BMC Filters Loss On Low End

[6SPD GOD]

Has anyone experienced loss on low end after the installation of BMC filters?

I tried it on an F82 ZCP and F80 ZCP LCI. Both had a substancial loss on low end, same effect as when running DCI's.


Stock tune.

[Thescout13]

What is a substantial loss? In the butt dyno? Or on an actual dyno? Assuming you removed the charcoal filters as well? Shouldn't be any loss unless you accidentally unplugged a vacuum tube or left something unsealed.

[6SPD GOD]

Originally Posted by Thescout13

What is a substantial loss? In the butt dyno? Or on an actual dyno? Assuming you removed the charcoal filters as well? Shouldn't be any loss unless you accidentally unplugged a vacuum tube or left something unsealed.

Butt dyno.

Both cars feel substantially slower.

No charcoal filters; also the throttle becomes loose just like if you were on a higher gear trying to catch up speed.

With OEM filters the vehicle feels tight and stronger.

================================================== ==============

We noticed the change whenever we return the vehicles to stock for service

[Thescout13]

Originally Posted by MNMWMWMN

Butt dyno.

Both cars feel substantially slower.

No charcoal filters; also the throttle becomes loose just like if you were on a higher gear trying to catch up speed.

With OEM filters the vehicle feels tight and stronger.

================================================== ==============

We noticed the change whenever we return the vehicles to stock for service

Interesting. Maybe the stock tune doesn't like the extra airflow? Idk just spit balling here.

[6SPD GOD]

Originally Posted by Thescout13

Interesting. Maybe the stock tune doesn't like the extra airflow? Idk just spit balling here.

That's my guess as well.

[CigarPundit]

I did a before and after dyno on my totally stock F80 just for shits and giggles. Gain of 3 on two runs, and 10 on the third. No loss anywhere.

[BuLoOoSki]

Originally Posted by CigarPundit

I did a before and after dyno on my totally stock F80 just for shits and giggles. Gain of 3 on two runs, and 10 on the third. No loss anywhere.

Can you please post the graph? Personally I'm not expecting them to make me any power, but it would be nice to see an independent dyno for these.

[CigarPundit]

Originally Posted by BuLoOoSki

Can you please post the graph? Personally I'm not expecting them to make me any power, but it would be nice to see an independent dyno for these.

I’ll see what I can do. I had them installed at Auto Talent and we did the dynos just for kicks (they didn’t charge me), so I never requested copies. We all had a good laugh while it was being done making wild predictions from -10 to +100. I didn’t expect power either, I just did it because I was planning a tune and exhaust and I love wasting money modding my car.

[DanMpower]

I felt the same thing when I installed the BMC drop in but I'm on a Stage 1 BM3 tune, a big enough loss to feel with my butt dyno. I don't think the loss will show up on a dyno since you are always full throttle, but partial throttle driving, I felt a big loss in throttle response and mid-range pickup. Went back to the stock paper filters and power and engine response was back!

My thread.

https://f80.bimmerpost.com/forums/sh....php?t=1493596

[hellcat2m4]

I have felt this on every car but my hellcat, and it seems like when I mention it people think I am crazy. I guess the big motor helped cover for it.

That being said, I still keep them in the car haha.

[Dr._Who]

Hey,

Sub'd.

!!Good Luck!!


Cheers!

[6SPD GOD]

Originally Posted by CigarPundit

I did a before and after dyno on my totally stock F80 just for shits and giggles. Gain of 3 on two runs, and 10 on the third. No loss anywhere.

Peak numbers might stay constant; however, low end feels slower.

A comparison would be when you go from comfort to SPORT +.

[Dr._Who]

Hey,

This may not be the case here but, would removing or not removing the charcoal filters make a noticeable difference?


Cheers!

[BIGW0RM]

I agree with OP. I too can clearly feel a difference between stock filter and drop in on the low end.

I assume it all has to do with back pressure and how it breaths, which changes what we feel in throttle and out of the hole. I actually like how it drives with the stock filter more. I just love the sound of aftermarket much more than that.

Seems you make up for the loss on the top end if at all.

[DanMpower]

So I guess with stock or stage tunes, the stock filter is best. Only once you go custom tune for big power is when an intake is needed I think.

[schnell1982]

Interesting. I've installed quite a few setups on BMC filters.
Never had a complaint of loss or noticeable performance loss.
I'll have to contact a few and see if they have noticed anything different since time has passed.

[Alan l.]

Originally Posted by Railgun

Que? What back pressure?

This is all pre-turbo. Any ability to get more air in is good. Unless these filters flow less, something else is wrong.

This.... There is no need for back pressure pre turbo. The only way it can cause power loss is if these filters are more restrictive than oem or they are causing disruptive airflow through the intake sensors causing the ecu to pull power.

Alan

[hellcat2m4]

I know on my hellcat the stock mahle branded filter actually flowed more then K&N based on the flow data shown on the filter/box. I wonder if this could be the same case? Has anyone looked into this?

[BIGW0RM]

Originally Posted by Railgun

Que? What back pressure?

This is all pre-turbo. Any ability to get more air in is good. Unless these filters flow less, something else is wrong.

If you open up the intake end, the exhaust end seems to loose some back pressure. Im not saying WHERE it happens. Im saying it feels that way.

[MSY]

That statement is a physics impossibilty.

Part throttle sensitivity can change has there is changes in pumping loss/gain so likely you feel some disruption in throttle sensitivity based on the ECU programming and effect the higher flow filter has on that pumping loss/gain effect but power is not lost

[6SPD GOD]

Originally Posted by MSY

That statement is a physics impossibilty.

Part throttle sensitivity can change has there is changes in pumping loss/gain so likely you feel some disruption in throttle sensitivity based on the ECU programming and effect the higher flow filter has on that pumping loss/gain effect but power is not lost

Loss on low end output is significant enough for the driver to notice.

The saying "The ECU has to learn the new set up" does not apply to neither my ZCP F82 Pre LCI(6SP) or ZCP F80 LCI(DCT). I have had both vehicles with BMC filters and aftermarket dual cone intakes. Both set ups yield a decrease on available power at low RPMs.


The reason I ditched DCI's was due to the loss on low end, heat soak was my first guess; however, after switching around with BMC and fully stock I have found that there is nothing better for stock map performance than the OEM filters.

[Justin.AutoTalent]

Originally Posted by CigarPundit

I did a before and after dyno on my totally stock F80 just for shits and giggles. Gain of 3 on two runs, and 10 on the third. No loss anywhere.

Just commenting to your quote because it's your car

BUT, the car was idling funny and misfiring for about 5 minutes and then idled out normally before we did a pull

OP could be experiencing lag as the car adapts.

If I recall CigarPundit we did 2 or 3 passes after the filters? Usually cars cycle through and adapt quickly after the first or second pass on the dyno.