E39 540 Twin Exhaust

[Dn540 67]

Hi folks,

Have searched everywhere and can't seem to find any information about exhaust sizes on 540's. Everyone seems to buy off the shelf systems or go with a simple 3".

I'm looking to go with something similar to my Ford 5.0 but in a smaller pipe and more mufflers so it's not too loud.

Currently thinking of a Magnaflow Tru-X x pipe, de-cat, twin 2.25 mild steel, a Magnapack 5" round muffler in each pipe and a small, simple resonator in each pipe and two Magnaflow double wall tips.

I already have the x-pipe and tips (left over from when i went bigger on my Ford set-up)

Piping runs side by side so it exits on the same side.

Is the twin 2.25" going to be too big?

[jeffbebe 1560]

2.25" inner diameter should be perfect.

[Michael. 2313]

^ You will find Magnaflow mufflers are very good quality Ron, as good as OEM specification in many cases.

Its flowmasters that are the rubbish ones designed for american v8s.

But yeah I'd go 2.25 or 2.5 tube with an M62

[Dn540 67]

2.25" inner diameter should be perfect.

Excellent, I'll go with that.

57mm too big? really? , they might suit a low revving push rod V8 or two valve engine.

Provided you have decent headers to actually structure the flow through the engine a well designed 4 valve will benefit from a lot more pipe.

For example 3 litre M3 runs twin 63mm pipes you have 4 litres of air to process at the same RPM or 30% more so correctly designed so you could go to 67mm ID

I run twin 63 mm pipes ( Actually an M3 system) on my 328 and they are just fine - with good headers good power and torque gain right across the rev range.

and put some decent mufflers on it not those rubbish magnaflows designed for strangled American V8s

I've just got the stock m62 headers.

On my highly modded, 5-speed pushrod 5.0, dual 2.5" probably isn't the best. Dual 2.25" probably would have provided better back pressure. And it's not exactly low revving.

Magnaflow are very good quality, full stainless steel and straight through. Flow master and the likes are complete rubbish.

I had also considered Borla, but I've never seen or heard them in person.

I was going to go with a 3" system and a Magnaflow 14815 back box but I'm not a big fan of single 3" systems and I love the sound of the Magnapacks.

^ You will find Magnaflow mufflers are very good quality Ron, as good as OEM specification in many cases.

Its flowmasters that are the rubbish ones designed for american v8s.

But yeah I'd go 2.25 or 2.5 tube with an M62

Thanks, I'll stick with 2.25 seeing as i have the x pipe and tips already.

[sonic_attack 89]

Headers would be nice. Seen the price though? The only rhd ones ive found are out of Australia for 2k. I havent investigated local fabrication but I imagine the price will be thereabouts +. I also assume lhd will be no good because something will be in the way.

Fwiw my 3" exhaust sounds like a subaru. New from previous owner though so im not touching it.