Close

Page 1 of 3 123 LastLast
Results 1 to 25 of 65
  1. #1
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,838
    Rep Points
    31,573.4
    Mentioned
    2066 Post(s)
    Rep Power
    316


    Reputation: Yes | No
    This is the route I am considering to go, big SC + stroker, but it isn't simple. I have also seen those who have suggested adding boost when aggressively adding stroke is asking for trouble. We have seen one stroker + SC fail already for whatever reason requiring a rebuild.

    So, I want to add stroke due to the need for torque down low especially when SC'd due to the SC drain mitigating throttle response.

    What do you guys think? Stroking it pointless and just adding unnecessary cost?

  2. #2
    Join Date
    Apr 2010
    Posts
    4,608
    Rep Points
    3,236.6
    Mentioned
    24 Post(s)
    Rep Power
    33


    Reputation: Yes | No

    The complexities of increasing stroke and supercharging - increase displacement or leave it be?

    When you sa big blower do you mean a blower that is not supplied by your typical cookie cutter gintani/ess setup? I for one would like to see that, in fact, i would like to see 2.4 liter kenne bell sitting atop your motor pusing 20 psi, with A/W IC.

    If you're staying centri, go with a vortech YSi or T trim if you want 'big blower'. There are bigger ones out there such as the procharger D2 or procharger F1 which is good for 1000 whp and is used in NHRA outlaw series IIRC. Anyway, centri blowers are CHEAP, easy as $#@! to tune compared to a twin screw or turbo and can make huge power RELIABLY. If you stroke it, watch your rod angles and take that into account when designing piston made for boost. Dont touch your rev limit, keep it 8300; f anything lower it to 7900 and push more boost and you will have rape powerband trust me.
    Some people live long, meaningful lives.

    Other people eat shit and die.

    I'm not racist, I hate everybody equally; especially fat people.


    Click here to enlarge

  3. #3
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,838
    Rep Points
    31,573.4
    Mentioned
    2066 Post(s)
    Rep Power
    316



    Reputation: Yes | No
    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    When you sa big blower do you mean a blower that is not supplied by your typical cookie cutter gintani/ess setup? I for one would like to see that, in fact, i would like to see 2.4 liter kenne bell sitting atop your motor pusing 20 psi, with A/W IC.
    Positive displacement just won't be done, check the thread in the S65 section to see why.

    I already had a t-trim so I was thinking YSI. I considered a procharger F1 setup as well but no one runs that setup on a BMW for some reason.

    I don't see why not rev it out? I am going to be running a ton of boost regardless. Revving it out to 8500+ with DCT and centrifugal will be insane.

  4. #4
    Join Date
    Apr 2010
    Posts
    4,608
    Rep Points
    3,236.6
    Mentioned
    24 Post(s)
    Rep Power
    33


    Reputation: Yes | No
    Only reason i wouldnt rev it out would be reliability with a stroker motor on boost. Like i was saying if it was stock displacement rev it out with boost but you are increasing rod angles ad piston speed and on top of that adding cylinder pressure. the rod angles contribute to piston slap (side to side rocking of the piston in the bore) if the angles get beyond a critical rod angle ratio/velocity. Boost will just amplify this problem and you will have an oil burner IF you dont design it correctly. Remeber, this motor is practically perfect from the factory, as soon as you change ONE thing it is imperfect and only god knows what that imperfection will lead to, let alone stroking it and boost.

    Strokers are hit and miss, domestics can handle strokers easy as $#@! because they rev low and have large displacement with easy rod angles. Import engines rev high even from the factory, have short strokes and short piston heights which may = piston slap when you add stroker kit. I am not sure if what i am saying applies to the S65 but you should really do a lot of homework before trying to add 20 psi boost to a 4.4 stroker M3 motor. And when i say homework i mean talk to the dean of the mechanical engineering or automotive engineering of georgia tech about the physics of your situation, u may even need to higher a consultant to do some basic calculations to help you take precautions, the last thing you want to see is your brand new 4.4 stroker turn itself into a pile of metal shavings because ofone thing overlooked.
    Some people live long, meaningful lives.

