it's probably in the 95 - 100 dB(A) range. 115 dB(A) at 0.5m / 45degs is possible, on open pipes, but I would suggest that you get a retest (from someone who knows what they're doing) before you accept Plod's opinion.

HTH

Matt

Chris L

I'm sure Bob T will correct me if I'm wrong, but when we were chatting about this he said that there was no actual MOT dB standard for exhaust noise. The police can do you if they think the car is causing a nusiance, but there isn't actually a specific level that you may or may not exceed (in relation to passing an MOT).

Matt P

Chris,

There's a new bit of legislation which is either about to or has just come into force regarding this.

catalunya199again

i have the same exhaust and would never change i live in an cul de sac and sometimes come in late just do what i do and role in in neutral

JohnD

iTrader: (5)

How far away from the tailpipe was the meter and at what angle? The distance is critical, the "inverse square law" applies. What was the ambient (background) noise level and were there any reflective objects close (eg buildings, cars etc.) You must get a written statement as to the procedure that was followed. Having said that, 115dbA is very loud. I did some testing at an evening meet recently and nobody got that high! Full de-cat systems were exceeding 100dbA but I was approx. 1meter from the tailpipe at 45deg.(ish) As was said before, you must consider yourself lucky they didn't insist on an emissions test!
JohnD

wide

If you got a longlife exhaust place near you they can fit a resonator also

Wizard

Gutted M8 i too have a system which just passes , instead of getting rid why not speak to Ian at Haywood & Scott and see if they can put some more exhaust baffle/padding in the back box for you. It shouldn't cost that muchand at least that way you still keep the system .

Kane

You were dobbed in m8 - thats obvious....115db is loud though..i used to have An RA with decat/downpipe/HKS Hiper muffler and that was loud enough at 99db. Used to coast down the road to when I used to leave for work at 05:30am...never had 1 complaint about noisey car...just as well i did do that i reckon...:-)

DJ WATTS

ffs soon its going to be so harsh owning a car with all the laws out and some that may come out, it may be better off getting a mondeo or some other family day crappy car...

Sorry to hear about this buddy. Real shame some traffic cops have to lower the tone some...

Well looks like exhaust levels could be the next big thing that is brought into legislation after window tints... All we need now is a granny going deaf from a de-cat scooby and we are all screwed... (thats the ones on here that like to modify there cars for the sweet sounding and perfomance gaining benefits).

Those that don't, well why the hell do you drive a scooby?

I will second that!! It was the first thing i thought of reading this thread and my guess is a neighbour has had a moan to the local plod who in turn came PREPARED for the stop check with the relevent equipment beforehand.
You got any busy busy grannys living on your street?

Chin up buddy and just thank god it was just a fine and no points or anything else.

Boarder1

Used to be big into the Car audio SPL scene (very loud cars of 150db and above) had a full Audiocontrol SPL meter for a few months.

If the police put the pic in the exhaust pipe then it will easily show 115db+, as if you take a microphone and blow air on it gently, the meter will show easily 130+db.

My friends BTCC car is very loud, but it is well under 110db.

Smudge

To play Devil's advocate, it's not so long ago that people on here were boasting that their exhausts would set people's car alarms off!

Surely if you buy one of these babies you know what you are getting yourself into? I passed a green MY98 on Saturday and it was unbelievably loud.

I got the PPP exhaust and a few people make some adverse comments to me about that!

It's like driving fast - you are p1ssed off when you get nicked, but you knew it was wrong in the first place?

Just a thought

Andy

Power Junkie

iTrader: (1)

Setting off alarms is not only down to volume, it is the type of low frequancy some produce. 115Db Is really loud. where did they take the test??

jas03WRX

Its a joke... If you go around streets in built up areas revving the nuts out your car I can understand getting pulled, your on a hidding to nothing there... but burbling home?? is taking the ****. What about your average TVR owner? We have someone in our close with a S4 (V8). Sounds the absolute bollox... nobody complains about these, or any other TVR, yet they’re still loud?

RRH

Our Clio cup race car is around 97db, and has been checked when we use it on track days. This is a full on race car and is horrendously noisy.

I would doubt that yours is over 100db or so, but, as has been mentioned, it would appear that it has been measured incorrectly.

Also, next time its being checked, dip the clutch- the drivetrain can add quite a lot of noise.

Scoobydick

A few more for you:

Standing on a footbridge above a speeding train amounts to 81 dB
A baby crying at a distance of 6ft is 90 dB
A Formula 1 car passing at speed rates 110 dB.

