How loud is loud?
 

http://www.hottrax-online.com/produc...ducts_id=15149

98dB means nothing to me, does that mean standard cans, or will my full system with no packing in the can be alright?

Re: How loud is loud?
 

Well I'm gonna have a viper can with da baffle out I can't wait how loud will that be:D

Re: How loud is loud?
 

Yup it'll sound sweet, but whats that in dB? :p

Reason being I'm wanting to do a trackday, but don't want to ride 110 miles only to be told I'm too antisocial to ride, sod off home.

Re: How loud is loud?
 

Its difficult to gauge 'loud' without correct measuring equipment. For instance my road legal Arrow can has people putting their fingers in their ears its so 'loud', but it meets legal specs.
It also depends on how they measure the 98dB - is it at 600RPM on a drive by in second gear, or simply burbling on tickover?

The small print says:

Please note that for the avoidance of any doubt all
motorcycles will be tested to conform to the ACU
blue book engine speed guidelines.

Though that throws up nothing in my quick google search

Re: How loud is loud?
 

Yeah I was thinking the same thing, unless they have a db metre which is caliabrted how will they know!

I would put da baffle in, which i beleive with my can makes it road legal....its depends on how much of the person doing it is a jobs worth i guess

Haha I was with some guys when I wa college, one Sunday we did a db test on his ICE, lol the college got a phone call from an aresy neighbour they heard a disco in their living room ace! We were disppaointed it only got to just 110 db.

By the way 110 db is a jet liner taking off, aything above can damage hearing on a permant basis. What people fail to realise about sound, is that it must be a pure sounds, ie no spikes and not dirty, it should sounds clean if it makes sesnse. Its hard to explain but you an tell when it something doesn't sound right, I made ppl reshoot becaseue I had a feeling that it didn't sound right, I guess you neeed to know what to being hearing out for.

Its the quality of the sounds, over how loud its....by increasig the volume of the sounds, it changes the wave form, but can distort which is bad. Quality sound is better than loud crap sound.

As for the track leave da baffle in, I would if in dought stick da old end can if it bothers you, otherwise get a db a metre but really even temperature can effect it.

Re: How loud is loud?
 

Problem is, my old can won't fit, and will make it run slobbery rich.

Re: How loud is loud?
 

It should be measured at about 5000 rpm with the microphone (or whatever) about a meter behind & above the exhaust.
98 is pretty quiet for a trackday I think. A standard system is obviously less than that but if you've changed it to something nice it could be borderline. Try & get it tested, baffled or look for a trackday with higher limits. You should be able to find 105 dB (which is many times louder).

As a reference my can measured 114 dB. And if someone is going to measure you it's not a matter of how much of a jobs worth they are - you will either pass or fail & go home.

By the way Bluethunder you sound like a real gangster rapper are you?

Re: How loud is loud?
 

Even if they use a meter you've also got to know what the measurement method is- a dim memory suggests the ACU method is 1 metre away at 45 degrees at 3000rpm but that could be total, total rubbish, I really don't know where I got that from :rolleyes:

98rpm isn't loud... According to the measurements I took, all with my oh-so-precise mobile phone at 1 metre, the stock exhaust idles at 89db and makes 103db at 7000rpm. By comparison, my race system makes 97db at idle and 111 at 7000rpm.

Re: How loud is loud?
 

I would have thought that most unbaffled aftermarket cans, might be too noisy for that limit.

Re: How loud is loud?
 

bloody hell only showed you the site 10mins ago and look you've made a thread, & already has 10 odd posts lol. good site this

Re: How loud is loud?
 

:confused:

Re: How loud is loud?
 

:cheers::smt048

Re: How loud is loud?
 

Woohoo.
Random smilies!
What do you mean you only showed someone the site 10 mins ago?
yorkie Chris has made himself a bit of a regular for a while now. :???:


And apart from yourself, the only relative newbie to this thread so far is some Northwindy chap with only 600 posts.

Re: How loud is loud?
 

Site for the trackday lmao :smt080

Re: How loud is loud?
 

your going for the baffle out eh, excellent choice.. it will be with you soon matey dont you worry :D and trust me that IS loud !

Re: How loud is loud?
 

