Welding aftermarket Muffler to bmw

pentium4, Jul 3, 10:05am
Hi there,

Before i do so i want to make sure im not going to jepradise the goodness of what ihave, my car is currently 100% stock standard as it came from the factory but im after a more deeper rumble and want to get a muffler welded to the back section of exhaust.

-will this decrease performance!
-will it increase fuel consumption!

Vechile and muffler info:

bmw 735il 1989, 93000km, auto, 3.5l

power pro euro twin tip muffler

cheers

pico42, Jul 3, 11:58am
What are you cutting out to install this muffler!

peril787b1, Jul 3, 1:07pm
Having had a power pro (same euro twin tip) on a BMW, don't do it. Car will sound awful, fuel consumption wil increase and the muffler will become noticebly louder after approx 9 months. At idle, it sounded awesome, but horrbly droney at cruise, and being auto (same as yours) sounded like a wet fart in a baked bean can on gear shifts. Changed to M series muffler (2nd hand), sounded great and fuel consumption returned to normal.

intrade, Jul 3, 3:56pm
normally you fit a other muffler with clamps or flanges not welded , if you are going to keep this then i would fit fully stainless muffler front to back and be done for the next 40 years

intrade, Jul 3, 4:00pm
if the mufflers have not the right backpressure then it will be noisy like boyracers and use loads of gas and produce less horspower .remus, bosal are 2 good muffler manufacturer for example
https://www.remusonline.com.au/products/088093%200548L

jason_247, Jul 3, 8:22pm
my first step would be to remove the cat if it has one
At this age it will be clogged to buggery
I decatted a 1990 750il and at idle it went from a smooth humm to a good rumble
fuel efficiency was greatly improved

sw20, Jul 3, 8:29pm
Back pressure. The myth of exhaust systems.

richardmayes, Jul 3, 8:36pm
Listen to #3 and #6.

You have a nice car. Don't ruin it with a boy racer "look at me!" exhaust.

The beauty of a straight six is that they are perfectly smooth at idle but the sound goes orgasmic when you rev them. "Rumble" is what V8s (or 4 cylinders with "look at me!" exhausts) do. Why would you want that!

chutneyman, Jul 3, 11:17pm
Why do some people who have Autos, put after market stupid loud exhausts on ! It just sound ridiculous !

peril787b1, Jul 4, 8:54am
Some autos sound right with loud exhausts - v8's and old 6's (like valiants). Bimmers not so much.

moosie_21, Jul 4, 10:21am
Oh dear lord, just NO! Leave it stock or replace it from headers to exhaust with M spec parts, not just weld some fart cannon on the back! Do it once, do it properly.

unbeatabull, Jul 6, 11:06am
Whats so mythical about it!