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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 LostMarine Click here to enlarge
        meth on the fins is actually good for these. i think it was KB or whipple actually suggest it
        I just found 2 separate threads (separate forums), both people are saying that Magnuson is against meth b/c it could damage the blower internals.

        http://www.camaro5.com/forums/showthread.php?t=165615 (Post #5)
        http://www.cherokeesrt8.com/forums/a...p/t-74003.html (Post from "Knuckles"
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        I just found 2 separate threads (separate forums), both people are saying that Magnuson is against meth b/c it could damage the blower internals.

        http://www.camaro5.com/forums/showthread.php?t=165615 (Post #5)
        http://www.cherokeesrt8.com/forums/a...p/t-74003.html (Post from "Knuckles"
        yes, but hundreds of svt and gt500 forums support it.. BUUUUUT Ford owners are not always the most critical thinking types Click here to enlarge

        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        Hopefully the S65 gets better gains than the RS4 with tis blower... APR is advertising only a 180 HP/130 TQ gains over stock at the flywheel. Can't find how much boost they're running tho
        on what motor and what psi?
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        on what motor and what psi?
        Mistake, APR is advertising the use of the TVS 1740 on the 4.2L FSI V8, which is in the B8 RS4, RS5 & R8. BUT if you go to the B8 RS4 or RS5 product pages, they're still listing the kit with the TVS 1320 (at least according to the pictures, it never explicitly says what s/c they're using in the product description). Apparently they were running the TVS 1320 at 5 psi for 91, 6 psi for 93 & 8 psi for 100+.



        ***Just found this thread from APR regarding the TVS 1740, hopefully there's some concrete numbers & data -- http://www.audizine.com/forum/showth...0-Supercharger
      1. benzy89's Avatar
        benzy89 -
        11 pages, not a single piece of data posted by APR


        Ironically, those idiots on Audizine are linking over to E90Post like technical $#@! actually takes place over there Click here to enlarge
      1. Ammonia's Avatar
        Ammonia -
        Curious, this is considered better than a centrifugal-style supercharger, correct? Since the immediate boost and torque and whatnot. Why are the gains so low? Conservative tuning? 500 whp is low for an S65 supercharger, no?

        I seriously am this big of a noob, sorry.
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Ammonia Click here to enlarge
        Curious, this is considered better than a centrifugal-style supercharger, correct? Since the immediate boost and torque and whatnot. Why are the gains so low? Conservative tuning? 500 whp is low for an S65 supercharger, no?

        I seriously am this big of a noob, sorry.
        its not a matter of better, just different. not everything in life is max HP and Peak HP. This thing will destroy centri's in certain aspects, and get hammered in others.
        If this was finalized, and released 4 months ago, Id have it
      1. Flinchy's Avatar
        Flinchy -
        curious - how do they intercool a PD blower when as it's stated - air is 'sucked' in rather than pushed?
      1. Jonathan@Aviva's Avatar
        Jonathan@Aviva -
        Click here to enlarge Originally Posted by Flinchy Click here to enlarge
        curious - how do they intercool a PD blower when as it's stated - air is 'sucked' in rather than pushed?
        After air has passed through the Supercharger rotors, its directed through the twin air-water inter-coolers before reaching the throttle bodies.
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by Ammonia Click here to enlarge
        Curious, this is considered better than a centrifugal-style supercharger, correct? Since the immediate boost and torque and whatnot. Why are the gains so low? Conservative tuning? 500 whp is low for an S65 supercharger, no?

        I seriously am this big of a noob, sorry.
        There isn't more peak power because they're limited by the blower size. People are making the same mistake on M3Post, you cannot directly compare a Centri Blower & a Roots/Twin Screw. They're going to have completely different curves & offer completely different power bands. IF there was a larger Roots blower that could be adapted to the S65 & offer the same peak power as the V3, then it'd easily be the better option with instant boost & better low end TQ.
      1. DFM's Avatar
        DFM -
        Now the question is...who will be the first adapt this manifold design to fit an E60 M5?
      1. Flinchy's Avatar
        Flinchy -
        Click here to enlarge Originally Posted by Jonathan@Aviva Click here to enlarge
        After air has passed through the Supercharger rotors, its directed through the twin air-water inter-coolers before reaching the throttle bodies.
        ahhh so yet another 'packaging' constraint

        impressive
      1. Puerto Rican 335d's Avatar
        Puerto Rican 335d -
        wow what a monster, congrats to them for doing the UNDOABLE!!!
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        There isn't more peak power because they're limited by the blower size. People are making the same mistake on M3Post, you cannot directly compare a Centri Blower & a Roots/Twin Screw. They're going to have completely different curves & offer completely different power bands. IF there was a larger Roots blower that could be adapted to the S65 & offer the same peak power as the V3, then it'd easily be the better option with instant boost & better low end TQ.
        didnt someone quote 1100CFM on this kit? if so, thats right there with the others.
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by DFM Click here to enlarge
        Now the question is...who will be the first adapt this manifold design to fit an E60 M5?
        Prob not just because there isn't a significant supercharger demand for the S85. I mean, ESS was the mainstream option until Gintani released their kit (late last year?)

        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        didnt someone quote 1100CFM on this kit? if so, thats right there with the others.
        Tried Googling', not a single tech spec has been released on the 1740 -- No compressor maps of CFM. It seems everything people know is word of mouth at this time, like Sticky estimating 5.5psi
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        Prob not just because there isn't a significant supercharger demand for the S85. I mean, ESS was the mainstream option until Gintani released their kit (late last year?)


        Tried Googling', not a single tech spec has been released on the 1740 -- No compressor maps of CFM. It seems everything people know is word of mouth at this time, like Sticky estimating 5.5psi
        the designation is probably pretty close to CFM #'s i would assume, possibly with some correction factor on there..
        i think the 5-6psi guesstimate is due to what basic mid-level kits offer for entry intercooled kits. Factor in the unkowns for strength and 5-6 psi is a realistic conservative fully backed package
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by DFM Click here to enlarge
        Now the question is...who will be the first adapt this manifold design to fit an E60 M5?
        I asked about that. No plans yet.
      1. THATDONFC's Avatar
        THATDONFC -
        Does this unit retain the factory itb's?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by THATDONFC Click here to enlarge
        Does this unit retain the factory itb's?
        Yes.
      1. Itsbrokeagain's Avatar
        Itsbrokeagain -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Yes.
        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?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Itsbrokeagain Click here to enlarge
        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 would think it would have to vent the boost.