Question for those with BMW Performance exhaust

[RD1M3]

Originally Posted by mermar

OP here - I should probably add that I am rather conservative when it comes to mods - really want to avoid a loud exhaust that gets tiring when you just want to take your wife out to dinner.
But I emphatically trust the engineers at BMW when it comes to the MPE - I doubt they would produce something obnoxious.
I would like a little more bark at start-up just dont want any form of droning. Also would like the rev match downshift to bark a little more. I have made mistakes in the past with exhaust and regretted it. It is a delicate balance.

I love the cold start with the MPE!! Expecially in my parking deck...

[FogCityM3]

You are partially right... at partial throttle the vent is an air escape as positive pressure from the snorkel and bumper intake is not all needed by the engine and the extra air escapes the through the vent. But at WOT along above 4-5k rpm, the engine is starved for air thus the hood vent serves as an INLET as air gets vacuumed by the engine. It's a brilliant design.

Originally Posted by s85e90

No it's not. The drivers side good vent is an air escape. Air flows in from the grill opening and left side Lower bumper and flows out th hood

[mermar]

Also, is it recommended that a dealer install the MPE or is it simple enough that most BMW indi's can handle it.

Lastly, I might consider powder coating the MPE mufflers black prior to install as the stock muffler look a little cheap/unfinished when approaching the car from the rear.

[Hyperjack]

Originally Posted by mermar

Also, is it recommended that a dealer install the MPE or is it simple enough that most BMW indi's can handle it....

it's a simple install that any reputable shop could handle it. it's simple enough that i think there some members here may have installed it themselves....

[deletedelete]

Originally Posted by stylelab

Same here!!! This would be the only exhaust I would go for because I don't want to encounter any warranty issues.

On the other hand, as my car is stored for the winter, when I take the car out in the Spring, it's like driving a new car and the stock sounds is already amazing to my ears....so by the time I get used to the sound, it's almost time to store it again! lol

don't want any warranty issues either since I've had them in the past so this is the only exhaust I'll get also. I had my car stored for most of the winter and just started driving it again and I'm still perfectly happy with the stock sound too.... for now haha. I bet me, you, and the op will all have the MPE soon.

[s85e90]

Originally Posted by FogCityM3

You are partially right... at partial throttle the vent is an air escape as positive pressure from the snorkel and bumper intake is not all needed by the engine and the extra air escapes the through the vent. But at WOT along above 4-5k rpm, the engine is starved for air thus the hood vent serves as an INLET as air gets vacuumed by the engine. It's a brilliant design.

okay. It's an outlet for air, it essentially acts as a pathway. If it was closed it would be like a pressurized ram air box. At speed air enters and is able to escape and flow through the box. It's an excellent design. Take a look at the size of the intake tubing. It's never starved for air at high RPM> I run an open round filter with a 6" mouth. this and well as the OEM setup should be enough airflow to support much, much more HP

[JabzSA]

Its a pity its so bloody expensive....what like $4k???

Id love to get one for mine....but gees....

[mermar]

Originally Posted by JabzSA

Its a pity its so bloody expensive....what like $4k???

Id love to get one for mine....but gees....

YEs - same way I feel...Ive seen others post about deals they have received. Sounds like install is no big deal - so just finding a deal on the part is the ticket.

[jhbrennan]

Originally Posted by mermar

Also, is it recommended that a dealer install the MPE or is it simple enough that most BMW indi's can handle it.

Lastly, I might consider powder coating the MPE mufflers black prior to install as the stock muffler look a little cheap/unfinished when approaching the car from the rear.

Suggest ceramic coating and not powder coating. Ceramic is better for high temp items.

[Law]

Originally Posted by stylelab

Same here!!! This would be the only exhaust I would go for because I don't want to encounter any warranty issues.

On the other hand, as my car is stored for the winter, when I take the car out in the Spring, it's like driving a new car and the stock sounds is already amazing to my ears....so by the time I get used to the sound, it's almost time to store it again! lol

There's nothing really that would be damaged or given extra wear due to an exhaust though.

Does Canada have similar legislation such as Magnuson-Moss Warranty Act that we have in the States?

For example, in the United States, say you have a "modified" exhaust and then your transmission blows up. The two are obviously not correlated. Per Magnuson-Moss, the dealer/mfr may not deny the repair/replacement of your transmission under warranty because of your "modified" exhaust.

If Canada has something like that for consumer protection, then mod away.

Originally Posted by s85e90

No it's not. The drivers side good vent is an air escape. Air flows in from the grill opening and left side Lower bumper and flows out th hood

Sorry but you're wrong & @FogCityM3 is correct.