    Other people eat shit and die.

    I'm not racist, I hate everybody equally; especially fat people.


    Click here to enlarge

  5. #5
    Join Date
    Apr 2010
    Posts
    4,608
    Rep Points
    3,236.6
    Mentioned
    24 Post(s)
    Rep Power
    33


    Reputation: Yes | No
    I am not sure why people arent running procharger F1s or D2s, this motor has enough CFM to make good use of it. The procharger F1 is a stupid $#@!ing blower, if seen 331 stroker mustangs with F1s run low 9s and then drive to mcdonalds afterwards.

    Anyway, I think an F1 would be nice. Perhaps fitment is an issue, its a big $#@!ing blower; have you ever seen one? Bracketry and mounting the pulley might be an issue, if the blower is too large in length you may never get the pulley to line up with your crank pulley even if the crank pulley is a dedicated cog setup. It depends on fitment at that point.

    You should consider an intercooler procharger, they come with FMICs, and if you go a mild stroker like 4.2 or something like that, keep your 8500 redline and boost 20+ make 1000 whp easy on meth and pump. I would invest more time in research before buying a single part.
    Some people live long, meaningful lives.

    Other people eat shit and die.

    I'm not racist, I hate everybody equally; especially fat people.


    Click here to enlarge

  6. #6
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,838
    Rep Points
    31,573.4
    Mentioned
    2066 Post(s)
    Rep Power
    316



    Reputation: Yes | No
    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    Only reason i wouldnt rev it out would be reliability with a stroker motor on boost. Like i was saying if it was stock displacement rev it out with boost but you are increasing rod angles ad piston speed and on top of that adding cylinder pressure. the rod angles contribute to piston slap (side to side rocking of the piston in the bore) if the angles get beyond a critical rod angle ratio/velocity. Boost will just amplify this problem and you will have an oil burner IF you dont design it correctly. Remeber, this motor is practically perfect from the factory, as soon as you change ONE thing it is imperfect and only god knows what that imperfection will lead to, let alone stroking it and boost.

    Strokers are hit and miss, domestics can handle strokers easy as $#@! because they rev low and have large displacement with easy rod angles. Import engines rev high even from the factory, have short strokes and short piston heights which may = piston slap when you add stroker kit. I am not sure if what i am saying applies to the S65 but you should really do a lot of homework before trying to add 20 psi boost to a 4.4 stroker M3 motor. And when i say homework i mean talk to the dean of the mechanical engineering or automotive engineering of georgia tech about the physics of your situation, u may even need to higher a consultant to do some basic calculations to help you take precautions, the last thing you want to see is your brand new 4.4 stroker turn itself into a pile of metal shavings because ofone thing overlooked.
    I'm probably going to move these posts to S65 since they are good.

    The thing is, the S65 is begging for stroke. There is so much displacement left on the table not using it seems silly. The piston speeds when adding stroke are still reasonable. I don't have to go overboard necessarily but if I can have a 4.5-4.6 liter why not do it especially with the lame throttle response down low due to the sc?

  7. #7
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,838
    Rep Points
    31,573.4
    Mentioned
    2066 Post(s)
    Rep Power
    316



    Reputation: Yes | No
    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    I am not sure why people arent running procharger F1s or D2s, this motor has enough CFM to make good use of it. The procharger F1 is a stupid $#@!ing blower, if seen 331 stroker mustangs with F1s run low 9s and then drive to mcdonalds afterwards.

    Anyway, I think an F1 would be nice. Perhaps fitment is an issue, its a big $#@!ing blower; have you ever seen one? Bracketry and mounting the pulley might be an issue, if the blower is too large in length you may never get the pulley to line up with your crank pulley even if the crank pulley is a dedicated cog setup. It depends on fitment at that point.

