Project E39 M5: K&N Filters and HPS Intake Hoses


Here you can see the changes in diameter and the corrugated area inside the elbow. This cannot be good for air flow, so we're thinking we should see some positive gains from the larger diameter HPS Performance Parts intake hose kit.


The HPS hoses measure in at a girthy 80mm and the diameter is even through the entire hose length. Since they are made of silicone it is easy to design them to have very smooth bends while still ensuring they retain their shape under all conditions with their reinforced 4-ply construction.


Here you can really see the difference in diameter between the OE intake elbow and upgraded HPS silicone intake hose.


The HPS Performance Parts intake hoses went on with no issues and fit perfectly. We really like the performance look the new silicone hoses along with the supplied stainless steel t-bolt clamps gave our M5's engine bay. A welcomed addition since they sit front and center in the engine bay. 


Though we were not expecting astronomical gains from the HPS intake hoses, we were expecting to see some gains – and we did! 3 horsepower and about 2.5 foot pounds of torque. The best part is that the gains were across the entire power band.



  1. Hi Martin, and Mike,
    I love that fact you guys are doing a project E39 M5, as I’m working on mine as well. This intake article is very interesting, and would also like to see if you’d be interested in (dyno) testing another intake (AFE) that’s very easy to swap on. My E39 M5 came with it when I bought the car, and in design, it looks like it makes sense… very similar to the silicone hose + K&N setup you tested. Except, mine my AFE has a hard molded, smooth pipe and runs cone (K&N style) filters. Would you guys be interested in testing this setup as well? I am in Torrance, and the swap would take 5 mins. Please let me know if this is possible~

    *Reason I ask is, the AFE kit seems to have a negative gain on performance for the S62, based on an old dyno run someone did years ago. Looking at the design, I don’t understand how it could be worse than stock. I recently dyno’d my car and numbers weren’t bad. Wondering how it fares compared to your setup. -Thanks~

    1. Hi Joe,

      Thanks for reading! We’ve actually been wanting to test the AFE intake too. We’ll reach out to AFE to see if they would be interested in supplying us with one of their intakes for another test. We think that would be great info for the E39 M5 community to have!

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