The Big Rod Discussion!

[Frank]

I should slap you. You missed what I was saying. Why do you say you must have aluminum in a race car? On what basis does everyone say you must have aluminum? Its not like you can buy super light pistons and pins....

[turbovanman²]

I should slap you. You missed what I was saying. Why do you say you must have aluminum in a race car? On what basis does everyone say you must have aluminum? Its not like you can buy super light pistons and pins....

You could try,

I missed nothing, your response was nothing but innuendo. I didn't say you must have aluminium but did you read his goals, 8000 rpm, to me, that would make a need for light rods? yes/no?

Eagle makes a great rod, we all know that, I would tend to believe that K1's are miles ahead, would you also not agree? if the goal is ultimate life, etc, I would say based on company reputation, then Carrillo would be the top choice, again, would you not agree?

[Frank]

Not the point. Aluminum rods while lighter and in tern allow you to rev easier have less strength. At 8k rpms, if I can't buy a light weight piston and pin, whats the point of an aluminum rod if I run the higher chance of breaking the rod compared to keeping with our common forged piston and say K1's.

My problem is someone tells someone to run aluminum without looking at the system as a whole when next to no one has run aluminum at those RPMs is not wise. It could very well be fine, but until you consider all aspects of the system even if they turn out to be null and void....

Frank

[turbovanman²]

Not the point. Aluminum rods while lighter and in tern allow you to rev easier have less strength. At 8k rpms, if I can't buy a light weight piston and pin, whats the point of an aluminum rod if I run the higher chance of breaking the rod compared to keeping with our common forged piston and say K1's.

My problem is someone tells someone to run aluminum without looking at the system as a whole when next to no one has run aluminum at those RPMs is not wise. It could very well be fine, but until you consider all aspects of the system even if they turn out to be null and void....

Frank

Exactly, his engine build up is vague at best, throwing out idea's, thats what we are here for and since only you and I have answered, his info is limited at best.

[Speedeuphoria]

Pauter Billet Rods are another option
http://www.pauter.com/billet_rods.htm

they run ~$700-800 a set

they normally have them in stock for the SRT4(so any Dodge 2.4) I have the weights that I'll post later on when I find my info

[Mario]

Bottom line IS if he has the cash for this "600HP" 8V, he has the cash to go with whatever rods he chooses, whether it be titanium, aluminum, steel, or lead (joke, haha).

I really wasn't being all that serious, I just thought I'd throw something out there. As Frank said, it really depends on the application.

Isn't titanium, really the best though?

[8valves]

Isn't titanium, really the best though?

Once again, totally application specific.

I'd venture to guess that above 7500 rpms in our engines, 2.5 need not apply, playing with geometry is probably a better bet than all out weight savings. Get a slightly longer rod with a rasied wrist pin location to let it want to live a little better up high.

[Directconnection]

That's my view on it.

[GLHNSLHT2]

ok, sorry for being vague. While aluminum rods would be much lighter I do plan to drive this thing whenever I want. Engine specs, 2.2 Forged crank Commonblock, JE pistons, scraper/windage tray blah blah all the other block tricks. For the head, 16v Maserati head, ported, lightweight valvetrain components (titanium retainers, dual race springs lighweight buckets etc.) and oversize valves, The exhaust valves are inconel, not sure on the intake. Ported exhaust manifold (flows over 700cfm according to the guy porting) I know it made the stock head flow 15cfm more just by bolting the stock exhaust manny on mmmmmmm. Ported intake stock intake manifold with bigger plenum and larger TB. GT35R turbo with 4" exhaust, external gate etc. Right now planning on going with a water/air i/c with 3" plumbing. As soon as aftermarket cams are available they will be bolted in.

Rods are the only unknown variable right now. I was thinking of using the masi crank as the rods are beautiful but the crank is too heavy and the bearings aren't as wide on the big end. I'd like something that will meet my goals while being as cheap as possible. The money I can save might be better spent elsewhere ya know.

I've looked at Pauter and they look really nice. And at about half the price of Carrillo's that'd be nice too. Are SRT4 rods longer or shorter than T2 rods? I was also thinking that having a slightly longer rod (would .050 be too much?) would be benificial and not hurt the strenth of the piston.

I also would like to stick with a steel rod. Aluminum is nice but only if you're gonna tear the motor down once a year. Titanium is a bit out of my price range . I'm not going to be tooling around town. When it get's driven it's gonna be driven hard Might even be a competitor for SCC's Ultimate Street Car Challange if I can get enough tire under it. Thanks guys.

[Mario]

Ahh, 16V.

