I've got a Performance exhaust from my e82 125i and I was hoping to install this on my 135i. The 125i has a 2.5" diameter pipe and the 135 a 2.75" pipe, I was considering using an adapter to mate the two.
I know this inducing a very slight restriction just before the back box but it's only a 7mm step down and the fact the performance back box is a freer flowing box in comparison to the stock 135i back box would surely counteract any added back pressure by the adapter?
I know in an ideal world i should just get the 135i version which is 2.75 straight through. I'm not really looking to add performance by doing this, just a little more sound and get rid of the stock looking pipes until I eventually buy the 135i version later in the year.
Am I going to do any damage running a 7mm step down?
I know this inducing a very slight restriction just before the back box but it's only a 7mm step down and the fact the performance back box is a freer flowing box in comparison to the stock 135i back box would surely counteract any added back pressure by the adapter?
I know in an ideal world i should just get the 135i version which is 2.75 straight through. I'm not really looking to add performance by doing this, just a little more sound and get rid of the stock looking pipes until I eventually buy the 135i version later in the year.
Am I going to do any damage running a 7mm step down?