say if one was to carry out this brillant idea what would he do afterwards to beef up the block to cope with the high piston speeds. would it be worth it to get some aftermarket cams as they car will not be revving past 8000rpm. what sort of max power output and torgue would one get with bolt ons such as i/h/e. what itake system would be more benificial e.g quad throttle bodies or would i get more bang for my far less buck with jst a short ram in a cold air box
k24a but then what
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I think "piston speed" is hype, kind of like "r/s ratio"
BTW a stroker is ALWAYS more reliable then a short stroke engine. They also make more power. RPMS don't really matter, power does.
You want to talk insane piston speed, take a gander at the hot street class in NMRA.
BTW a stroker is ALWAYS more reliable then a short stroke engine. They also make more power. RPMS don't really matter, power does.
You want to talk insane piston speed, take a gander at the hot street class in NMRA.
Piston speed and rod/stroke ratio are definitely not hype. And I'm not sure how you can say that a stroker motor is "ALWAYS" more reliable than a short stroke engine. Care to explain your reasoning behind that?
There are a few things we need to consider when discussing these issues. When talking about rod/stroke ratio the main effect is piston sideloads. A long stroke with a short rod means a more extreme rod angle when the crank is at the 3o'clock and 9o'clock positions. This is pulling the piston harder into the cylinder walls which creates more stress on the piston and the sleeves. This can also cause accelerated wear of these components.
Another issue is that with this same short rod/long stroke combo you are placing more bending force on the rods. The rod is strong in tension and compression (pulling on it from both ends, or pushing on it from both ends) but not as strong when you try to bend it in the middle.
Now the only issue I am aware of that is directly associated with piston speed is "ring flutter" which is just what it sounds like and can cause poor ring seal at high piston speeds. But the more important issue you have to deal with is piston acceleration. More abrupt acceleration of the piston (more of a sudden jerk rather than a smooth pull) can have a negative effect on durability.
Bottom line is this: all other factors being the same (same rpm, each component is the same strength, etc.) a motor with a shorter stroke and longer rod will be more reliable than one with a longer stroke and shorter rod - the components will see lighter loads which leads to improved durability.
BUT the bigger stroke motor will make more power in the lower rpm ranges so you may not have/want to rev it high. Whereas with the shorter stroke motor you may need to rev it higher to get the power which will have it's own negative effect on component durability. So you may end up with something of a wash-out.
I think I've gone way off this post's original topic...
There are a few things we need to consider when discussing these issues. When talking about rod/stroke ratio the main effect is piston sideloads. A long stroke with a short rod means a more extreme rod angle when the crank is at the 3o'clock and 9o'clock positions. This is pulling the piston harder into the cylinder walls which creates more stress on the piston and the sleeves. This can also cause accelerated wear of these components.
Another issue is that with this same short rod/long stroke combo you are placing more bending force on the rods. The rod is strong in tension and compression (pulling on it from both ends, or pushing on it from both ends) but not as strong when you try to bend it in the middle.
Now the only issue I am aware of that is directly associated with piston speed is "ring flutter" which is just what it sounds like and can cause poor ring seal at high piston speeds. But the more important issue you have to deal with is piston acceleration. More abrupt acceleration of the piston (more of a sudden jerk rather than a smooth pull) can have a negative effect on durability.
Bottom line is this: all other factors being the same (same rpm, each component is the same strength, etc.) a motor with a shorter stroke and longer rod will be more reliable than one with a longer stroke and shorter rod - the components will see lighter loads which leads to improved durability.
BUT the bigger stroke motor will make more power in the lower rpm ranges so you may not have/want to rev it high. Whereas with the shorter stroke motor you may need to rev it higher to get the power which will have it's own negative effect on component durability. So you may end up with something of a wash-out.
I think I've gone way off this post's original topic...
r/s is hype. Have you ever figured out what the actual angles are?
from say a 1.5:1 to a 1.7:1 there is VERY minimal difference in angles. Yes im talking about 3 oclock and 9 oclock. I don't have a scientific calculator with me, but I did calculate several different r/s ratios and was very very surprised at the results. I encourage you to do the same.
Not only that the very notion of "rod to stroke ratio" is flawed. It should be "rod to *crank throw* ratio". Even smokey yunick, the "father" of r/s ratio, laughed when people destroked their engines or went with smaller stroke cranks to improve rod stroke ratio.
