My Peugeot 407 (EW10A) exhaust system modification


Wrench Pro
Malaysia, Kuala Lumpur
Peugeot 407
Passion crept day by day and eventually I succumbed to it, if you get what I mean ;). Eventually, dream turned into reality and I had a 4-2-1 extractor customized for my car.

As the local car accessory industry does not have an off-the-shelf unit specifically for my model, my extractor had to be R&D-ed and made from scratch so I guess mine is the first of its kind from where I come from. It was found the stock exhaust pipe was respectably 2" in diameter so it did not have to be changed.

Upon receiving the car, surely as expected, performance improved by a big margin but the now more efficient exhaust system began to show the weakness of another component: the rear muffler. It could not handle the increase pressure and would resonance between 1,500-2,500 rpm.

For one accustomed to this quiet car, it was too irritating to hear. After the weekend ended, the car was returned and from R&D carried out, it appeared even a custom rear muffler was not good enough to bring the exhaust system to a stock note and that required an additional fast flow mid-muffler. Now, the car was received and apparently, it has better performance than before with just the 4-2-1 extractor alone.

This was because the mid and rear mufflers effectively control back pressure much needed in automatic geared cars to give it that extra oomph which I was told this was not an easy thing to do.

Lack of rear space prevented the creation of a bigger rear muffler to meet my technical requirement of "as quiet as the stock sound" however the end result is very good muffled hum which wifey and me said it's okay.

The car now delivers a more pronounce torque upon taking off from standstill and performance gets better and better, the faster one goes. Conclusion: I'm a satisfied customer!


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Very interesting, keep us up to date with your project progress and thanks for the pics and writeup.

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