DJ WATTS

Maybe the sensors are set too high then?

hades

Whilst there aren't strictly MOT noise regs, there are noise limits in the SVA test, IIRC. Something like 102dB at 1m, 45º, measured on an open concrete surface at the same height as the tailpipe? My brother has the full SVA manual and could confirm. 115dB at that sort of situation would be ridiculously loud.

For interest (?), on some impromptu tests, at a held 5000rpm, I measured a standard 02 WRX at 78dB(A), an STi7 with prodrive backbox and TSL centre (standard downpipe) was 89db(A), my full APS system on an 02WRX (standard up-pipe and headers at the time, both since modified) got 88.5db(A).

From figures I found somewhere on NASIOC, a Blitz nurspec R catback from the USA measured 104dB at 20" straight behind the exhaust (seems to be the USA standard test), HKS ~100dB, and most others were mid 90s. Quietest of them was the MRT (quieter than prodrive). Aussie exhausts tend to be fairly quiet as they are a lot stricter about enforcing their rules, which are somewhere around 90 or 92db(A) at 1m, 45º, IIRC - hence MRT and my APS is relatively quiet. Even so, my exhaust is still loud enough to draw comments. Loudest I've ever heard of was Knowlesy (now of Xtreme scoobies) who a while back had an experimental 3" or bigger system with no silencer worth mentioning, no resonator etc, that got near to 120, allegedly.

Based on that, 115db(A) from an H&S system is either (a) not measured correctly (e.g. microphone stuck up exhaust pipe), or (b) got something horribly wrong (e.g. forgot to fit the backbox. )

Not sure how much that all helps, but might be interesting to someone?

STI-R/A

Wow! so much feedback, I'm speaking with my solicitor to see if I can do anything but will probably end up paying the fine and getting a bung from h&s - £35. As for the reading 115db, I dont know how they got that but it cant be right, i heard a tvr tuscan today and that was almost twice as loud - (sounded amazing!). I spoke with my ex, who works at the police station and she says the guy that pulled me is a complete tosser and he hates boy racers or anyone whose young with a nice car - he pulled my mate whos got a clio 1.2 with a k+n induction kit and he reckoned it was too loud! he said to my mate - "have you got an induction kit?" my mate says - "yes officer" and the cop goes - "there illegal, you'll need to remove it."!!!!! can you believe that!? what an absoloute dick head!
cheers.

Underwriter

puts my mind at rest then as i just got a h&scott 99dbl pipe & box yesterday, they do sound loud but not as much as my old blowing jap one lol

cong

i agree with matt p the sound level meter should have had a yearly calibration certificate. i dont think they need a daily calibration, at work we have a sound level meter which we use to test toys the limit for any in the c weighted peak emmission is 100db and even a rattle toy has a A weighted peak emmission is 85db so i really doubt the plod can get away with fineing you, take em to court ask if it was calibrated and as one of the mods said there isnt a actually limit to sound produce in the mot, but dont push your luck just say you will however get it quitened

richto

I asked at my local MOT station - they dont even have noise testing equipment.

richto

No fight it. The fact that he clearly hasnt tested it correctly will mean you win. They cant pull the car into court and do it again....Get a good solicitor - you get the costs back if you win - and fatso and mate have to do lots of paperwork...

Also im surprised your car made 'much' noise at 4000 revs while stationary. Shouldnt even be coming on boost with no load.

GC8

You cant really be paying the fine now that you know that the test wasnt conducted properly?

Ive seen a triple rotor Wankel engined racer with an extractor exhaust, similar to tha found on a Norton F1; it was painfully loud, I had to leave the scrutineering shed (it was unbearable @ 4000 RPM; you needed protectors). The sound level was just over 110 Db at one metre; 45 degrees. You DO NOT put the measuring kit in the tail pipe and rev it ffs.

As an increase of three decibels reflects a doubling of sound pressure this would mean; using Hades's figures; that youre 3.5 times louder then a Blitz Nurspec; it isnt likely is it?

***** like this give the Police a bad name.

Simon

Mackers

Make them produce a certificate, ask them for an effin current calibration certificate and whether the fatso has been adequately trained, no doubt they giv out badges or the likes for this sort of thing, something to show the missus & kids!!!

Diesel

I have (had) a full de-cat Scoobysport exhaust from the turbo back on my STi V made by H&S. This was 101dB at Goodwood at 6000rpm. 115dB PARDON???? Doubt it!!!!

Ohh and just tickle the throttle will you when coppers are about - dohhhh!!!!!