• 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. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        For sure.
        +1
      1. mfatuation's Avatar
        mfatuation -
        Click here to enlarge Originally Posted by MisterEm Click here to enlarge
        I like the blue contrast with the gold wheels. Outside of interlagos, BMW makes some lovely shades of blue - Estorilblau, Atlantic, LSB, Topasblau etc. Your car reminds me of the contrast of the Santori (sp?) blue and gold BBS rims circa 2005-2006 STi's - albeit a much better chassis!
        Well I came really close to getting an STi when they first came to the US a while back... I've always liked gold wheels, but not many people run them. I think seeing all of the BMW '80s racecars while visiting their museum in Munich made up my mind for me.

        Click here to enlarge Originally Posted by rooringhusky Click here to enlarge
        THIS!! Saw this car at bimmerfest....at first I took a double take on the rim/color combo but thats what drew me in to look at the car...then I noticed the twin screw and I was caught starring for quite a few minutes Click here to enlarge Love the rim/color (just like MisterEm mentioned its on a way better chassis and reminds me of the older STis)...
        Yeah, color combo probably isn't for everyone. My friends begged me not to do it, but until they write me a check for the car/wheels... Click here to enlarge
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        Build it the way you'll love it bro, $#@! everyone else
        My thoughts exactly sir.

        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        Haha it's def got the Subaru WRX STI vibe with the blue body/gold wheels contrast, but it looks awesome.. I'm North NJ (Morris County), but I adventure into South Jerz every so often
        Glad you like it! I'll be at meets for sure if I ever get it back. lol
      1. BavarianBullet's Avatar
        BavarianBullet -
        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.
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        That's some interested detective work and an interesting theory too but is it true? APR claimed Eaton worked with them.
        Yeah, well, I have nothing major against APR, but they claimed on Stupidzine to have completely cracked the DME for the B8 S4 when it's pretty clear they likely just have access to some number of tables useful to their immediate needs.

        Eaton on their website clearly states it's actually 4 companies they do aftermarket work with; Manguson, Harrop, Edelbrock and Roush: http://www.eaton.com/Eaton/ProductsS.../FAQ/index.htm

        More importantly, Harrop advertises they already make the APR RS4 and S5 1320 TVS kits: http://www.harrop.com.au/sc_detail.p...d=HTV1320APRS5

        I surmised that APR paid Harrop to build the parts they need and APR could have well done a lot of the CAD work etc and just sent them the CAD files. Maybe APR talked a lot about the project with Eaton. Who knows. Long story short is APR has apparently worked with Harrop for years, APR likely can't get SC rotorpacks from Eaton direct and likely just paid Harrop to make the 1740 kit for them just as they seem to have done for at least their RS4/S5 kits.

        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.
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        No it was that Chris would not do it due to the cost. Turbos are coming.
        I guess I misquoted (from memory) then, sorry for that. The point is, after reading your article about it back 2010 or whatever, it seemed like the market was waiting for someone to do the dev work required for the tuning of turbos since Chris clearly wasn't interested. And with this Harrop SC for the M3, I was wondering if Harrop was going to throw some serious resources behind engaging a top tuner to go into the S65 DME to make it work or what the next step was.
      1. BavarianBullet's Avatar
        BavarianBullet -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        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.
        I disagree that PD SCs are that much different that SCs from a load perspective. Yes it's an oversimplification because turbos are untethered to engine RPM unlike a SC but the primary reason I said it was because with either PD SC or (smaller) Turbo you can make full boost at say 2500rpm. The load is dramatically higher than anything a NA engine or centrifugal SC is able to produce at low-mid RPMs.

        That just pushes the tuning because you can't just adjust correction factors you now have to plan for load that's way beyond biasing O2's/warm up tables/ACT etc a little.

        Honestly I have no idea how much the current tuners have unlocked with the S65 DME but from the few posts I've read on the subject, it doesn't sound like it's developed to the degree needed to run turbos, PD SC or anything like that.

