Weak link = connecting rods
06-19-2004, 04:04 PM
#22
Most high performance rods are forged steel. By billet...are you talking billet aluminum??
AL is lighter, but steel is much stronger, and I havent seen too many...if any...billet aluminum con-rods. Aluminum..even forged...doesnt have the tensile (side by side breaking) strength of forged steel. But I dont have a whole lot of experience with engine building...so someone else can chim in. It's always a trade off between strength and weight. Of course, if money is no object, you can go with forged titatium pistons (the M3 comes stock with these). They are about as light as AL, but stronger than steel.
Typically, I see forged steel rods, and forged aluminum pistons....thats what 95% of the people go with.
AL is lighter, but steel is much stronger, and I havent seen too many...if any...billet aluminum con-rods. Aluminum..even forged...doesnt have the tensile (side by side breaking) strength of forged steel. But I dont have a whole lot of experience with engine building...so someone else can chim in. It's always a trade off between strength and weight. Of course, if money is no object, you can go with forged titatium pistons (the M3 comes stock with these). They are about as light as AL, but stronger than steel.
Typically, I see forged steel rods, and forged aluminum pistons....thats what 95% of the people go with.
06-21-2004, 05:39 AM
#23
Research results:
Cast vs. Billet vs. Forged:
A cast piston is when molton metal is poured into a cast.
A billet is simply a solid piece of material that is shaped into it's finished form by machining. Most finished products are either cast or molded into shape. A billet is a raw block of material.
A forged piston is when an already solid piece of metal is forced into a certain shape. it could be forced into the shape of the wheel or it could be a block of metal that was spun on a lathe and mill into the shape.
Generally forged metal is stronger (like cast vs. forged pistons) and doesn;t have as many impurities or possible weak points. That's why a finish on a forged wheel is usually nicer than the finish on a cast wheel. The cast wheel will sometimes have small airbubbles on the surface that make the surface not look smooth.
..........
I have researched this topic and discovered that BILLET RODS are good for DRAG RACING but are not known for their longevity.
FORGED rods and pistons are good for strength, but they need additional room for expansion and shrinkage (due to heats effect on them).
I have personally experienced CRACKED forged pistons (overheated engine) as well as broken and bent (stock Ford) connecting rods.
BMW's HAVE TITANIUM RODS !!! ????
Does anyone offfer titanium rods for the -Z- ???
Cast vs. Billet vs. Forged:
A cast piston is when molton metal is poured into a cast.
A billet is simply a solid piece of material that is shaped into it's finished form by machining. Most finished products are either cast or molded into shape. A billet is a raw block of material.
A forged piston is when an already solid piece of metal is forced into a certain shape. it could be forced into the shape of the wheel or it could be a block of metal that was spun on a lathe and mill into the shape.
Generally forged metal is stronger (like cast vs. forged pistons) and doesn;t have as many impurities or possible weak points. That's why a finish on a forged wheel is usually nicer than the finish on a cast wheel. The cast wheel will sometimes have small airbubbles on the surface that make the surface not look smooth.
..........
I have researched this topic and discovered that BILLET RODS are good for DRAG RACING but are not known for their longevity.
FORGED rods and pistons are good for strength, but they need additional room for expansion and shrinkage (due to heats effect on them).
I have personally experienced CRACKED forged pistons (overheated engine) as well as broken and bent (stock Ford) connecting rods.
BMW's HAVE TITANIUM RODS !!! ????
Does anyone offfer titanium rods for the -Z- ???
06-21-2004, 09:59 AM
#28
I've milled titanium on a Bridgeport before. It is definately VERY tough. Because of it's tough-ness, it is hard to achieve (not impossible) a high tolerance specification.
It is also difficult to grind since it is not magnetic (easily gripped by a magnetic baseplate or chuck).
Because of this and it's rarity, I can see why it would be so expensive.
Anyone:
The Nismo (forged) pistons are 8.5 to 1. Is this the stock compression?
It is also difficult to grind since it is not magnetic (easily gripped by a magnetic baseplate or chuck).
Because of this and it's rarity, I can see why it would be so expensive.
Anyone:
The Nismo (forged) pistons are 8.5 to 1. Is this the stock compression?
06-24-2004, 11:14 AM
#31
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forged pistons
anyone running a CR less agressively low as 8.5:1 for FI.
Such as 9.5:1. If so , were'd you get em?
Want a stronger bottom end for added boost but not an
off-boost slug.
Such as 9.5:1. If so , were'd you get em?
Want a stronger bottom end for added boost but not an
off-boost slug.
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