Why did/does my Bosal backbox not fit?

Need technical Q/A then you're in the right place

Moderator: martauto

George
E30 Zone Addict
E30 Zone Addict
Posts: 2153
Joined: Sat Nov 11, 2006 11:00 pm
Location: Landarn

Post Thu May 23, 2013 8:48 pm

Bit of a grump about this tbh and wondering whether someone could shed some light on it.

3 piece system, 1986 325i cabrio.

Couple of years ago, had an issue with the centre section, was replaced for an item from ECP. The OEM back box was maintained.

Over the last few months, backbox was on its last legs, as such purchased a Bosal item.

Image

Item 247-981 from here.

All the other bits, brackets/joining things were bought from BMW.

Anyway, my Dad took it to the local mechanic to get it fitted (unfortunately I had work commitments) and they stated they couldn't get it to fit!

I wasn't there at the time but the (second hand) feedback I got was that the bores were different sizes and didn't match up (or something like that).

This is a decent mechanic I've used before so I have no reason to believe they were lying.

As a desperate measure, my dad told them to get a backbox from ECP (which I hate - not particularly good quality at all tbh) and that managed to fit ok.

As such, I now have a ECP centre and back section on the car and a Bosal backbox sitting in the hallway.

Can anyone shed some light or have any experience with this Bosal part? It seems to be the correct item for the car, I don't see why it didn't fit.

Any advice/opinions very much appreciated. :)
Image

Sold: 1986 E30 325i Cabriolet, Alpine White :(
Sanchez
Married to the E30 Zone
Married to the E30 Zone
Posts: 7578
Joined: Sun Apr 17, 2005 11:00 pm
Location: Sunny Scotland

Post Thu May 23, 2013 9:21 pm

Was the bosal box correct for you car?
Image
Rtaylor2208
E30 Zone Addict
E30 Zone Addict
Posts: 3004
Joined: Mon Oct 11, 2010 11:00 pm
Location: Ayr, Ayrshire, Scotland

Post Fri May 24, 2013 9:49 am

Any chance they have supplied you a back box for a 320i, as far as I know the pipes are a smaller diameter on them.
Quaser
E30 Zone Addict
E30 Zone Addict
Posts: 2622
Joined: Sun Jan 09, 2005 11:00 pm
Location: West London

Post Fri May 24, 2013 9:55 am

From the diagram, it looks like you need to use sleeves (part 265-909), and clamps with the bosal system.

Maybe its so that you have the same bore all the way through and less restriction??
BMW E30 2.0 Convertible (M52B28)
BMW E30 2.0 2 Door (M20B28 Turbo project to start)
BMW E36 328i Sport (M52B28 Turbo Project)
http://www.e30zone.net/modules.php?name ... ic&t=68663
Sanchez
Married to the E30 Zone
Married to the E30 Zone
Posts: 7578
Joined: Sun Apr 17, 2005 11:00 pm
Location: Sunny Scotland

Post Fri May 24, 2013 10:05 am

The back box should have the same diameter pipes but at the end which joins the center section they should be expanded to fit over the center box pipes.
Image
George
E30 Zone Addict
E30 Zone Addict
Posts: 2153
Joined: Sat Nov 11, 2006 11:00 pm
Location: Landarn

Post Fri May 24, 2013 7:36 pm

@ Sanchez - I believe it is correct.

@ RTaylor - Double checked, they supplied the correct one.

Thanks for the feedback chaps. I'm a bit annoyed about it as I've now paid twice for an exhaust. Nothing fancy was required as the ECP one managed to fit with no issues.

Anyway, I'm selling the car next month. If I get a decent price, I'll include the exhaust too as it saves the bother of selling it here.
Image

Sold: 1986 E30 325i Cabriolet, Alpine White :(