Does Engine Modifications Cause Harm?

[Sandye90m3]

The other day, my Dad and I were driving back from the golf course and I told him that the engine in this car sounds unreal but the fuel consumption is pretty bad.

He then replies saying "I don't think it sounds right, whatever you did to the engine is probably making it sound even raspier and I don't know, but that filter might be making the fuel consumption even worse"

Me: "The airfilter makes slightly more power, and increases the air flow by 30% it makes the fuel consumption better."


To cut this thread short he then says this statement "If BMW could have made more power out of the engine, they would have done so. They have put so many years of engineering into this engine, don't you think they know better than you? If an air filter would have made the engine breath better and produce more power, they would have done so. That is why I don't want you to modify the engine"

I then told him that BMW doesn't care about the power, all they care about is the amount of money that goes into the corporation by consumers buying their products. I further said that if they made this car faster, the car would beat the M5 and M6, which would attract less consumers to purchase the M5/6 which would inevitably would make the company lose money. That is why the M3 is not made to it's full power. With all the bolt-ons the car can make around 460HP (random guess) which is enough to beat the M5 in a straight line.

Anyways please disregard the he said/she said, but I come to my main point. Why didn't BMW make the M3 come with the extra power that you can get from a Pulley, Airfilter, Exhaust, Throttle bodies, Headers and etc...? More specifically, why doesn't the M3 come with a better intake/air flow system, and pulley that would actually take off stress on the engine?

[KGB7]

TrackRat


I dont know what to say. But you just took us back in to 18th century.

[disapr]

In some cases the manufacturer will limit the power that a vehicle produces due to insurance limitations, emissions restrictions or sound/comfort specifications.
Well engineered aftermarket components will allow the engine to produce more power and circumvent the above restrictions by stating that they are “for off road use only”.

[elp_jc]

Originally Posted by Sandye90m3

"The airfilter makes slightly more power, and increases the air flow by 30% it makes the fuel consumption better.

You're wrong in using 'racing filters' . Why? Does your engine need 30% more air flow? The answer is NO. But you're getting 30% (or whatever the number is) more dirt ALL THE TIME. Furthermore, if the stock paper filter is restricting the engine at all (questionable), it'd happen at the VERY TOP of the rpm range, where the tach spends less than a fraction of a percent of the time the engine runs. And if anything, it's only a few HP you can't even feel or notice. Fuel mileage and power is unchanged anywhere else than the very top of the rpm band. Again, just because a filter can flow 'x'% more than stock, means the engine can use it. All people are doing with racing filters is adding cheap-sounding noise (I HATE it), and dirt to their engines, which is not good in the long run. And for those with not enough common sense to realize a filter that you can see thru will let a lot of dirt pass thru, can do a very easy test blowing dirt thru a shopvac into both stock and racing filter with a wet, white shop towel on the back, and watch the results. I'm amazed what marketing can do in this country, from those filters, to magic weight-loss pills, to products that erase scratches like they were never there . Good day gang.

[lve2xlr8]

Originally Posted by KGB7

TrackRat


I dont know what to say. But you just took us back in to 18th century.

Hahahahaha

[KGB7]

Here is a BMW dyno run with stock and after market air filters. Aftermarket Air filter has given 13whp gain across the curve.

http://www.n54tech.com/forums/showthread.php?t=959

[Singletrack]

I have yet to see any filter on any of my last 3 cars that made any sense to me in terms of the reduced filtering vs power gained. I swapped my us filter for the eu to lose the charcoal element (orig AA filter), but that's all. Most high performance cars these days come with incredibly well engineered intake tracks.

[drvai]

I used to mod my cars and have some experiencie on it (no BMWs). Your dad is right and wrong.
BMW "knows what is doing" but at the same time car manufacturers have a lot of limitations in terms of pollution, noise, maintenance and price. They develop a car with a budget, government regulations and 100 other variables. I don't think the M3 is limited by the fact there are higher end cars of the same brand in other segments. Even though the M3 is supposed to be a performance car, it must meet several requirements in order to be a production car, including emission requirements, maintenance, price,etc
The most simple example are the reflectors.... They had to adapt the front bumper with those ugly reflectors in order to comply with the US rules. They also need to sell a car capable of withstanding thousand of miles with no need of frequent maintenance, or been able to be driven through Temps of -10 or 110 degrees.....They will not fit the car with 10k-dollar brakes, or a full carbon fiber body, etc.

