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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. dzenno@PTF's Avatar
        dzenno@PTF -
        I'm not sure this is a good idea without datalogging and retuning timing and possibly fuel...just my 2c but regardless gains are good
      1. inlineS54B32's Avatar
        inlineS54B32 -
        Look at that sexy curve (or lack of it) - argh, I need a damn blower on my car.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by dzenno@PTF Click here to enlarge
        I'm not sure this is a good idea without datalogging and retuning timing and possibly fuel...just my 2c but regardless gains are good
        A retune isn't quite as important here as it would be with a turbo car as boost ramps in progressively with rpm so you can swap pulleys with the same tune.
      1. BlownE92M3's Avatar
        BlownE92M3 -
        Click here to enlarge Originally Posted by dzenno@PTF Click here to enlarge
        I'm not sure this is a good idea without datalogging and retuning timing and possibly fuel...just my 2c but regardless gains are good
        The DME auto compensates for fuel/timing. This was our original hunch and we were correct. The boys over at the other forum are having a mild heart attack because we bypassed a $2500 sale for the "tuner" upgrade, and spent a total of $200 for belt and a pulley (had them machine the correct offset) and made more power safely then their 650 upgrade would have.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BlownE92M3 Click here to enlarge
        $2500 sale for the "tuner" upgrade, and spent a total of $200 for belt and a pulley (had them machine the correct offset) and made more power safely then their 650 upgrade would have.
        How about that... Click here to enlarge
      1. DubSport's Avatar
        DubSport -
        Nice results. Just remember to swap back to original pulley if you plan to drive down to the coast, else it would be running a bit lean.
      1. Linracing's Avatar
        Linracing -
        Amazing! Power must feel great.
      1. TZ04XJR's Avatar
        TZ04XJR -
        Damn.. Nice pickup on power! I bet it moves the hell out on 9psi.
      1. M&M's Avatar
        M&M -
        Hey there, that's incredible power gain. I have seen similar results at the same elevation. What belt are you using on the 3.2" pulley & are you getting any slippage? What injectors do you have?
      1. BlownE92M3's Avatar
        BlownE92M3 -
        Click here to enlarge Originally Posted by M&M Click here to enlarge
        Hey there, that's incredible power gain. I have seen similar results at the same elevation. What belt are you using on the 3.2" pulley & are you getting any slippage? What injectors do you have?
        We are running a 2100mm belt w/ 3.2 pulley and we are actually on the ESS 585 injectors Click here to enlarge
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BlownE92M3 Click here to enlarge
        We are running a 2100mm belt w/ 3.2 pulley and we are actually on the ESS 585 injectors Click here to enlarge
        Why aren't you on higher injectors?
      1. BlownE92M3's Avatar
        BlownE92M3 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Why aren't you on higher injectors?
        Well, I purchased the 585 kit, but day after decided to upgrade to the 625 kit. They sent the pulley and retune, but received no injectors. Roman stated these injectors would be "fine" at 6psi but no more... Well come to find out they flow enough for 9psi haha
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BlownE92M3 Click here to enlarge
        Well, I purchased the 585 kit, but day after decided to upgrade to the 625 kit. They sent the pulley and retune, but received no injectors. Roman stated these injectors would be "fine" at 6psi but no more... Well come to find out they flow enough for 9psi haha
        Is there a difference between the injectors?
      1. BlownE92M3's Avatar
        BlownE92M3 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Is there a difference between the injectors?
        Honestly no idea. We couldn't get actual flow numbers from ESS. We were just told that they are different but et wouldn't need them.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BlownE92M3 Click here to enlarge
        Honestly no idea. We couldn't get actual flow numbers from ESS. We were just told that they are different but et wouldn't need them.
        Shouldn't they know their injectors a bit better than saying 6 psi would be the limit?

        Do you know what % they're at?
      1. benzy89's Avatar
        benzy89 -
        You can probably just Google & find out what Bosch injectors come with the higher ESS s/c kits & buy them directly.

        I noticed in the video you had ice bags packed on the blower & manifold, I hope you weren't using the dyno pulls under those super optimal conditions to log the car & determine it's running perfectly.


        ON a side note, it's great to hear that someone is finally looking to upgrade the air/water intercooling capabilities, especially with a nice feature like the ice tank to keep IATs down real low. It's something that's really been lacking, especially when you look at Weistec (who sells a trunk mounted ice tank for everyone one of their s/c platforms).
      1. BlownE92M3's Avatar
        BlownE92M3 -
        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?
        They wouldn't give us the info. I'm sure they know exactly what they flow.

        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        You can probably just Google & find out what Bosch injectors come with the higher ESS s/c kits & buy them directly.

        I noticed in the video you had ice bags packed on the blower & manifold, I hope you weren't using the dyno pulls under those super optimal conditions to log the car & determine it's running perfectly.


        ON a side note, it's great to hear that someone is finally looking to upgrade the air/water intercooling capabilities, especially with a nice feature like the ice tank to keep IATs down real low. It's something that's really been lacking, especially when you look at Weistec (who sells a trunk mounted ice tank for everyone one of their s/c platforms).
        We used the ice because it was hot as balls outside 102* outside, and the shop was a damn sauna. The cars IATs at idle were 130-140, and a $#@!ty fan. She would have heat soaked mid run, so we decided to just toss a bag on the mani and half a bag on the compressor housing. This resulted in IAT's around 100-120ish IIRC during the pull. 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. 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.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BlownE92M3 Click here to enlarge
        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.
        Well... not so fast Click here to enlarge

        I will be running FTW Purple.
      1. BlownE92M3's Avatar
        BlownE92M3 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Well... not so fast Click here to enlarge

        I will be running FTW Purple.
        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.
      1. inlineS54B32's Avatar
        inlineS54B32 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Well... not so fast Click here to enlarge

        I will be running FTW Purple.
        Does their fuel really smell like grape soda? If so, that's awesome. Click here to enlarge


        Fuel Name Purple
        Color Purple
        Scent Grape Soda
        Type Ethanol / Leaded
        M.O.N. 113
        R.O.N. 119
        R+M/2 116
        o2 Content (By Weight) 31.6%
        Dissolved o2 Content 7.37 mg/L
        Specific Gravity .819

        edit - i am nearly certain it's a joke - considering their FTW Red smells like "Snozberries"