How loud is loud?

[Peter Carmichael]

Subjectively, I know it is loud. Damn.

 

This is not my new engine I am talking about. I have just got a new exhaust made up and it is stupidly loud, even attached to an ordinary 1.6 Supersport - embarrassing to start the car after dusk in a city location.

 

After much deliberation, the exhaust is a 4-1 with 28 inch long 1 7/8 primaries collecting into a long 2 1/4 inch section leading to an SBD carbon can which has a 2 3/4 through pipe. I think this big through pipe is to blame for the noise. Fortunately it seems to get quieter on light loads and middling to highish rpm (static test). It is difficult to form an opinion on the noise under power.

 

The configuration is specced with the intention of keeping everything going at high rpm while getting a bit of a boost to the mid range torque coming from the step up in diameter at the entry to the exhaust can. The rolling road session will tell all if I get everything bolted up by next Friday.

 

The headers and collector have been done by Exhausts By Design near Milton Keynes and the craftsmanship appears very good. If anybody is interested, this is the final delivery from an exhaust consortium that was set up earlier in the year. Darren Smith, John Howe and I now have custom made exhausts in various specs and at very reasonable prices. Between us we are getting quite an understanding of the variables involved, although we haven't found out how to make them quiet yet.

[EFA]

Peter,

 

Drill the baffle holes in the silencer from the 1/8 they currently are to 3/16. It'll need repacking more often, but it'll certainly be quieter.

 

Of course it could be that having drilled the 3080 holes with a black an decker you are just a little more mutton and its actually no quieter at all!!!

 

So I take it from the rest of your message that its still not up and running - Your engine is becoming the Sevenesque version of the Millenium Wheel

 

Arnie

[Andrew Dent]

Peter,

I have just weight the silencer box off my SLR, and it come in at a heafty 8 kgs. The car used to have a second box across the back that weighed even more. So much for super light. I would be intereted to know more about your exhaust people. Over the winter I will probably shelve the old exhaust and try some thing louder and lighter.

 

Andrew