[V10R8]

Right side has flapper/valve. It’s closed with engine off. Has anyone played around with it? My guess it opens in sport/sport plus. Wandering if it will throw a code if unplugged or tied open.

[AlZ4]

I think the valve is only closed when the engine is cold, but I'm not 100% sure. I'll have to check when the weather clears up later in the week.

[GeneticX]

It opens in sport mode.

[AppieH]

Bij mij staat de klep open als de motor uit staat

[jeffp1105]

The E89 Z4 had the same valve. It's normally closed when the engine is cold to speed up engine warming which reduces emissions. In that car they were pneumatically operated and folks would simply remove the rubber hose and plug it with a golf tee. It was the "golf tee mod" (google it). In this version, I think it's electronically operated but same purpose. It's a fairly minor emissions helper but if you prefer it open all the time, shouldn't throw a code. Most engine modding software let you change the settings for it. Since it's electronically controlled, it may open at lower temps for Sport or Sport plus or under any other conditions the engineers deem appropriate.

[TheNextCorner-roadtrips]

I noticed my m40i used much more fuell after pulling the fuse 203. Valve stays open, but engine stays longer cold in winter conditions , resulting in 12L in 100km, with fuse 203 back in it does 9.3L in 100km
With valve open (‘fuse pulled) in eco pro it does a lot of vibrating and exhaust Noise in lower speeds and rpm when the transmission is in 8e gear. Dont like it, I put the fuse back in, much better.



I tested this for more than 500 km.

[BEAR-AvHistory]

Been running with the fuse out for a few years. Get 31/32 MPG @ 80/85MPH over the road in Adaptive. Not especially an MPG centric guy but the small tank had me concerned when I bought the car. Like to be able to make my longest regular round trip, 400 miles, on a single tank if I have to.

Don't pay any attention to city mileage as I run the car in Sport or Sport+ in town which is not MPG friendly but gives much better response when you have to push the GO pedal.

Glad I saw this thread. Car goes in for annual service tomorrow & need to plug the fuse back in. 25,253 miles in 35 months. So far one set of tires & no service visits outside of annual inspections.

[MisanoblueZ4]

Just a note if you want to improve MPG you can use Sport Individual and set the transmission to (Comfort). Will allow the exhaust to be a bit louder but win back some MPG with quicker/lower shift points.

Also I hear that valve open cold starts can be pretty loud and be disruptive to neighbors, so if that’s a concern leave the fuse in lol.

The factory setup is pretty nice imo.

[BEAR-AvHistory]

Originally Posted by MisanoblueZ4

Just a note if you want to improve MPG you can use Sport Individual and set the transmission to (Comfort). Will allow the exhaust to be a bit louder but win back some MPG with quicker/lower shift points.

Also I hear that valve open cold starts can be pretty loud and be disruptive to neighbors, so if that’s a concern leave the fuse in lol.

The factory setup is pretty nice imo.

Its pretty open here as the lots are pretty big. FWIW the Z4 at its loudest is the least loud of any BMW I have owned. All only factory equipped.

Loudest was the 2013 135is 6MT second loudest was the 2011 335is 7DCT & tied for third a 2014 435 and 2018 440, used the same factory exhaust on both cars. Rest including the Z4 are pretty much all the same, nice sounds but not excessively loud.

That said this one with straight outside pipes can be heard two or three blocks away when pushed. It has 32 ECU controlled overhead valves like the BMW's & is very neighborhood friendly at idle. Will set off car alarms when goosed.



Rather than being that guy I always idle it out of the subdivision.

My Z4 trans individual setting is Sport +. I maxed out all the settings on individual. When wife is in the car run straight comfort. Highway Adaptive.

[BEAR-AvHistory]

Car went through the state inspection, BMW oil change & annual check up this morning. No issues with the exhaust flap. Replaced the fuse yesterday & valve was functioning normally. Tires replaced at 19,000 miles are showing even ware.

Expect no hidden fault codes or if there were they were cleared when the fuse went back in.

[MisanoblueZ4]

Originally Posted by BEAR-AvHistory

Car went through the state inspection, BMW oil change & annual check up this morning. No issues with the exhaust flap. Replaced the fuse yesterday & valve was functioning normally. Tires replaced at 19,000 miles are showing even ware.

Expect no hidden fault codes or if there were they were cleared when the fuse went back in.

For those curious to try this…. Do you place car in sport mode before pulling fuse?

[BEAR-AvHistory]

Originally Posted by MisanoblueZ4

For those curious to try this…. Do you place car in sport mode before pulling fuse?

Yes you want the valve open before you pull the fuse.

[cezary97]

Is it the same 203 fuse for sdrive 20i?

[Living Dead]

Originally Posted by BEAR-AvHistory

When wife is in the car run straight comfort. Highway Adaptive.

I know one can buy a replacement red start button, I wonder if anyone is making a replacement button for the comfort that says WIFE

[RavenGX]

Originally Posted by Living Dead

I know one can buy a replacement red start button, I wonder if anyone is making a replacement button for the comfort that says WIFE

i have an EJECT button