        I agree with most everything else you said too. The S65 DME is either going to need a bit of work or go standalone. Turbo or PD SC are going to twist up the stock DCT just like the 335is already has I would think. The connecting rods look pencil thin, block is claimed to flex at high HP and the rods supposedly already have bearing/oiling issues. Doesn't sound like a layup of an upgrade to go PD SC or turbo and high HP.
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        I disagree that PD SCs are that much different that SCs from a load perspective. Yes it's an oversimplification because turbos are untethered to engine RPM unlike a SC but the primary reason I said it was because with either PD SC or (smaller) Turbo you can make full boost at say 2500rpm. The load is dramatically higher than anything a NA engine or centrifugal SC is able to produce at low-mid RPMs.

        That just pushes the tuning because you can't just adjust correction factors you now have to plan for load that's way beyond biasing O2's/warm up tables/ACT etc a little.

        Honestly I have no idea how much the current tuners have unlocked with the S65 DME but from the few posts I've read on the subject, it doesn't sound like it's developed to the degree needed to run turbos, PD SC or anything like that.

        I agree with most everything else you said too. The S65 DME is either going to need a bit of work or go standalone. Turbo or PD SC are going to twist up the stock DCT just like the 335is already has I would think. The connecting rods look pencil thin, block is claimed to flex at high HP and the rods supposedly already have bearing/oiling issues. Doesn't sound like a layup of an upgrade to go PD SC or turbo and high HP.
        how would you list the differences between a PD blower and a turbo, as far as tuning?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        but they claimed on Stupidzine to have completely cracked the DME for the B8 S4 when it's pretty clear they likely just have access to some number of tables useful to their immediate needs.
        That's no doubt true and the S4 received an updated ECU too right that just recently people are tuning?

        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        I surmised that APR paid Harrop to build the parts they need and APR could have well done a lot of the CAD work etc and just sent them the CAD files. Maybe APR talked a lot about the project with Eaton. Who knows. Long story short is APR has apparently worked with Harrop for years, APR likely can't get SC rotorpacks from Eaton direct and likely just paid Harrop to make the 1740 kit for them just as they seem to have done for at least their RS4/S5 kits.
        Can't we just ask Harrop or would them keeping quiet be part of the agreement?

        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        it seemed like the market was waiting for someone to do the dev work required for the tuning of turbos since Chris clearly wasn't interested. And with this Harrop SC for the M3, I was wondering if Harrop was going to throw some serious resources behind engaging a top tuner to go into the S65 DME to make it work or what the next step was.
        Yes someone had to put in some serious work, not easy at all. I know who Harrop asked to help with this btw... not sure who they ended up.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        I disagree that PD SCs are that much different that SCs from a load perspective. Yes it's an oversimplification because turbos are untethered to engine RPM unlike a SC but the primary reason I said it was because with either PD SC or (smaller) Turbo you can make full boost at say 2500rpm. The load is dramatically higher than anything a NA engine or centrifugal SC is able to produce at low-mid RPMs.
        Exactly but you are also forgetting with a positive displacement there are numerous issues with the factory DME in this particular case of the S65 V8 that need to be solved.
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        Yes it's an oversimplification because turbos are untethered to engine RPM unlike a SC but the primary reason I said it was because with either PD SC or (smaller) Turbo you can make full boost at say 2500rpm. The load is dramatically higher than anything a NA engine or centrifugal SC is able to produce at low-mid RPMs.
        I don't think that'll make the tuning significantly more difficult though. I do agree that the stress/load will be significantly higher than the Centri Kits, but all that low end TQ will be a bigger test on the physical components (specifically the OEM rods) then any difficulties the tuners may face. Otherwise (unless I'm missing something), it should be virtually the same as tuning the current, Centri options. Regardless of the s/c, the tuners have to consider every possible throttle condition (partial, WOT, off throttle), except the major difference being the Harrop/Roots will generate full boost at any RPMs. And because they're using an electronic controller, you can tune the S65 completely independent from the boost for all throttle conditions.
      1. BavarianBullet's Avatar
        BavarianBullet -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        how would you list the differences between a PD blower and a turbo, as far as tuning?
        Typo on my part. I meant to say that turbos and PD SC are similar. Centrifugal SCs are a lot more like a NA engine until they start to build significant boost.
      1. BavarianBullet's Avatar
        BavarianBullet -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        I don't think that'll make the tuning significantly more difficult though. I do agree that the stress/load will be significantly higher than the Centri Kits, but all that low end TQ will be a bigger test on the physical components (specifically the OEM rods) then any difficulties the tuners may face. Otherwise (unless I'm missing something), it should be virtually the same as tuning the current, Centri options. Regardless of the s/c, the tuners have to consider every possible throttle condition (partial, WOT, off throttle), except the major difference being the Harrop/Roots will generate full boost at any RPMs. And because they're using an electronic controller, you can tune the S65 completely independent from the boost for all throttle conditions.
        All good points, esp about the EBC. I admit I know very little about the state of the S65 DME and who can likely do what with it at the moment. Given the fact no one has turbo'd the S65 and its been kicked around that the reason is the tuning, I thought that and the PD SC and turbo load patterns being similar meant that when one was able to be tuned the other wouldnt be far behind.

