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Baus525i
06-01-2009, 09:15 AM
If I take the muffler off of my 525i do I have to worry about back pressure Problems?

In 2000 I brought a brand new 2001 Harley Davidson Fat Boy and when i asked the dealer about taking the mufflers off and just going straight pipe I was warned about Messing up the engine if not retuned after removal. The dealer stated that with all engines after removing the exhaust or changing it, the back pressure can screw up the engine.

Does anyone know what i am talking about, because I really don't
Thanks

tturedraider
06-02-2009, 01:01 AM
Welcome to the 'fest. You posted this in the Z4 forum.

teagueAMX
07-11-2009, 05:05 PM
If I take the muffler off of my 525i do I have to worry about back pressure Problems?

In 2000 I brought a brand new 2001 Harley Davidson Fat Boy and when i asked the dealer about taking the mufflers off and just going straight pipe I was warned about Messing up the engine if not retuned after removal. The dealer stated that with all engines after removing the exhaust or changing it, the back pressure can screw up the engine.

Does anyone know what i am talking about, because I really don't
Thanks

Not sure why you want to remove you muffler, but the dealer should have said lack of back pressure.

When I was a teenager, I was really stupid but thought I was smart by having a straight exhaust pipe made for my French car (which will remain nameless).

Well, it was a rear engine and the pipe was relatively short. It was fun driving down the road for a while, but a funny thing happened - the exhaust valve seats came loose in the cylinder head. I suspect the short exhaust pipe allowed cool air to travel up the pipe caused the exhaust valve seats to shrink in the aluminum cylinder head and they came loose.

Potentially that could happen to a Harley in like manner but not your 525i. Some will claim that an engine needs some back pressure to run properly, at least for street use. I don't buy it personally. True high performance exhaust systems eliminate back pressure to improve engine efficiency. Back pressure means the engine is having to push the exhaust gases out you tail pipe.

Headers on the other hand use a "scavenging" effect of pulling exhaust gases pulses as each one exits the cylinder head, a type of vacuum is created in an adjacent cylinder prior to the piston pushing the exhaust out.

On cars with normal exhaust systems you lose nothing and gain nothing except more noise when you remove your muffler. Buy a nice free flow muffler with a good sound.