Inliners International Forums General Discussion Hi Performance Exhaust sound from vacuum leak? Or something else?

I am running long tube headers on my 250 and it does not have a crossover/h pipe. At the back of the truck, the pipe that exits on the drivers side I can hear and feel a distinctive pop that stays constant. On the pipe the exits on the passenger side, I feel air moving out but not a smooth distinct pop. More of a 'pluff' sound. I have 120 psi compression on the cylinders and the spark plugs are firing in order. I assume I want the constant and distinct pop sound. Would a vacuum leak cause the 'pluff' sound? I know I have a vacuum leak, just have not found it yet.

So all 3 pulses out the driver's side pipe sound different than all 3 pulses out the passenger's side pipe?

I would expect an exhaust issue before a vacuum leak in that case.

Is the system new? If it is how sharp are the bends in the pipe that get it to the passenger's side?

If the pipe is small enough and the bends are sharp enough that might make the difference.

If the system is older and this situatuion is new then I would suspect an exhaust restriction.

Perhaps the muffler is collapsing internally?


Just out of curiosity how do you know for sure you have a vacuum leak?

A mouse nest inside the pipe might cause what you descripe. Rev it up until it blows out. Watch for acorns and other debris at high velocity out the pipe!

The pipe on the passenger side is longer and runs a different route. How much difference is there?