Well for every 3 DB increase the loudness doubles... :cheers:

How do you all measure them? I think my exhaust is pretty quiet at tick over but give it some beans and it roars a bit. Got told off for scaring my mum when I shot past her on the back of my dad a while ago :rolleyes:.

Re: How loud is loud?
 

Me n Luke measured ours (fnaaar) before we did a limited noise trackday at Mallory.

Both were hovering around the 98db limit. I pinched our clubs noise meter for it, roughly using the ACU method, around half of max revs, 1 meter behind and off to the side.

I stuck my standard can back on to make sure I didn't get there and they say it was too loud - there were full blown race bikes out there with straight through race systems, so I don't know how strick the tracks are.

Re: How loud is loud?
 

Just buy a removable baffle that will fit in the end of the can.

The first track day I was 101db with the baffles in.

2nd track day I left them out to see how loud it was - when they tested it was well over so I had to stick them back in.

No drama and I had my base numbers to work from.

Re: How loud is loud?
 

Re: How loud is loud?
 

98 is not massivly loud. You will most probably need a baffle in to make that if you have an aftermarket can. When i was looking to do a day at snetterton I phoned them up and asked them about the noise limit and they said that i could go allong on any day and get it noise tested so i went to bedford speedway (which doesnt let bikes on, cars only) as its owned by the same guys and is closer to me and got it tested there where it put out a spectacular 122db which means im not doing any track days on that bike.

The other thing to remember is that twins are loud compaired to il4's. My zzr600 has a full race system and even at high revs its dwarfed out by the tl even when the tl is on tickover.

I would say give them a ring and see if you can get it tested and certified prior to actually booking your session. That way you know 100% with a little bit of paper that your either going to be fine or you going to loose your money.

Re: How loud is loud?
 

I may be wrong I'm crap at maths, but isn't db based on a logirthic scale? I once knew how to work out, but forgot that now...

As I said expsoure to over 105/110db can do permant damage to your hearing. Best wear ear plus eh? I'm sure a sounds enginner will know this...anyone?

Re: How loud is loud?
 

Sound Pressure Level is measured in dB and is indeed calculated on a logarithmic scale due to the wide spectrum of pressures associated with the sound.

SPL= 20log(recorded pressure/reference pressure) where the reference pressure in air is 20 micro Pascals.

3dB represents a doubling in sound energy but for every doubling of distance away from the source the level also drops by 3dB. Hence why there is so much confusion about sound levels.

Re: How loud is loud?
 

When i did a trackday recently at snetterton they measured mine, it was 102db cold without a baffle, i got pulled in later on in the day for it being too noisy and re measured and it had shot up to 111db as it was hot, this is a pointy with a high level ccc can. You might get away with a db killer in the end and do it cold.

Re: How loud is loud?
 

mine has a race micron so i think i might get kicked out, it doesnt have a fitting for a baffle

Re: How loud is loud?
 

Mine doesn't have provision for a baffle either, but I bought one off Ebay which fits in with a bolt, just had to drill a wee hole in the neck of the can. It's pretty rubbish but it does take some of the volume out of it (I've got another which I only use for MOTs which is more or less a cork, the bike barely runs with it in)

Re: How loud is loud?
 

Brother-in-law just got a new can for his GSXR 1000.

He has yet to ride out with it on but goodness knows how many times he'll get stopped the first time!

Re: How loud is loud?
 

I wonder how loud my viper can will be? I guess if the da baffle is then it should be okay for track days right?

Re: How loud is loud?
 

To echo (fnaaar fnaaar) what has been said already I took mine down to Castle Coombe to be tested before a possible track day. I failed at 110db, but can't remember their limit.

The test was done with the bike at 3/4 revs 1m back and off to the right at about 45 degrees. They don't count over run pops (or I'd be off the scale) just an average. By the sounds of things all track are going to be slightly different so best get yourself down there for a check. Alternatively a db meter costs c.£30.

Re: How loud is loud?
 

.... its loud and very deep.. with the baffle out.. the baffle takes away the rumble.
i did however do a track day a mallory with the baffle out.. no one said anything plus twins arnt as irritating to the ear as IL4 when they scream past