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    • Compensating for elevation - ESS VT2-625 E92 DCT M3 Dynojet dyno results testing different pulleys at 6, 7, and 9 psi of boost

      BimmerBoost member BlownE92M3 lives in Denver, Colorado where the elevation has a substantial affect on engine performance. When one goes up in altitude air is less dense than at lower altitude and air that is less dense will cause a motor to make less power. It's the classic density altitude issue you likely have heard from people discussing drag strip results. BlownE92M3 decided to compensate for the elevation by changing the pulley on his ESS-VT2 650 supercharger kit to increase boost pressure.

      Now, the effect of the elevation is seen from the bone stock baseline which is 315 to the wheels. This is roughly ~40 wheel less than an E92 M3 DCT will make at sea level. The first graph you see here shows the difference between stock, with full bolt ons (tune, exhaust), and as it currently sits supercharged at 9 psi. With full bolt ons the car put down 344 to the wheels which is roughly a stock number at sea level showing just how big of a difference Denver's elevation makes:


      He's taking a roughly 8.5% penalty in power. The nice thing about being supercharged is he can compensate for this by changing the supercharger pulley effectively spinning the blower faster. He tried three different pulleys at roughly 6, 7, and 9 psi of boost. That result is below:


      524 wheel with the standard pulley in the ESS-VT2 650 kit, then 565 wheel horsepower dropping down a pulley size, and then an awesome 613 wheel horsepower going to a pulley giving 9 psi of boost. He compensated for the elevation and then some.

      Awesome graphs overlaying the difference. Thank you very much to @BlownE92M3 for sharing. Dyno video below.


      This article was originally published in forum thread: ESS 625 pulley swap results! Dyno inside started by BlownE92M3 View original post
      Comments 31 Comments
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BlownE92M3 Click here to enlarge
        Wait, you're running corn? Mind sharing some details of the fuel system and what you used to tune and who did the tune?!?!?!? (PM if needed) Would GREATLY appreciate it. Andrew and myself thought we would have to pioneer corn on this car, and honestly the headache ahead with tuning is daunting.
        Gintani is doing all my work.
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by BlownE92M3 Click here to enlarge
        Yea, we were looking at what we could do to improve safety/power without touching boost/timing/fuel and the liquid to air IC setup that came with this kit is jimmyjuice to say the least. We are going to mount a 4 gallon tank in the trunk with a much better pump and we are looking at swapping the actual heat ex changer out for something that flows a bit better as well.
        Luckily you've already got all the speciality bits specific to the M3 (manifold & supercharger bracket), so upgrading your heat exchanger, pumps & hoses shouldn't be difficult as long as you "measure twice and cut once" with the various measurements & mounting locations.


        Click here to enlarge Originally Posted by BlownE92M3 Click here to enlarge
        This is the next step, as well as we are looking into a full E85 conversion also. Injector and pump shouldn't be hard to source and install, but rather the tune and finding someone who i would trust that would even be willing to jump on a E85 project is the issue. As of right now, I don't think anyone has ever done a full E85 setup on a supercharged M3, much less tune one as well.
        I know that @BrenM3 was experimenting with E85 on his supercharged M3, since he personally tuned it so you could ask him (especially since he's got a similar setup with an ESS kit + custom software). Off the top of my mind, I'm sure there's a ton of BMW specific & high level tuners (like Garth @undercover ) who could tune/offer lots of useful information.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        I know that @BrenM3 was experimenting with E85 on his supercharged M3, since he personally tuned it so you could ask him (especially since he's got a similar setup with an ESS kit + custom software). Off the top of my mind, I'm sure there's a ton of BMW specific & high level tuners (like Garth @undercover ) who could tune/offer lots of useful information.
        Duh of course good suggestion @BrenM3 has run E85.
      1. BlownE92M3's Avatar
        BlownE92M3 -
        Paging @BrenM3 Click here to enlarge
      1. BlownE92M3's Avatar
        BlownE92M3 -
        About to go do a few 40-140 pulls and log data. Will post up after I get back and get it uploaded to PC.
      1. M&M's Avatar
        M&M -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Shouldn't they know their injectors a bit better than saying 6 psi would be the limit?

        Do you know what % they're at?
        Yeah but at high altitude the demand for fuel is less. I think the whole injector thing is dodge though.
      1. Andrew@activeautowerke's Avatar
        Andrew@activeautowerke -
        Holy Iats ! Wonder if you can get a bigger reservoir?
      1. BlownE92M3's Avatar
        BlownE92M3 -
        Click here to enlarge Originally Posted by Andrew@activeautowerke Click here to enlarge
        Holy Iats ! Wonder if you can get a bigger reservoir?
        That's next on the list. 4 gal in tank reservoir with better pump and larger/more efficient heat exchanger. Following that will be an E85 fuel setup and tune!
      1. Andrew@activeautowerke's Avatar
        Andrew@activeautowerke -
        Click here to enlarge Originally Posted by BlownE92M3 Click here to enlarge
        That's next on the list. 4 gal in tank reservoir with better pump and larger/more efficient heat exchanger. Following that will be an E85 fuel setup and tune!
        Yeah I was talking to Andrew about it yesterday. You have the car in good hands buddy. Good luck with your future modifications Click here to enlarge
      1. LostMarine's Avatar
        LostMarine -
        how are you logging? Im using the bmwlogger software. its easy and cheap Click here to enlarge
      1. DavidV's Avatar
        DavidV -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        how are you logging? Im using the bmwlogger software. its easy and cheap Click here to enlarge
        Welcome back man!