Close

Page 3 of 3 FirstFirst 123
Results 51 to 65 of 65
  1. #51
    Join Date
    Feb 2010
    Location
    Corpus Christi, Texas, United States
    Posts
    3,106
    Rep Points
    1,236.6
    Mentioned
    6 Post(s)
    Rep Power
    13


    Yes Reputation No
    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I don't really have a good understanding of rod angles, explain?

    The piston speed even pushing the stroke to maximum is still below the S54 stock. With top of the line rods, why would it be an issue?
    It won't, just make sure you have a good builder and tuner.

  2. #52
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    119,487
    Rep Points
    32,174.6
    Mentioned
    2112 Post(s)
    Rep Power
    322



    Yes Reputation No
    Click here to enlarge Originally Posted by SlicktopTTZ Click here to enlarge
    It won't, just make sure you have a good builder and tuner.
    So the rod angles won't be an issue?

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

  3. #53
    Join Date
    Apr 2010
    Posts
    4,614
    Rep Points
    3,236.6
    Mentioned
    24 Post(s)
    Rep Power
    33


    2 out of 2 members liked this post. Yes Reputation No
    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I don't really have a good understanding of rod angles, explain?

    The piston speed even pushing the stroke to maximum is still below the S54 stock. With top of the line rods, why would it be an issue?
    Extreme rod angles can cause strange $#@! to happen at high RPM. Basically it goes like this, imagine your connecting rod 10 feet long, keep your stroke the same, keep your bore the same; i just built a motor with a 10 foot rod for the S65. Just bare with me, what you have is a rod that almost always stays vertical, during combustion the rod will impart its force through the rod, always through the rod; the rod is a COLUMN essentially.

    Now during combustion the rod being so long, you can say that the force due to combustion is imparted through the rod unto the crank journal during a specific interval of crank rotation.

    And that this force is not always optimal, i.e tangential being optimal for the crank.

    Now here is the other extreme, a very short rod, the rod now makes very extreme angles with the bore and the piston must absorb more SIDE FORCES induced by this extreme rod angle.

    The short rod also a problem when trying to balance the crank, it is displacing and ROTATING much more severely in space at the same time and is less forgiving during balance. But, the forces on the crank journal are DIFFERENT than those compared to the long rod. Because the short rod is not always vertical, it imparts its forces for a different crank rotation interval WHICH MAY be advantageous to the engine designer.

    There is a WHOLE SCIENCE behind stroke/rod angle ratio and what the effects of it are on high performance engines. basically, you would want to stay away from extreme rod angles as you increase stroke. The only way to remedy this is to get a physically bigger block, but since you cant, you may just have to go with 4.4 liters and trust that BMW did their homework on side loads on pistons, now you add boost.
    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

  4. #54
    Join Date
    Feb 2010
    Location
    Corpus Christi, Texas, United States
    Posts
    3,106
    Rep Points
    1,236.6
    Mentioned
    6 Post(s)
    Rep Power
    13


    Yes Reputation No
    Sticky, while you are at it, grab the flat-plane crank from the BMW 4.4 Motorsport engine! Click here to enlarge

  5. #55
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    119,487
    Rep Points
    32,174.6
    Mentioned
    2112 Post(s)
    Rep Power
    322



    Yes Reputation No
    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    Extreme rod angles can cause strange $#@! to happen at high RPM. Basically it goes like this, imagine your connecting rod 10 feet long, keep your stroke the same, keep your bore the same; i just built a motor with a 10 foot rod for the S65. Just bare with me, what you have is a rod that almost always stays vertical, during combustion the rod will impart its force through the rod, always through the rod; the rod is a COLUMN essentially.

    Now during combustion the rod being so long, you can say that the force due to combustion is imparted through the rod unto the crank journal during a specific interval of crank rotation.

    And that this force is not always optimal, i.e tangential being optimal for the crank.

    Now here is the other extreme, a very short rod, the rod now makes very extreme angles with the bore and the piston must absorb more SIDE FORCES induced by this extreme rod angle.

    The short rod also a problem when trying to balance the crank, it is displacing and ROTATING much more severely in space at the same time and is less forgiving during balance. But, the forces on the crank journal are DIFFERENT than those compared to the long rod. Because the short rod is not always vertical, it imparts its forces for a different crank rotation interval WHICH MAY be advantageous to the engine designer.

    There is a WHOLE SCIENCE behind stroke/rod angle ratio and what the effects of it are on high performance engines. basically, you would want to stay away from extreme rod angles as you increase stroke. The only way to remedy this is to get a physically bigger block, but since you cant, you may just have to go with 4.4 liters and trust that BMW did their homework on side loads on pistons, now you add boost.
    Ok, well the science of rod angles is beyond me for now but if anyone gets this I assume the BMW engineers would. Plus, everyone is stroking these things. Really, if you look at the bore x stroke figures and the piston speeds you can see the motor is begging for stroke. If BMW does it on the V10 and the V8, and everyone in the aftermarket does the same, it is a safe bet the rod angles are within reason, right?

    The question is how boost changes this.

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

  6. #56
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    119,487
    Rep Points
    32,174.6
    Mentioned
    2112 Post(s)
    Rep Power
    322



    Yes Reputation No
    Click here to enlarge Originally Posted by SlicktopTTZ Click here to enlarge
    Sticky, while you are at it, grab the flat-plane crank from the BMW 4.4 Motorsport engine! Click here to enlarge
    I might as well just buy the race car lol.

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

  7. #57
    Join Date
    Apr 2010
    Posts
    4,614
    Rep Points
    3,236.6
    Mentioned
    24 Post(s)
    Rep Power
    33


    Yes Reputation No
    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Ok, well the science of rod angles is beyond me for now but if anyone gets this I assume the BMW engineers would. Plus, everyone is stroking these things. Really, if you look at the bore x stroke figures and the piston speeds you can see the motor is begging for stroke. If BMW does it on the V10 and the V8, and everyone in the aftermarket does the same, it is a safe bet the rod angles are within reason, right?

