How far can you go with a stock or maybe modified Z4 35is N54 airbox?

[studio54]

Unless I’m missing something that is completely different. It is just adding another intake BEFORE the stock panel filter.

My idea is to add an external cold air intake (including filter) and dump the filtered air into the stock airbox AFTER the stock panel filter. 2 intake sources (red arrows). 2 filters. 2 filtered air outputs (blue arrows).

The mr5 intake like, google images this : mr5 intake n54

You will see a lot of variants, some are sourcing the air just behind headlight, some are sourcing the air in the bottom like you plan, some put a cone filter at the end of the tubing, some put a carbon filter just side to the stock airbox like you plan.

I was also thinking to doing that, but I wanted to buy a used OEM airbox to do this, so I still keep the stock airbox for MOT control and so on.

 

[Torgus]

Once the car is moving there is plenty of air in the engine bay. This is why metal hot side intakes work just fine and is what I would run.

You guys are massively overthinking all of this. Obviously it is best to start with colder air but the air goes through flowing white hot turbines:

A quality IC is much more important. If you want to cool down your AITs you can use water, meth, water & meth. Or just run E50.

 

[carabuser]

Did anything ever happen with the 7 series intake conversion?

I like the idea of cleaning up the vacuum cannisters and routing the intakes over the engine. Seems a huge improvement over the shitty silicon intakes.

 

[studio54]

Front turbo throw as large a cone filter as you can fit up by the headlight w/ 2'' pipe, rear turbo 2'' silicone inlet to stock box. Should be about the best of both worlds. Ideally both would be solid pipes but the rear makes fitting a 2'' pipe impossible.

A bit like this (except he uses the 7 airbox) https://www.spoolstreet.com/threads/740i-intake-setup-on-335i-updated.4218/

Last pic of the first post

He said the result was better with this setup

 

[Torgus]

A bit like this (except he uses the 7 airbox) https://www.spoolstreet.com/threads/740i-intake-setup-on-335i-updated.4218/

Last pic of the first post

He said the result was better with this setup

I assume you mean this one:

or

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

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...

www.spoolstreet.com

Either way they get the same thing done basically.


Again, way too much thought and posts on car forums since FOREVER is about air intakes and placement etc. The difference is lost in the minutiae in almost every case. If anyone is worried about AITs there are very simple and easy ways to lower them, again you can just spray in water.

 

[studio54]

I assume you mean this one:

View attachment 74518


or

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

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...

www.spoolstreet.com

View attachment 74519




Either way they get the same thing done basically.


Again, way too much thought and posts on car forums since FOREVER is about air intakes and placement etc. The difference is lost in the minutiae in almost every case. If anyone is worried about AITs there are very simple and easy ways to lower them, again you can just spray in water.

Oh yeah, intake are debated to death for the moment I just run the stock air box with a BMC drop in (I also have DCIs somewhere in a bag)
You mean, like simply just spray (cold?) water on the FMIC ?

 

[Torgus]

Oh yeah, intake are debated to death for the moment I just run the stock air box with a BMC drop in (I also have DCIs somewhere in a bag)
You mean, like simply just spray (cold?) water on the FMIC ?

IC water sprayers and frosters I think are just gimmicks. Not worth the hassle and illegal on most tracks and drag strips(not allowed to leak water)

Spray water into the intake track. Just like you would do with meth and water. The M3 came with this from the factory to lower AITs: https://www.bmw-m.com/en/topics/magazine-article-pool/5-litres-of-water-for-500-horses.html <--please IGNORE the "innovative and trailblazing water injection system" this has been done forever.

If you are going through the hassle of water injection you might as well mix in meth and run 50:50. The meth chemically cools the intake track and give you a higher AKI best of both worlds. All you need is a $150 pump, some line, and a nozzle, oh and a hobbs switch to a relay, but all can be done for relatively small money and will have a HUGE impact, unlike moving air filters in different positions around an engine bay.

edit: the water meth also makes the car VERY consistent. Heatsoak goes away, sucking in 95 degree air is fine, etc. Meth usually drops the AITs by 20-30 degrees while adding AKI. Allows you to run a more aggressive tune with consistent low AITs.

 

[wheela]

IC water sprayers and frosters I think are just gimmicks. Not worth the hassle and illegal on most tracks and drag strips(not allowed to leak water)

Spray water into the intake track. Just like you would do with meth and water. The M3 came with this from the factory to lower AITs: https://www.bmw-m.com/en/topics/magazine-article-pool/5-litres-of-water-for-500-horses.html <--please IGNORE the "innovative and trailblazing water injection system" this has been done forever.

