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  1. #26
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    In my experience, if you don't HAVE TO, you DON'T want to sleeve floating deck engines. They are a real pain to get the sleeve to fit and stay.

    have we sleeved open deck engines? Sure have. The biggest thing for success is to machine the sleeve to have a lip at the top of it (which depending on the bore and length of the sleeve can take quite a while on the lathe) and then a receiving groove at the top of the cylinder to accept the sleeve...... Then, with the head bolted on, it clamps the sleeve and locks it in. In general its a lot of extra work.

    closed deck blocks don't really have this type if issue, since the interference fit doesn't really get compromised when heated/cooled over and over. Compared to an open deck block it has a chance to expand the "tower" of cylinder material, dropping the sleeve down.... And we all know what that means Click here to enlarge
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  2. #27
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Why don't you share what equation you're using with everyone?
    The equation is very long. It's the derivative of the piston position equation with respect to time. This derivative is very long.

    Piston position equation is:
    piston position equation = [sqrt (R^2 - (Rcr* Sin (t*rpm*6))^2)]-(y-Rcr)

    where R is rod length, Rcr is crank radius, t is time

  3. #28
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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    I wasn't defending anything or saying that the n54 was built to rev higher than the s65. I highly doubt that would be the case. My blind faith is called math and engineering. All I'm saying is that those numbers are mean piston speeds. Mean piston speeds are a good starting point, but you can vary rod length to decrease max piston speed. This is not shown in the calculation of mean piston speed.
    Ok well the math provided does show that piston speeds for one motor that revs 1400 rpm higher are about the same on average due to its design, right?

    As I understand it you don't need the rod length to have an accurate comparison as most formulas do not take it into account:

    Click here to enlarge

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    Click here to enlarge Originally Posted by alex@ABRhouston Click here to enlarge
    Compared to an open deck block it has a chance to expand the "tower" of cylinder material, dropping the sleeve down.... And we all know what that means
    This. But it can be prevented. And in my case, has been.

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
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  5. #30
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    Problem with mean piston speed is that when do you think you are most likely to have failure? Max speed or mean speed? After a little searching I found that the s65 rod length is 140.7mm. This is shorter than the n54 rods. But with the shorter stroke, the rod/stroke ratio is 1.87. This is much better than the n54 for high revving. The n54 comes out to 1.62. Rod/stroke ratio is a great indicator of whether or not is capable of revving high.

    Max piston speed for s65 is approx. 34.22 m/s or 6736 ft/min. Mean piston speed is only 4145 ft/min. That's a difference of 2591 ft/min.

  6. #31
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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    Problem with mean piston speed is that when do you think you are most likely to have failure? Max speed or mean speed?
    Max but mean still takes into account the max it just averages it through the rev range.

    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    After a little searching I found that the s65 rod length is 140.7mm. This is shorter than the n54 rods. But with the shorter stroke, the rod/stroke ratio is 1.87. This is much better than the n54 for high revving. The n54 comes out to 1.62. Rod/stroke ratio is a great indicator of whether or not is capable of revving high.
    I think it's a combination of factors but if you look a the S54 you may be surprised for example. But, glad we clearly established the S65 was built to rev and it sure can rev.

    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    Max piston speed for s65 is approx. 34.22 m/s or 6736 ft/min. Mean piston speed is only 4145 ft/min. That's a difference of 2591 ft/min.
    No doubt due to having the wider powerband it will be more pronounced. I'm sure an F1 cars difference is insane at low and high revs.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    No doubt due to having the wider powerband it will be more pronounced. I'm sure an F1 cars difference is insane at low and high revs.
    Those numbers are all at the same rpm (redline - 8400). They have nothing to do with power band or low and high revs. If you hold the engine at 8400 rpm, the piston will still go from 0 ft/s to 6736 ft/min on each stroke and back to 0 on each stroke.

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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    Those numbers are all at the same rpm (redline - 8400). They have nothing to do with power band or low and high revs. If you hold the engine at 8400 rpm, the piston will still go from 0 ft/s to 6736 ft/min on each stroke and back to 0 on each stroke.
    Maybe we are saying different things but I was saying the difference at max piston speed versus mean which I assume will be a fairly large spread depending on how far the motor revs and its stroke of course?

    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Maybe we are saying different things but I was saying the difference at max piston speed versus mean which I assume will be a fairly large spread depending on how far the motor revs and its stroke of course?
    Correct. But the peak speed is affected by rod length as well. Peak speed or true speed is calculated from rpm, stroke and rod length along with geometry of the crank. Mean speed is calculated by rpm and stroke [but can also be calculated by averaging the true speed].