IMO, most simple engine mods won't make a big difference. In other cases, they will definitely improve performance but are very expensive and you will loose reliability (e.g. turbo). In summary, you usually either loose something and/or pay a lot of money.

Regarding air filters, I haven't done a lot of research for the M3, but the OEM filter has a charcoal liner that will decrease the backflow of contaminants. Aftermarket filters do not have this liner. In the M5, you can actually remove that filter. Changing the air filter won't "harm" the engine unless it's really a crappy one that is not "filtering" the air as it should. At the same time, you will not gain a lot (5HP in a 410HP car is almost nothing).

[KGB7]

Originally Posted by TrackRat

Simply bad data as you would expect from a chassis dyno. That's why car makers use engine dynos and steady state testing in accordance with SAE test standards. Chassis dyno data isn't worth the paper it is printed on.

Those who understand how an engine functions and airflow vs. engine speed, would know immediately that the dyno data is bad data. If you don't understand how an engine functions, then yes I can see where you could be duped by bogus dyno data or performance claims like 30% more airflow. As a trained professional, specifically in the area of advanced engine design and dyno development, I post technically accurate comments to help people better understand how an engine actually functions.

BTW, you misunderstand the bad dyno data. There was not a 13 WHP gain across the rpm band. You could have completely removed the air filter and not gained 13 WHP or even 13 HP anywhere in the operating band.

How about you provide accurate dyno data where many brands of after market filters were tested using only engine dyno.

Thanks.

[KGB7]

Originally Posted by TrackRat

Sure, if you're willing to pay the $3,500 per day dyno test fee, I'd be glad to oblige.

Since you dont have any data on hand what so ever, let alone a link to a website/s, then everything you have said has very little to no value. Why? If YOU payed me $6,000 per day dyno test fee then i would show you that air filters do make a difference.


Thanks.


p.s.

Dinan uses Engine Dyno to test all their products before they sell to customers. And every single product, even an air filter shows gains on an engine dyno. They do have an in house engine dyno. Or are you going to tell me that Dinan is BS marketing as well?

[disapr]

I didn't buy into the high flow air filter.. I just removed mine

Pretty sure I picked up at least 20hp

[kitw]

So, you know, that driving a car, reduces it's life. Running a motor causes wear on the bearings and rings and all the internal parts. OH NOES!

My car sounds cooler and goes faster than stock. I'm happy with that.

[dogears]

Question.

Why did BMW use a much more restrictive carbon impregnated filter in the US, but a higher flowing non carbon filter in the rest of the world and on their competition vehicles?

Why?? Because it is better and they did not have to worry about the EPA.

So, the answer is that replacing the restrictive US filter is worthwhile, but most gains are going to the less restrictive German version, as designed by the factory!

Originally Posted by TrackRat

Simply bad data as you would expect from a chassis dyno. That's why car makers use engine dynos and steady state testing in accordance with SAE test standards. Chassis dyno data isn't worth the paper it is printed on.

Those who understand how an engine functions and airflow vs. engine speed, would know immediately that the dyno data is bad data. If you don't understand how an engine functions, then yes I can see where you could be duped by bogus dyno data or performance claims like 30% more airflow. As a trained professional, specifically in the area of advanced engine design and dyno development, I post technically accurate comments to help people better understand how an engine actually functions.

BTW, you misunderstand the bad dyno data. There was not a 13 WHP gain across the rpm band. You could have completely removed the air filter and not gained 13 WHP or even 13 HP anywhere in the operating band.

I am aware that many enthusisats want to believe these types of foolish claims, but they are just that foolishness. Don't be duped by those looking to cash in on your lack of technical knowledge. Don't you think that if BMW could get 13 HP or 10 HP or 5 HP by changing the air filter, they would? On a $60,000 car a $3.00 air filter is not even a cost concern when they spend MILLIONS to develop these engines.

[FStop7]

Why did BMW use a much more restrictive carbon impregnated filter in the US, but a higher flowing non carbon filter in the rest of the world and on their competition vehicles?

Because of an emissions rule in the US that does not exist in Europe.

[dogears]

Err... Yeah. I posted that. I was proving Trackrat is wrong and that there may actually be measureable gains by changing to the less restrictive EU filter. Otherwise it would be cheaper for BMW to have one part. Clearly the EU filter is the higher flow and speced part. The US version is an emissions requirement that is a detriment to flow.