If you are going through the hassle of water injection you might as well mix in meth and run 50:50. The meth chemically cools the intake track and give you a higher AKI best of both worlds. All you need is a $150 pump, some line, and a nozzle, oh and a hobbs switch to a relay, but all can be done for relatively small money and will have a HUGE impact, unlike moving air filters in different positions around an engine bay.

edit: the water meth also makes the car VERY consistent. Heatsoak goes away, sucking in 95 degree air is fine, etc. Meth usually drops the AITs by 20-30 degrees while adding AKI. Allows you to run a more aggressive tune with consistent low AITs.

So I always see chargepipe meth on this platform, but on a different forum, I just saw an s55 guy is planning on plumbing his meth nozzle into his single turbo's compressor housing. This seems like a really good idea to me, as the hotter air before the intercooler will more reliably evaporate the water droplets, and also help heat soak with the intercooler, as you get some cooling before the charge air enters. Any body run their meth/water injection nozzles before the intercooler vs. on the charge pipe? Sorry if this is too much of a thread jack, but it kind of relates.

 

[ShocknAwe]

Pretty sure where you're adding it is post filter

 

[wheela]

Pretty sure where you're adding it is post filter

Are you talking about meth nozzle placement, or where the intake enters in the pic noquarter posted? If meth nozzle, I was asking if anybody has put the nozzle before the intercooler vs. in the charge pipe after the intercooler?

 

[ShocknAwe]

@wheela Even pre-turbo meth has been tried. Consensus is just do low flow nozzle in CP if truly just using it for cooling, or bite the bullet and do PI if using for fuel in any capacity.

 

[Darke Peak]

I think this is all good debate. Nobody has a gun to your head. If you are sick of it then ignore this thread.

For me, I have a specific purpose (roll racing) that causes issues and some options are not suitable. These racing conditions are very different to any street driving. I have seen a distinct performance difference between sucking cold air (factory airbox & filter) and sucking hot air (DCI). The turbos might be glowing hot after a minute of WOT in a static engine room but…
1. My race is over less than 8 secs after I go WOT. The turbos aren’t glowing red yet.
2. It would take at least 5 seconds of driving before the hot air in the engine bay is expelled and the temperature is reduced to something anywhere near close to external ambient. The winner of the race is already determined by this point.
3. The air doesn’t stop to have a picnic in the turbo on its way to the intercooler. There’s more than 80L/sec of air flowing through each turbo at WOT. Sure, it picks up heat but if your IAT is 20c cooler to start with then it makes a difference.
4. DCI are not legal for road use in Australia. After bald tyres it is probably the most common defect handed out. If a cop looks in the engine bay they stand out like a set of dirty great big dogs balls. He hands you a defect for them and then you have to revert the whole car back to stock for a roadworthy inspection.
6. External water spray onto FMIC is not allowed on any race track. It also doesn’t work very well when stationary for 10-20 mins.
5. Meth is not allowed at Roll Racing events because spectators complained it was burning their eyes. I’ve also seen too many engines fail because either the meth injection stopped suddenly and/or the CP injection was not uniform (some cylinders get less than others but engine can’t detect which ones).
6. Water injection is an option but much less effective and similar issues to point above.
7. I’m already running E50.

All my work on intakes is to support the upgrade to hybrid turbos. The factory airbox is ok with MHD stage 2+ on factory turbos but I expect it could cause a catastrophic failure at 550whp if the extra vacuum in the silicone inlets causes them to collapse. Rob Beck has already warned me against keeping my VRSF silicone inlets because he’s seen them collapse, his are apparently stronger. So I’m trying to find a way to bring more filtered cold air into the intakes.

 

[Torgus]

if your IAT is 20c cooler to start with then it makes a difference.

20c is 68 degrees Fahrenheit for those of us who use freedom units. How are you going to find ambient air 68 degrees cooler or why would a DCI be sucking in air 68 degrees warmer?

if you are roll racing you are not at a stop. Your car is already up the speed and the engine bay is full of ambient temp air. The front scoop only draws in more ambient air. Unless of course air is compressible at highway speeds through an air filter.

Why would the dci be sucking in hot air? There is nothing warm on the side of the engine and when roll racing lots of fresh ambient air.

I hear DAW makes good hybrids

 

[Darke Peak]

20c is 68 degrees Fahrenheit for those of us who use freedom units. How are you going to find ambient air 68 degrees cooler or why would a DCI be sucking in air 68 degrees warmer?

if you are roll racing you are not at a stop. Your car is already up the speed and the engine bay is full of ambient temp air. The front scoop only draws in more ambient air. Unless of course air is compressible at highway speeds through an air filter.

Why would the dci be sucking in hot air? There is nothing warm on the side of the engine and when roll racing lots of fresh ambient air.