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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    Correct. But the peak speed is affected by rod length as well. Peak speed or true speed is calculated from rpm, stroke and rod length along with geometry of the crank. Mean speed is calculated by rpm and stroke [but can also be calculated by averaging the true speed].
    Yes I know but as my post on calculating mean and max speed stated one can get a fairly accurate number without the rod length. I mean if you want to be absolutely perfect get it and use the formula but I don't think it's even necessary to get the picture.

    And mean speed of course will take into account the high and low values.

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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    Problem with mean piston speed is that when do you think you are most likely to have failure? Max speed or mean speed? After a little searching I found that the s65 rod length is 140.7mm. This is shorter than the n54 rods. But with the shorter stroke, the rod/stroke ratio is 1.87. This is much better than the n54 for high revving. The n54 comes out to 1.62. Rod/stroke ratio is a great indicator of whether or not is capable of revving high.

    Max piston speed for s65 is approx. 34.22 m/s or 6736 ft/min. Mean piston speed is only 4145 ft/min. That's a difference of 2591 ft/min.
    and honda makes motors that rev to 8 or even 9k with even lower R:S ratios (much closer to 1.5). it's not the be-all and end-all of what makes a motor able to rev high

    1.87... being SO high, though, is probably a pretty damn good indication of the design intent haha

    whats the max/mean piston speeds in the N54 if you're able to get the data?

    nvm saw it on the last page: 34.37 m/s... 6765f/min

    what's the MEAN though?
    boop

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Yes I know but as my post on calculating mean and max speed stated one can get a fairly accurate number without the rod length. I mean if you want to be absolutely perfect get it and use the formula but I don't think it's even necessary to get the picture.

    And mean speed of course will take into account the high and low values.
    Good for an estimation when quick numbers are needed. Using the estimation formula, they get a max speed 300 ft/min less than true speed for the n54, and a max speed of 225 ft/min less than true speed for s65 (when using stock rod lengths). Good estimation (<5% off), but I wouldn't use it if I was building an engine.

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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    Good for an estimation when quick numbers are needed. Using the estimation formula, they get a max speed 300 ft/min less than true speed for the n54, and a max speed of 225 ft/min less than true speed for s65 (when using stock rod lengths). Good estimation (<5% off), but I wouldn't use it if I was building an engine.
    We're just discussing design intent which is more than enough data and accurate enough to get the picture.

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    This thread has actually been a blessing in disguise. We are going to be building a S65 high revving race engine for the new shop race car. I actually was going to start putting information together so my machinist and I could sit down and figure out what it's ultimate rev limit will be with hydraulic lifters, and with custom mechanical tappet/shim lifters would be. We're hoping to hit 10k+

    but, I'm getting off topic.
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    Click here to enlarge Originally Posted by alex@ABRhouston Click here to enlarge
    This thread has actually been a blessing in disguise. We are going to be building a S65 high revving race engine for the new shop race car. I actually was going to start putting information together so my machinist and I could sit down and figure out what it's ultimate rev limit will be with hydraulic lifters, and with custom mechanical tappet/shim lifters would be. We're hoping to hit 10k+

    but, I'm getting off topic.
    That's going to be a lot of fun to see. Looking forward to it in the S65 section.

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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    and honda makes motors that rev to 8 or even 9k with even lower R:S ratios (much closer to 1.5). it's not the be-all and end-all of what makes a motor able to rev high

    1.87... being SO high, though, is probably a pretty damn good indication of the design intent haha

    whats the max/mean piston speeds in the N54 if you're able to get the data?
    Strength of the materials used is the end all be all. But holding that and everything else the same, R:S ratio is very important. It affects the angle that the rod will get as it moves along the crank. The greater the angle, the more side wall force on the cylinder wall and bending moment on the rod. The greater the length of the rod, the less side wall force on the cylinder and bending moment on the rod.

    The mean piston speed is 20.9 m/s or 4115 ft/min

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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    Stock bore is 84mm. Stroke is 89.6mm. Stock rod length is 145mm.