    The question is how boost changes this.
    I would confident that you are right about the rod angles being ok.

    I would not be confident that the rod angles are 'ok' with X amount of boost. Remember, boost raises your average cylinder pressure, more cylinder pressure produces greater rod forces and sidewall forces.

    Since you are saying that many people have boosted using this configuration (stroke/rod angle) than you should be ok, but I would keep asking around about what some builders have done with specifically S65 strokers.

    For instance, have you seen any S65 strokers on nitrous?
    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

  8. #58
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    119,487
    Rep Points
    32,174.6
    Mentioned
    2112 Post(s)
    Rep Power
    322



    Yes Reputation No
    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    For instance, have you seen any S65 strokers on nitrous?
    No, not a single one. The stroker guys just aren't as hardcore for whatever reason.

    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    Since you are saying that many people have boosted using this configuration (stroke/rod angle) than you should be ok, but I would keep asking around about what some builders have done with specifically S65 strokers.
    Well, only one has been boosted to my knowledge and that only one is being rebuilt. So... does not exactly build confidence, right?

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

  9. #59
    Join Date
    Feb 2010
    Location
    Corpus Christi, Texas, United States
    Posts
    3,106
    Rep Points
    1,236.6
    Mentioned
    6 Post(s)
    Rep Power
    13


    Yes Reputation No
    It's ok Sticky, everything will be o-BOOM! Click here to enlarge

  10. #60
    Join Date
    Apr 2010
    Posts
    4,614
    Rep Points
    3,236.6
    Mentioned
    24 Post(s)
    Rep Power
    33


    1 out of 1 members liked this post. Yes Reputation No
    Well I may be pussyfooting and causing some anxiety for you sticky, but the last thing I would want to see is a motor that goes poopy after 2000 miles because things we are discussing now were 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

  11. #61
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    119,487
    Rep Points
    32,174.6
    Mentioned
    2112 Post(s)
    Rep Power
    322



    Yes Reputation No
    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    Well I may be pussyfooting and causing some anxiety for you sticky, but the last thing I would want to see is a motor that goes poopy after 2000 miles because things we are discussing now were overlooked.
    Dude, this is great. I still have a month or so before the car is back with all the new transmission goodies so I'm not just going to throw thousands down a drain, I want to know what I'm doing.

    This isn't the first time rod angles with boost have been brought up to me.

    Problem is we have so little data in the M3 world because few do anything. We have a handful of guys whereas with domestics or Japanese cars lot's of people are modding and pushing the limit. Instead, we have kids with leases their parents got them trying to scrape together their allowance to get rims.

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

  12. #62
    Join Date
    Apr 2010
    Posts
    4,614
    Rep Points
    3,236.6
    Mentioned
    24 Post(s)
    Rep Power
    33


    Yes Reputation No
    lmfao ^^^

    Yea, the M3 isnt exactly the 'ford mustang' or 'honda civic' for the modding world. Most people are weary of tearing into a 70k dollar car so you probably wont find as much data and experiences to guide you. You are undertaking treacherous terrain, building up an expensive car such as this etc... a very complicated computer controlled engine to boot.

    I say go 4.2 liter and 20 psi max and make reliable power. Still a stroker, but your anus wont pucker everytime you get on the gas.
    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

  13. #63
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    119,487
    Rep Points
    32,174.6
    Mentioned
    2112 Post(s)
    Rep Power
    322



    Yes Reputation No
    Click here to enlarge Originally Posted by DBFIU Click here to enlarge
    I say go 4.2 liter and 20 psi max and make reliable power. Still a stroker, but your anus wont pucker everytime you get on the gas.
    Going to only 4.2 would be pointless, increasing the stroke from 75.2 to 79. That would be $5000 for 200 cc's, no way, I would rather leave it stock displacement.

    What I'm thinking is that RDsport has too long of a stroke at 85mm for the boost. That is almost 10 mm longer than stock, what do you think? Dinan only goes 83mm. The GTS is 82mm.

    A 93 mm bore with 82 mm stroke (likely the safest stroke to go with out of the stroker motors) will give you a 4.457 liter motor, not bad. However, with an 83 mm stroke that is 4.512.

    I think I should try to take the bore as far as possibe. With sleeves, I would think 94mm should not be an issue, Dinan gets there on the stock material. RDsport goes 93mm.

    Check this out: 94mm bore with 82mm stroke is 4.554. With 83mm bore it is 4.6 liters, exactly what Dinan does.

    I think the more conservative stroke, either Dinan or M3 GTS would be the way to go as PencilGeek has stated on various forums he is getting new rods. If the compression ratio of the motor was the issue, why get new rods?

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

  14. #64
    Join Date
    Feb 2010
    Location
    Corpus Christi, Texas, United States
    Posts
    3,106
    Rep Points
    1,236.6
    Mentioned
    6 Post(s)
    Rep Power
    13


    Yes Reputation No
    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I think the more conservative stroke, either Dinan or M3 GTS would be the way to go as PencilGeek has stated on various forums he is getting new rods. If the compression ratio of the motor was the issue, why get new rods?
    He probably bent them under detonation.

  15. #65
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    119,487
    Rep Points
    32,174.6
    Mentioned
    2112 Post(s)
    Rep Power
    322



    Yes Reputation No
    Click here to enlarge Originally Posted by SlicktopTTZ Click here to enlarge
    He probably bent them under detonation.
    I think he sold or is selling them so that isn't it.

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

Page 3 of 3 FirstFirst 123

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
  •