Talking about a longer stroke vs shorter stroke engine. It's quite simple, if engine A spins 6000 rpms x amount of piston speed and engine B spins 9000 rpms with the same piston speed, both will make "similar" power. However, we all know that as RPM's increase, the stress in internal parts increases EXPONENTIALLY. Therefore, even given the same piston speed, engine B is much much more stressed. Rev engine A to 9000 rpms? more power to ya, if you want.
piston speed, well, is *kind* of hype. Build the engine around the horsepower and rpms, not the other way around. Any properly designed components should withstand almost any piston speed we can toss at it. The limit of the induction should be reached before this. Parts failure? Something wasn't designed right. There are many more factors in this then we can possibly imagine, piston speed, instant G's, average G's, weight of piston/assembly, compression ratio, peak cylinder pressure, rpms, yadda yadda. To say an engine is going to blow at x piston speed is ridiculous.
from say a 1.5:1 to a 1.7:1 there is VERY minimal difference in angles. Yes im talking about 3 oclock and 9 oclock. I don't have a scientific calculator with me, but I did calculate several different r/s ratios and was very very surprised at the results. I encourage you to do the same.
Not only that the very notion of "rod to stroke ratio" is flawed. It should be "rod to *crank throw* ratio". Even smokey yunick, the "father" of r/s ratio, laughed when people destroked their engines or went with smaller stroke cranks to improve rod stroke ratio.
Talking about a longer stroke vs shorter stroke engine. It's quite simple, if engine A spins 6000 rpms x amount of piston speed and engine B spins 9000 rpms with the same piston speed, both will make "similar" power. However, we all know that as RPM's increase, the stress in internal parts increases EXPONENTIALLY. Therefore, even given the same piston speed, engine B is much much more stressed. Rev engine A to 9000 rpms? more power to ya, if you want.
piston speed, well, is *kind* of hype. Build the engine around the horsepower and rpms, not the other way around. Any properly designed components should withstand almost any piston speed we can toss at it. The limit of the induction should be reached before this. Parts failure? Something wasn't designed right. There are many more factors in this then we can possibly imagine, piston speed, instant G's, average G's, weight of piston/assembly, compression ratio, peak cylinder pressure, rpms, yadda yadda. To say an engine is going to blow at x piston speed is ridiculous.
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so, if i was going to swap, it would be better to have a lower revd K24 engine than a high revd K20
you need to remember that a k24 at 7600rpm has a higher piston speed than a S2K engine at redline. If you want to grab your crotch and say you can rev higher, then get the K20. But if you want power where it counts and still be reliable, get a K24A2 and feel the torque. Though i hate to bring it up, there really is no replacement for displacement when you get down to it. 
2.0L vs. 2.4L which would you choose?
Personally i'm going with the TSX engine, hopefully when cam manufacturers get off their asses I can put a nice valvetrain set in there to top it off, if not i'll just use a K20 head.
2.0L vs. 2.4L which would you choose?Personally i'm going with the TSX engine, hopefully when cam manufacturers get off their asses I can put a nice valvetrain set in there to top it off, if not i'll just use a K20 head.
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7,171 Posts
I believe all you have to do is install the RSX-S valve train in the TSX head and you are good to go with any of the aftermarket cams out there. Maybe change the valve seats to, I think that is all Ron said you had to change.Kracer427 said:you need to remember that a k24 at 7600rpm has a higher piston speed than a S2K engine at redline. If you want to grab your crotch and say you can rev higher, then get the K20. But if you want power where it counts and still be reliable, get a K24A2 and feel the torque. Though i hate to bring it up, there really is no replacement for displacement when you get down to it.
Personally i'm going with the TSX engine, hopefully when cam manufacturers get off their asses I can put a nice valvetrain set in there to top it off, if not i'll just use a K20 head.
and I will be using the K24a2 as well...
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7,171 Posts
well you brought this thread back from the dead...jon v said:
but to ansewer your question, yes the RSX valvtrain is swappable in to the TSX head. the heads are almost identical castings except the TSX intake ports are a little smaller than the RSX's. If you want to upgrade the valvetrain to OEM RSX or any other combo of OEM or aftermarket parts, all you need to do is change out the valve seats, and from there just install eveything as it would be on the K20 head...
If you are going to mess with the valve train you might as well just go aftermarkety and get some good springs and retainers, so you can be ready to upgrade the cams in the future... Thats just the way I look at it though. Ron's IPS recomended OEM valvetrain setup is rated to handle his cams which are some of the sickest street cams available, so eigther way would work...
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