Do i need to be forged to run high revs?

A

AdamB

Member +
pilgrim_fgau said:
is it not that gt rods are thicker, although glanza rods are thinner, they are made of a more lightweight and stronger material, but being thinner this sort of balances the two different types out?

I remember reading that on here not so long ago...
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It's not rev's that kill rods it's boost. You run too much boost and the rods will end up like a banana. Seen it happen before. Rev's kill engines if you don't adjust the timing to suit.
 
starletgtturbo1

starletgtturbo1

Member +
Revs kill con rods a lot more than people give them credit for, often the failure actually occurs on after the exhaust stroke when there is no pressure above the piston and the rod/bolts have to take all the strain of reversing the direction of the piston, its this stretching that kills rod bolts in particular.
 
B

buckets

Member +
starletgtturbo1 said:
Revs kill con rods a lot more than people give them credit for, often the failure actually occurs on after the exhaust stroke when there is no pressure above the piston and the rod/bolts have to take all the strain of reversing the direction of the piston, its this stretching that kills rod bolts in particular.
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so better to forge the engine if thinking of revving that high what about the springs in the head are they able?
 
perreau

perreau

Member +
So to avoid all these doubts..........go all the way forge everything :)

BUT, we will never know the minimum mods needed to get high revs will we?
 
spuddy

spuddy

Ulster Area Rep.
starletgtturbo1 said:
Revs kill con rods a lot more than people give them credit for, often the failure actually occurs on after the exhaust stroke when there is no pressure above the piston and the rod/bolts have to take all the strain of reversing the direction of the piston, its this stretching that kills rod bolts in particular.
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Exactly.

Just think of the speed a piston is traveling in the bore and then having to come to a complete stop and then back the way it came accelerating at a god awful speed. The G-forces exherted on the gudgeon pin and rod can soon go up to 1000Gs, that means the piston can weigh 1000 times more at that point.

Wee read for those that are interested.
http://www.eng-tips.com/viewthread.cfm?qid=85349
 
A

AdamB

Member +
starletgtturbo1 said:
Revs kill con rods a lot more than people give them credit for, often the failure actually occurs on after the exhaust stroke when there is no pressure above the piston and the rod/bolts have to take all the strain of reversing the direction of the piston, its this stretching that kills rod bolts in particular.
Click to expand...

Agreed and rep for you.

Saying this though generally turbocharged engines don't tend to rev that high that rod bolts wiggle their way loose.
I think that people tend to raise boost before they raise the rev limit, and by the time they raise the boost it is a thoughtful process wether to go forged or not due to the boost pressure. And when going forged ARP bolts are used.
 
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