Exhaust noise

[marlineer]

My Pinto engined Berlinetta has a single box exhaust as is more or less standard but it's a little loud for my taste (or perhaps I'm just getting older!). Is it just a matter of adding an extra box to reduce the noise level and if so does anyone have any recommendations?

[billjackson54]

I've had three cars single box systems on cars I've owned...2 on Pinto engines and one on a DOHC I4. Without exception they were all OK to start with, but got much noisier over time. With the last one, which was a stainless steel custom made single box 34" long by 6.5 inches in diameter mounted under the near side running board, I removed it and working with a friend cut off one end, welded in a flange so that we could repack it. The original packing was just fibre-glass wadding which had all drifted down to one end, so we used two rolls of material from Car Builder Solutions, carefully rolled round the interior to avoid the migration all to one end. The problems to balance are the loss of ground clearance with underslung twin box systems and the extra noise likely from a single box under the running board. So my suggestion is the biggest single box you can manage, freshly packed, under the running board and be prepared for repacking every couple of years. Having said that, my Hunter has a catalytic converter just under the nearside footwell feeding a single silencer box just forward of the back axle which in turn feedis into a tail pipe passing diagonally across the rear of the car exiting behind the rear off side wheel. It's wonderfully quiet, but ground clearance is a problem!

[marlineer]

Thanks for that Bill, that is a very comprehensive answer. Ground clearance is alw


ays a problem with cars like this. Given the regular maintenance required by the rest of the car I was hoping for a fit and forget solution with off the shelf parts that didn't require stripping down and refurbishing the system every 2 years.

[andyf]

I don't usually worry about mine until it starts triggering car alarms as I drive past!

[marlineer]

Yeah, I think the simplest solution would be a pack of earplugs from screwfix.

[MOC Chair]

My pinto is reasonably quiet when cruising but noisy when pulling, especially up hills. I have two silencers fitted but the second one has a large bore tailpipe.
To keep the noise down, a silencer with baffles may be needed.

[marlineer]

Thanks, I'll look into that.

[Ye Ol Ripper]

Just to add to the above comments. Rectangular boxes are significantly quieter than circular/ tubular boxes. Also stainless steel exhausts are noisier than mild steel.
The type of air filtering system can also contribute to the exhaust noise, so that maybe an area to look at; but is not always the case.