128i with N55 Magnaflow 15527 & AA headers

[E30ROB]

Recently changed my exhaust to the N55 Magnaflow 15527 for a few reasons..

Ill list MY reasons, and my opinion about it, and some photos to follow when I get the car on a lift.

Reasons I got it:
1. I needed/wanted a full, matching exhaust system to replace my chop shop
OEM exhaust.
2. I needed an exhaust without cats but also needed to quiet the car down,
because N52's are notoriously loud after 5,000 rpm.
3. Versatility with the muffler for when I finish the 1M conversion I can slip on
the 1M magnaflow, or 1M Akrapovic slip on.
4. Price! I got the full system on sale for $775 shipped from HOTTEXHAUST.COM

My opinion and fitment:
I think it definitely toned the car down from where it was on Db. It gave the car alot deeper sound, with some slight rasp under load between 1000 and 2000. The sound has characteristics of a VQ echaust note.

The fitment was good as far as bends, however I am running aftermarket headers and aftermarket exhaust so the midpipe is currently touching against the heat shield. On thursday we will change the header flanges to V-Bands and re-align the midpipe.

The system is 3" all the way through, and the tips are big for the N52 non m-sport bumper.

[LcossE82]

Originally Posted by E30ROB

Recently changed my exhaust to the N55 Magnaflow 15527 for a few reasons..

Ill list MY reasons, and my opinion about it, and some photos to follow when I get the car on a lift.

Reasons I got it:
1. I needed/wanted a full, matching exhaust system to replace my chop shop
OEM exhaust.
2. I needed an exhaust without cats but also needed to quiet the car down,
because N52's are notoriously loud after 5,000 rpm.
3. Versatility with the muffler for when I finish the 1M conversion I can slip on
the 1M magnaflow, or 1M Akrapovic slip on.
4. Price! I got the full system on sale for $775 shipped from HOTTEXHAUST.COM

My opinion and fitment:
I think it definitely toned the car down from where it was on Db. It gave the car alot deeper sound, with some slight rasp under load between 1000 and 2000. The sound has characteristics of a VQ echaust note.

The fitment was good as far as bends, however I am running aftermarket headers and aftermarket exhaust so the midpipe is currently touching against the heat shield. On thursday we will change the header flanges to V-Bands and re-align the midpipe.

The system is 3" all the way through, and the tips are big for the N52 non m-sport bumper.

What's the stock exhaust diameter? 2.5"

[Taskmaster]

Pictures and sound clips!

[E30ROB]

Originally Posted by LcossE82

What's the stock exhaust diameter? 2.5"

Not sure, I believe it is 2.5" or 2.75" but no bigger or smaller.

[E30ROB]

Originally Posted by Taskmaster

Pictures and sound clips!

On it, will report back tomorrow

[JimD]

Real OEM doesn't list the piping size but does have the clamp at the inlet to the muffler size. For our 128is, it is listed as 65mm which is just over 2.5 inches. That must be at least very close to the pipe OD.

The highest rated n52 is some of the n52B30 at 200kW, 268 hp. Some of them (I looked at the 330) seem to have the same size muffler inlet. But the E70 (X5) with this motor has a 75mm - 2.95 inch - muffler inlet.

I like the idea of a 3 inch exhaust for the n52. There seems to be an association between that size and considerably more hp than our n52s are rated at.

[Taskmaster]

Originally Posted by JimD

Real OEM doesn't list the piping size but does have the clamp at the inlet to the muffler size. For our 128is, it is listed as 65mm which is just over 2.5 inches. That must be at least very close to the pipe OD.

The highest rated n52 is some of the n52B30 at 200kW, 268 hp. Some of them (I looked at the 330) seem to have the same size muffler inlet. But the E70 (X5) with this motor has a 75mm - 2.95 inch - muffler inlet.

I like the idea of a 3 inch exhaust for the n52. There seems to be an association between that size and considerably more hp than our n52s are rated at.

Been saying this for a while. I bought the parts to make my own custom exhaust at 3", but I don't have the car anymore.

[E30ROB]

Just finished up at the exhaust shop. Got the midpipe to hang free and clear of any interruptions.

Sounds great, feels great. Definitely getting louder as I put the miles on it. Here are some photos from today.

One thing to keep in mind that I should have mentioned in the OP , the flanges are different size and so is the pipe diameter (header to midpipe flange). LUCKILY I have the AA headers and the holes are elongated as well as the holes on the Magnaflow. I trimmed the gasket for the bolts and it seems to be doing just fine. New OEM gaskets of course.

