Paxton on Stock Block
Senior Member
Joined: May 2002
Posts: 4,928
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From: The People's Republic of Los Angeles
Originally posted by cpeapea
less torque on the higher end means less stress on the rods, which might enable you to spin it a little higher
just a thought
less torque on the higher end means less stress on the rods, which might enable you to spin it a little higher
just a thought
"The loads on a rod are greatest as the rod makes the downturn from TDC and wants to pull itself apart. Way greater than compressive loads from combustion. And it goes up exponentially with RPMs (remember that when you have your tuner up the rev limiter)."
Longer strokes (like in the 5.4) only make the problem worse. Long stroke or high rpms. Pick one.
Senior Member
Joined: Oct 2001
Posts: 2,456
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From: SE Mich
What Tim says is true. However it's not as simple as the strength of the rods.
Compressive strengths are less than tensile strengths.
But... engines are not comprised of all static parts.
There are harmonics, thermodynamics, delta P's, and acceleration (changing speeds) involved.
A finely balanced motor can reach high rpms if done right. Even ones like ours with stock cast iron rods. I've seen it first hand.
I'd say other than detonation the number one killer is imbalance (for a given rpm) of the whole assembly.
Rich
Compressive strengths are less than tensile strengths.
But... engines are not comprised of all static parts.
There are harmonics, thermodynamics, delta P's, and acceleration (changing speeds) involved.A finely balanced motor can reach high rpms if done right. Even ones like ours with stock cast iron rods. I've seen it first hand.
I'd say other than detonation the number one killer is imbalance (for a given rpm) of the whole assembly.
Rich
Last edited by wydopnthrtl; Jul 31, 2004 at 03:04 PM.
Senior Member
Joined: Jan 2003
Posts: 5,097
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From: DETROIT, (formerly Eaton County, Michigan)
Rich,
what are your thoughts on removing the stock blower pulley (think a few lbs to absorb vibration) and replace it with a 1lb aluminum pulley?
Should we add a fluid (SFI) harmonic balancer? I know RDY2RAC is using one. Would that help reaching the 6000 RPMS?
what are your thoughts on removing the stock blower pulley (think a few lbs to absorb vibration) and replace it with a 1lb aluminum pulley?
Should we add a fluid (SFI) harmonic balancer? I know RDY2RAC is using one. Would that help reaching the 6000 RPMS?
