[lecatrache]

Most brands are now releasing new models with flashier exhausts, I guess responding to consumer demand.

BMW has taken the exhaust as a differentiator: 330i vs 325i - difference was on the chrome; the M3 has four. New 335i has dual exhaust but now is split.

I recall several threads dealing with people spending a fortune to install split exhausts in the 330i.

I have some questions:

1. Is this only about style, or also performance?
2. Are the new split dual exhaust in the 335i better (performance-wise) that in the 330i?
3. Is the 328i also split, or will it be the same as in the 325i?
4. Why a cheap Nissan Maxima can come with quads and a 335i only dual?

[jadeddjay]

correct me if i am wrong but each turbo feeds 3 cylinders right? makes sense to have two.
http://www.e90post.com/forums/showthread.php?t=14884

the 328 just has a splitter at the end.
http://www.e90post.com/forums/showthread.php?t=18241

[KL2DC]

1. Its a true dual exhaust
2. Dunno... I'd think more exhaust gas is expelled through the dual exhaust.
3. 328i is as per 325i
4. You can change your 335 tips to quads. Some Y-pipes and cutting/welding ought to do it.

[E90Fleet]

1) 1 for each turbo
2) better for the 335i, wouldnt help a 330i
3) same as 325i
4) Because its just for looks

[inTgr8r]

... Exhaust 101

[radgator1]

This reminds me, I wrote a couple of threads a while back looking for a pic of the stock 335i exhaust and never got any replies. Usually you can find a pic or schematic of the exhaust from the manufacturer but I haven't seen one for this car. Does anyone have a pic of the exhaust or if not could someone snap one when their car is on a lift.

Thanks

[vantage]

the reason for the dual exhaust is to help the engine breathe easier. The main reason the 335i has a dual however is because of the turbo. Each turbo feeds of a seperate exhaust.

(ps. no idea why the hell the maxima has 4 )

[goldminer]

Originally Posted by jadeddjay

correct me if i am wrong but each turbo feeds 3 cylinders right? makes sense to have two.
http://www.e90post.com/forums/showthread.php?t=14884

This is wrong. Each turbo is fed BY 3 cylinders. They do not feed 3 cylinders. The output pipes of the 2 turbos merge immediately ahead of the front turbo. You can see this in the photos you linked to. The merged pipe goes to a single intercooler and single intake plenum so each turbo feeds all six cylinders.

I suspect that this engine, under boost, flows a lot more gas than the NA engine and the N54 engine benefited from the increased ability to flow gas offered by a true dual exhaust.

[PiperD]

So the 335i has two completely seperate systems? From the brief looks I've had at the underside of my e46, there appear to be two headers and two downpipes into a single cat, then two intermediates into a single muffler, then two tips. Never understood why it was like that, but whatever.

[Dante]

Originally Posted by radgator1

This reminds me, I wrote a couple of threads a while back looking for a pic of the stock 335i exhaust and never got any replies. Usually you can find a pic or schematic of the exhaust from the manufacturer but I haven't seen one for this car. Does anyone have a pic of the exhaust or if not could someone snap one when their car is on a lift.

Thanks

I already posted this one in one of your threads:

http://www.e90post.com/forums/showthread.php?t=32061

[lecatrache]

The muffler and exhaust pipes also determine the classical pitch note that the BMW is known for. Too much moding around might screw those sacred notes up.

[John 070]

The H pipe? that joins the two mufflers is interesting. I never quite got the true dual concept down, because it can be a true dual where the exhaust is mixed and separated again.

In the case of the Maxima, Acura, Kias of the world, they have a Y-pipe after the cat which does nothing more than have two outlets at the back. It's for looks.

Actually, I was a bit disappointed when I first saw the two pipes on the 335, but I had faith that BMW would never just put something phoney on the car for looks. But I do wish that my 335 would have led brake and turn lamps, not that ribbon parking lamp thing a ma jig.....

