[i2iSTUDIOS]

Looks like something i'll be doing shortly

[Mr. 5]

Originally Posted by Mike@N54Tuning.com

How is the sound? Like stock?

Mike

Yah, pretty much. I bet there is a little sound difference from in front of the car, but inside the cabin is close to the same.

Originally Posted by cstavaru

If you read the (lenghty) Dinan article about how to correctly dyno a car, they say that opening the hood helps in fact create realistic conditions, because the dyno fans cannot blow enough air so extra cooling is needed in order to avoid unrealistic timing pulling on the dyno. I did my dynos with hood closed until I read that article but it changed my mind. However, when testing intakes I think almost no approach can truly replicate real driving conditions.

I know what you are talking about but it's a catch 22.
I have always dyno'd with the hoods open to cool down the engine but lets be realistic here. How could you not gain HP if you take out the air box, put dual cones and then put a fan blowing air directly on the cones?
If you don't gain hp then there's something seriously wrong.

I performed the test a while back about the IATs and dynos of the OEM air box vs DCIs and the tests were what I expected.
There's no doubt that the DCIs make more power than the OEM air box...when the engine is cold, but if the engine bay is hot then the OEM air box will take the cake.
http://www.e90post.com/forums/showth...054&highlight=

I don't know how much time I'll have tomorrow but I would really like to try all three intakes to see the differences.

[Big Tom]

Originally Posted by cstavaru

If you read the (lenghty) Dinan article about how to correctly dyno a car, they say that opening the hood helps in fact create realistic conditions, because the dyno fans cannot blow enough air so extra cooling is needed in order to avoid unrealistic timing pulling on the dyno. I did my dynos with hood closed until I read that article but it changed my mind. However, when testing intakes I think almost no approach can truly replicate real driving conditions.

How often do you drive with your hood open in 70-100 mph? (70-100 mph ~ capacity of a highspeed dyno fan)

[Big Tom]

Originally Posted by Mr. 5

I don't know how much time I'll have tomorrow but I would really like to try all three intakes to see the differences.

That would be very interesting!
But maybe the meth will take care of it?

[scheherazade]

Originally Posted by Big Tom

How often do you drive with your hood open in 70-100 mph? (70-100 mph ~ capacity of a highspeed dyno fan)

50 mph is 75 feet per second

If your engine bay has a 1 foot area grille, then at 50 mph it will get 73 feet per second of fresh air, minus any resistance.

There's not that much free space under the hood, it's getting flushed all the time when you're moving.

When you stand still, there's the difference.

-scheherazade

[cn555ic]

Originally Posted by Mr. 5

I really appreciate the props guys.
I don't know if I'm really going to market it though.
This is kind of like the Mr. 5 catch can. I made it and that's it.
Who knows though, if I get a crap load of persuasion then maybe.

So I went for a drive today and it feels really strong.
The best thing I like about it is that it sounds identical to the stock air box.
I know a lot of people like the sound of the turbos but I personally like the sound of a tuned engine accommodated with a nice sounding exhaust.
I'll see if I could get a baby sitter for tomorrow so I can dyno test it before Christmas.
I'll do with stock air box and then with the Mr. 5 intake.
Dynos will be done with the hood closed.

All you need to do is pretty up the laundry duct and you have a winner for sure...maybe a custom CF tubing that mimics your piping without the accordian flex piping...

[Big Tom]

Originally Posted by scheherazade

50 mph is 75 feet per second

If your engine bay has a 1 foot area grille, then at 50 mph it will get 73 feet per second of fresh air, minus any resistance.

There's not that much free space under the hood, it's getting flushed all the time when you're moving.

When you stand still, there's the difference.

-scheherazade

A closed hood will require extra efforts from your scoops, air duct, snorkel, heat shield, filters etc etc.
Open it, and all the real life driving conditions will be totally gone.

[F104]

Originally Posted by scheherazade

50 mph is 75 feet per second

If your engine bay has a 1 foot area grille, then at 50 mph it will get 73 feet per second of fresh air, minus any resistance.

There's not that much free space under the hood, it's getting flushed all the time when you're moving.

