exhaust silencer knocks on bodywork cutout

[Epiphone]

Hi, I put on a new exhaust silencer and end piece, but it seems to be knocking on the body work at low revs (when it shakes the most) on the cut away arch where the exhaust sits.

Its the shorter silence as I have a cat.

It didn't knock at first, only after a couple of runs, I may have not had the straps done tight enough but I can remember how it was on the old exhaust now. Should the exhaust not poke out beyond this part of the bodywork, or should it sit more flush into the circular cutout or do I need to do the exhaust straps tighter simply?

You can see that its not sitting flush in the curve, but is knocking on the top left of the pic

Thanks, Rich

[NicBeeee]

Hi,

I am not 100% sure but I think your silencer might be upside down, If memory serves me right the tailpipe should exit from the top and not the bottom, if it is upside down then it will be sitting to high, also answers why its not sitting in the brackets correctly.

[Epiphone]

Although the u maybe right (that the exit should be at the top), it's a round silencer so it doesn't sit higher or lower when I rotate it.

I thought I had it when I swapped round the silencer(end to end, it then didn't poke out past the cutout in the body work, as there is an extended end piece on each side, one side being shorter. But the shape and bolt holes match the cat and the exhaust end piece. So I can't do that.

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I think it seems to be also related to the exhaust pipe before the cat, I didn't replace this part and it dictates the angle that the cat can then connect to the silencer.

[Epiphone]

I finally found a petrol bus with a cat on the street and I can see that indeed, the silencer should not poke out past the cut out in the bodywork.

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I believe this come from the angle of the pipe before my cat. I need to loosen it and position the cat joining end more to the left hand side of the bus.

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[California Dreamin]

The exhaust silencer is shorter on models with a CAT..to compensate for the CAT.
Why are you refitting the CAT BTW? I've used a CAT by-pass pipe why gains you a little power and improves fuel consumption. CATS don't need to be fitted on pre-91/92 vans, you just fit a by-pass pipe with a lambda boss for the sensor and the silencer will mount further to the nearside avoiding the chassis.

Martin

[Epiphone]

Hi, yes I bought the shorter silencer. It's a matter of a couple of centimetres now that is poking past. I hope to gain that back when I refit the pre-cat pipe properly.

The cat allows me to have a green sticker on my bus and I can drive in the city centre.

But interesting I never knew u could bypass the cat and the lambda sensor would still work normally.