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H beam vs I beam
hey guys couldn’t find any info on this but my engine builder texted me last night he’s gonna throw in a set of 4340 I beams for free cause he thinks the stock titanium ones won’t handle 600-700whp what do you guys think? I couldn’t find much information on this. What are the stock rods capable of? Am I gonna see a difference in racing with heavier rods? My goals is to be NA then either stay NA or add boost or nos down the road if I wanted to. 11:1 compression |
Would you first care to elaborate of why the motor is being rebuilt in the first place? The rods are not the weakest link in the motor- no idea why you'd replace them unless side wear has been found. Most, if they're making the bottom end more stout, replace the pistons (weakest link in the bottom end). If you're NA with stock compression (11:1), just leave the stock rods.
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Originally Posted by encasedmetal
(Post 1597030694)
Would you first care to elaborate of why the motor is being rebuilt in the first place? The rods are not the weakest link in the motor- no idea why you'd replace them unless side wear has been found. Most, if they're making the bottom end more stout, replace the pistons (weakest link in the bottom end). If you're NA with stock compression (11:1), just leave the stock rods.
but I’m doing a ls7 again with diamond pistons. But my builder wants to change the stock rods. He’s asleep so I can’t ask him why but I want 600whp NA again and then down the road do a blower for 700-800whp or a nos shot with e85 and c16 but most likely I’ll just be NA trying to hit 600whp+ or 140+ in the quarter mile |
The stock LS7 Ti rods will handle 600-700whp without issue. That isn't the weak link in an LS7.
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Originally Posted by lt1z
(Post 1597032054)
The stock LS7 Ti rods will handle 600-700whp without issue. That isn't the weak link in an LS7.
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Originally Posted by Must_Have_Z
(Post 1597033109)
^This. If your builder thinks the stock rods won't handle 600-700 I'm not sure I'd trust him working on my LS7.
oh oh trust me lol he prob knows more than 99% on this forum but I like to hear from others as well and he got back to me he says there hasn’t been enough testing to know these rods will last 600-700whp for ever and since I might go with no’s or boost he doesn’t like the stock rods for it they were meant for 505 crank hp. I also talked to Cunningham Motorsports in so cal and they said not to use any boost or nos on stock rods if you want them to last for ever they just were not built for it. They said they can take 800whp NA but not boosted or sprayed the way the torque comes in just beats them down from what I was told i think it’s cause he knows I’m also putting every penny into this and doesn’t want the same thing happening again so hes giving me some free I beams to help me with my build this guy is so nice that he isn’t charging me for my new btr4 cam and head work. But me as I am I’m gonna pay him all back for it. Just how I am wish there were more people like my engine builder. |
Yeah stock rods are total trash, Ti is very dangerous too. Wrap them up carefully in bubble wrap and send them to me and I will dispose of them properly for you, no charge.
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Originally Posted by MikeOC
(Post 1597033508)
Yeah stock rods are total trash, Ti is very dangerous too. Wrap them up carefully in bubble wrap and send them to me and I will dispose of them properly for you, no charge.
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Titanium rods are great for high rpm applications, but if you're going to have high compression loads from boost or n2o, then steel is better, with h-beams generally stronger than i-beams.
Aluminum fatigues the fastest, then titanium, and then steel. I think you're more likely to break a ring or ring land than a rod, even if you're using nitrous. If this builder of yours is willing to give you "free" i-beam rods, that means you get to keep your stock Ti rods, correct? If he's talking a swap, I'd say hell no. |
As everyone else has said, the stock rods don't seem to be a problem. They're also only 464 grams a piece (https://www.corvetteactioncenter.com.../06232006.html) which is significantly lower than most other after market steel rods. Someone correct me if I'm wrong, but it seems that before the rods, the weaker points are the pistons and the cylinder sleeves (though you don't need to resleeve at your power level goal).