When you stand still, there's the difference.

-scheherazade

very interesting thread. Don't quite agree though, i your car had effectively one sq ft intake area thru radiator and intercooler (i have the feeling it's more), show me where that one sq ft exit is. I'm on the page intake area exceeds exit, as such air flow will stagnate under the hood, and pick up temperature. Any additional outlet created (such as an open air filter) will take that hot air.

[CBR335]

Cool Mr. 5,

Replacing the flexible tubing would undoubtedly improve the airflow by reducing turbulence. Obviously this is a prototype, but that is where I would start.

Why dont you also block the stock intake and see what the difference is on the dyno/road for a complete experiment.....if you don't starve the engine that is.

Also, perhaps an insulated intake tube would be even better. Perhaps wrapped with insulating tape? Even though this is the cold side of the engine.

[Mr. 5]

Originally Posted by CBR335

Cool Mr. 5,

Replacing the flexible tubing would undoubtedly improve the airflow by reducing turbulence. Obviously this is a prototype, but that is where I would start.

Why dont you also block the stock intake and see what the difference is on the dyno/road for a complete experiment.....if you don't starve the engine that is.

Also, perhaps an insulated intake tube would be even better. Perhaps wrapped with insulating tape? Even though this is the cold side of the engine.

Thanks for the input.
I know it's on the colder side of the engine but I checked it today and the flexible ducting was really hot. It was a while after I stopped the car but I was surprised at how hot that was compared to the abs pieces.

Also, you are correct. All I need to do to check the OEM intake is put a lip over the piece portruding inside the air box and it will act almost identicle to an OEM air box. When I take it off, we'll see if power jumps up or not.

[CBR335]

Definitely argues for some sort of insulation of the intake tube then, which might reduce but not eliminate the problem of course.

Perhaps another thing to do would be to have another parallel tube/scoop that would be pick up air from the "foglight area" and eject cool air under the hood adjacent to the stock airbox to "flush" the heat buildup.

Isn't that kinda like what the BMW performance kit uses to supply air to the supplemental cooler?

I think that the overall strategy might work very well for those that track/autox their cars

[Kroy]

Wow. Mr. 5, your inginuity never ceases to amaze me. First the catch can and now this? I can't wait to read up on the results.

[McMuffin]

A lot of Honda guys do this. Well they use a short ram intake and run a vac hose to the front bumper, so more air flows to the intake. Your creativity never seems to run out. Good job man!

[Makushr1]

Originally Posted by Mr. 5

Also, you are correct. All I need to do to check the OEM intake is put a lip over the piece portruding inside the air box and it will act almost identicle to an OEM air box. When I take it off, we'll see if power jumps up or not.

That was going to be my suggestions. I am currently running DCI, but hate how dirty the engine bay gets when the stock air ducts are off. I have a film of dirt. Recently, I have been thinking about putting the stock air box back on, but if your dynos are promising, I may use your idea. Keep us posted!

[F104]

This thread got me thinking and had to throw some physics at it. Bottomline I think Mr.5's concept (or any other similar) is fairly brilliant.. Although only having a 320d i wondered too what happened if I floor it, and diesels are looking at higher boost levels than petrols. Food for thought though. What would be interesting is some supplier coming up with an radiator/FMIC combo that leaves room for simple 5" straight in ram air inlet.

Just physics then:

1) The entry of the stock intake system on all E9x's is the same bit over the radiator. If you take that apart and measure it my estimate is 2 * 29 cm2 for 58cm2 total. On my intake system that 58 cm2 is present everywhere, although over quite different shapes. Now assuming you had a straight in, round, optimized, 58cm2 size (about 3.5" dia), and friction less air intake, facing the car's airflow directly, then it would give these airflows:
10 m/s = 36 kph (22.5 mph) = 58 ltr/sec,
20 m/s = 72 kph (45.0 mph) = 116 ltr/sec
30 m/s = 108 kph (67.5 mph) = 174 ltr/sec
40 m/s= 144 kph (90 mph) = 232 ltr/sec
Since the routing and shape of the air piping is far from the ideal, I'm assuming you could take 50% of the these as more realistic. What that effectively means is at the 90 mph speed, air flows into the filter housing at only 45 mph, and the resulting volume is either sufficient for the engine or not. A 3ltr running at 3000 rpm and say 1.5? bar boost is theoretical taking in 112 ltr/sec, due to volumetric efficiencies less, so my guess is the stock intake flows enough air for most or all steady state conditions. What i mean by that is the free ram air flow is sufficient to keep the pressure in the air filter housing at or just above ambient pressure. Any open style filter, sitting in an open connection between an air duct and engine bay, is not going to see much ram air at all, and is in my view therefor less efficient

