longer rods = higher rev?
05-10-2008, 05:27 PM
#26
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right, im not talking about chaning the distance.
i want to rev high. im asking whats easier on the engine, so i can rev higher. im not talking about changing the rod length to change the piston's traveling distance. but i would think that the taller rods would increase C/R slightly?
i want to rev high. im asking whats easier on the engine, so i can rev higher. im not talking about changing the rod length to change the piston's traveling distance. but i would think that the taller rods would increase C/R slightly?
05-10-2008, 05:27 PM
#27
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No... you will be decreasing COMPRESSION. With the shorter rod... the piston will still move the same distance (hence, the same amount of STROKE)... but it just won't be doing it in the same spot.
If you want Higher Revs though... you don't Stroke... you DESTROKE. And you could do that by installing the LSJ Crank & Rods... but then you need a new Flywheel, etc... it gets complicated.
If you want Higher Revs though... you don't Stroke... you DESTROKE. And you could do that by installing the LSJ Crank & Rods... but then you need a new Flywheel, etc... it gets complicated.
05-10-2008, 05:28 PM
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05-10-2008, 05:30 PM
#30
88958620 Ecotec Billet Crankshaft
MSRP: $4,948.57 Your Price: $3,679.90
This full race billet 4130 steel crankshaft comes internally balanced and uses a 1.888 inch rod bearing and a stock main bearing size. The stroke is reduced to 3.505 inches for high RPM use. This will result in approximately 2.0 liters of displacement when used with a 3.400 inch bore.
05-10-2008, 05:30 PM
#31
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let me just ask this, because this is getting confusing.
can i rev to 8000 with my factory crank/rod dimensions (aftermarket rods of course)?
so i can just get taller pistons to achieve my C/R desired?
can i rev to 8000 with my factory crank/rod dimensions (aftermarket rods of course)?
so i can just get taller pistons to achieve my C/R desired?
05-10-2008, 05:31 PM
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05-10-2008, 05:34 PM
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hmm.. think i can get to 250 hp at the flywheel with that setup revving at 6500?
Last edited by bridfi; 05-10-2008 at 05:34 PM. Reason: Automerged Doublepost
05-10-2008, 05:36 PM
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i want to have that kind of power all day, not only when i hit a button.
05-10-2008, 05:43 PM
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http://auto.howstuffworks.com/engine1.htm
watch the video, and keep this in mind:
from P to O is stroke.
from O to M is rod length.
M, being the piston, if taller, will compress the gas/air mixture more, compared to a shorter piston.
05-10-2008, 05:53 PM
#42
...I dunno, 100 hp with just high compression pistons doesn't seem feasable. you could get closer to that with head work though, you could do cams, porting, valves and springs maybe...I also am no expert, i just have some mechanical knowledge(as for these particular computerized enginges though I don't know much)
05-10-2008, 05:54 PM
#44
...I dunno, 100 hp with just high compression pistons doesn't seem feasable. you could get closer to that with head work though, you could do cams, porting, valves and springs maybe...I also am no expert, i just have some mechanical knowledge(as for these particular computerized enginges though I don't know much)
NAWZ or F/I is your answer.
05-10-2008, 05:56 PM
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You can get longer rods without changing the crank and it will allow you to rev to a higher rpm. However, you will need to get the rods custom made and then have the pistons custom made to match.
For example, if you wanted rods that were 5mm longer, you would have to get custom made pistons with a pin hight that was 5mm lower. And since your getting custom made pistons, you can get them in almost any CR you wanted.
To clear something up here, if you want higher revs, it is: Shorter Stroke, Longer Rods
I would suggest a full valve train replacement, head work, neutral balance shafts, and cam as well. You have to make sure your engine can breath well enough to go to the higher rpms and that you have enough cam to make power there.
For example, if you wanted rods that were 5mm longer, you would have to get custom made pistons with a pin hight that was 5mm lower. And since your getting custom made pistons, you can get them in almost any CR you wanted.
To clear something up here, if you want higher revs, it is: Shorter Stroke, Longer Rods
I would suggest a full valve train replacement, head work, neutral balance shafts, and cam as well. You have to make sure your engine can breath well enough to go to the higher rpms and that you have enough cam to make power there.
05-10-2008, 05:57 PM
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05-10-2008, 05:57 PM
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05-10-2008, 05:58 PM
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Heres one of those ricer calculators to figure out static compression ratio horsepower increases. No idea how accurate it is which is why I call it ricer.
http://www.wallaceracing.com/hp-cr-chg.php
http://www.wallaceracing.com/hp-cr-chg.php
05-10-2008, 06:03 PM
#50
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You can get longer rods without changing the crank and it will allow you to rev to a higher rpm. However, you will need to get the rods custom made and then have the pistons custom made to match.
For example, if you wanted rods that were 5mm longer, you would have to get custom made pistons with a pin hight that was 5mm lower. And since your getting custom made pistons, you can get them in almost any CR you wanted.
To clear something up here, if you want higher revs, it is: Shorter Stroke, Longer Rods
I would suggest a full valve train replacement, head work, neutral balance shafts, and cam as well. You have to make sure your engine can breath well enough to go to the higher rpms and that you have enough cam to make power there.
For example, if you wanted rods that were 5mm longer, you would have to get custom made pistons with a pin hight that was 5mm lower. And since your getting custom made pistons, you can get them in almost any CR you wanted.
To clear something up here, if you want higher revs, it is: Shorter Stroke, Longer Rods
I would suggest a full valve train replacement, head work, neutral balance shafts, and cam as well. You have to make sure your engine can breath well enough to go to the higher rpms and that you have enough cam to make power there.
Heres one of those ricer calculators to figure out static compression ratio horsepower increases. No idea how accurate it is which is why I call it ricer.
http://www.wallaceracing.com/hp-cr-chg.php
http://www.wallaceracing.com/hp-cr-chg.php