[LcossE82]

Originally Posted by JimD

Real OEM doesn't list the piping size but does have the clamp at the inlet to the muffler size. For our 128is, it is listed as 65mm which is just over 2.5 inches. That must be at least very close to the pipe OD.

The highest rated n52 is some of the n52B30 at 200kW, 268 hp. Some of them (I looked at the 330) seem to have the same size muffler inlet. But the E70 (X5) with this motor has a 75mm - 2.95 inch - muffler inlet.

I like the idea of a 3 inch exhaust for the n52. There seems to be an association between that size and considerably more hp than our n52s are rated at.

This may be a dumb question but my factory specs of my 2013 128i day 230 stock hp. Every forum I've read doesn't back it up. Is a 128i really 230 or is it a gimmick?

[asbrr]

Originally Posted by LcossE82

This may be a dumb question but my factory specs of my 2013 128i day 230 stock hp. Every forum I've read doesn't back it up. Is a 128i really 230 or is it a gimmick?

Where/what have you read that it is not backed up? 230 is crank horsepower, around 200 at the wheels. With modifications you can get it up to about 270hp, which is around 230hp at the wheels.

There are plenty of people that have dyno'd stock and modified cars to back this up.

[LcossE82]

Originally Posted by asbrr

Where/what have you read that it is not backed up? 230 is crank horsepower, around 200 at the wheels. With modifications you can get it up to about 270hp, which is around 230hp at the wheels.

There are plenty of people that have dyno'd stock and modified cars to back this up.

Haha I've since done research and corrected my flawed thinking, thanks for the reply😀
Also with the right mods is it not possible to push her to maybe 300🤔

[asbrr]

Originally Posted by LcossE82

Haha I've since done research and corrected my flawed thinking, thanks for the reply😀
Also with the right mods is it not possible to push her to maybe 300🤔

With the regular mods, 270-280 is the typical limit (intake, headers, 3 stage IM, software, exhaust).

To get to 300 will take more extensive work, cams maybe, intake manifold re-work (like using an N54 manifold), and full custom dyno tuning.

[LcossE82]

Originally Posted by asbrr

With the regular mods, 270-280 is the typical limit (intake, headers, 3 stage IM, software, exhaust).

To get to 300 will take more extensive work, cams maybe, intake manifold re-work (like using an N54 manifold), and full custom dyno tuning.

Figured, good thing I'm taking it slow, and if she lasts (not hopeful only 3 months in and I already have a cel issue that's screwing with me :/) there is a plan to supercharge it... cause why not😂

[Taskmaster]

Any power gains or losses noticed OP?

[E30ROB]

Originally Posted by Taskmaster

Any power gains or losses noticed OP?

No noticeable power gains over the last setup, will hit the dyno soon! Having an issue with the car stalling at idle and running very rich at idle. CEL comes and goes so its something dabbling on the line of flicking the sensors.

I suspect tune related possibly, not sure though.

[E30ROB]

Originally Posted by asbrr

With the regular mods, 270-280 is the typical limit (intake, headers, 3 stage IM, software, exhaust).

To get to 300 will take more extensive work, cams maybe, intake manifold re-work (like using an N54 manifold), and full custom dyno tuning.

My car makes 252whp NA N52, hoping to make 270whp before digging into cams. Maybe we will do N54 intake cam and remove valvetronic. Already running N54 intake manifold!

[chris_flies]

Originally Posted by E30ROB

My car makes 252whp NA N52, hoping to make 270whp before digging into cams. Maybe we will do N54 intake cam and remove valvetronic. Already running N54 intake manifold!

I am developing an adapter to allow the mounting of S54 throttle bodies and velocity stacks to our motor. My thinking was mostly for sound purposes, but I also expect some power delivery improvements over the 3-Stage manifold I have, mostly in the top end (the 3-Stage just dies past 6k), maybe some actual power gains, too.

You're car is completely insane, BTW. 252whp N/A is awesome!

[desertman123]

I'm so excited for this motor lol now people are just doing wild stuff

[E30ROB]

Originally Posted by chris_flies

I am developing an adapter to allow the mounting of S54 throttle bodies and velocity stacks to our motor. My thinking was mostly for sound purposes, but I also expect some power delivery improvements over the 3-Stage manifold I have, mostly in the top end (the 3-Stage just dies past 6k), maybe some actual power gains, too.

You're car is completely insane, BTW. 252whp N/A is awesome!

You need to do the N54 intake manifold! My car revs to 8000, Ive got good power delivery up until about 7400.

Thanks!!! Its such a fun, reliable and responsive car. Definitely post up a thread about the S54 throttle bodies with that adapter, I would be very interested in running that with the BMW Performance carbon plenum lol!