Ideas to improve ram-air in the n52 Air intake duct/Suction hood

[andrey_gta]

Hey guys
What are your thoughts on the Suction hood/duct (the pipe before the airbox)?



Does it provide the most efficient path to the airbox?
e8x - 13717547593
e9x -13717541737

I do not think it is very efficient. In fact I think it creates turbulence areas that can be avoided with some DIY work. When I examined mine, I wasn't very impressed with it.

So here is my Idea to improve it:

This applies to both OEM and Performance spec hoods(The BMW performance version increases its channel size and also the opening at airbox by 17-20%. )
At the very least the RIGHT side could use a better separator into the airbox from the grille

Those with with air scoops stand to benefit the most.

[justpete]

Originally Posted by andrey_gta

Hey guys
What are your thoughts on the Suction hood/duct (the pipe before the airbox)?



Does it provide the most efficient path to the airbox?
e8x - 13717547593
e9x -13717541737

I do not think it is very efficient. In fact I think it creates turbulence areas that can be avoided with some DIY work. When I examined mine, I wasn't very impressed with it.

So here is my Idea to improve it:
Attachment 1123373
This applies to both OEM and Performance spec hoods(The BMW performance version increases its channel size and also the opening at airbox by 17-20%. )
At the very least the RIGHT side could use a better separator into the airbox from the grille

Those with with air scoops stand to benefit the most.

The thing is the engine acts as the pump to pull air through the intake system but the pressure drop is relatively low if it's laminar flow so the designers would take care to avoid the possibility of turbulent flow. The location of the snorkel inlets are in a relatively high pressure region ahead of the radiator which helps lower the work needed to get the air into the manifold. Not sure if scoops will really help, got a set coming in to try but I imagine the effect is relatively small.

The only way to make the snorkel have less flow resistance is to increase its cross section which the PI snorkel does as you mentioned. The air has to flow through bends in the inlet tract though and the losses inherent to the resultant change in momentum of the mass flow will tend to dominate the pressure drop so there's a limit to how much increasing the cross section can help.

Ram air is a way to further increase pressure at the filter in order to increase flow by effectively decreasing the filter's effective pressure drop. And this is done with an intake tract with far less momentum changes in the mass flow so it's much more efficient than the snorkel to the grill. The M3 does this as well as using a pickup on the surface of the hood where pressure is a bit higher and that tract is shorter yet. Then again the engine needs a lot more air per unit time.

Everything I've read indicates the ram air method is the most effective way to improve intake breathing. But it's wholly dependent on the engine's intake suction which is a function of the head design. That's the actual limiting factor in how much of a charge the engine can take in per cycle so there's a more fundamental limit in how much an improvement in intake efficiency can actually make.

Not what you wanted to hear I know, had the same letdown looking at improving (lowering) flow resistance myself. Looking at ways to get a ram air function working.

[edit] Sorry, forgot to clarify that the snorkel isn't a ram air structure [/edit]

[Taskmaster]

So...how do We fix it?

[justpete]

Originally Posted by TheAxiom

So...how do We fix it?

The Dinan ram air intake or anything like it is the only solution I can find but it depends on the design of the bumper so that's where I've been looking to change things, just haven't found a solution I like yet. There're are some excellent airboxes out there but the headlight's in the way, dangit...

[justpete]

Originally Posted by TheAxiom

So...how do We fix it?

Any idea what bumpers provide a way to use a version of the Dinan ram-intake? Assuming a pickup could be fab'ed, etc. Aftermarket bumpers get kinda confusing to an idiot like me since I gave up on the widebody conversion thing. TIA

[Taskmaster]

Originally Posted by justpete

Any idea what bumpers provide a way to use a version of the Dinan ram-intake? Assuming a pickup could be fab'ed, etc. Aftermarket bumpers get kinda confusing to an idiot like me since I gave up on the widebody conversion thing. TIA

It's just the bumper grill:



Vs



Dinan gives a replacement grill insert for the Pre LCI, but they obviously don't make it for the LCI bumper. he easiest thing to do is make your own and use the Dinan hardware.

[justpete]

Originally Posted by TheAxiom

It's just the bumper grill:



Vs



Dinan gives a replacement grill insert for the Pre LCI, but they obviously don't make it for the LCI bumper. he easiest thing to do is make your own and use the Dinan hardware.

Oh. Toldja I was an idiot...

So I lose the driver side brake duct and/or foglights. Not as concerned about the brake ducts now and the foglights aren't really useful so this would be the way to go then, thanks.

But doesn't the CAI port to the stock airbox only? I wonder if it'd match up with the PI airbox. I'm guessing the shop can fabricate anything. Looking at a bored throttle body now in case it's possible at a rational cost in advance of the possibility of improved cams. The CAI would be an important improvement, I think.

Thanks again.

[Taskmaster]

Originally Posted by justpete

Oh. Toldja I was an idiot...

So I lose the driver side brake duct and/or foglights. Not as concerned about the brake ducts now and the foglights aren't really useful so this would be the way to go then, thanks.

But doesn't the CAI port to the stock airbox only? I wonder if it'd match up with the PI airbox. I'm guessing the shop can fabricate anything. Looking at a bored throttle body now in case it's possible at a rational cost in advance of the possibility of improved cams. The CAI would be an important improvement, I think.

Thanks again.

Let me check

[Taskmaster]

Originally Posted by justpete

Oh. Toldja I was an idiot...