There are actually 3 sources of air for the S65B40 in the E9X. You're correct about the first two being the left bumper inlet and the kidney grill opening. The third would be the inlet on the domed hood.

Per the Aftersales Training Information PDF, pg. 30
"New "Powerdome" aluminium hood lid with air apertures. The aperture on the left when viewed in the direction of travel is used for incoming engine air, and the right-hand aperture offers optical symmetry."

Also on pg. 54 there is a highly detailed diagram. See below.


OR...open the hood and take a look!

[dparm]

The MPE does not overwhelm the induction sound, in my opinion.

[Beemdog]

Despite the official training info, it's a safe bet that air spills _out_ of the hood vent during conditions where air flow from the large front intake (at speed) overwhelms the engine's demand for air. That vent would act as a ram-air relief port during high-speed closed throttle decel.

[Law]

Originally Posted by Beemdog

Despite the official training info, it's a safe bet that air spills _out_ of the hood vent during conditions where air flow from the large front intake (at speed) overwhelms the engine's demand for air. That vent would act as a ram-air relief port during high-speed closed throttle decel.

Perhaps, but it definitely wasn't designed as an escape path, even if that was a side-effect of combining multiple inlets in those positions so to call that hood inlet an "escape" is not proper labeling.

[Beemdog]

Originally Posted by Law

Perhaps, but it definitely wasn't designed as an escape path, even if that was a side-effect of combining multiple inlets in those positions so to call that hood inlet an "escape" is not proper labeling.

Got it. I was actually quite impressed with the design of the M3 airbox when I first pulled it out to change the spark plugs. Other than the lack of threaded metal inserts for the top cover screws to thread into, it is a nicely engineered piece.

[FogCityM3]

Yes and thanks for finding this. Actually, for the S85 E60 M5 Steve Dinan actually figured out that the engine was starved for air at the high rpms and the airboxes and filters that Dinan made corrected this problem (by allowing more air to enter the engine). Dinan has stated that the problem was corrected in the M3 air box, while he didn't say this specifically, my guess would be the hood vent provides that additional air and its placement on the hood is actually a high-pressure area.

I realized the function of the hood vent very quickly when I had a bird strike with my bumper and a bunch of feathers got into the lower intake (not the bird itself thankfully). Initially, the feathers went through the intake and popped out of the hood vent, but once I went WOT, the stuck feathers popping halfway out got sucked right back into the hood vent!

Originally Posted by Law

Perhaps, but it definitely wasn't designed as an escape path, even if that was a side-effect of combining multiple inlets in those positions so to call that hood inlet an "escape" is not proper labeling.

[Denk]

Can't argue with the feather test...poor bird. Nice, I learned something today!

[M3-S65]

Originally Posted by stylelab

Same here!!! This would be the only exhaust I would go for because I don't want to encounter any warranty issues.

On the other hand, as my car is stored for the winter, when I take the car out in the Spring, it's like driving a new car and the stock sounds is already amazing to my ears....so by the time I get used to the sound, it's almost time to store it again! lol

Any axel back exhaust will not create warranty issues. There are no sensors past the X pipe and hence it does not interfere with anything beyond that point. You are not doing anything just simply changing the sound. Now if you change up the X pipe w/the cats and sensors on it then you have changes that BMW could argue with you. I believe that the MPE is axel back, however it may be a full system....??
By the way all exhausts (axel back are an easy install) I bought the ESS exhaust, installed it myself ...and it sounds amazing.

[radiofrequency]

I concur with the sentiment that the sound gets better with time. At first I could hardly hear a difference between stock and MPE, after a couple of thousand miles that all changed!

[AJ_MO]

Hi all! I have done 50k kilometer with MPE...I have replace it TWO TIMES on warranty because the cans crack always in the same place...now I have my third one on and have done only 4k kilometers...let's see if this one will last!

I made a mistake, maybe Akra slip-on was a better choice.

I choosed MPE because oem and didn't want to have any issues...didn't went well.

[Justin Case]

Has anyone installed the X-pipe with the MPE?

[s85e90]

my apologies to @fogcitym3 but I still doubt that book. Where is that from. Dealer PDF?

In any event, interesting read

[dparm]

Originally Posted by AJ_MO

Hi all! I have done 50k kilometer with MPE...I have replace it TWO TIMES on warranty because the cans crack always in the same place...now I have my third one on and have done only 4k kilometers...let's see if this one will last!

I made a mistake, maybe Akra slip-on was a better choice.

I choosed MPE because oem and didn't want to have any issues...didn't went well.

The Akra slip is too bassy for my tastes. You can't even hear it above 4000rpm, whereas the MPE is still somewhat audible across the entire RPM range.

I wonder if you got a replacement MPE from the same batch of bad ones. Is there batch information stamped on those things anywhere?