[JVFan]

lol

Can't you get a Vette with 8 now? Looks like the Millenium Falcon.

[climkt]

the stock 335i pipes and bumper does not look very sporty, despite it being a fast car. guess they want to be really discreet.
in contrast stock is250 pipes and rear look more sporty and aggresive. any comments?

[Darklighter]

The IS ones look more aggressive because they're closer to the corners. Maybe if the stock 335 ones were a little bigger to fill out the cutout on the bumper it would help.

[climkt]

Originally Posted by Darklighter

The IS ones look more aggressive because they're closer to the corners. Maybe if the stock 335 ones were a little bigger to fill out the cutout on the bumper it would help.

yah. agree with u. the position of the pipes does make a diff.
quads near the centre is the exception but quads look cool anyway.

[number9]

how tough would it be to fit the 335's dual exhaust on a 2006 330?

[BMW E90]

Originally Posted by vantage

(ps. no idea why the hell the maxima has 4 )

it "looks" fast

[crashoverride]

Originally Posted by goldminer

This is wrong. Each turbo is fed BY 3 cylinders. They do not feed 3 cylinders. The output pipes of the 2 turbos merge immediately ahead of the front turbo. You can see this in the photos you linked to. The merged pipe goes to a single intercooler and single intake plenum so each turbo feeds all six cylinders.

I suspect that this engine, under boost, flows a lot more gas than the NA engine and the N54 engine benefited from the increased ability to flow gas offered by a true dual exhaust.

A bit bothered by your incorrect correction of someone else than I read this article here are a couple of quotes that were of interest.


Built to BMW specifications, the two small low-inertia Mitsubishi turbochargers provide air to three cylinders and operate together rather than sequentially.

BMW specified that it wanted its turbines to tolerate high-heat operating conditions of up to 1050 degrees, more than 100 degrees higher than other turbos with durability equivalent to the life of the car. It claims the special heat-resistant steel used in their construction is better than a ceramic turbine.

Why has BMW returned to turbocharging? "Direct injection has helped us return to turbos," he said. "We can increase the compression ratio and also help reduce fuel consumption and increase engine efficiency.

"The 335i has the fuel economy of a six and performance of a V8.

http://www.editorial.discountnewcars...2571A00080FE09

[radgator1]

Originally Posted by Dante

I already posted this one in one of your threads:

http://www.e90post.com/forums/showthread.php?t=32061

Opps (where's that embasrrassed smilie when you need it) I guess I forgot to keep checking back. Thanks bro, that true dual system looks pretty sweet. I was hoping for some pics of everything from the cats back to see if there are any superfilous resonators that could possibly be removed.

[radgator1]

Originally Posted by number9

how tough would it be to fit the 335's dual exhaust on a 2006 330?

Close to impossible I would assume since there are sure to be parts in the way on the undercarriage. Since the car wasn't designed to have 2 mufflers and such there is no way it is going to fit. Why not just go for the new Eisenhaus with the quad tips?

[goldminer]

Originally Posted by crashoverride

A bit bothered by your incorrect correction of someone else than I read this article here are a couple of quotes that were of interest.


Built to BMW specifications, the two small low-inertia Mitsubishi turbochargers provide air to three cylinders and operate together rather than sequentially.

I also have repeatedly read in magazines that each turbo feeds three cylinders but this is definitely wrong. Look at the red circled area in the attached photo of the 335i's induction, exhaust and fuel injection systems. You can see that the outlet pipes from the 2 turbos merge immediately and enter a single pipe leading to the intercooler (the box-shaped thing on the lower right of the photo). The two turbos have to each be feeding all six cylinders as their compressed gases have mixed. This can be clearly seen in the photo. The magazines are wrong.

By the way this photo also shows that this system is a fully dual exhaust from the engine back as the are two cats (or resonators?) and two pipes, one each, behind each turbo (lower left of photo).