[3LiterBeater]

As the title states, is there any real difference from the M2’s block compared to the M235i, for example?

It’s settled that the block is open deck (which matters far, far less than people make it seem). I’m wondering if there are any real changes. I understand part numbers are a little inconsistent on many sites.

Thanks!

[AmuroRay]

Originally Posted by 3LiterBeater

As the title states, is there any real difference from the M2’s block compared to the M235i, for example?

It’s settled that the block is open deck (which matters far, far less than people make it seem). I’m wondering if there are any real changes. I understand part numbers are a little inconsistent on many sites.

Thanks!

None really significant.

[chris719]

99% sure it's the exact same.

[XutvJet]

The block itself is the same, but I recall that the M2 block does have different piston oil squinters though. The M235/M2 share the same forged crank, S55 rods, and S55 bearings. The M2 has different pistons and also has the MUCH better S55 oil pump/sump system too.

[3LiterBeater]

Originally Posted by XutvJet

The block itself is the same, but I recall that the M2 block does have different piston oil squinters though. The M235/M2 share the same forged crank, S55 rods, and S55 bearings. The M2 has different pistons and also has the MUCH better S55 oil pump/sump system too.

Interesting! Do you by chance remember where you found that information about the oil squirters? I’d enjoy reading that.

There isn’t a track day that goes by that I’m not thankful for the sump we have

[PackPride85]

Search for M2 Technical Training document and it will explain the differences.

[3LiterBeater]

Originally Posted by PackPride85

Search for M2 Technical Training document and it will explain the differences.

From a technical standpoint, that guide is lacking in many ways. Also, BMW’s documents have shown false information historically, I would take it with a grain of salt.

[PackPride85]

[QUOTE=3LiterBeater;29799762]From a technical standpoint, that guide is lacking in many ways. Also, BMW’s documents have shown false information historically, I would take it with a grain of salt.

Their technical training docs are historically very accurate. Unlike their marketing materials.

[3LiterBeater]

[QUOTE=PackPride85;29799767]

Originally Posted by 3LiterBeater

From a technical standpoint, that guide is lacking in many ways. Also, BMW’s documents have shown false information historically, I would take it with a grain of salt.

There technical training docs are historically very accurate. Unlike their marketing materials.

Ah yes, I grouped them together unintentionally.

That said, the training document doesn’t go into the “nitty gritty” details as to exact part differences. I think it’d have to be much larger to capture all of that

[AmuroRay]

Because of this thread https://f87.bimmerpost.com/forums/sh....php?t=1981744 and the current one, thinking about the differences between the M235/m2 - I decided to "dethrottle" (per the words used in the BMW technical document found in the link above) my car. I went ahead and bought the AWE 3" midpipe for the M235 to install with my MPE, though I may change for a more custom muffle later.

Lets see if I can get a few more ponies, especially at the top end. I think the N55's weaker head flow means every bit helps.

[3LiterBeater]

Originally Posted by AmuroRay

Because of this thread https://f87.bimmerpost.com/forums/sh....php?t=1981744 and the current one, thinking about the differences between the M235/m2 - I decided to "dethrottle" (per the words used in the BMW technical document found in the link above) my car. I went ahead and bought the AWE 3" midpipe for the M235 to install with my MPE, though I may change for a more custom muffle later.

Lets see if I can get a few more ponies, especially at the top end. I think the N55's weaker head flow means every bit helps.

I thought the M2 N55 and S55 had a lot of head similarities (despite camshafts being different numbers).

Then again, I shouldn’t be quoted there lol.

[///M TOWN]

Originally Posted by AmuroRay

Because of this thread https://f87.bimmerpost.com/forums/sh....php?t=1981744 and the current one, thinking about the differences between the M235/m2 - I decided to "dethrottle" (per the words used in the BMW technical document found in the link above) my car. I went ahead and bought the AWE 3" midpipe for the M235 to install with my MPE, though I may change for a more custom muffle later.

Lets see if I can get a few more ponies, especially at the top end. I think the N55's weaker head flow means every bit helps.

