Project E39 M5, Installing the Dinan Cold Air Intake

Next, the Dinan air guides are installed. These block hot air from the engine compartment and the radiator from getting near the air filter.

The air guides rivet to the factory brake ducts.  Holes are drilled into the tabs that attach the under tray to the brake ducts and the air guides rivet to them.

Here we rivet the air guides to the brake duct brackets.  This is repeated on both sides of the car.

Next, the air-water separators are riveted to the air guides This prevents water coming in the bumper inlets from saturating the air filter elements.

Holes are drilled into the air guides for the rivets.


  1. Schrick cams and a lightweight flywheel, please. VAC Motorsports has both. They really transform the car.

    1. My experience with rwd & light flywheel, it’s most nticeable in only 1st gear, when revs build up quickly .. it’s less rotary inertia at engine speed accelleration. I found I would spin the tires more easily at take off. It may improve heal-toe shifting, depends on several other things like throttle response. Good cam up grades are winners, have done a few.

  2. Great install write up.

    It looks to be very well made, but based on the Dinan site, not sure it’s worth the trouble and expense.

    “More Power: + 5 HP @ 7000 RPM, + 4 LB-FT @ 7000 RPM (coupled w/ engine software).”

    A BMW M5 is likely to have a good intake already.

    1. We noted that the stock intake was a pretty good design. The biggest part of the equation could be relocating the intake air temp sensor as power drop due to the sensor getting hot is a pretty big deal on these cars.

      1. Out of curiosity, I would measure the air temp entering the manifold , vs at the MAF sensor, after heat soak. If the same, the hot retarded timing may be justifed for engine health?

  3. Did we ever compare these to the stock intakes
    On the dyno? I have the same set up with headers debating adding these.

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