Side exit exhaust and carb tuning

[b3nson]

Inspired by a couple of cars at RRG i'm thinking about getting a side exit exhaust made up for my Sprint (the historic racing Sprints have them and they sound awesome). Question is, if it's just a straight through pipe is it likely to affect the tuning I need on the carbs compared to my current sports exhaust with one rear box?
The plan would be to keep both exhausts and swap between them when I fancy it.

[ChasR]

IME it is the manifold that makes the biggest difference. It "may" run leaner but I doubt it. An AFR gauge would give you a conclusive answer though .

[elmotheewokking]

When I did this to my 1850, 5he difference was insane. With stock needles in, she wouldn't rev beyond 3k before the afr took a nosedive. Granted, also fitted stupid huge k&n filters at the same time which didn't help.
Either a rolling road session with someone like Tom Airey or an AFR gauge (and lots of time learning twin SU theory) will see you right. Be warned though, a single glass pack type silencer will be stupid loud.

[ChasR]

It was probably the air filters that caused the leaning out. My 'B ran pretty well with stock filters but a single 'box exhaust system, still on stock needles. I was quite surprised.

My Spitfire however was a nightmare! When I got it the car barely made it home. OK, it ran but it flatter than a pancake made from the last drops of battermix. It also had zero pace, a bit different to most 1500s I have driven, and the last one I had!

It was stock bar a TriumphTune 4-2-1 manifold, stock exhaust and K&N filters

From ABT needles I went to AAQs which did improve matters, but it always wanted more fuel. Maybe AARs would have helped more.

b3nson, what is your budget? You could get a seperate take off further upstream from the exhaust a bit like alot of Yanks do, so as to give the noise you want.

Alternatively, if you have the cash to splash, get silencer which goes quieter with the flick of a switch. Cheap however they are not.

[b3nson]

To be honest, budget would be fairly small as it would be mainly for shows etc, would want it less anti-social for normal days out! So anytime of tapping into the current system would probably go too far, ideally just wanted to unbolt and bolt up the other pipe.
I just remember when my downpipe was leaking halfway down I lost a shed load of power and torque, didn't know whether this would be different with another couple foot of pipe! Maybe a small cherry bomb or something inthere as well?