[turbovanman²]

The SRT rod is the same length as our T2 rods, the Eagle version weights like 150 grams less, check out my FAQ on weights. Use need to use SRT rod bearings but the wrist pin end is .866 so you need custom pistons like I am having done or remove the bronze bushing and run metal on metal, which would be fine too.

I would see if you could get lighter pistons made and maybe use some titanium or casdium? wrist pins, there 20-40 grams lighter than our steel ones.

Rods, not an expert but maybe give Pauter a call, for $700-800 bucks, sounds like a good deal.

[TurboJerry]

Put a 3.250" stroke in it and it will make really good top end power. (or at least make the stroke the same dimension as the bore)Aluminum rods are not weaker, they just have a limited life cycle. You can put 5000 hp on them, but when the life cycle is up, they will break. I prefer steel rods only because of street use. Steel is much heaver then aluminum, so there is a big weight savings. Any exotic metal rods have a limited life span. Eagle rods would be fine for 99.9% of applications. Running a rod and pin steel on steel will start to gall if run for a longer periods of time.

[glhs727]

agreed, on the Eagles do NOT remove bushing and run the wrist pin as Simon suggested.
Rebush the small end and open bushing for new pin.
later,
Cindy

[turbovanman²]

agreed, on the Eagles do NOT remove bushing and run the wrist pin as Simon suggested.
Rebush the small end and open bushing for new pin.
later,
Cindy

I have talked to some of my hipo shops that build insane motors that live and they say it won't be an issue. There is also not enough material on the small end to safely make it bigger for .901 pins.

[2.216VTurbo]

Ahh, 16V.

Ahh, MASI 16V

Jay Joined the 'club' a few months ago

[Reaper1]

I know that it is REALLY expensive...and most of us would never try this, but what about titanium rods? Lighter than steel, stronger than aluminum, and less bunky than aluminum. Also, you don't run in to the "life cycle" issue.

I've asked about using aluminum rods on a street motor. It *can* be done. You just have to be careful. The big issue was back in the day the aluminum wasn't as good of anb alloy and would work harden over time, making it brittle as well as making it so you had to allow for a lot of stretch for high rpm. Nowdays the newer alloys are much better and have quelled these issue to an extent. Would I suggest this for a DD? NO! But for a weekend warrior that has fun and drives it once ina while to work and such..no biggie....

[8valves]

I know that it is REALLY expensive...and most of us would never try this, but what about titanium rods? Lighter than steel, stronger than aluminum, and less bunky than aluminum. Also, you don't run in to the "life cycle" issue.

I've asked about using aluminum rods on a street motor. It *can* be done. You just have to be careful. The big issue was back in the day the aluminum wasn't as good of anb alloy and would work harden over time, making it brittle as well as making it so you had to allow for a lot of stretch for high rpm. Nowdays the newer alloys are much better and have quelled these issue to an extent. Would I suggest this for a DD? NO! But for a weekend warrior that has fun and drives it once ina while to work and such..no biggie....

I think people are looking at this the wrong way possibly. Steel rods are not obsolete whatsoever, and just because he wants to run up to 8K doesn't mean that all the weight in the world needs to be done away with.

Taking stroke into account, a steel rod can live to much higher than 8K. Heck, a stock B16A Honda turns 8600, and stock motors with removed limiters will go as high as 9400.

It's not the material, it's the geometry. Pauter, Crower, and I believe Carrillo will make you any rod you want, you just have to wait for a bit and give them dimensions... if they're wrong that's your problem. They're not out of this world expensive either. If you're going to such extents I would invest in a strong set of steel rods and go with the longer rod. Take or send a stock piston to a manufacturer such as Wiseco who will make a custom piston and ask how much higher can the pin go without sacrificing strength. That answer plus a stock rod will give you your new rod length. Voila, same displacement, less bottom end torque, more top end HP.

[Frank]

Eactly! Geometry is everything... it determines how fast the piston must slow down, how much bending the rod must endure on the down stroke, and how fast the piston must slow down.

[Directconnection]

I have talked to some of my hipo shops that build insane motors that live and they say it won't be an issue. There is also not enough material on the small end to safely make it bigger for .901 pins.

I have not seen one metal on metel full floating setup here in this shop and would advise against that idea as well. You would need to find a bushing for a different application which fits in the small end's bore that has alot of material in it so you could bore/hone the bushing to the new smaller size.

[Directconnection]

I know that it is REALLY expensive...and most of us would never try this, but what about titanium rods? Lighter than steel, stronger than aluminum, and less bunky than aluminum. Also, you don't run in to the "life cycle" issue.

All out lightweight STEEL rod is the Crower Maxi-lite. Not sure of the forging material, but it is the cat's meow of steel rods in the circle track region. Not Ti though and is very strong and light (and $$)