    I have calculations for piston speed at all rpm too. It was a fun little math exercise. At 7000rpm, the pistons get up to 34.37 m/s! That's pretty fast.
    not as fast as some other cars i could quickly find... even up to 42+!

    but it does go to show that the S65 no matter what would be capable of revving wahaaaaaaay higher than the N54

    though, by either one's limit going strictly from a piston speed/rod:stroke standpoint.... there's a boat load of other roadblocks first haha.
    boop

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    Click here to enlarge Originally Posted by alex@ABRhouston Click here to enlarge
    This thread has actually been a blessing in disguise. We are going to be building a S65 high revving race engine for the new shop race car. I actually was going to start putting information together so my machinist and I could sit down and figure out what it's ultimate rev limit will be with hydraulic lifters, and with custom mechanical tappet/shim lifters would be. We're hoping to hit 10k+

    but, I'm getting off topic.
    wow, i'll look forward to seeing that

    what's the highest anyone's taken an S65 that you know of?
    boop

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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    not as fast as some other cars i could quickly find... even up to 42+!

    but it does go to show that the S65 no matter what would be capable of revving wahaaaaaaay higher than the N54

    though, by either one's limit going strictly from a piston speed/rod:stroke standpoint.... there's a boat load of other roadblocks first haha.
    42 m/s is retardedly fast. I'll bet those engines have long rods and very strong materials.

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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    Strength of the materials used is the end all be all. But holding that and everything else the same, R:S ratio is very important. It affects the angle that the rod will get as it moves along the crank. The greater the angle, the more side wall force on the cylinder wall and bending moment on the rod. The greater the length of the rod, the less side wall force on the cylinder and bending moment on the rod.

    The mean piston speed is 20.9 m/s or 4115 ft/min
    that's not ESPECIALLY high mean wise

    there's nothing PHYSICS wise stopping the N54 from revving higher... just ECU/hardware limitations.

    it's not a R:S ratio that they went right off the bat 'we're going to rev the tits off this' of course, i agree.

    then again, a B18C has a 1.58:1 R:S and revs to 8000rpm (same for the H22A, 1.58, and it will rev like mad if you let it).. same for many other honda motors. which is strange considering the S2k's 1.82 and obvious design intent... heck, the RB26 and jz motors have a 1.64 and 1.65 respectively... yet the RB30 has a 1.76... and the 30 is designed to be a lower rev high torque, yet the 26 is the exact opposite. (though of course, again with enough money and the right parts, an RB30/32 will, of course, rev it's tits off, same with a jz)
    boop

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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    that's not ESPECIALLY high mean wise

    there's nothing PHYSICS wise stopping the N54 from revving higher... just ECU/hardware limitations.

    it's not a R:S ratio that they went right off the bat 'we're going to rev the tits off this' of course, i agree.

    then again, a B18C has a 1.58:1 R:S and revs to 8000rpm.. same for many other honda motors. which is strange considering the S2k's 1.82 and obvious design intent... heck, the RB26 and jz motors have a 1.64 and 1.65 respectively... yet the RB30 has a 1.76... and the 30 is designed to be a lower rev high torque, yet the 26 is the exact opposite.
    Exactly. R:S ratio, piston speed are not limiting factors. They just give you a picture of what the engine parts have to endure. You can build an engine to take anything. Better R:S ratio, lower piston speed (through either shorter stroke or longer rod), longer rods (less harsh rod angles) all give the engine components a mechanical advantage on the stresses it has to take (some at a cost of hp through loss of leverage). Some conditions are just more ideal than others.

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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    42 m/s is retardedly fast. I'll bet those engines have long rods and very strong materials.
    yup

    bah, can't find it again.... it's one of the honda B18's at 9k RPM

    i wouldn't call them particularly strong... can't comment on the strength (i think they're OK but not world leading, i've never thought of any of them as particularly hardy hahaha), nothing in a honda motor would i call strength over weight lol... but it's a pretty low (1.54 this time) R:S ratio

    that would mean fairly short rod relative to stroke?
    boop

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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
    Exactly. R:S ratio, piston speed are not limiting factors. They just give you a picture of what the engine parts have to endure. You can build an engine to take anything. Better R:S ratio, lower piston speed (through either shorter stroke or longer rod), longer rods (less harsh rod angles) all give the engine components a mechanical advantage on the stresses it has to take (some at a cost of hp through loss of leverage). Some conditions are just more ideal than others.
    so basically higher rod to stroke means longer rod relative to stroke length which GENERALLY means less unwanted stresses due to smaller angles. got it!

    there's just SO MANY engines that don't comply to that design goal that are easy to find

    i mean... it's strange.. when we talk about the S65 we talk about how it was designed around being revved high all the way with things like R:S

    then there's so many other high revving engines that aren't, and no one really mentions it either way haha
    boop

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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    but it does go to show that the S65 no matter what would be capable of revving wahaaaaaaay higher than the N54
    As I stated a while ago. It's no contest and this helps the S65 make up for its displacement.

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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    wow, i'll look forward to seeing that

    what's the highest anyone's taken an S65 that you know of?
    BMW themselves took it to 10k in testing. VAC destroked one recently with a 3.5 liter crank and who knows how high they are revving but it's more than any N54 ever will.

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