    You should consider an intercooler procharger, they come with FMICs, and if you go a mild stroker like 4.2 or something like that, keep your 8500 redline and boost 20+ make 1000 whp easy on meth and pump. I would invest more time in research before buying a single part.
    I have read up on the YSI vs. Procharger F1 and it seems both are really good but the Porcharger has a better step up ratio. I also see belt slip issues with YSI's necessitating a cog drive setup. I don't know how difficult it would be or if it even could be done to have a cog drive YSI on the S65. The YSI is a very badass blower from what I have read. Seems you can't go wrong with either.

    I just don't know why Vortech seems to dominate the market for BMW. The F1 will fit, there is enough room where the blower already sits. Creating a bracket would be a problem but it could be done I think. It would also be cool to be different.

    Investing time and research is exactly why we have this thread Click here to enlarge This is the fun $#@! to talk about.

  8. #8
    Join Date
    Apr 2010
    Posts
    4,608
    Rep Points
    3,236.6
    Mentioned
    24 Post(s)
    Rep Power
    33


    1 out of 1 members liked this post. Reputation: Yes | No
    I think you are on the right track. A YSi blower can support a lot of power, because this is a small V8 (I dont mean that in a bad way, I am used to see YSi blowers on 331 or 347 small block ford strokers and those are considered small) you wont really need a very large blower to get your target boost, albiet your motor revs high.

    Contrary, too big of a blower; and whatever little bit of lowend you have will be gone because the engine displacement is just too low and the blower just too big (engine has to rotate the big mamajama alone at this point) to be making boost so low in the rev range (not that centri's do, but it will be detrimentally expounded if you go too big on a centri).

    I think a YSi would be your upper limit unless someone else has experience. A 4.0 liter engine redline at 8400 RPM consumes volumetrically about the same amount of air a 347 stroker does at 6500 RPM and that is about the right size blower.

    Whatever you do, dont go twin centri blower setup; thats just stupid. You are asking for parasitic loss and no low end torque with mediocre gains. Single big blower.


    EDIT: I love prochargers too, I like the FMIC procharged motors.
    Last edited by DBFIU; 10-30-2010 at 11:40 PM.
    Some people live long, meaningful lives.

    Other people eat shit and die.

    I'm not racist, I hate everybody equally; especially fat people.


    Click here to enlarge

  9. #9
    Join Date
    Apr 2010
    Posts
    4,608
    Rep Points
    3,236.6
    Mentioned
    24 Post(s)
    Rep Power
    33


    Reputation: Yes | No
    Here is an example of what I like.

    A gear driven procharged engine.
    Attached Images Attached Images    
    Some people live long, meaningful lives.

    Other people eat shit and die.

    I'm not racist, I hate everybody equally; especially fat people.


    Click here to enlarge

  10. #10
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,838
    Rep Points
    31,573.4
    Mentioned
    2066 Post(s)
    Rep Power
    316



    Reputation: Yes | No
    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    Whatever you do, dont go twin centri blower setup; thats just stupid. You are asking for parasitic loss and no low end torque with mediocre gains. Single big blower.
    I would never go twin centri, needlessly complex and less efficient than one big single. This is why I laugh at the people defending the g-power setup as OMG amazing because it has twin blowers.

    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    Contrary, too big of a blower; and whatever little bit of lowend you have will be gone because the engine displacement is just too low and the blower just too big (engine has to rotate the big mamajama alone at this point) to be making boost so low in the rev range (not that centri's do, but it will be detrimentally expounded if you go too big on a centri).

    I think a YSi would be your upper limit unless someone else has experience. A 4.0 liter engine redline at 8400 RPM consumes volumetrically about the same amount of air a 347 stroker does at 6500 RPM and that is about the right size blower.
    YSI has been done on the S65, cog driven no less. Still some things to iron out from what I understand. The low end response obviously will suck but the S65 has no problem turning a YSI and could likely do something even bigger, pretty amazing for its displacement. With the curve the motor has all that boost with the flat curve at 8400 rpm would make for some amazing HP figures, that is for sure.

