740i intake setup on 335i (updated!!)

[mikeseli]

I got to thank Dimitri from BQ Tuning. All the info he provided me helped me finish this 740i intake setup.

Here are some pics.

Also a big thanks for Charles from BMG Performance for doing the install and making my aluminum inlets.

UPDATE (Aug.2021)

I decided to have each turbo being fed by its own air filter. Here are the results.

This is a custom 3D printed intake tube assy that was designed specifically for this setup. There was a few revisions done to get this tube to fit like a glove.

The front turbo uses this blue cylindrical air filter.

A difference was felt vs the older setup during a few runs.

 

[Panzerfaust]

Saw this on FB, definitely a clean install if you're going for an OEM style look. Personally I really, really dig the 740i engine cover itself but can't help but think from a pure power standpoint relocated is still the way to go.

Either way, props for a unique and well done setup. I'm assuming you want to stick with the OEM airbox but just out of curiosity, are there many aftermarket intake options you could use with that setup?

 

[doublespaces]

Nice, now if someone could make an aftermarket airbox that fit this cover that would be pretty sweet. Definitely preferable to the typical pancake inlet route in front and behind the engine.

 

[Dmak]

Very nice, clean, oem looking.
Any reason for the front inlet pipe connect to the rear of air box outlet? I m guessing something to do with the angle of the rear turbo inlet or clearance?

Now just need to run a cool air feed hose/duct from left side fog light area to the air box inlet and you get cold ram air.

 

[ShocknAwe]

What size are your inlets?

 

[iminhell1]

So you NEED the M3 cowling to make this work.
And it looks half completed until you have it married to the fresh air from the front.


The only things I find neat are that this setup looks close to workable with the other AWIC thread.

 

[mikeseli]

The piping is 57mm (2.25”).

What size are your inlets?

 

[mikeseli]

Very nice, clean, oem looking.
Any reason for the front inlet pipe connect to the rear of air box outlet? I m guessing something to do with the angle of the rear turbo inlet or clearance?

That portion of the air box is a “Y” so it makes no difference. I would of preferred to do it like Dimitri but the 335i has less space to clear that area.

 

[mikeseli]

Nice, now if someone could make an aftermarket airbox that fit this cover that would be pretty sweet. Definitely preferable to the typical pancake inlet route in front and behind the engine.

The 740i and X6 airbox is much larger and better designed to the common n54 air box.

 

[ShocknAwe]

Any idea if the 335i and 135i are different with pipe routing and brace clearance? I'd love to do this.

Wonder about clearance for the PR coils.

 

[mikeseli]

Any idea if the 335i and 135i are different with pipe routing and brace clearance? I'd love to do this.

Wonder about clearance for the PR coils.

The 740i intake setup will not work with PR coils.

 

[PUTC]

Looks awesome and I have been following BQs carbon fiber build. I’m wondering why the pipes were crossed going into the Y, seems a little cluttered and hitting ignition wires. Really want to do this instead of standard relocation. Looks nice and clean

 

[Hydra Performance]

Forgive the dusty engine bay (not mine), and the blue silicone bits which would have looked a lot cleaner in black, but this is my preferred setup all in all, stock-style airbox for the R turbo, with relocated front inlet while keeping the overflow tank and the vacuum canisters on the passenger side where they belong...

I am running dual 3" inlets on my personal vehicle FWIW...

 

[mikeseli]

Forgive the dusty engine bay (not mine), and the blue silicone bits which would have looked a lot cleaner in black, but this is my preferred setup all in all, stock-style airbox for the R turbo, with relocated front inlet while keeping the overflow tank and the vacuum canisters on the passenger side where they belong...

I am running dual 3" inlets on my personal vehicle FWIW...

View attachment 16693

The biggest restriction is the rear inlet, hence why I did want to route it between the rear of the engine and the firewall. Everyone with driver side silicone inlets has the rear inlet compressed that it’s a flow restriction.

 

[fmorelli]

The biggest restriction is the rear inlet, hence why I did want to route it between the rear of the engine and the firewall. Everyone with driver side silicone inlets has the rear inlet compressed that it’s a flow restriction.

How is it a flow restriction? Seems to me that area squared is constant whether the silicone hose is round, oval, or whatever inbetween.

Filippo

 

[Hydra Performance]

The trouble with most silicone inlets I've seen is that they are quite thick, and are no more than 2.25" ID for most of their run - hardly ideal if you want to support 350-400bhp/turbo. I managed to fit a 3" hose on my car, the proviso being that the entire driveline needs to be out for this to happen. I will post more pics in a separate thread, so as not to derail this one any further...

 

[mikeseli]

How is it a flow restriction? Seems to me that area squared is constant whether the silicone hose is round, oval, or whatever inbetween.

Filippo

This is where fluid dynamic courses come into play. The area is the same, however airflow is moving at 300+ ft/s therefore boundary layers are created within the inner diameter tubing. The air is moving from the air filter to the inlet throat of the turbo's compressor housing. The squeezed area is located less than 6" from the compressor's inlet and air does not have enough time/distance to fully correct itself at these airflow speeds. At the end this squeezed area is similar as having a 1.5" to 1.7" diameter tube section at those 6".

 

[fmorelli]

This is where fluid dynamic courses come into play. The area is the same, however airflow is moving at 300+ ft/s therefore boundary layers are created within the inner diameter tubing. The air is moving from the air filter to the inlet throat of the turbo's compressor housing. The squeezed area is located less than 6" from the compressor's inlet and air does not have enough time/distance to fully correct itself at these airflow speeds. At the end this squeezed area is similar as having a 1.5" to 1.7" diameter tube section at those 6".

I understand this is a factor. If you are referring to this as your reasoning, may I ask if have performed the tests and calculations to determine actual loss and that it is significant, and significant being compared to the same measurements from a stock unit since obviously that would be the baseline? At this point, every aspect of the pipe's design effects the flow, which automotively speaking (so we don't move to other domains) is well understood with exhaust system design. Well aside exhaust pulse and hemholtz and what not - yeah it's rocket science.

What I'm saying is, yes I completely agree your statement that area is hardly just the factor (you are right), but only measurements bear out significant differences. The rest is speculation. Hence my statement using area as a gross characterization. Until flow measurements are done, we are speculating and throwing stones in the lake I believe.

Filippo

 

[BQTuning]

Very nice, clean, oem looking.
Any reason for the front inlet pipe connect to the rear of air box outlet? I m guessing something to do with the angle of the rear turbo inlet or clearance?

Now just need to run a cool air feed hose/duct from left side fog light area to the air box inlet and you get cold ram air.

Yes the angle and clearance. Rear to front and front to rear is the best setup for the E9x N54 cars

 

[BQTuning]

Hmm wonder if the airbox snout would fit. It should point downwards to the driver-side air duct. Of course this will not work on a 335is which has the 2nd rad that takes up that spot.

https://www.ecstuning.com/b-genuine-bmw-parts/air-channel/13717582310/