Difference between I-beams and H-beams

Matt H.

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May 23, 2005
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I am looking at buying better internals so I can put in a supercharger, so I wanted to know what the difference between I-beams and H-beams, the I-beams are much more expensive so I suspect that they are better, but how?
 
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It is the geometry of the connecting rod. If you were to cut it in half and then look straight down at it, the shape looks either like an I or H. Both are good designs, it just depends on the application you are going for.
 
Yep, I beam rods are desinged for high RPM (8K usually) H beams are designed for higher HP lower RPM engines (7K usually). With the 05 I doubt you will turn over 7K, so i would go H beam...FWI 03-04 cobras are H beam and the red line starts at 6500, meaning the engine can be damaged at anywhere over 6500. But again, depends on what you want, if you dont plan on sending 17+ PSI through it, I beams would be great as you could run it to 7500RPM, and with a centri it would just make more and more power.
 
Thanks for confirming that. One crazy thing is that a guy around town with an 03 spins his all the way to 7400, but we shall see for how long it lasts.

Know, can you explain to me what the "powdered cracked" connecting rods and "hyperneuic" pistons on the 05 are. And yes, I probably spelled those wrong.
 
The powdered rod is what it souds like they take powdered metel and compress it under extream heat and pressure. It makes for a fairly strong rod and it is inexpensive to make.
The hyperutectic pistons are like an average piston. They are not as good as forged but better than cast. They have a higher silicon content in the metal than cast pistons. You can use them in a supercharged motor. The only thing that you have to careful with is detonation. If you are using hyperutectic pistons in a supercharged motor and it detonates it shakes the piston so hard that it knocks the ring lands off of the piston. As long as it doesn't detonate then you shouldn't have a problem. We run superchargers on motors with hyperutectic's all the time with no problems.
 
Cool info, I never knew that.

Can anyone confirm a rumor I heard, that the 05 has the same shortblock as the Machs had? I know the Machs had a forged crank, but I felt certain that the 05s had a standard unit?
 
kmatWhipple said:
The powdered rod is what it souds like they take powdered metel and compress it under extream heat and pressure. It makes for a fairly strong rod and it is inexpensive to make.
The hyperutectic pistons are like an average piston. They are not as good as forged but better than cast. They have a higher silicon content in the metal than cast pistons. You can use them in a supercharged motor. The only thing that you have to careful with is detonation. If you are using hyperutectic pistons in a supercharged motor and it detonates it shakes the piston so hard that it knocks the ring lands off of the piston. As long as it doesn't detonate then you shouldn't have a problem. We run superchargers on motors with hyperutectic's all the time with no problems.
But wouldn't it be worth the extra cash to go with a good set of forged pistons just so you won't have to worry so much about it breaking?
 
alfman9 said:
Cool info, I never knew that.

Can anyone confirm a rumor I heard, that the 05 has the same shortblock as the Machs had? I know the Machs had a forged crank, but I felt certain that the 05s had a standard unit?

It is not the same shortblock as the Machs.
The 4.6 - 3V bloc is a new casting, it's supposed to be stonger than the only Lincoln / Cobra / Mach 4.6 DOHC block.

Also I belive that only manual trannie Machs have a forged crank.
 
You can spent the extra money if you want. However I feel that it isn't absolutly necesary to do. If you are going to get new pistons then you might as well change the compression ratio also. A good set, like ross, can get pretty expensive though. You can pay around 800 dollars for a good set like that