So I lose the driver side brake duct and/or foglights. Not as concerned about the brake ducts now and the foglights aren't really useful so this would be the way to go then, thanks.

But doesn't the CAI port to the stock airbox only? I wonder if it'd match up with the PI airbox. I'm guessing the shop can fabricate anything. Looking at a bored throttle body now in case it's possible at a rational cost in advance of the possibility of improved cams. The CAI would be an important improvement, I think.

Thanks again.

It could work. I don't have the PI, but as long as the box is shaped similar to the half removed from the car, it will work.

I don't think it covers the brake duct either.
http://www.e90post.com/forums/showthread.php?t=183780

Still haven't installed mine.

[justpete]

Originally Posted by TheAxiom

It could work. I don't have the PI, but as long as the box is shaped similar to the half removed from the car, it will work.

I don't think it covers the brake duct either.
http://www.e90post.com/forums/showthread.php?t=183780

Still haven't installed mine.

Definitely goes where the brake duct would be, post #22 indicates it won't work on the 128i because of the brake ducts.

But it can work in the same way Mr. 5's intake works by using the space where the foglight is along with the contour of the volume behind it and along the brake duct to do the same thing. The trick would then be creating a new grill for each side. Shouldn't be difficult I think. The center one is already broken and there's a long dead bird jammed in there, too. But that'll all get taken care of with the new radiator. So maybe we'll just fab some stronger grill screens at the same time.

Thanks for the link, helps a heckuva lot!

[Taskmaster]

Are you sure? It looks like it takes air from the same tract, but doesn't block it:
The big airbox diverter has a fairly open back end


Then, the splash guard has the opening to allow air through:


Fully connected


Maybe Tom_Droze or @TSM330i can give us some insight?

[Taskmaster]

Something like this:
http://www.e90post.com/forums/showth...rsprint&page=5

[justpete]

Originally Posted by TheAxiom

Something like this:
http://www.e90post.com/forums/showth...rsprint&page=5

Thanks, this helps visualize the differences. The brake ducts on my car are flush or nearly so with the inside of the grill and extend from the inner edge of the opening in the bumper to within a couple of inches or so of the foglight and the grill is solid over this area. It looks like it'd be very easy to remove the foglights (which we'll be doing anyway) and use that space for a ram-air CAI, replacing the grills with some other type along the way, or not, dunno.

Will have to use a fabricated 'scoop' to block the air from escaping so it can be drawn up to the airbox but without allowing water ingress although as someone else pointed out air follows the path of least resistance.

Thanks again for the help, it makes a lot more sense now.

[justpete]

Installed AFE scoops this morning, just cuz. While the airbox cover was off I looked into the area between the airbox and the headlight with a bright flashlight and it's definitely easy to modify the PI airbox ahead of the filter for a silicone hose down to a fabricated box placed where the foglight is. Plenty of room for the ram-air box and for the hose. Will have to figure out the grill pieces for both sides though, maybe just that metal mesh I was thinking of.

And the shop's checking with Dinan (they're a dealer) about the bored out TB -- what's special about it, can it be used on a 2011 with a three stage manifold, is the price for real, that sort of stuff. Depending on how it turns out they have a shop that can bore the TB and fabricate a new butterfly for a lot less. Does it matter? Dunno. Might matter with better cams and head/valve work. Guess we'll see.

[andrey_gta]

Originally Posted by justpete

And the shop's checking with Dinan (they're a dealer) about the bored out TB -- what's special about it, can it be used on a 2011 with a three stage manifold, is the price for real, that sort of stuff. Depending on how it turns out they have a shop that can bore the TB and fabricate a new butterfly for a lot less. Does it matter? Dunno. Might matter with better cams and head/valve work. Guess we'll see.

http://www.maxbore.com/

Email him - he was responsive to me a year ago - he did about 2 of the e9x TB's
The Dinan Large bore has shrink wrap seal - the newer TB have clips - so maybe no need for the seal
My plan is to buy from ebay for $100 or less a TB, send it to him direct and have him do it plus ship to canada

Seems to me your living the n52 dream ( all the possible mods plus exotics things), and we are spectators lol

[justpete]

Originally Posted by andrey_gta

http://www.maxbore.com/

Email him - he was responsive to me a year ago - he did about 2 of the e9x TB's
The Dinan Large bore has shrink wrap seal - the newer TB have clips - so maybe no need for the seal
My plan is to buy from ebay for $100 or less a TB, send it to him direct and have him do it plus ship to canada

Seems to me your living the n52 dream ( all the possible mods plus exotics things), and we are spectators lol

Sweeeet! That's a steal in comparison, can't thank you enough! Looks like that's another line item down.

For grins the finished engine will have the valve cover painted in a blue wrinkle finish, cuz racecar...

[andrey_gta]

Originally Posted by justpete

For grins the finished engine will have the valve cover painted in a blue wrinkle finish, cuz racecar...

VTEC?

[justpete]

Originally Posted by andrey_gta

VTEC?

Huh. Never saw a VTEC engine, who'd'a thunk it. OTOH, paint adds weight...

[Taskmaster]

Why not a tube type intake from the TB to the fender - like the old Sport Compact days?

[andrey_gta]

Originally Posted by justpete

Huh. Never saw a VTEC engine, who'd'a thunk it. OTOH, paint adds weight...

I was just joking. Blue looks good

[justpete]

Originally Posted by andrey_gta

I was just joking. Blue looks good

Thanks, would hate to rack up poser points without knowing it...