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    • Harrop Engineering doing the "impossible" - Introducing the world's first positive displacement E92/E90/E92 S65 V8 supercharger

      Wow. That is exactly what came out of my mouth when I saw this supercharger kit at Bimmerfest. In all honesty, it was my main motivation for attending the event once I heard it would be there. Some people may be reading this and wondering what the big deal is as superchargers already exist for the M3. That is true, superchargers do exist, but they are all centrifugal style blowers. This is the world's first positive displacement supercharger for the S65 V8.

      Why is that a big deal? Because it's a completely different type of blower with completely different power delivery. This is the solution for those who complain about the M3's torque or for those who do not like the response down low of a centrifgual blower which needs rpm to make boost. This style of supercharger is always making boost, from anywhere in the rev range.

      That is what makes incorporating it on the S66 V8 difficult with its independent throttle bodies as positive displacement blowers usually are set to pull air through a throttle body not blow into it. The centrifugal blowers send air into a manifold. If a positive displacement were to use a similar setup it would be blowing air in while the throttle bodies attempted to close as it is always making boost. See the problem?

      The solution Harrop Engineering came up with was a manifold that fits in between the throttle bodies with a bypass valve fit that relieves pressure as needed and makes sure boost is not made as throttles are closing. Pretty trick setup eh? You can see the design in the photos and also how tight the packaging is. I do not even want to know how many hours were put in trying to get this all to fit.

      The blower employed is a TVS1740 unit from Eaton. This is a roots blower and likely will be set to 5.5 psi or so initially. Boost from this blower is different from a centrifugal and will be harder on the stock rods since it is at full boost right away. Expect horsepower in the low 500's to the wheels.

      Oh and see that little black box to the left of the manifold off a metal area at the inlet? There will be electronic boost control which is likely the first of its kind on a positive displacement setup although I am not able to confirm this. Different maps with different boost levels for different fuel? A possibility, yes.

      This is a big deal and an engineering feat for the S65. My complete and utter respect and that of this network to the guys at Harrop. There is still work to be done here. It is not quite ready although pricing is initially set at $12,990. There is still a lot of tuning to be done but this will be coming eventually.

      Pictures below, much respect Harrop and it was a pleasure meeting you guys at Bimmerfest. You were incredibly nice and answered all my (MANY) questions. Thank you:























      This article was originally published in forum thread: Harrop Engineering Twin Screw S65 V8 Supercharger started by CookieCrisp View original post
      Comments 276 Comments
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by Itsbrokeagain Click here to enlarge
        from the looks of it, the manifold is set up the same way as an ESS one would be. im assuming the diverter/recirculation valve is setup to vent during partial cruise to keep boost from piling up in the intake unlike a centrifugal?
        I think it's a VTA setup, to specifically avoid the problem some recirc systems *cough*ESS*cough* are have having with cars continuing to accelerate after letting off the throttle (most likely due to boost not being fully released)... In respect to the manifold, it's basically like every other Air/Water Manifold on the market (air travels through into the mani, passes through the intercooler & enters the ITBs). Wats interesting about the Harrop (vs. others) is it has 2 intercoolers, specific to each side of the V8 with the roots blower mounted in between the intercoolers (you can see this in the cut up mani pics in post 108).
      1. 600whp S4's Avatar
        600whp S4 -
        I can get a good deal on this kit im friends with Aviva instruments owners
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by 600whp S4 Click here to enlarge
        I can get a good deal on this kit im friends with Aviva instruments owners
        I'm learning more about Aviva seems they have some awesome Audi RS4 superchargers.
      1. 600whp S4's Avatar
        600whp S4 -
        yup
      1. BavarianBullet's Avatar
        BavarianBullet -
        I think I'm connecting some of the dots here.

        This whole arrangement of blower shooting air upwards then down thru twin a/w i/c is what is done one the B8 S4. And someone linked to the stupidzine article on the apr release of the 1.7 TVS upgrade for the B8 S4.

        I read that thread a while ago when it was first posted by apr and I dont think it was ever mentioned who did the actual design work to create the new manifold etc for the S4. AFAIK there are only 2 main companies in the world that Eaton really works with at that level supplying rotor packs for new designed SCs and they are harrop and magnuson. Re APRs 1.7L kit on Stupidzine, based on similar fittings and style etc, I surmised it was Harrop that produced it for APR.

        Where the OEM B8 S4 SC is all cast together and the rotor tubes are literally cut into a one piece manifold/SC combo, the new APR/Harrop creation for the S4 seems to be the new 1.7L blower case just bolted upside down onto a newly made manifold with integral a/w i/c.

        So it seems with that APR B8 S4 product almost done, the M3 SC kit was designed by Harrop around the same time as it's only slightly behind it in release date. Blower is a little different too as they apparently had to cast a different snout for it and air enters on the drive end.

        M3 kit looks really cool from a power perspective though I'd be a little concerned about rod bearings, DCT and tuning as was already said. The tuning in particular I know very little about but I remember @Sticky quoting Chris from HPF saying the S65 would never be turbo charged because it was simply too hard and too expensive given what they went thru with the S54. But if Harrop can get someone to tune the DME for this PD 1.7L TVS, wouldn't that potentially open the door to potentially turboing the S65? The point is both build boost and raise load tremendously at much lower rpms than a say a centrifugal SC.

        Overall, great news for the S65 crowd. Sounds like a lot of fun.