Post a picture up of that puppy once you receive it

[AmuroRay]

Just to quote myself from another thread:

Inspired by my post here https://f87.bimmerpost.com/forums/sh...7&postcount=18 on the differences why the F87 makes more power than other tuned N55s, BMW claims that along with the intake airbox being dethrottled (which we have tested this to be true) they have done the same to the exhaust.

https://www.bimmerpost.com/goodiesfo...l-training.pdf

Intake air system
The air intake system is in principle comparable with that of the N55B30O0 engine. The most important changes in the air intake system are adaptation of the intake silencer housing. On the N55B30T0 an additional opening is provided in the bottom housing section, to optimize the power potential and for dethrottling purposes

4.1.6. Exhaust system
The exhaust system was newly developed for the F87 BMW M2.
Differences in the exhaust system:
• Vacuum operated exhaust flap replaced by electrical exhaust flap.
• Dethrottling of the exhaust system for optimum gas exchange.
• Exhaust routing adapted to F87 BMW M2.
• Sporty exhaust sound combined with ASD to the vehicle occupants.

I also read into it more - and I believe the exhaust sizing is actually undersized for a lot of guys, especially the ones running huge turbos/boost.

The 2JZ Supra has basically the same stock exhaust flow through the head (155CFM) but have seen 66WHP by moving up half an inch
https://www.motortrend.com/how-to/mo...ust-test-tech/ Interestingly enough, they claimed that the 3.5" exhaust was even a benefit over the 3" in the 300whp range:

While many turbo cars out there use 3-inch exhausts, we've proven that a hefty amount of horses are left in the stable when doing so. In fact, with just the 3.5-inch rear section, 20-whp gains started as low as at the 300-whp level and kept climbing. With PHR's downpipe, those gains mattered more at 500 whp.

This is again confirmed on the S55 cars using a larger center 3.5 midpipe with 20whp on stock tune/boost.

Basically, the more boost we run, the greater the restriction it becomes. The graphs showing a handful of HP at peak on these aftermarket systems is likely because on the stock tune, the cars are only running 7-10psi (Stock M235i) that tapers to redline. It should be noted there is a (claimed) significant increase at the low end.
Changing a muffler isn't an exhaust system, and unfortunately, there isn't really any R&D in most aftermarket parts - so who really knows what those $1,000 mufflers do (nothing) or what's the true optimal size for FBO 16-18psi, I would bet it's larger than stock.

With that being said, I picked up a AWE 3" midpipe to pair to my MPE. I wanted larger, but there is nothing commercially available I'm aware of, and this will bolt up with minimal to no modifications.
I might to a better muffler, we'll see.

[AmuroRay]

The cool thing about that turbo catback test was a bigger exhaust diameter net more power even on a stock sized downpipe - increasing the size of the downpipe even lead to bigger gains (I think almost 100whp)

guys going with Big turbos should really consider upping the exhaust diameter - unfortunately, it will likely have to be a custom job.

[///393]

Originally Posted by AmuroRay

guys going with Big turbos should really consider upping the exhaust diameter -

I hear more boost can make more power as well. Wild stuff.

[AmuroRay]

Originally Posted by wilson kop

I hear more boost can make more power as well. Wild stuff.

So they say, but who has done it?

[///393]

good stuff.

Before and after dyno of this would be incredible Ray. I know that’s not free but as a man that loves data, you know you wanna! I got $5 on it!

[AmuroRay]

Originally Posted by wilson kop

good stuff.

Before and after dyno of this would be incredible Ray. I know that’s not free but as a man that loves data, you know you wanna! I got $5 on it!

Dyno time used to be CHEAP for me, and plentiful - since the pandemic, it's hard finding performance shops...

[3LiterBeater]

Good stuff! Makes me want to explore a larger single exit exhausts but can’t say I’ll ever exceed stock boost targets.

Either way, interesting information.

[AmuroRay]

Eldor S55 coils (proper p/n) installed - hopefully this cooler weather holds, going to try to get a clean baseline dyno. I found a local shop, we’ll see

[///393]

What tune?

[AmuroRay]

I’m on a StageFP tune - formerly the tuner of Bimmer Performance Center