Standard Exhaust Box Compatibility

[WIL35]

Hello,
Does anyone know if a standard exhaust back box from a Speed Six is the same as the one for a 4.2? I know the 4.5 is different to a 4.2, but not sure if the 4.2 and straight six are the same.

Thanks

[spitfire4v8]

It's a while since I've seen a standard sp6 back box but I'm pretty sure that (for some inexplicable reason) the inlet pipes are spaced further apart on the sp6 box. You could cut and re-weld some appropriate pipes on (or re-orientate the existing pipes if possible) if the rest of the box was in good condition (note that they are prone to collapsing internally whilst looking outwardly sound)

[WIL35]

Thank you sir.

I have just bought the 4.2 that was for sale at Amore Autos, it is decatted and has a sports exhaust, which I find quite loud. I had a 4.2 few years back which had a standard exhaust and had the cats in, which was easier to live with and I didn't smell of exhaust fumes each time I went out in it!. I may enquire with ACT and see what they can do.

[Byker28i]

ACT do a quiet exhaust system which has silencing in the central long pipes. Decatted adds 8-10db. Personally I've leave the cats out as the cabin and gearbox is much cooler. It might be worth adding the ACT silenced decats
http://www.actproducts.co.uk/product/sjd02a-silenc...


The large original back box design weighs a lot. I think it was 12kg lighter for my exhaust system, plus you get a lot more road clearance at the rear.

From what I remember, the 4.2 and 4.5 exhaust systems are the same, just the length of cats changed - maybe. It depends on whats been fitted to your car.

[Byker28i]

Oh and exhaust fumes means it's leaking somewhere.

Have you standard cast manifolds? Worth looking to see if they are cracked, or any signs of soot around the exhaust joints

[WIL35]

The custom exhaust that is fitted has nice big bore tailpipes, so I'd like to keep those.

[url]

|https://thumbsnap.com/89xiJeZk[/url]

Those decat silencers seem to be a good solution. Thanks, I shall investigate.

[Byker28i]

I've no idea what they will reduce the noise by, I've not tried them. I know the cats do 8-10db

My exhaust looks like this. It's been on 10 years now and still excellent. Silencing in the center pipes and tail pipes.
[img]http://www.pbase.com/byker28i/image/99619272.jpg [/img]