I hear DAW makes good hybrids

Have you looked at the engine bay of a Z4 35i/s? The engine bay is almost fully enclosed. Hot air rises. There are rubber seals along every top edge to stop heat escaping. The underside of the bonnet/hood is lined with insulation. The whole underside of the engine bay is covered with a plastic panel. Fresh air has to come through the central part of the bumper past a hot radiator or FMIC. The side scoops don’t feed into the engine bay. The hot air escapes through small gaps either side of the transmission at the bottom of the engine bay - once again hot air rises. For emissions reasons it is designed NOT to be ambient temperature inside the engine bay. It is stinking hot in that engine bay (especially if you aren’t moving) - on both sides of the engine.

This is formal roll racing, not some illegal Mexican highway activity. I am stopped (and idling) for 10-20 mins immediately prior to each race. From a standing start I have only a few seconds to get up to 50kmh (30mph) before light goes green.

These are some of the numbers I’ve recorded at the last few events….
Ambient temp: 8-12C (46-53F)
Engine bay temps (DCI side) at staging: 45-65C (113-149F)
Staging IAT with DCI: 42-47C (108-116F)
Staging IAT with airbox: 35-42C (95-108F)
Race start IAT with DCI: 40-46C (104-115F)
Race start IAT with airbox: 22-32C (72-90F)

PS: if Fahrenheit represents freedom then why do the US military use the metric system to fight for it?

 

[Torgus]

Do you have any AIT numbers from when you get up to 30mph and beyond?

Is e50 not enough to get rid of your corrections?

 

[Darke Peak]

Do you have any AIT numbers from when you get up to 30mph and beyond?

Is e50 not enough to get rid of your corrections?

The IAT’s you request are quoted above.
Staging = 0mph
Race start = 30mph
As you can see they aren’t anywhere close to ambient, even with the airbox.

E50 doesn’t resolve the timing corrections. I’m guessing the target timing is more aggressive with E50 tune anyway. Frequently seeing the timing pulled by 3 degrees, but sometimes as much as 9 degrees. Also seeing the AFR’s are richer and it appears to pull boost (although I didn’t think this was possible through MHD OTS tunes).

 

[Darke Peak]

I’d heard that the N54 powered 135,335 & Z4 all had the same airbox & filter, but the Z4 had a different lid. I got hold of a 335 airbox+lid and can confirm this is all true.

I tried fitting the 335 lid to my Z4. The bonnet/hood closes properly but there is slightly less clearance than with the Z4 lid.

Which lid flows more?
Test 1: calculate the volume of each lid by filling them with water. The 335 lid holds 2.83L and the Z4 holds 2.67L. 335 lid wins. This is the less relevant test in my opinion.
Test 2: measure the surface area of the “choke” point the air has to flow through to get from the filter into the cavity to feed the inlet pipes. The Z4 lid has 79.3cm2 and the 335 lid has 73.8cm2. Z4 lid wins. This is the more relevant test in my opinion.
Summary: Without complicated laminar flow modelling I’m presuming both these tests are irrelevant since the surface area restriction into the inlets (2 x 55mm diameter) is 47.5cm2. If it was a big concern then the 335 lid could more easily be modified to flow more than the Z4 lid (completely remove the dimple area that allows for the 135/335 cowl and replace it with a 3D printed section that could be glued on).

 

[Armando1969]

I’d heard that the N54 powered 135,335 & Z4 all had the same airbox & filter, but the Z4 had a different lid. I got hold of a 335 airbox+lid and can confirm this is all true.


View attachment 74885
I tried fitting the 335 lid to my Z4. The bonnet/hood closes properly but there is slightly less clearance than with the Z4 lid.

Which lid flows more?
Test 1: calculate the volume of each lid by filling them with water. The 335 lid holds 2.83L and the Z4 holds 2.67L. 335 lid wins. This is the less relevant test in my opinion.
Test 2: measure the surface area of the “choke” point the air has to flow through to get from the filter into the cavity to feed the inlet pipes. The Z4 lid has 79.3cm2 and the 335 lid has 73.8cm2. Z4 lid wins. This is the more relevant test in my opinion.
Summary: Without complicated laminar flow modelling I’m presuming both these tests are irrelevant since the surface area restriction into the inlets (2 x 55mm diameter) is 47.5cm2. If it was a big concern then the 335 lid could more easily be modified to flow more than the Z4 lid (completely remove the dimple area that allows for the 135/335 cowl and replace it with a 3D printed section that could be glued on).

View attachment 74884View attachment 74883

I always assumed that the complete airbox of the Z4 was bigger than that of the 335i and the one from the 7 series BMW even bigger but then with other piping.

 

[Darke Peak]

I always assumed that the complete airbox of the Z4 was bigger than that of the 335i and the one from the 7 series BMW even bigger but then with other piping.

The N54 powered Z4, 135 & 335 definitely have the same part number for the base/box and the air filter. Only the lids are different.

I’m not sure about the 5 & 7 series.

 

[fmorelli]

I'd be looking at the slinky air entry but the front radiator support.