2) to compare intake air temp and ram air: From from 20C ambient to 35C intake air, density will drop 4.8%. That is 0.32% density drop per degree C. Theoretic ram air effect is as per the below, and does not take in account:
- air friction losses the stock system has, so effective ram air boost will be less, maybe more than 50% if you ask me:
- the air demand by the engine. The below is based on a pitot tube (closed at the back end, the engine will be one large hole at the back end)
10 m/s = 36 kph (22.5 mph) = 1.0006 bar = 0.06%, (0.5 * 1.2 kg/m3 * 10 m/s^2)
20 m/s = 72 kph (45.0 mph) = 1.0024 bar = 0.24%
30 m/s = 108 kph (67.5 mph) = 1.0054 bar = 0.54%
40 m/s= 144 kph (90 mph) = 1.0092 bar = 0.92%
So to me coldest air intake has the priority. Even at 90 mph the net efective positive effects of ram air are close to nothing, but it still beats the open style filter. Such open intake needs to create a vacuum to start pulling the airflow. I assume that is why bmw designed it such it takes if from before the radiator, while still having some ram air.
Placement of the (main) air filter low by the ground is not ideal for winter (rain, mud), and in summer it will see the higher temps just above the road surface .
PS1: If that low placed filter gets punctured and you don't notice it you'll have a problem, i would protect it.
PS2: If one does dyno runs with such 'open' filter design, that filter might be seeing airflow from the dyno fan at zero car speed. In real life that open filter starts sucking in engine bay air flow and temps as well and heat soak the entire intake. I know it does on mine. I don't believe these dyno fans simulate real vehicle speed changes
PS3: hood open dyno runs - wow! what's next to simulate reality?

3) Yes when you floor it there will be conditions were the stock intake won't flow enough. What that means is the engine/turbo starts pulling a vacuum in the air filter housing. In my view, on Mr5's setup that vacuum now starts pulling air in thru the second inlet as well - that's why i like it. For those who state you loose the efficiency of the closed (stock) ram air system, from the above, at 90 mph that pressure is well below 1.0092 bar at best , after the air filter even less, and i bet what pressure you have left is not sufficient to create a backflow thru the second intake pipe and back up thru the second air filter. So I believe it is a nice self regulating system.

But like I said - food for thougt.

[mwscircle]

OMG^ i cannot believed you just typed that shit out! HAHAHAH MR.5... when are you goign to the dyno, I can come with you and we can check out the difference together!

[Mr. 5]

Thanks a bunch F104 for that detailed explanation.
I just got back from the dyno and this setup does seem beneficial.
I'm extremely happy with the results.
Stay tuned for dyno plots.

[marconi118]

increase the intake area with scoops, this will increase the pressure inside the filter box

[Dan335i]

Simply amazing!

[jpsimon]

Originally Posted by Mr. 5

Thanks a bunch F104 for that detailed explanation.
I just got back from the dyno and this setup does seem beneficial.
I'm extremely happy with the results.
Stay tuned for dyno plots.

can't wait to see this! you didn't compare vs. the dual cones as well did you? some real on-road testing will be more telling though I assume

[Mr. 5]

I was thinking of starting a new thread but I'll just post here.

The first graph was with dual cones.
The first 2 dynos were done with the hood open and the 3rd was with the hood closed.

The second graph was with my intake.
The same goes with the hood open for the first 2 dynos and the 3rd was done with the hood closed.

[JohnL135I]

Very nice.

Thanks for testing your results. Looks like this will now become a very popular mod.