how legal is this?

4-2-1 manifold, 50cell racing cat, 2.25in pipe straight thru to the back... no silencers included...

would be to accompany a throttle body conversion... i know it would be damn loud, but how loud would be expected, and how LEGAL would this be?

cheers

I guess the db's will be over the legally allowed limit... but I think someone who knows more will help you out

Constructions and use , nick' Im' Hoffizer'

Strangely I don't think there is a legal noise limit on the road.
That won't stop you getting locked up if it is too loud though!

Noise isn't an issue for the MOT either.

Way to loud for track days as well as the road, you can get systems that have a butterfly valve to swop from straight thru to silencers at the touch of a button

Originally Posted by marko

4-2-1 manifold, 50cell racing cat, 2.25in pipe straight thru to the back... no silencers included...

would be to accompany a throttle body conversion... i know it would be damn loud, but how loud would be expected, and how LEGAL would this be?

cheers

an db outputs for it?

the castle donnington track website gives some db figures for their track, mot allowed db etc.
may be of some use?

You would be ok at un-silenced trackdays.
We took a LeMans 996RSR to Donnington in November (that has no silencers at all, just the manifolds poking out the back...).
VERY loud, it actually hurts when it comes past!


No way you could ever run it on the road though.

Completely std 911's with std road exhausts often fail noise tests at silenced trackdays.

Side Winders to blow the pedestrians away Eh? Van? Naughty boy, pulling that cable in town!

hmm shame, maybe that mid silencer will have to stay! ah who knows... watch this space

I know of cops pulling cars for being too loud. Providing the system is legal you'll be ok. But is it road legal?

My recently finished setup is 4-2-1 manifold, racing cat, resonator box and supersprint rear silencer. You can find more info here:
http://www.alfaowner.com/Forum/tunin...old-remap.html (New exhaust manifold + remap)

It sounds amazing when fooling around, but yesterday I did a 300 km trip and I am considering replacing the resonator with a center silencer now. I will post sound clips this week how it sounds now. My opinion is that with no silencers at all, the exhaust would not be acceptable even for racing enthusiasts.

My exhaust designer suggested trying to install a piece of special pipe in the exhaust with uneven diameters. Something like coca-cola bottle. It should make some turbulence and break the sound waves. Maybe I will give it a try before the silencer version...

Originally Posted by David C

Strangely I don't think there is a legal noise limit on the road.
That won't stop you getting locked up if it is too loud though!

Noise isn't an issue for the MOT either.

Yep, thats' how I understood it as well, when I was looking at decatting my RX-7

But.... you can fail an MoT if the tester deems the car to be significantly louder than when the car was type approved. You can also get a £30 fine, or even an ASBO if you get enough complaints.....

because there isn't a standardised road side test for vehicle noise plod can't do anything AFAIK....they can give you a producer and go over the car with a fine tooth comb but legally there's not much they can do. Anti social behavior laws are something new and that's probably how they'd try to get you but unless you're ragging it around housing estates i can't see you getting many complaints

Originally Posted by vantastic

Way to loud for track days as well as the road, you can get systems that have a butterfly valve to swop from straight thru to silencers at the touch of a button

Butterfly? as in Aston Martin style? I like that idea, and if someone sells them, iam gonna get me one!
(for the record, i had a side exit on my 75, sounds and looks awsome, but gets on your t1ts on a dual carrageway!)

Originally Posted by alfaspence

Butterfly? as in Aston Martin style? I like that idea, and if someone sells them, iam gonna get me one!
(for the record, i had a side exit on my 75, sounds and looks awsome, but gets on your t1ts on a dual carrageway!)

HKS do a system for them check out there site only problem is that they are made for Japanse cars but you might be able to get some ideas from the pictures.

Not 100% sure about limit on cars,but i can confirm that plod will pull bikes with race cans on,been there done that !

But of course where there is a law,there is a way to get round it in most cases,with a bike you change the cans over,get the re-test and bob's ya uncle,not so simple with cars tho

A call to your local traffic office will clarify b4 mobile plod does if it bothers you that much.

no i aint

just not visiting so much now!

guess this topic is obsolete now given i sold the alfa in an impulsive moment!

there was one of those butterfly valve things is in this months practical preformance car the one with the alfa 155 feature