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Exhaust size: standard or big bore, does it make a difference?

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Luegolover Avatar
Luegolover Steve L
London, London, UK   GBR
I am looking at getting an exhaust for my 100 and am befuddled by the options available and as money is a challenge for me I thought I'd ask for some advice. I have a standard engine and currently have no plans to modify it. I would prefer a stainless system as I don't want to deal with the inevitable problems associated with rust. I was thinking of a standard bore system to mount on to the standard manifold and would like to option of a side exit tail pipe (I have found somewhere that will supply a 90 degree bend for that). The going rate for a standard system is about £250 including tax which is manageable. I remember fitting a large bore system to my Midget when I was a kid and it made no noticeable difference other than being louder and I am not interested in loud.

Should I look at the larger bore systems? Do they make any difference?

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simon62BT7 simon ackers
Tadley, Hants, UK   GBR
Hi, if the engine is standard I would stick with standard bore, although SS not an issue but may get slightly different exhaust note. You won't get any noticable performance improvement. Learnt my lesson when building a 1275 stage 2 for my Sprite using Maniflow manifolds. I visited Maniflow, who were really knowledgeable and advised bore size to match engine tune/manifold.

Its something to do with creating the right amount of back pressure. Higher tune = greater exhaust output, to which you match Manifold and exhaust bore. Complex maths that i can't begin to understand!

I also have a 100/4 kicking out 150bhp into tubular manifold/large bore. Works a treat! Good luck.

Edited 3 time(s). Last edit at 2018-10-14 05:37 AM by simon62BT7.

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