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I am re-designing a ferrari exhaust system with 2 objectives:

1: enhance the specific high pitch raspy sound that you expect from a small ferrari V8.

2: achieve a good free-flow design.

There is approx 1.5m of tubing between the header and the tail pipe, where along this should I place a sliencer in order to get the best raspy tone? Does this make a difference anyway?

There are 2 headers, would there be any advantage to using some sort of x-piece? and how will the use of that (and indeed the size of its x-flow port) effect the sound?

Background: The car is an old 3.0L V8, and the factory exhaust has had it - factory replacements are not available and after market ones are ridiculous money.

The exhaust on it isn't very loud, and doesn't really do justice to the engine, as more recent cars with the same basic block sound MUCH better.

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In theory, point 1 should follow from point 2 (assuming the engine's in good shape). Have you looked at the layout of the original exhaust? You are going to be somewhat bound by the layout and geometry of the components under the body. You won't have a blank sheet to draw arbitrary shapes of piping. What is the problem with matching the original layout with new piping? –  Bob Cross Nov 26 '13 at 19:50
    
Yes the engine's good :-) I have yes - I had the top off the box to have a look inside and its certainly nothing special - minimally restrictive, but not a piece of art! I'll post some photos soon. –  Digital Lightcraft Nov 26 '13 at 20:54
    
AFAIK silencer positioning doesn't make a huge amount of difference - it's the size and flow rate that do. Are you using the original manifolds? If not, try and match the header lengths as well as possible - and try and match the lengths of the two systems. IIRC the MOT regs don't quantify the maximum noise level, so it is all subjective as to what is "too loud" - and most people expect a Ferrari to be nice and burbly :) –  Nick C Nov 27 '13 at 10:24
    
What i was thinking was the amount of pipe AFTER the silencer could affect the sound as it becomes a resonance stack. Thats true there is no measurement for noise during an MOT, my mini was FAR to loud (for me) on its last mot but passed. –  Digital Lightcraft Nov 27 '13 at 11:48

1 Answer 1

As you are in the UK, try someone like www.simonscustomexhausts.co.uk/‎. At the least they will keep you on the straight and narrow. As you will know vehicles used in the UK will fail an MOT inspection and be prohibited for use on the Queens highway if: 1. An exhaust system is not adequately supported. 2. Has a major leak of exhaust gases from any part of the system. 3. A catalytic converter missing where one was fitted as standard. 4. A silencer in such condition, or of such a type,that the noise emitted from the vehicle is clearly unreasonably above the level expected from a similar vehicle with a standard silencer in average condition.(Source- VOSA MOT manual) Another point to bear in mind is that if you change the exhaust you can seriously affect the engine temperatures and performance. If the gas flow is restricted from an exhaust fitment, catalytic convertors and silencers may be irrepairably damaged. A further point is the vehicle is described as 'an old V8 Ferrari'. Modifications and adaptions from the factory specification would quite possibly wipe thousands of pounds of off its value, especially when you think even a new factory fresh Ferrari would be regarded by most as a classic.

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errm, well thanks for your time, but you have in no way answered my question... indeed the first part (well most) of your answer is completely irrelevant. –  Digital Lightcraft Nov 26 '13 at 16:19
    
-1 While the content of this is accurate, it does not solve the question at hand. Instead answers that make points like this should be summarized into a small comment on the question. –  jzd Nov 26 '13 at 18:32
    
It just seemed to me that if someone wanted to bomb out the exhaust of a Ferrari they might be oblivious to a lot of things. –  Allan Osborne Nov 26 '13 at 20:10
    
Well Allan you have only been a member for 11 days, don't just assume everyone has no clue (however i have no idea what you mean by 'Bomb out', some semi-insulting Americanism?). The first part of your answer is completely irrelevant. I get the impression you are just here trying to build rep. Do you actually have any in-depth knowledge of exhaust design? –  Digital Lightcraft Nov 26 '13 at 20:50
    
A bomber exhaust is a replacement silencer that is put together to make an exhaust sound louder, it is NOT an offensive remark. I have been involved in vehicle adaptations which included stretch limo's, bullet proofing, tear gas proofing, and on-board life support systems, to many to list here. This did involve exhaust mods and re-design. The point I was making is that Ferrari's are a car apart. I do regret it if you feel offended. –  Allan Osborne Nov 26 '13 at 21:19

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