Backbox help

18th February 2014, 11:27

So I've recently passed my test and I bought a 2002 saxo furio recommended by my brother.
Anyway, I am wanting to tune my car and without little knowledge or joining up to this prior to buying, I bought a sportex backbox which is 4" in diameter and the tail pipe is 3" long. After reading the massive thread by Dan, I realised bigger isn't better due to not having enough pressure. Will this backbox actually make my car go slower or will it have no impact on speed/acceleration?
Thanks

18th February 2014, 11:34

its doubtful it'd make any noticeable difference but its going to look rather awful and probably sound just as bad

18th February 2014, 11:34

Quote:

Originally Posted by Angus_Law

So I've recently passed my test and I bought a 2002 saxo furio recommended by my brother.
Anyway, I am wanting to tune my car and without little knowledge or joining up to this prior to buying, I bought a sportex backbox which is 4" in diameter and the tail pipe is 3" long. After reading the massive thread by Dan, I realised bigger isn't better due to not having enough pressure. Will this backbox actually make my car go slower or will it have no impact on speed/acceleration?
Thanks

Back pressure on an injection car doesn't really affect it much really unless you're running on the very edge of what the engine can cope with, ie running a 400bhp saxo

but don't worry about back pressure and all that for now, its only a backbox so it won't affect anything no matter what the size of it really.
If you want an exhaust that gives more performance, you need a decent backbox, straight through centre pipe and a 4-2-1 manifold

Hope this helps

18th February 2014, 13:40

Thanks Brady! Well on the furio it came with a stock fitted straight through centre pipe and the back box hasn't arrived yet but looking forward to putting it on! It has the stock manifold on it as well but I don't know what the pipe layout is. I'm glad it won't hopefully slow it down anyway!

18th February 2014, 13:48

Quote:

Originally Posted by Angus_Law

Thanks Brady! Well on the furio it came with a stock fitted straight through centre pipe and the back box hasn't arrived yet but looking forward to putting it on! It has the stock manifold on it as well but I don't know what the pipe layout is. I'm glad it won't hopefully slow it down anyway!

Yeah fair enough, the standard manifold is a 4-1 layout technically but its completely different to an actual performance 4-1 or 4-2-1 manifold plus you'll have the cat in the standard manifold which restricts breathing quite a bit

Are you sure the backbox will fit on to the standard centre pipe? As I'm guessing the sportex backbox is made for an aftermarket system which will have bigger diameter pipe, so it may not fit onto the standard Furio exhaust...not 100% sure on that though but its what I'd expect

18th February 2014, 14:15

I messaged the sportex people and they said that it should fit on to it, if not then I will have to invest more money in to it!

18th February 2014, 14:50

Quote:

Originally Posted by Angus_Law

I messaged the sportex people and they said that it should fit on to it, if not then I will have to invest more money in to it!

Ahh ok, hopefully it fits then! Would be worth getting a sportex centre pipe too though

18th February 2014, 17:08

Yeah I'll see how this one performs as to whether I get one or not, probably will but just not yet