[3LiterBeater]

I’ve been reading a bit on the M2/M235i’s engines and it seems that there is mixing information on what’s different (if anything) about the turbocharger/ exhaust systems.

Ignoring all of the “x makes more on the dyno” and other variables or part numbers, is there any hard data/ measurements/ images saying there’s any difference between the EWG N55s exhaust manifolds or turbochargers? I’ve heard stories saying opposite things.

[EvanP246]

I’m very curious about this as well. A higher flowing manifold and turbine housing would explain higher power numbers that tuned M2’s produce in the upper RPM range vs a regular EWG car.

[///MPhatic]

Originally Posted by 3LiterBeater

I’ve been reading a bit on the M2/M235i’s engines and it seems that there is mixing information on what’s different (if anything) about the turbocharger/ exhaust systems.

Ignoring all of the “x makes more on the dyno” and other variables or part numbers, is there any hard data/ measurements/ images saying there’s any difference between the EWG N55s exhaust manifolds or turbochargers? I’ve heard stories saying opposite things.

This guy would probably know. He tears down a lot of engines.

[3LiterBeater]

Originally Posted by EvanP246

I’m very curious about this as well. A higher flowing manifold and turbine housing would explain higher power numbers that tuned M2’s produce in the upper RPM range vs a regular EWG car.

I’ve heard some saying the M2 makes “no more than a standard EWG car” as well as exactly what you’re saying. I don’t buy too heavily into dyno results so I was hoping there was some proven information floating around out there.

[PackPride85]

M2 uses the N20 BOV. That’s the only difference. BMW essentially made the engine more stout for race duty and modified the tune to squeeze a little more power out of it + overboost function.

[EvanP246]

Originally Posted by PackPride85

M2 uses the N20 BOV. That’s the only difference. BMW essentially made the engine more stout for race duty and modified the tune to squeeze a little more power out of it + overboost function.

So you’re saying there are absolutely no changes to the turbo manifold? That’s contrary to this article from BMWBlog.

https://www.bmwblog.com/2016/07/28/b...ven-better-m2/

[PackPride85]

Originally Posted by EvanP246

So you’re saying there are absolutely no changes to the turbo manifold? That’s contrary to this article from BMWBlog.

https://www.bmwblog.com/2016/07/28/b...ven-better-m2/

The technical training document that details all the changes doesn’t list it. Its possible it was omitted but it’s also possible bmwblog is incorrect (they have been before). Part # is different but as anyone who has dug into BMW part #’s knows, they often change on a yearly basis with no actual physical changes.

[EvanP246]

Originally Posted by PackPride85

The technical training document that details all the changes doesn’t list it. Its possible it was omitted but it’s also possible bmwblog is incorrect (they have been before). Part # is different but as anyone who has dug into BMW part #’s knows, they often change on a yearly basis with no actual physical changes.

Gotcha, someone from Pure Turbos or any hybrid turbo manufacturer would probably know as they use the oem part for their base.

[ZM2]

I was told by TTE that the manifolds are the same.

There are dynos out there of similarly mod'ed N55's on the same OTS tune and the M2 does put down a little more power. Some folks think it is due to less engine friction bc of the cylinder wall linings in the M2 motor.

[AmuroRay]

Could be the exhaust as well.

[3LiterBeater]

Can’t recall, aren’t the intake/ exhaust cams a different part? In conjunction with the valvetronic thing that makes the “brrrt” sound when we let off throttle (can’t recall the name)

[AmuroRay]

Originally Posted by 3LiterBeater

Can’t recall, aren’t the intake/ exhaust cams a different part? In conjunction with the valvetronic thing that makes the “brrrt” sound when we let off throttle (can’t recall the name)

Nope.

[F87source]

Yup it is only the diverter valve that is the difference.

[AmuroRay]

Originally Posted by F87source

Yup it is only the diverter valve that is the difference.

And a larger diameter exhaust system.

[F87source]

Originally Posted by AmuroRay

And a larger diameter exhaust system.

That's not part of the exhaust manifold though, the exhaust is post cat and the cat is the same size as on the ewg n55 (since it's the same part).

[PackPride85]

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

[AmuroRay]

Originally Posted by PackPride85

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

I’ve seen and read it before, but here are the relevant facts:

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

Differences in the oil supply in the N55B30O0 and N55B30T0 engines
The oil supply was adapted in the N55B30T0 for race circuit suitability:
• Additional oil sump cover to restrict oil movements at high acceleration.
• Additional suction pump to return the oil to the rear area of the oil sump during high lateral and longitudinal acceleration.
• Extraction from the exhaust turbocharger in the event of high lateral acceleration.
With these changes the oil supply can be guaranteed up to a longitudinal acceleration of 0.61 g. This can even be achieved up to - 1.2 g in the case of deceleration. Also with lateral acceleration, for example during cornering, this structure enables a secure oil supply up to constant 1.2 g

4.1.5. Exhaust turbocharging Overboost
On the N55B30T0 engine, the torque is increased from 465 Nm/343 lb-ft to 500 Nm/369 lb-ft (overboost) by a brief increase in the charging pressure of 0.1 bar above the normal charging pressure.
Blow-off valve
A blow-off valve without diaphragm from the N20 engine is used in the N55B30T0 engine.

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.

4.2.1. Manual gearbox
A manual gearbox is standard on the F87 BMW M2. It is an adapted K-transmission, which is known from the production vehicles of BMW AG or the F80/F82 and F83. The following components were already adapted in the F80/F82 and F83:
• Weight reduction compared with predecessor gearbox.
• Smaller size and thus lower weight.
• Improvement of the shifting comfort thanks to use of new type of carbon friction lining at the synchronisation units.
• Reduction of noise level.
• Increased efficiency due to dry sump lubrication (“churning” in the oil is prevented, specifically designed oil ducts). This made it possible to reduce heat generation to such an extent that external cooling is no longer required.

[AmuroRay]

nd now proofs:
The midpipe is worth about 10whp+ on the low to mid range - the power dropps off up top because boost is tapering, and restriction is lower.

On a FBO car, I think a midpipe and muffler (standard N55 cars) is worth 10-15whp peak gains:

[EvanP246]

Originally Posted by AmuroRay

nd now proofs:
The midpipe is worth about 10whp+ on the low to mid range - the power dropps off up top because boost is tapering, and restriction is lower.

On a FBO car, I think a midpipe and muffler (standard N55 cars) is worth 10-15whp peak gains:

Thanks for this information. Is the BOV less of a failure point as a result of being the N20 design vs the EWG BOV?

[AmuroRay]

Originally Posted by EvanP246

Thanks for this information. Is the BOV less of a failure point as a result of being the N20 design vs the EWG BOV?

From what I understand, the N20 Diverter valve was made to handle more boost vs the standard N55 valve. I would still upgrade to a Turbosmart or DV+

[F87source]

Originally Posted by AmuroRay

nd now proofs:
The midpipe is worth about 10whp+ on the low to mid range - the power dropps off up top because boost is tapering, and restriction is lower.

On a FBO car, I think a midpipe and muffler (standard N55 cars) is worth 10-15whp peak gains:

That's still proof of a better exhaust leading to more power, this thread is still about the turbo exhaust manifold not the exhaust pipes post turbo.

[AmuroRay]

Originally Posted by F87source

That's still proof of a better exhaust leading to more power, this thread is still about the turbo exhaust manifold not the exhaust pipes post turbo.

The thread is about what makes it different, because people are noticing a difference in power production between a M2 and other N55 cars. Per BMW, It’s the intake and exhaust system, not the manifold directly.