Much better mileage after changing oem air box.

[e30cabrio]

My boot broke and I am waiting for it to come from Germany. I had a circular CAI filter sitting around so bolted it to the MAF housing.

I have averaged 13.5 mpg mixed driving (12x miles per 1/4 tank) I am at 98 miles on 1/16 on 100% street since I removed the oem box.

Does this make any sense?

[Clockwork]

something doesnt seem right. BMW designs their air boxes/hoses VERY well and you'd be VERY hard pressed to find a better solution!!! CAI are usually a JOKE if its sitting in the engine bay still. ONLY if its actually routed through the existing engine hosing and wiring and metal down to the bottom of the engine bay (in front of a wheel usually) will any difference be made by a CAI. if its just sitting in the engine bay its more of a hot air ram intake.
are you getting your numbers from calculations or just the fuel gauge and MID?

[e30cabrio]

My mileage numbers are from months of usage (13.5 mixed) in an app I put odometer numbers into & gallons purchased.

This current tank is the needle being 1/2 way from full to 1/4 and the miles traveled.

I do not want a cai, I had a choice. Not drive or find a solution to get a filter on the motor.

[Moezer]

Originally Posted by Clockwork

something doesnt seem right. BMW designs their air boxes/hoses VERY well and you'd be VERY hard pressed to find a better solution!!! CAI are usually a JOKE if its sitting in the engine bay still. ONLY if its actually routed through the existing engine hosing and wiring and metal down to the bottom of the engine bay (in front of a wheel usually) will any difference be made by a CAI. if its just sitting in the engine bay its more of a hot air ram intake.
are you getting your numbers from calculations or just the fuel gauge and MID?

I got a so called CAI lol, it has a shield and the way I see if you are driving then the engine is getting cold air or air from outside straight to its insides.... the only time I would see the engine getting warm/hot/or mixed air is when its at a stand still

heres mine


if you look at where the green sticker is over it that's where the outlet/inlet of the intake is, so if you are driving the air is just raming in to the intake while its sucking air in, with the hood closed it seals the top of the intake so the only air it would get at a stand still is from the front and the bottom from where its open

[motordavid]

Looking at a partial tank use, via gauge or whatever, is purely anecdotal and not any real measurement of 'new mpg', imo. Do several full tanks, usual driving, do the airth and see what the outcome is...

Agree that the oe air intake is extremely well designed.
GL, mD

[e30cabrio]

It will be gone Friday or Saturday when the hose wanders in.

Like I said this was simply a means of being able to drive the X.

It is now at 170 and just above 3/4 which is more than I have ever seen on a quarter tank.

[tmv]

It might just mean that your old air filter clogged up and blocking some air intake. Now the filter is new(er?) the mixture gets closer to the perfect ratio. Just a thought!
If I didn't have Dinan CAI already paid for by the PO, I would leave the OE intake alone.

[e30cabrio]

I have a K&N in the stock box, with 4k miles on it. I'd hope it's not clogged but I'll clean and oil it today to see. We do have a ton of micro sand here in Az, silica is the only high number I have ever seen in my Blackstone Lab results.

[ProfessorX5]

Wow, that's one big honking intake.

[e30cabrio]

That is visibly exactly the filter I have, it's directly on the MAF housing.

I waited until the delivery date was past and it was clear a week was going to pass before I did it as I like driving my X & did not want it sitting for over a week.

Originally Posted by Moezer

I got a so called CAI lol, it has a shield and the way I see if you are driving then the engine is getting cold air or air from outside straight to its insides.... the only time I would see the engine getting warm/hot/or mixed air is when its at a stand still

heres mine


if you look at where the green sticker is over it that's where the outlet/inlet of the intake is, so if you are driving the air is just raming in to the intake while its sucking air in, with the hood closed it seals the top of the intake so the only air it would get at a stand still is from the front and the bottom from where its open