btw I don't understand the thread title. The LS7 uses I-beams, and your tuner was gonna use I beams as well. |
Originally Posted by SivaSuryaKshatriya
(Post 1597034427)
As everyone else has said, the stock rods don't seem to be a problem. They're also only 464 grams a piece (https://www.corvetteactioncenter.com.../06232006.html) which is significantly lower than most other after market steel rods. Someone correct me if I'm wrong, but it seems that before the rods, the weaker points are the pistons and the cylinder sleeves (though you don't need to resleeve at your power level goal).
btw I don't understand the thread title. The LS7 uses I-beams, and your tuner was gonna use I beams as well. |
Originally Posted by 427V8BB
(Post 1597033171)
oh oh trust me lol he prob knows more than 99% on this forum but I like to hear from others as well and he got back to me he says there hasn’t been enough testing to know these rods will last 600-700whp for ever and since I might go with no’s or boost he doesn’t like the stock rods for it they were meant for 505 crank hp. I also talked to Cunningham Motorsports in so cal and they said not to use any boost or nos on stock rods if you want them to last for ever they just were not built for it. They said they can take 800whp NA but not boosted or sprayed the way the torque comes in just beats them down from what I was told i think it’s cause he knows I’m also putting every penny into this and doesn’t want the same thing happening again so hes giving me some free I beams to help me with my build this guy is so nice that he isn’t charging me for my new btr4 cam and head work. But me as I am I’m gonna pay him all back for it. Just how I am wish there were more people like my engine builder. Then why are you asking the question?? The 1% (as you claim) that knows more than your builder has already blocked you... |
Originally Posted by Undy
(Post 1597037376)
Then why are you asking the question?? The 1% (as you claim) that knows more than your builder has already blocked you...
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Originally Posted by 427V8BB
(Post 1597036245)
builder* he said he hasn’t seen enough evidence for it to be safe. They were built for a NA 505hp motor |
Originally Posted by SivaSuryaKshatriya
(Post 1597038582)
yeah and the 2jz was built for 276 HP but can do much more than that stock. My point is it isn't uncommon for stock motors to be capable of more than stock. Anyhow, there is no evidence the stock rods are the failure point at that level. And given how light they are, they're one of the last components I'd be trying to replace with aftermarket.
of course, he’s telling me this I beam and my piston it will be on the money. Same weight as stock |
Originally Posted by 427V8BB
(Post 1597036245)
builder* he said he hasn’t seen enough evidence for it to be safe. They were built for a NA 505hp motor |
No one really knows the exact, or even close yield point of these rods. People claiming to know it, are generally full of shit. There are some owners who have used them in builds that make over 1000whp. I certainly wouldn't recommend that, but they did hold up....at least for a little while.
Your builder is being conservative. He's being smart and I share his opinion - at least with you. You are all over the board with what you want to do and what your goals are. I'd build this engine hell for stout just because of this. You'd have Darton sleeves, forged pistons and a new crank. The thread title, I or H beam is an entirely different argument. A good one too, but not worth getting into in this thread. These Ti rods serve a purpose. Going heavier will reduce the longevity of this engine. I would not swap them out if staying N/A. Boost or spray?......I probably would swap them out. |
Originally Posted by 427V8BB
(Post 1597038727)
of course, he’s telling me this I beam and my piston it will be on the money. Same weight as stock |
Originally Posted by Must_Have_Z
(Post 1597033109)
^This. If your builder thinks the stock rods won't handle 600-700 I'm not sure I'd trust him working on my LS7.
Consider who's asking the builder; look at the posters history |
I sold my LS7 bare block and had HPR rebuild a Darton sleeved block with CP pistons and i reused my Ti rods and crank. I generally use my Z06 n/a the majority of the time but I wanted a build that would allow me to spray up to a 250 shot in 1/2 and 1/4 mile events 5 to 10 times a year. You really need to figure out your goals first. I would not reuse the rods in a boosted application. If if I ever have a failure with this motor I will go back to HPR and buy their 468 shortblock. |
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