amrksh

Which is better and why?

4g63

wreckless969

iTrader: (11)

Heres a good write up.

http://forums.corvetteforum.com/c3-t...beam-rods.html

03whitegsr

iTrader: (8)

That pretty much sums it up.

The H-beams however hold up in the sub-600 HP cars very well and they are cheaper. If you just want something a bit stronger then stock, but still on the budget side, H-beams will get the job done.

bbyevo8u

iTrader: (14)

I-beams ftw

L888Apex

iTrader: (94)

"Connecting Rods

Catering for the market's demands is PAR's innovative I-beam connecting rod. Physics tells us that an I-beam will carry more weight/load than the same size H-beam. A great example is the use of I-beam girders in the building industry, you will not find an H-beam girder used to support a ceiling or wall."

http://www.par-engineering.com/secti...TypeId=Conrods

03whitegsr

iTrader: (8)

If you read all of that thread posted and follow the links to other discussions in it, it gets good and informative.

In the end though, I believe it ultimately comes down to quality of the product and rod bolt material.

Carrillo makes great rods with their Pro-H being the flagship rod. Carrillo made a name for themselves by having exceptionally high quality standards. From machining tolerances to surface finish, they make a great product. It shows, Carrillo Pro-H rods are used in some of the fastest turbo imports in the world.

Yet I've seen somebody replace the Carrillo rod bolts with "better" ARP2000s and toss a rod out the side of the block in no time...

A great rod and a **** fastener is just a ticking time bomb.

wreckless969

iTrader: (11)

With that said, all things beling equal I beam appear to be superior to H Beam.

Ted B

iTrader: (6)

That's the long and short of it. One critical aspect of 'quality' is the metallurgy, and whether it be the rod or the fastener, one gets what he pays for in this realm. Some can get away with the 'cheap seats'. For others, it's a death wish.


A quality billet I-beam rod is always the top choice for our motors, simply because drawing tremendous torque from a 4-cyl means each rod is being subjected to very high loads.


I would no more cheap out on a set of rods and fasteners than step into an elevator in the Empire State Building that's operated by a cable bought from Harbor Freight.

JC evo1

If the cable is used well within its limits even though its not the absolute best cable available would you step into the elevator?

Ted B

iTrader: (6)

If the cable failed to pass metallurgical verification testing 60% of the time, that wouldn't make me feel confident.

94AWDcoupe

iTrader: (125)

careful guys. lots of misinformation in those links.

I will start with the pac guy. sounds great but his argument is flawed. of course you dont see H beams as steel girders. but its not because the H beam flexes more its because the I beam has a wider surface to mount the floor too. imagine two 6 ft beams laid out supported on both ends. one H and one I beam. which would you rather stand on? standing on top of the H is gonna hurt. I will stand on the I any day. if you did stand on the H the beam would flex less than standing on the I.

Love that post on the corvette forums. Did anyone even ask if he calculated the I =stiffness correctly? well he didnt. he is way off. given the same cross sectional area. (.439) the H beam is stiffer in the N and S direction. Which would make it a stiffer rod in your engine. and a stiffer beam in the paragraph preceding.

lets take a 6 ft long piece of steel .200 thick and 1.5 inch wide. and a second .150 thick and same
1.5 wide. the .200 inch thick piece is stiffer is it not? now look at those pictures again. clearly the I beam is .150 thick. and the H beam is .200 thick.(.100 x 2)

connecting rod need to be stiffer in the N and S direction than it does in the E and W. The I beam would be stiffer than the H beam in the E and W direction.

comparing connecting rods by simply stating one designed shape is better than another is really pointless. what counts most is the quality of the steel used. there was a show I saw last month on how Japan makes the samurai sord. the process was off the charts interesting. unbelievable how long it takes to make a sword. the forging process was extremely interesting and very informative.

problem with these manufactures is there is no way to gauge how strong rods are from any data given by these manufactures. I am sure there are billet rods out there that are stronger than some forged ones. and heck the manufactures arent being honest on the process used. its mostly fancy advertising that sells rods. I see some china made rods claiming they are forged.. imagine that.

The only real way to prove which rods are better is to actually test them against each other. that could be done but it sure wouldnt be cheap.

03whitegsr

iTrader: (8)

Huh...

I don't think you know how to figure out the moment of inertia correctly. His numbers seem inline to me with just a few quick simplified calcs.

The I beam is definitely stiffer for the given mass then the H-beam when bending about the horizontal line.

Simply put, the further away the material is for the neutral axis, the stiffer it is. If you look at some of the F1 rods that are linked in that thread, it gets pretty interesting. They start to use a shape that puts more material out at the corners and removes it from the middle. It basically increases the bending stiffness in BOTH directions while keeping weight down. I don't see any aftermarket rods for the 4G63 doing that, yet it makes the most sense.

As for twisting a rod about it's length, I don't see how people are saying the H-beam is stiffer. Which ever rod has the thinnest cross-section is going to be the least stiff to torsion. H-beams are usually a lot thinner on their minimum dimension.

I'm with Ted here. Material is king. Material and heat treat for strength, surface finish/surface processing for long-term durability.

Neither of these you can see with your naked eye (unless one is just completely unacceptable).

JC evo1

Why is it that Carrillo are pretty much the only rod manufacturer to offer a high end H beam?

Erik@MIL.SPEC

iTrader: (94)

They're not.

miragevo

iTrader: (21)

The Carillo H-Beams are 574 grams with the upgraded Carillo rod bolts and direct from Carillo, can handle 1000+ hp. Why do we need an I-Beam that weighs 100 grams plus? How many are producing 1000+ hp?