        Rough numbers:
        TVS 1900 = 2000 M^3 = 1177cfm from Eaton maps using 1.9L per rev of SC, max sc rpm
        TVS 1740 = 1.74L per rev and should do about 8.5% less airflow based on displacment diff.
        1177 * .915 = 1077cfm / 1.6cfm per hp = 673CHP * .85 = 572WHP potential at max sc rpm
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        AFAIK there are only 2 main companies in the world that Eaton really works with at that level supplying rotor packs for new designed SCs and they are harrop and magnuson. Re APRs 1.7L kit on Stupidzine, based on similar fittings and style etc, I surmised it was Harrop that produced it for APR.
        That's some interested detective work and an interesting theory too but is it true? APR claimed Eaton worked with them.

        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        quoting Chris from HPF saying the S65 would never be turbo charged because it was simply too hard and too expensive given what they went thru with the S54.
        No it was that Chris would not do it due to the cost. Turbos are coming.

        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        Rough numbers:
        TVS 1900 = 2000 M^3 = 1177cfm from Eaton maps using 1.9L per rev of SC, max sc rpm
        TVS 1740 = 1.74L per rev and should do about 8.5% less airflow based on displacment diff.
        1177 * .915 = 1077cfm / 1.6cfm per hp = 673CHP * .85 = 572WHP potential at max sc rpm
        Repped, good stuff.
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        The tuning in particular I know very little about but I remember Sticky quoting Chris from HPF saying the S65 would never be turbo charged because it was simply too hard and too expensive given what they went thru with the S54. But if Harrop can get someone to tune the DME for this PD 1.7L TVS, wouldn't that potentially open the door to potentially turboing the S65? The point is both build boost and raise load tremendously at much lower rpms than a say a centrifugal SC.
        The tuning is always the most difficult element when going from N/A to Turbo. HPF couldn't afford to get involved because they had already invested too much in the S54 market to start all over. Once the tuning is figured out, the Harrop S65 supercharger will def test the strength & long term reliability of the OEM internals, but I don't believe there's as much as a connect with the tuning (related to turbo tuning) as you're making out. Regardless of what kinda supercharger you're going with (Roots, Twin Screw, Centri), the boost generated will always be the same because of whatever pulley you're using. Meanwhile, a turbo setup is forced to deal with significantly more "headaches" -- achieving boost target, boost overshooting, timing adjusting through the boost curve, timing corrections, VANOS adjustments to aid in turbo spool, etc etc.

        IMO, for the S65 to be turbo'd safely, it'll need a standalone (especially to manage the knock sensors) & forged internals (a CR adjustment might not be necessary, depending on your power goals). It could possibly be done on the stock DME with an external boost controller, but it certainly won't be as advanced as the Maximum PSI Stock DME Turbo E46 (with multiple maps saved on the OEM DME with map switching off the Sport button) because the E9x M3 DME hasn't been "cracked" (let alone tuned) to those levels.
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        but I don't believe there's as much as a connect with the tuning (related to turbo tuning) as you're making out. Regardless of what kinda supercharger you're going with (Roots, Twin Screw, Centri), the boost generated will always be the same because of whatever pulley you're using. Meanwhile, a turbo setup is forced to deal with significantly more "headaches" -- achieving boost target, boost overshooting, timing adjusting through the boost curve, timing corrections, VANOS adjustments to aid in turbo spool, etc etc.
        its very similar, as you have tons of part throttle and on/off tuning to work through, especially since boost comes in so early. If in fact they are using an E-BOV, it acts the same as a wastegate. tuning i would say is about 70% similar if not more between the 2 as oppsoed to about 40% with a centri, if that
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        IMO, for the S65 to be turbo'd safely, it'll need a standalone (especially to manage the knock sensors) & forged internals
        A stock internal kit is coming... along with built motor kits.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        its very similar, as you have tons of part throttle and on/off tuning to work through, especially since boost comes in so early. If in fact they are using an E-BOV, it acts the same as a wastegate. tuning i would say is about 70% similar if not more between the 2 as oppsoed to about 40% with a centri, if that
        You can't use %'s like that not how it works.
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        You can't use %'s like that not how it works.
        its fact until proven wrong. maybe write one of your technical discussions on it, citing your experience and expertise on the matter..?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        its fact until proven wrong
        Ok made up numbers in you rhead are fact ok whatever you say.
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Ok made up numbers in you rhead are fact ok whatever you say.

        or from the 4 highly skilled tuners i talked to 15 months ago about doing the custom job, but lets not bring that up.. you remember that right..?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        or from the 4 highly skilled tuners i talked to 15 months ago about doing the custom job, but lets not bring that up.. you remember that right..?
        I've never heard a tuner in my place describe tuning different forced applications setups like that in my life. If anything, I've heard them describe the differences with technical details not %'s. Kind of like how the problem of tuning the E46 M3 turbo stock DME setup is part throttle acceleration and not oh 70% similar to a centrifugal which makes no sense.

        But whatever you want to say...
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        I've never heard a tuner in my place describe tuning different forced applications setups like that in my life. If anything, I've heard them describe the differences with technical details not %'s. Kind of like how the problem of tuning the E46 M3 turbo stock DME setup is part throttle acceleration and not oh 70% similar to a centrifugal which makes no sense.

        But whatever you want to say...
        you dont have much experience with many tuner shops, this is why you havent heard of anything about tuning. Go ahead and write an article about it. you will learn just how close the 2 are
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        you dont have much experience with many tuner shops, this is why you havent heard of anything about tuning. Go ahead and write an article about it. you will learn just how close the 2 are
        Click here to enlarge
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Click here to enlarge
        you could always write an article about how close they are NOT..
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        you could always write an article about how close they are NOT..
        Or you could make sense. One or the other.
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Or you could make sense. One or the other.
        if you understand basics, it makes sense
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        if you understand basics, it makes sense
        For sure.