[W37V]

Just installed my euro intake. However, per my butt dunno, it seems like I lost good amount of very low end tq (~1300-3000 rpm). With stock intake, in that range, you can feel car push you against the seat. With euro intake, it’s very linear and not as strong push. I got used to the tq down low. It almost felt like a diesel thanks to MILVS.

However, euro intake does seem like it made too end stronger (above 5000rpm).

Anyone else had similar observations?

I have milvs, so I have much low end tq compared to stock car.

[Biginboca]

The euro intake should have a 3” diameter MAF area (same as stock) and you are using the same connection from throttle body to intake? I would measure the diameter of that section where the maf goes.

The only way you lose torque would be if the connections past the air filter were larger diameter and you lost some velocity on the airflow.

But if that’s the case you would/should make more top end power as a trade off.

[W37V]

Biginboca
Between US and EU intake all attachments - snorkel and throttle body connection - fit the same. I am using rev hose between box and TB.

It is just interesting to feel this much difference. And you are absolutely right. It feels I lost some power down low, but got more on top.

The only bad thing with the power shift is that I am using my car as DD and in my commute, it takes me about 40 min to do 10 miles, so low end tq was much appreciated.

I might swap them back just to see if it is all in my head.

[hassmaschine]

There's no way an intake can cause a loss in torque, especially one that came stock.

Probably your butt Dyno just needs recalibration.

[Biginboca]

It could be a weather thing or gas level thing. A 25 degree F temp rise costs you 5.5% power on n/a motors. And a full tank of gas weighs about 70 lbs more than a nearly empty tank. (~6lbs/gallon)

Those are differences you can definitely feel.

[W37V]

I wish you guys were close by to feel it yourself.

Originally Posted by hassmaschine

There's no way an intake can cause a loss in torque, especially one that came stock.

Probably your butt Dyno just needs recalibration.

Possible. I will swap and see if it is all in my head.

Originally Posted by Biginboca

It could be a weather thing or gas level thing. A 25 degree F temp rise costs you 5.5% power on n/a motors. And a full tank of gas weighs about 70 lbs more than a nearly empty tank. (~6lbs/gallon)

Those are differences you can definitely feel.

Nagh man. Temps are similar - it's been 50's here. I didn't put any more fuel. Parked the car. Swapped the box, drove the car. Immediately felt the difference.

US Box had BMW airfilter while the EU has new K&N filter.

[Biginboca]

Well I am very interested to hear your impressions if you swap back. I agree with Hass I don’t see how there could be a difference, but never having seen how a Euro airbox is designed I guess anything is possible.

The inaccuracy of my butt dyno is why I don’t ended up buying a Dragy gps timer. So often we do mods and don’t even know if they made a positive difference.

Also as a final thought, there’s always been issues with these cars pulling timing for seemingly random reasons. This is well documented too.

[The Nightman]

For what it's worth, I noticed zero difference switching between my Euro box and NA box w/ charcoal delete and I have a finely tuned butt dyno. Both had new Mann paper filters.

[freakystyly]

I'll put a vote in for loss of tq with the euro box cover opened vs closed. I tried this recently to hear the induction noise at higher rpms, which is nice but quickly gets annoying.

I can't speak for NA vs euro tho, that's been a couple years since the swap.

At first removal the torque is normal, but after a few cold restarts over the next few days, I guess the engine adapts and pulls low end power (and gains some high end I suppose). Weather had been around freezing for weeks so it shouldn't be heat related.

It's hard to tell if there is any added high end power because of the added noise, I guess it scares my butt dyno.

There's probably an explanation why the airbox should be sealed for optimum power but I don't see it other than heat soak after running for a while.

[juld0zer]

You didn't do up the clamp on the throttle body gorilla tight by any chance?
I can't remember which car was particularly sensitive to this.

[W37V]

I think I found an issue.

In the new box, MAF wasn't sitting flush in its housing. MAF was sitting slightly slanted. MAF housing on the EU box seems to be tighter than US box. I used a bit of lube around the maf seal and made it in the hole just fine.

Not sure if the readings were off because of that, but I got most of the TQ back. Car pulls very strong.

Now that I put in some miles with this set up, I can def say that the car breathes much better especially on top end. DISA transitions are also a bit smoother. This box def (or maybe it was K&N filter) made a difference.

Now I am tempted to do a Dinan mod. However, that would be a super tight fit on e92.

[Biginboca]

Originally Posted by W37V

I think I found an issue.

In the new box, MAF wasn't sitting flush in its housing. MAF was sitting slightly slanted. MAF housing on the EU box seems to be tighter than US box. I used a bit of lube around the maf seal and made it in the hole just fine.

Not sure if the readings were off because of that, but I got most of the TQ back. Car pulls very strong.

Now that I put in some miles with this set up, I can def say that the car breathes much better especially on top end. DISA transitions are also a bit smoother. This box def (or maybe it was K&N filter) made a difference.

Now I am tempted to do a Dinan mod. However, that would be a super tight fit on e92.