Originally Posted by FStop7

Because of an emissions rule in the US that does not exist in Europe.

[KGB7]

Originally Posted by FStop7

Because of an emissions rule in the US that does not exist in Europe.

Originally Posted by dogears

Err... Yeah. I posted that. I was proving Trackrat is wrong and that there may actually be measureable gains by changing to the less restrictive EU filter. Otherwise it would be cheaper for BMW to have one part. Clearly the EU filter is the higher flow and speced part. The US version is an emissions requirement that is a detriment to flow.

Especially in California where emissions laws are x10 stricter then the rest of US.

[elp_jc]

Originally Posted by KGB7

Since you dont have any data on hand what so ever, let alone a link to a website/s, then everything you have said has very little to no value.

You don't need that if you use common sense. IF there's any restriction, it's at the top of the rpm band, when the engine needs the most air. And if you still can't see that, just do a dyno with no air filter. If you don't get your 13HP 'across the board' (you won't ), then how the hell can you get it with a filter in place? That should answer your question, even if you don't understand why .

Originally Posted by dogears

Err... Yeah. I posted that. I was proving Trackrat is wrong and that there may actually be measureable gains by changing to the less restrictive EU filter.

Again, if there's any restriction, it'd be at very high rpm, when the engine needs the most air. But 'measurable' doesn't translate to 'meaningful' . Even with the stock filter, you're talking 2 to 3 HP real difference. ALL aftermarket manufacturers want to justify their crap to potential buyers, so by simple common sense (again) you need to realize those results are completely biased. And it's not like I'm defending trackrat (he's in my ignore list), but many folks just don't understand a lot of those claims are just ridiculous. If you live in the desert, like I do, filtration should be WAY more important than any little gains in HP at top rpm (how long do you keep your engine up there?) and/or cheap intake noise a racing filter provides, but to each his own. I'm signing off this thread. Good day gang.

[kitw]

Originally Posted by dogears

Question.

Why did BMW use a much more restrictive carbon impregnated filter in the US, but a higher flowing non carbon filter in the rest of the world and on their competition vehicles?

(and the 2010+ cars, which have the Euro filter)

[kitw]

Originally Posted by elp_jc

You don't need that if you use common sense. IF there's any restriction, it's at the top of the rpm band, when the engine needs the most air. And if you still can't see that, just do a dyno with no air filter. If you don't get your 13HP 'across the board' (you won't ), then how the hell can you get it with a filter in place? That should answer your question, even if you don't understand why .

So, this is being a little pedantic and not really applicable to the M3, but I have seen some additional and measureable power gains from running a filter that has a nicely radiused velocity stack before a round intake tube, vs no filter at all.

Carry on.

[dogears]

Yep. I just had my 12K service and requested they either leave my AA Euro filter or replace with the new carbonless one.

There is a point of diminishing returns IMO.

Originally Posted by kitw

(and the 2010+ cars, which have the Euro filter)

[KGB7]

Originally Posted by TrackRat

So you're saying you have no dyno data, you were unable to read the bogus dyno data correctly, you have no engine expertise, you don't understand airflow or air volume vs. time which determines if there is a restriction and at what engine speed this would occur, how this relates to engine power and yet you're unwilling to pay for accurate engine dyno testing. This is the norm for people in denial.

Do you see how silly your argument is? You don't know what you don't know technically and you don't want to be confused by facts that refute your technically uninformed beliefs.

Unfortunately denial has never changed reality. People believe whatever they want to believe even when it is untrue. I can lead a person to knowledge but I can't force them to educate themselves.

I posted dyno data, but you chose to ignored it because it is a chassis dyno, even though chassis dyno is used world wide to accurately measure data. Plus you have no engine dyno data either.

Whos in denial now? The door swings both ways buddy.

p.s.

Here, you can read from the horses mouth. They use engine dyno among many other equipment to test air filters.
http://www.knfilters.com/facts.htm

[kitw]

Originally Posted by TrackRat

A round tube without a radius entry is technically a sharp edge orifice and will always flow less than a properly radiused entry. Look at any modern auto air cleaner assembly and it has a radiused entry for that exact reason.

Again, nit picking here, but the M3's intake tube does NOT have a radiused entry.

(of course, the velocity stacks inside the manifold do!)