    What do you think would be better personally, twin screw or centri like a YSI on this motor?

  11. #11
    Join Date
    Apr 2010
    Posts
    4,608
    Rep Points
    3,236.6
    Mentioned
    24 Post(s)
    Rep Power
    33


    Reputation: Yes | No
    If you intend to stroke it, I would go YSi just because you will have the extra displacement and you will make better peak numbers. It will also put less stress on the engine, it is already stroked so you want to not stress it as much as possible.

    If you stay stock displacement I would go TS.

    Word of caution, if you find yourself needing to tighten the belt down due to slippage, be very careful you dont overdo it as this will put huge forces on the snout of the crank and you could actually break it off, ive seen that happen many times as people try to crank down the tension on the blower belt. You wont need to worry about that though unless youre pushing 20+ psi on a centri and spin it to the moon.
    Some people live long, meaningful lives.

    Other people eat shit and die.

    I'm not racist, I hate everybody equally; especially fat people.


    Click here to enlarge

  12. #12
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,838
    Rep Points
    31,573.4
    Mentioned
    2066 Post(s)
    Rep Power
    316



    Reputation: Yes | No
    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    Word of caution, if you find yourself needing to tighten the belt down due to slippage, be very careful you dont overdo it as this will put huge forces on the snout of the crank and you could actually break it off, ive seen that happen many times as people try to crank down the tension on the blower belt. You wont need to worry about that though unless youre pushing 20+ psi on a centri and spin it to the moon.
    If I did go this route I would go cog drive and not worry about it, especially with a YSI that is notorious for belt slipping issues.

    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    If you intend to stroke it, I would go YSi just because you will have the extra displacement and you will make better peak numbers. It will also put less stress on the engine, it is already stroked so you want to not stress it as much as possible.

    If you stay stock displacement I would go TS.
    I think you nailed it, stroker = centri and stock crank = twin screw.

    This is fun to discuss Click here to enlarge

  13. #13
    Join Date
    Feb 2010
    Location
    Corpus Christi, Texas, United States
    Posts
    3,053
    Rep Points
    1,236.6
    Mentioned
    6 Post(s)
    Rep Power
    13


    Reputation: Yes | No
    stock crank = twin turbo Click here to enlarge

  14. #14
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,838
    Rep Points
    31,573.4
    Mentioned
    2066 Post(s)
    Rep Power
    316



    Reputation: Yes | No
    Click here to enlarge Originally Posted by SlicktopTTZ Click here to enlarge
    stock crank = twin turbo Click here to enlarge
    I don't want to be a guinea pig for another year.

    I'm debating stock stroke and TS or stroke and centri. Decisions.... decisions.

  15. #15
    Join Date
    Feb 2010
    Location
    Corpus Christi, Texas, United States
    Posts
    3,053
    Rep Points
    1,236.6
    Mentioned
    6 Post(s)
    Rep Power
    13


    Reputation: Yes | No
    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I don't want to be a guinea pig for another year.

    I'm debating stock stroke and TS or stroke and centri. Decisions.... decisions.
    Sticky, if you want to set records, stroker + centri. Just do it right the first time.

  16. #16
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,838
    Rep Points
    31,573.4
    Mentioned
    2066 Post(s)
    Rep Power
    316



    Reputation: Yes | No
    Click here to enlarge Originally Posted by SlicktopTTZ Click here to enlarge
    Sticky, if you want to set records, stroker + centri. Just do it right the first time.
    So you really think TS will be slower on the top end, eh?

  17. #17
    Join Date
    Feb 2010
    Location
    Corpus Christi, Texas, United States
    Posts
    3,053
    Rep Points
    1,236.6
    Mentioned
    6 Post(s)
    Rep Power
    13


    Reputation: Yes | No
    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    So you really think TS will be slower on the top end, eh?
    Not to mention you will be needing more boost to multiply your torque to match the power of the Stroker/Centri setup, which means a larger TS and/or more heat plus sapping power to spin the thing.

