Rev limit on the 4g64 crank
http://mitsuoafl.com/board/showthread.php?t=9293-30psi stockeverything 4g64 motor without evo8 head,
http://mitsuoafl.com/board/showthread.php?t=8980-25psi video stock 4g64
http://mitsuoafl.com/board/showthread.php?t=8673-And this is a dyno that i found quickly. THIS IS HOW MUCH POWER IT MAKES WITHOUT THE EVO8 DOHCAMS
so my point hail to the 4g64 and bow..lol
http://mitsuoafl.com/board/showthread.php?t=8980-25psi video stock 4g64
http://mitsuoafl.com/board/showthread.php?t=8673-And this is a dyno that i found quickly. THIS IS HOW MUCH POWER IT MAKES WITHOUT THE EVO8 DOHCAMS
so my point hail to the 4g64 and bow..lol
Last edited by Karacing; Feb 1, 2007 at 07:34 AM.
I would say 7900 with good rods/rod bolts, and light weight pistons with upgraded wrist pins.
I have seen and know a few to go to 8700-9000 with the 100mm stroke and it just baffles my mind.
I have seen and know a few to go to 8700-9000 with the 100mm stroke and it just baffles my mind.
To keep it safe I say 7300-7600 rev limit any higher the rod ratio starts exceeding that of Formula 1 race cars.
Evolving Member
Joined: Nov 2006
Posts: 255
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From: Tampa, Florida
The prevailing consensus in the race engine industry is that durability takes a real dive above piston speeds of 25 m/sec, and piston ring sealing efficiency takes a dump around 30 m/sec.
For any 100mm stroke crank, 25 m/sec works out to 7500rpm. Unless one has deep pockets, a lift, engine building equipment/skills, and access to spares, adhering to that figure is wise advice. Spinning any motor faster than necessary is the quickest way to kill it, and high rpm coupled with the short rod/stroke ratio (1.5:1) of conventional 100mm 4G63 strokers doesn't make a recipe for either efficient high rpm operation or longevity.
For any 100mm stroke crank, 25 m/sec works out to 7500rpm. Unless one has deep pockets, a lift, engine building equipment/skills, and access to spares, adhering to that figure is wise advice. Spinning any motor faster than necessary is the quickest way to kill it, and high rpm coupled with the short rod/stroke ratio (1.5:1) of conventional 100mm 4G63 strokers doesn't make a recipe for either efficient high rpm operation or longevity.
Evolving Member
Joined: Aug 2005
Posts: 282
Likes: 0
From: Mooresville, NC
The prevailing consensus in the race engine industry is that durability takes a real dive above piston speeds of 25 m/sec, and piston ring sealing efficiency takes a dump around 30 m/sec.
For any 100mm stroke crank, 25 m/sec works out to 7500rpm. Unless one has deep pockets, a lift, engine building equipment/skills, and access to spares, adhering to that figure is wise advice. Spinning any motor faster than necessary is the quickest way to kill it, and high rpm coupled with the short rod/stroke ratio (1.5:1) of conventional 100mm 4G63 strokers doesn't make a recipe for either efficient high rpm operation or longevity.
For any 100mm stroke crank, 25 m/sec works out to 7500rpm. Unless one has deep pockets, a lift, engine building equipment/skills, and access to spares, adhering to that figure is wise advice. Spinning any motor faster than necessary is the quickest way to kill it, and high rpm coupled with the short rod/stroke ratio (1.5:1) of conventional 100mm 4G63 strokers doesn't make a recipe for either efficient high rpm operation or longevity.
my 250 at 20k doesn't even hit 25m/s
Good info Ted! I assume those speed specifications on durability take into account having light weight pistons and rods and that a stock 4g64 would really be in sad shap if you reved it to 7500 very often due to the heavier stock parts correct?
Keith
Keith
Yes, that is definitely a safe assumption.
Evolving Member
Joined: Aug 2005
Posts: 282
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From: Mooresville, NC