2” tubing is easy Dinan mod with the e92. I’m running this 2.5” now on my e92 and it also fits but is a little tricky...

https://www.amazon.com/POWERTEC-7019.../dp/B01N0RH9PH

To run the 2.5” you need to install everything with the fender liner removed, including the airbox etc. Then as the last step you replace the fender liner over the 2.5” flex tubing.

This 100% works fine... but if you ever need to remove the airbox you will need to remove the fender liner first. I think with the euro box you can now change the air filter without removing the airbox so I don’t see that as a negative because you shouldn’t need to remove the airbox again.

[FlaPatsFan]

When I switched to Euro Box/K&N air filter from stock charcoal delete/K&N I definitely thought car was breathing better. Butt dyno couldn’t feel much difference in terms of tq/hp.

I will say when I made some changes in my exhaust I picked up more low end torque but prob lost a few high end HPs. Car was much more responsive out of the hole with more pep.

[david in germany]

My wife’s 328i felt better across the power range after the euro box mod. Fuel efficiency also bumped up 2-3mpg. Win win!

[bluewater328]

I don't know if it's torque you're losing or not getting the jerky reaction to air draw that the stock box creates.

I wrote a reaction about this in a post awhile back for feedback. The eurobox along with the silicone hose will smooth out the airflow. No disruptions, no hidden resonators to fill, none of that reverse blowing a balloon effect trying to pull air through an air filter and then charcoal filter.

Granted, the same effect could be argued for by just removing the charcoal filter with the silicone tube in place of the resonator inlet.

What you're probably NOT feeling is the jerky reaction the MAF sends through while it's suffocating its own air through the stock box. Then with a silicone tube, its skipping the air cycling of the resonator and just blowing by at full stream without turbulence. Same power, just more linear reaction and ramping in reality.

[hassmaschine]

Delete the MAF. problem solved.

[bluewater328]

Originally Posted by hassmaschine

Delete the MAF. problem solved.

touché

[FIREWORKKS]

Originally Posted by freakystyly

I'll put a vote in for loss of tq with the euro box cover opened vs closed. I tried this recently to hear the induction noise at higher rpms, which is nice but quickly gets annoying.

I can't speak for NA vs euro tho, that's been a couple years since the swap.

At first removal the torque is normal, but after a few cold restarts over the next few days, I guess the engine adapts and pulls low end power (and gains some high end I suppose). Weather had been around freezing for weeks so it shouldn't be heat related.

It's hard to tell if there is any added high end power because of the added noise, I guess it scares my butt dyno.

There's probably an explanation why the airbox should be sealed for optimum power but I don't see it other than heat soak after running for a while.

what does it sound like with and without the lid?

[AoS810]

Originally Posted by FIREWORKKS

what does it sound like with and without the lid?

It sounds way too obnoxious, almost drone'y in my experience as it added a lot of NVH as the rpm's climbed. Had it like that for 2 days and put the lid back on cause it sounded like garbage.

[freakystyly]

Agreed, I wonder how it compares to the other open airboxes from AFE for example noise wise. I don't see why anyone would want that noise constantly.

[W37V]

Originally Posted by bluewater328

I don't know if it's torque you're losing or not getting the jerky reaction to air draw that the stock box creates.

I wrote a reaction about this in a post awhile back for feedback. The eurobox along with the silicone hose will smooth out the airflow. No disruptions, no hidden resonators to fill, none of that reverse blowing a balloon effect trying to pull air through an air filter and then charcoal filter.

Granted, the same effect could be argued for by just removing the charcoal filter with the silicone tube in place of the resonator inlet.

What you're probably NOT feeling is the jerky reaction the MAF sends through while it's suffocating its own air through the stock box. Then with a silicone tube, its skipping the air cycling of the resonator and just blowing by at full stream without turbulence. Same power, just more linear reaction and ramping in reality.

You are right, the whole rpm range is way smoother with this box and I got more power on top.

However, I def lost low end tq and my mileage is worse. On my daily commute, I used to average 25-26mpg. Now, my average is about 22.5 - 23mpg.

Today, I tried logging rpm / speed / afr.
Did few pulls in 4th gear. It seems like my AFR is too lean at lower RPM. I am running BPC Milvs tune.

View post on imgur.com

[Biginboca]

Originally Posted by W37V

You are right, the whole rpm range is way smoother with this box and I got more power on top.

However, I def lost low end tq and my mileage is worse. On my daily commute, I used to average 25-26mpg. Now, my average is about 22.5 - 23mpg.

Today, I tried logging rpm / speed / afr.
Did few pulls in 4th gear. It seems like my AFR is too lean at lower RPM. I am running BPC Milvs tune.

View post on imgur.com

I don’t see why you would be running lean if the maf housing is the same diameter as the N/A airbox maf housing.

The ecu should be able to correctly calculate airflow unless you have unmetered air leaking in somehow. Easy way to check is look at your fuel trims at idle, they should be close to zero and short and long terms for each bank should sum under 10.

Everything you are reporting is contrary to everyone else’s experience. Very strange!