  18. #18
    Join Date
    Feb 2010
    Location
    Corpus Christi, Texas, United States
    Posts
    3,053
    Rep Points
    1,236.6
    Mentioned
    6 Post(s)
    Rep Power
    13


    Reputation: Yes | No
    Small discussion here you might want to read: http://www.eng-tips.com/viewthread.c...=274271&page=3

    I'll try to find some better info.

  19. #19
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,838
    Rep Points
    31,573.4
    Mentioned
    2066 Post(s)
    Rep Power
    316



    Reputation: Yes | No
    Click here to enlarge Originally Posted by SlicktopTTZ Click here to enlarge
    Not to mention you will be needing more boost to multiply your torque to match the power of the Stroker/Centri setup, which means a larger TS and/or more heat plus sapping power to spin the thing.
    Interestingn, and all that power will come on instantly putting a lot of stress on the rods low in the RPM band plus make traction a huge problem. I'll have to think Click here to enlarge

  20. #20
    Join Date
    Feb 2010
    Location
    Corpus Christi, Texas, United States
    Posts
    3,053
    Rep Points
    1,236.6
    Mentioned
    6 Post(s)
    Rep Power
    13


    Reputation: Yes | No
    Pretty lengthy discussion with good info, for some reason I can't do anything with the text on that site.

    http://www.bmwauto.net/forums/bmw/p/...uperchargers/1

  21. #21
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,838
    Rep Points
    31,573.4
    Mentioned
    2066 Post(s)
    Rep Power
    316



    Reputation: Yes | No
    Click here to enlarge Originally Posted by SlicktopTTZ Click here to enlarge
    Pretty lengthy discussion with good info, for some reason I can't do anything with the text on that site.

    http://www.bmwauto.net/forums/bmw/p/...uperchargers/1
    Bad link.

  22. #22
    Join Date
    Feb 2010
    Location
    Corpus Christi, Texas, United States
    Posts
    3,053
    Rep Points
    1,236.6
    Mentioned
    6 Post(s)
    Rep Power
    13


    Reputation: Yes | No
    That is weird. I just tested it and it works great for me. Just copy and paste.

    w w w .bmwauto.net/forums/bmw/p/172545/twinscrew_vs_centrifugal_superchargers/1

    I haven't read the whole thing but there is good stuff in there.

  23. #23
    Join Date
    Feb 2010
    Location
    Corpus Christi, Texas, United States
    Posts
    3,053
    Rep Points
    1,236.6
    Mentioned
    6 Post(s)
    Rep Power
    13


    Reputation: Yes | No
    Well, it auto-linked........




    *fixed

  24. #24
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    117,838
    Rep Points
    31,573.4
    Mentioned
    2066 Post(s)
    Rep Power
    316



    Reputation: Yes | No
    Click here to enlarge Originally Posted by SlicktopTTZ Click here to enlarge
    That is weird. I just tested it and it works great for me. Just copy and paste.

    w w w .bmwauto.net/forums/bmw/p/172545/twinscrew_vs_centrifugal_superchargers/1

    I haven't read the whole thing but there is good stuff in there.
    Still not working for me, error 403, forbidden.

  25. #25
    Join Date
    Apr 2010
    Posts
    4,608
    Rep Points
    3,236.6
    Mentioned
    24 Post(s)
    Rep Power
    33


    1 out of 1 members liked this post. Reputation: Yes | No
    I agree with slicktop, if you want to set a record and go real fast go stroker centri. I like TS but it will be a lot of work since no one has ever gone that route.
    Some people live long, meaningful lives.

    Other people eat shit and die.

    I'm not racist, I hate everybody equally; especially fat people.


    Click here to enlarge

Page 1 of 3 123 LastLast

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •