[koreez88]

New lucky owner of 2011 335D here.

Since diesel relies on air to create combustion inside the engine, would that mean that air scoops should create a fairly dramatic increase in car power? I've transfered my old MDF scoops from my ex 325i and haven't driven the car yet due to quite nasty weather. But some knowledgeable feedback would be great.

[Bimmer84]

Sounds logical although I've heard you don't notice your big power increase with scoops until about 70mph+. Never owned any though and not sure if diesel would be a differencing factor...

[chiaobaby]

scoops will not make a difference especially on a TURBO CAR it is being force feed already.

[E90jonno]

Would a pannel filter not be a better buy?

[cgom3z]

I havent seen any gains to speed or power after 70+ mph; however, they do look good.

[hipnotic]

nothing under 70 mph

[SV Concepts III]

It's difficult to dyno the improvement as these are only functional at speed but they do help with channeling more air into the intake system.

[roadkillrob]

Originally Posted by chiaobaby

scoops will not make a difference especially on a TURBO CAR it is being force feed already.

+1 people need to stop wasting money on scoops on a car that has turbo - the scoop will not feed more air into the engine in any scenario ever!

[AltecBX]

Originally Posted by roadkillrob

+1 people need to stop wasting money on scoops on a car that has turbo - the scoop will not feed more air into the engine in any scenario ever!

+2

[cssnms]

VAC or JBD for you my friend

[tibra1]

Originally Posted by roadkillrob

+1 people need to stop wasting money on scoops on a car that has turbo - the scoop will not feed more air into the engine in any scenario ever!

Not into the engine directly... but wont it provide more air through the intake to then be compressed into the engine by the turbos? I am on the fence with this mod..i am thinking to get the CYBA scoops..they are only $39!

[Shellacked135i]

The scoops power increase is negligible but it shouldnt take power away. ITs not a waste of a mod, but there are other modifications which actually might yield some in the seat of the pants power. I would invest in an intake or panel filter first. In reality a intale/panel filter and tune first.

[tscdennab]

Originally Posted by tibra1

Not into the engine directly... but wont it provide more air through the intake to then be compressed into the engine by the turbos? I am on the fence with this mod..i am thinking to get the CYBA scoops..they are only $39!

My belief is that because of the water radiator being in the air path and restricting air flow, a positive pressure is created in front of the radiator anyway (with or without scoops) so the air in need of an easy escape path is forced through the intake snorkel regardless of scoops being present or not.

Anyway, looking at the Cyba scoops they are a bit too large for my liking. They cover too much of the radiator. If you choose them, maybe you can trim them somehow.

[tibra1]

Originally Posted by Shellacked135i

The scoops power increase is negligible but it shouldnt take power away. ITs not a waste of a mod, but there are other modifications which actually might yield some in the seat of the pants power. I would invest in an intake or panel filter first. In reality a intale/panel filter and tune first.

Well that goes w/o saying scoops by themselves will do nothing ...I am trying to decide whether to use the scoops w my simota closed air intake.. here is a pic..I think the scoops may really help feed air into the intake or its going to really just scoop bugs and debris..lol..im still unsure

Thoughts?

[tibra1]

Originally Posted by tscdennab

My belief is that because of the water radiator being in the air path and restricting air flow, a positive pressure is created in front of the radiator anyway (with or without scoops) so the air in need of an easy escape path is forced through the intake snorkel regardless of scoops being present or not.

Anyway, looking at the Cyba scoops they are a bit too large for my liking. They cover too much of the radiator. If you choose them, maybe you can trim them somehow.

Great point..i may just opt to run the intake w/o the scoops

[WilliamE92]

Things which ram air intakes actually make a difference on:

[Thud]

The negligible power increase you'd get (over 70mph), especially on a turbo car, is probably going to be offset by the additional weight of whatever ram-air ducting is installed.

For performance improvements, you're probably going to get better results by just removing the rear floor mats to lower weight. Or emptying your bowels before you drive. In other words, it's not going to make any difference outside of the margin of error.

Now, install a JBD, and that's another story....

[dcorn]

lol, I bet all the people saying scoops are pointless have upgraded air filters too. What do you think that does for the engine?

[Shellacked135i]

Originally Posted by tibra1

Well that goes w/o saying scoops by themselves will do nothing ...I am trying to decide whether to use the scoops w my simota closed air intake.. here is a pic..I think the scoops may really help feed air into the intake or its going to really just scoop bugs and debris..lol..im still unsure

Thoughts?

Attachment 476371

Attachment 476372

I dont see it hurting performance, I have scoops. I noticed on avg a 5-10 degree intake air temp reduction. When I used a stock intake with the scoops I noticed a good throttle response. Again, they shouldnt really hurt performance. Like I recommended above, I would get an intake or filter first, then throw scoops on.

The cyba scoops are like $40, I lost more money in a bar personally, so oh well.

There is a theory of a pressurized area w/out scoops and as much as it might be true i think a lower resistance air pathway would flow better air, as opposed to waiting for a pressure build up in the front of the radiator and possibly taking some heat from radiator itself. Who knows I'm not a fluid/aerodynamic engineer.

[E90Brad]

I am not a fluid/aerodynamic engineer, I am also a crappy physicist... I even had to look up the spelling of physicist but I have something to add futher to what Shellacked has said.

There is a relationship between pressure, tempature and volume in thermodynamics (pv=nRT). Let's assume related rates (air into engine and air going into intake) are negligible.

Without scoops, air is being forced into an area of consistant volume (ie stock airbox) with an (assumably) relatively consistant temperature. If we assume that volume and ambient temp remain the same then we can use some logic to make an guess at what is actually happening when we add scoops.

Now we add scoops. If we assume that the scoops channel more air into the intake box (which I think is correct), then the increase in air should cause an increase in pressure (constant volume of airbox) which in turn will cause a decrease in intake temperature.

I would think that this effect would be greater with a stock airbox as the closed in area would allow air pressures within to increase. Those with upgraded intakes should see a lesser effect as the intake temperature would be manipulated by the engine temperature and there is usually no confined volume for pressurization to take place.

Now this is only one arguement. You could also argue (as someone has previously done) that the scoops get air from a (slightly) lower height and that contributes to lower air intake temps.

I am thinking of grabbing some Cyba scoops and looking at the difference in air intake temps and maybe even 0 - 100 times using a stock airbox and then a DCI.

Just my 0.02 on air scoops.

[Thud]

Originally Posted by E90Brad

I am not a fluid/aerodynamic engineer, I am also a crappy physicist... I even had to look up the spelling of physicist but I have something to add futher to what Shellacked has said.

There is a relationship between pressure, tempature and volume in thermodynamics (pv=nRT). Let's assume related rates (air into engine and air going into intake) are negligible.

Without scoops, air is being forced into an area of consistant volume (ie stock airbox) with an (assumably) relatively consistant temperature. If we assume that volume and ambient temp remain the same then we can use some logic to make an guess at what is actually happening when we add scoops.

Now we add scoops. If we assume that the scoops channel more air into the intake box (which I think is correct), then the increase in air should cause an increase in pressure (constant volume of airbox) which in turn will cause a decrease in intake temperature.

I would think that this effect would be greater with a stock airbox as the closed in area would allow air pressures within to increase. Those with upgraded intakes should see a lesser effect as the intake temperature would be manipulated by the engine temperature and there is usually no confined volume for pressurization to take place.

Now this is only one arguement. You could also argue (as someone has previously done) that the scoops get air from a (slightly) lower height and that contributes to lower air intake temps.

I am thinking of grabbing some Cyba scoops and looking at the difference in air intake temps and maybe even 0 - 100 times using a stock airbox and then a DCI.

Just my 0.02 on air scoops.

If you compress air, it heats up, not the other way around.

As a matter of fact that's how diesels work. Remember the ideal gas law: p*V = n*R*T
All else being equal, if you increase pressure then temperature also goes up.


As I said in my last post a few months back, any negligible power increase will be offset by the increased weight of the equipment you need to install, as well as the increased drag coefficient you'll have.

You'll get better results by simply reducing weight: i.e. removing the toolkit from the trunk, losing 5 pounds of beer gut, or driving naked.