Is a single 2.25" exh. too small for an s52?

[Adrian_Visser]

As the title says, my 325is has a new custom 2.25 single pipe exhaust with 2.25" cat and a resonator after the cat to magnaflow 14815 muffler, it is loud with the m20, but will I be losing alot of power with the S52 if I use this?

[318isbmw]

I think its definitely pushing it in terms of diameter, I would go 2.5 personally, but it doesn't hurt to bolt it up and see how it feels. Worst case take it off and do 2.5. I think my m42 had a single 2.25 so that's my reasoning for saying 2.5 would be better.

[e30polak]

Considering that a stock s52 exhaust is dual 2" (I think), I'd say ya it's too small. 2.5" is a good size, that's what most of us run.

[Adrian_Visser]

fair enough thanks for the advice, adding exhaust to parts list.

[Mr Two]

I thought stock was closer to dual 2.25" OD?

My personal aim was for dual 60mm, or around 2.36"

[ColdAccord]

I'd like to make myself an exhaust. I'm running e36m3 currently, that bish is heavy as hell.

single 2.5 is kosher?

[MR 325]

I think single 2.5 is a good way to go.

[daniel]

i have single 2.5 with magnaflow in the back. sounds great but it is really raspy at full throttle, even after putting like 10k miles on the car. i hate it.

[matt]

It doesn't really matter.

Stock is not even dual 2" BTW. It's dual wall pipe, the outside is just a heat shield.

[Adrian_Visser]

Okay I think I read something like that it is 40mm inner wall or something isn't it? maybe 44mm I might be mixing up stock e30 and stock e36 M3 sizing fuck I must of spent an hour and a half reading various posts about this shit and now I can't remember it aghh. I know I have read several good threads about what is the perfect 24v rasp free exhaust but all the searching I did didn't turn up the threads I wanted to re-read. So single 2.5 will still give you rasp? does a dual with a x-pipe have alot less rasp than a dual w/o? I always thought that a proper x-pipe would cut down the shit sound alot.
then a y-pipe into single doesn't do the ame job i guess eh?

[e30polak]

Rasp is more over the cause of thin walled ebay headers and raspy mufflers like Magnaflow. Mine is only raspy when I let off the throttle at high rpms and up top. I'm running a Vibrant muffler and a Borla in the middle:

http://www.youtube.com/watch?v=nS2RJCk_itY&feature=related

http://www.youtube.com/watch?v=r2H5YreLZqk

[Mako18]

My M roadster has dual 2.25 (OD looks closer to 2.5) exhaust.

[MR 325]

Rasp is more over the cause of thin walled ebay headers and raspy mufflers like Magnaflow. Mine is only raspy when I let off the throttle at high rpms and up top. I'm running a Vibrant muffler and a Borla in the middle:

http://www.youtube.com/watch?v=nS2RJCk_itY&feature=related

http://www.youtube.com/watch?v=r2H5YreLZqk

I still want to swap a Vibrant on to my car!

[7pilot]

As the title says, my 325is has a new custom 2.25 single pipe exhaust with 2.25" cat and a resonator after the cat to magnaflow 14815 muffler, it is loud with the m20, but will I be losing alot of power with the S52 if I use this?

Yes.
A good 1.8 can use 2.25"
A 2.0 can use 2.25 before cams.
You'll be choking a 3.2.
A stock BMW 2.3l s14 is using dual 1 7/8" pipes to handle 195 to 240 hp flywheel.
The s52 will run like an Eta :yawn:

m

[Adrian_Visser]

Haha well I don't want that now do I.