        I'm slowly increasing my meager knowledge of the S65 and what it can do. Ive yet to even drive an m3 cuz the local dealer rarely even has one on the lot (grrr).
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        Typo on my part. I meant to say that turbos and PD SC are similar. Centrifugal SCs are a lot more like a NA engine until they start to build significant boost.
        oh i know what you meant, but you and i know the list for differences is smaller than the list of similarities, so i wanted the easy way
      1. BavarianBullet's Avatar
        BavarianBullet -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Exactly but you are also forgetting with a positive displacement there are numerous issues with the factory DME in this particular case of the S65 V8 that need to be solved.
        Not sure if this changes things but I made a typo earlier. Meant to say PD SC and turbos were similar in load pattern and likely both were more challenging to tune which is why none were built yet. Chicken and egg problem like big turbos for the n54 (tuner waiting for hardware and fabricators waiting on tuners).

        In either case, what major DME challenges do you think are holding the process up?
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        In either case, what major DME challenges do you think are holding the process up?
        At this point, it seems like what tuners have control over is very little -- AFR Target, Ignition Advance, VANOS Timing & Fueling. Obviously adding turbos complicates everything a lot, which is why HPF originally used the AEM piggyback to control Fueling & Boost. With a lot of the advances in tech, I think it'd just be easier to use a standalone, get full control of the engine + turbo system, while maintaining all the OEM features (iDrive/NAV, Comfort Access, EDC control, etc etc).

        Like I previously said, from what tuners seem to have under control, we're very far from tuning a turbo S65 on the stock DME w/ a boost controller.
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        At this point, it seems like what tuners have control over is very little -- AFR Target, Ignition Advance, VANOS Timing & Fueling. Obviously adding turbos complicates everything a lot, which is why HPF originally used the AEM piggyback to control Fueling & Boost. With a lot of the advances in tech, I think it'd just be easier to use a standalone, get full control of the engine + turbo system, while maintaining all the OEM features (iDrive/NAV, Comfort Access, EDC control, etc etc).

        Like I previously said, from what tuners seem to have under control, we're very far from tuning a turbo S65 on the stock DME w/ a boost controller.
        i dont think its a matter of access, as there are numerous tuning options now, but a matter of ROI for time spent
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        Otherwise (unless I'm missing something), it should be virtually the same as tuning the current, Centri options.
        You are, a few things. I mean it's not my place to comment about it.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
        Meant to say PD SC and turbos were similar in load pattern and likely both were more challenging to tune which is why none were built yet.
        Yes, that would be much more accurate.
      1. benzy89's Avatar
        benzy89 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        You are, a few things. I mean it's not my place to comment about it.
        Than can you explain the differences in tuning (centri vs. PD) on a non-BMW platform??
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        Than can you explain the differences in tuning (centri vs. PD) on a non-BMW platform??
        I'm not a tuner but I imagine the torque values aren't easy to address as well as the air flow since you aren't ramping in boost with rpm which is comparatively easier to tune for.

        I mean I did go over this with a tuner a bit at bimmerfest but once again not my place to comment.
      1. LostMarine's Avatar
        LostMarine -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        I imagine the torque values aren't easy to address as well as the air flow since you aren't ramping in boost with rpm which is comparatively easier to tune for.
        interesting you say that as it would be very similar to, oh whats that other option for FI...? a turbo i think its called?
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by LostMarine Click here to enlarge
        interesting you say that as it would be very similar to, oh whats that other option for FI...? a turbo i think its called?
        It was already mentioned by me and others the tuning would be close to having tune for a turbo in the respect of how the boost comes in versus how you tune based on rpm set point with a centrifugal. So you're rehashing what was stated again?