Single box or twin box exhaust system??

Single box or twin box exhaust system??

Author
Discussion

volores

Original Poster:

116 posts

204 months

Monday 4th July 2011
quotequote all
Hi all

Quick question......single or twin.....have ordered am RC40 rear box with large bore tail pipe and cant decide whether to keep as a twin box system or get rid of the middle box.

I would like a throatier exhaust tone but don't want anything too loud...my boy racer days are over and already have an elise which wakes the neighbours!

Would the new rear box along with a middle silencer be sufficiently different than than standard system it currently has - or would I only really get an improved exhaust tone from removing the middle silencer?

Cheers

FWDRacer

3,564 posts

231 months

Monday 4th July 2011
quotequote all
Twinbox RC40. That'll give you what you want - deep and purposeful without being overly noisy.

Cobbling an RC40 rear onto your current middle box - total waste of time.

A single box RC40 could give an aspirin, a bl**dy headche! There isn't any gain in running a single box RC40 system. I think you'll run the risk of getting your collar felt too.

Edited by FWDRacer on Monday 4th July 11:26

volores

Original Poster:

116 posts

204 months

Monday 4th July 2011
quotequote all
cheers...that answers my question perfectly.....twin box it is!

guru_1071

2,768 posts

241 months

Monday 4th July 2011
quotequote all
i run a single box one on my std 1725 and the noise is ok, a twin would certainly make it more mellow and quieter.

smash

2,062 posts

235 months

Monday 4th July 2011
quotequote all
I must be missing something here - I had an RC40 twin box on a Cooper 998 and it was very disappointing (read very quiet), our previous stock 998 (well stage one) had single box system and sounded great.

guru_1071

2,768 posts

241 months

Monday 4th July 2011
quotequote all
smash

its to do with old age.... smile

anonymous-user

61 months

Monday 4th July 2011
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I have a single box twin DTM. Bought it from JonSpeed and it's loud but sounds good as well, not to chavy.
Recommend it to anyone.

Plus it looks great!

cone

471 posts

242 months

Monday 4th July 2011
quotequote all
Singlebox RC40 is my choice ( on a 1071 ) , gives a nice sporty rasp - twin boxes are too quiet IMHO , though I would have ordered a standard bore , depends on what you're after , Large bore = deep noisey , standard bore = what you expect a mini to sound like.

AlleyCat

811 posts

178 months

Monday 4th July 2011
quotequote all
im running a twin dtm 2" Maniflow single box system on my supercharged jobby, its a bit louder than i would like!

Cooperman

4,428 posts

257 months

Monday 4th July 2011
quotequote all
I always run twin box Maniflow or RC40 as I don't like noisy cars.
What you want for a 1275 is a 1.75" internal dia. exhaust right to the end of the final exit pipe. What you don't want is a larger diameter final pipe as this causes the exhaust gas to slow down and the pressure to increase in the pipe, thus losing efficiency. Ideally the velocity of the gas molecules needs to be constant right to the exit point.

nick1275

1,272 posts

177 months

Monday 4th July 2011
quotequote all
i had a single box on my fisrt 998 it wasnt to bad, still going strong on another car and not to loud. however my current 1380 has a twin box maniflow with a huge rear silencer to get the noise down

FWDRacer

3,564 posts

231 months

Tuesday 5th July 2011
quotequote all
Cooperman said:
I always run twin box Maniflow or RC40 as I don't like noisy cars.
What you want for a 1275 is a 1.75" internal dia. exhaust right to the end of the final exit pipe. What you don't want is a larger diameter final pipe as this causes the exhaust gas to slow down and the pressure to increase in the pipe, thus losing efficiency. Ideally the velocity of the gas molecules needs to be constant right to the exit point.
It's an exhausting subject - but clearly you understand it.

Cooperman

4,428 posts

257 months

Tuesday 5th July 2011
quotequote all
It's covered by a thing called 'Bernoulli's Theorem'. This states that when a fluid passes along a pipe, if the cross-sectional area of the pipe increases, the fluid velocity decreases and the pressure increases. If the area of the pipe decreases the velocity increases and the pressure decreases (that's how a spray gun works).
As the molecules of exhaust gas rush along the exhaust pipe they gain an inertia and it's this inertia which makes them exit the end of the pipe efficiently. So if you fit a larger diameter rear final pipe, or even (God forbid) twin large pipes, you screw up the gas velocity/molecular inertia causing increased pressure in the end of the pipe and loss of power.
Sorry if it's a bit theoretical, but that's briefly the physics of it.

R4NDY

144 posts

231 months

Saturday 9th July 2011
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As previously mentioned, same bore all the way through is required.
RC40 the only one i'd recomend.
I would recomend twin box for a car you use regular and with some motorway miles or single box if its just a thrash toy.
Or when you fit it make it easy to swap between the 2?

volores

Original Poster:

116 posts

204 months

Sunday 10th July 2011
quotequote all
update....Twin box RC40 fitted....spot on...nice exhaust tone.

volores

Original Poster:

116 posts

204 months

Sunday 10th July 2011
quotequote all
update....Twin box RC40 fitted....spot on...nice exhaust tone.

volores

Original Poster:

116 posts

204 months

Sunday 10th July 2011
quotequote all
update....Twin box RC40 fitted....spot on...nice exhaust tone.

Cooperman

4,428 posts

257 months

Wednesday 20th July 2011
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You must like it 3 times more than the old one!

iamvandam

10 posts

160 months

Wednesday 20th July 2011
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lol