7 replies to this topic

[mini-luke]

Now I know twin box exhaust's are going to be quieter, but how much so? I'm all for a nice exhaust note, but I equally like my eardrums intact and functioning.

I did try and search, but to be honest, the search is dreadful.

[Cooperman]

With a single box (Maniflow or RC40) on a 1.75" exhaust my 'S' won't pass the noise test for rally scrutineering as it's just over 100 db. With a twin-box RC40 it is about 94 Db at the same 5000 rpm. Don't forget, the Db scale is logarithmic, so 94 to 101 is a lot of difference.

[racingbob]

I will NEVER buy a single box again, I say this for the drone inside not the exhaust note

All these sports exhausts seem to give a droning particulary at certain revs like 3400 - 3800 and then starts to go

the twin box is better i know tried both within a month, even then took back to maniflow and asked them to replace middle one with slighty larger one

had 3 types on in about 4 months

Now going thro different soundproofing to help more

[MrBounce]

I had a single box RC40 on my Mini when I first dropped in the 1300cc lump. It was extremely loud although it had a great sound. I replaced this with a twin-box centre exit Maniflow (1.75") and this sounded fantastic but without the loudness.

I also had a straight 2" pipe with a single Peco backbox on my 1330cc GT with 286 cam. That popped and banged on the overrun (it was never set up properly) and set car alarms off. Fun, but too loud! So yes, I would go for a twin box every time now

Edited by MrBounce, 13 November 2011 - 09:39 PM.

[Gulfclubby]

In some countries you are required to have a twin box exhaust by law, including Switzerland, where I live. There's a good reason for that too: the car(s) are still plenty loud even with a twin box system. or in car http://www.youtube.c...?v=DhKkx7sOr9c. I wear earplugs during longer trips...

[mini-luke]

Great thanks all - that's my mind made up!

One more - Maniflow or RC40? I'l leaning towards Maniflow, any words of wisdom?

[MrBounce]

Maniflow every time. They may cost more but compared to the RC40 they are beautifully made. If you're on a budget then an RC40 is fine, but if you can stretch to the extra for the Maniflow, do it!!

[mini-luke]

Maniflow every time. They may cost more but compared to the RC40 they are beautifully made. If you're on a budget then an RC40 is fine, but if you can stretch to the extra for the Maniflow, do it!!

For the cat back one I want, there's all of £20 in in. Mind made up