Strength of ls7 titanium rods?
08-27-2006, 12:05 PM
#61
Originally Posted by Quickin
All they're good for is conversation, as this thread proves.
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08-27-2006, 12:56 PM
#62
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Originally Posted by 11 Bravo
I'm going to have to disagree with you 100%. An LS7 rod weighs 480 grams. An Eagle forged rod, for example, weighs 650 grams. So, the complete set of LS7 rods are 1360 grams less, or almost 3 pounds (2.998). That is a whole lot of rotating mass. Doesn't matter if it is a 450rwhp production engine, or a F1 engine. You are in fact going to make more power and rev quicker. It's just the law of physics. Now weather it's worth the money or not is a matter of opinion. They are proven to not be "brittle" lol, and I would take a set in a heartbeat.
08-27-2006, 01:42 PM
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quickin
I don't see why anyone would want those weaker Ti rods in their engine
I'd agree with you if GM were making a 900 RWHP
08-27-2006, 03:02 PM
#64
Of note NSX engines also have titanium rods in them.... And they run forever.
I would like to see how far the production LS7 rods can go. At the original price they were offered at... it was a great deal. Now if you were to purchase them for $2K+ there won't be hardly any takers.
I put Lunati ProMod Billet rods in my LS7 build up with Wiseco pistons and stock LS7 knife edged crank. I want to be able to spin it to 7500rpm from time to time.
I would like to see how far the production LS7 rods can go. At the original price they were offered at... it was a great deal. Now if you were to purchase them for $2K+ there won't be hardly any takers.
I put Lunati ProMod Billet rods in my LS7 build up with Wiseco pistons and stock LS7 knife edged crank. I want to be able to spin it to 7500rpm from time to time.
08-27-2006, 03:32 PM
#66
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Originally Posted by wvaboy
Ti rods are weak rods but,
it's ok to use if im gonna be makin 900 rwhp in a bad *** vette?
it's ok to use if im gonna be makin 900 rwhp in a bad *** vette?
In a production Vette engine its a complete waste of money because it offers nothing over a steel forged rod. And the question about revving faster is meaningless because its just a tiny 400+ RWHP engine, not some all out badass race engine where every bit counts. Whats it gonna make, another 2 hp????
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08-27-2006, 05:08 PM
#67
Originally Posted by Quickin
read my entire post....high RPM is all they're good for because they're lighter.
Last edited by 11 Bravo; 08-27-2006 at 05:14 PM.
08-27-2006, 05:54 PM
#68
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Originally Posted by 11 Bravo
That's way off. Rotational mass affects acceleration. The more a mass weighs, the more energy it takes to get it rotating. Even on a slow tiny 450hp engine lol. That is just very basic Physics 101. It's Kinetic energy, KE = 1/2 m v2. Three pounds is nothing to thumb your nose at. That's a whole lot of weight saved in the heart of the engine. If LG took the top end package off the Z06 that made 640rwhp and put it on my shortblock, I would be overjoyed if I even made 600.
The Ti rods are just unnecassary in every way for these applications, simply because it doesn't offer enough to make a difference that can be measured unless its on a dyno. It won't make a difference in 1/4 mile time over the same LS7 engine with steel forged rods and a person certainly won't be able to feel it while driving. If they were worth using than people that have been building badass stroker engines for the past 8 years would use them. Just not worth it. And they do not handle the amount of power that good steel forged rods do. An LS7 rod will never see big power. What was it....700ish and they're supposed to fail?
But I guess for a N/A engine its neat to say you have Ti rods.
.
08-27-2006, 06:18 PM
#69
Originally Posted by Quickin
Oh I know, thats why I mentioned high RPM's. But you're still not gonna recognize it while driving with an LS7. Its gonna feel and sound exactly like any other stroker 427 LSx engine.
The Ti rods are just unnecassary in every way for these applications, simply because it doesn't offer enough to make a difference that can be measured unless its on a dyno. It won't make a difference in 1/4 mile time over the same LS7 engine with steel forged rods and a person certainly won't be able to feel it while driving. If they were worth using than people that have been building badass stroker engines for the past 8 years would use them. Just not worth it. And they do not handle the amount of power that good steel forged rods do. An LS7 rod will never see big power. What was it....700ish and they're supposed to fail?
But I guess for a N/A engine its neat to say you have Ti rods.
.
The Ti rods are just unnecassary in every way for these applications, simply because it doesn't offer enough to make a difference that can be measured unless its on a dyno. It won't make a difference in 1/4 mile time over the same LS7 engine with steel forged rods and a person certainly won't be able to feel it while driving. If they were worth using than people that have been building badass stroker engines for the past 8 years would use them. Just not worth it. And they do not handle the amount of power that good steel forged rods do. An LS7 rod will never see big power. What was it....700ish and they're supposed to fail?
But I guess for a N/A engine its neat to say you have Ti rods.
.
The only way to determine if you are correct in saying it will not make a power difference it to run back to back tests on a motor with both LS7 and forged steel rods. I don't think you, I, or anyone else here has seen that. Personally I believe you would be proven flat wrong. We aren't talking about a few ounces of weight difference. Where did you hear that ti rods will fail at 700ish? I don't believe that for a minute. Forged steel rods are not stronger than titanium. Stiffer, yes. Better for a big hp motor with a power adder and high cylinder pressures? Yes. Stronger? I don't think so. Actually, the LS7 rods are rated to be as strong as a 900 gram forged steel rod. Don't get strength mixed up with stiffness. If GM were going to use a marketing gimmic to sell C6 Z06's, I highly doubt they would use a connecting rod to do so lol. But for the average Joe building a street engine, I do think spending $2300 for rods is overkill. But I'd gladly take a set and put them in mine.
08-27-2006, 06:26 PM
#70
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the force on a rod has nothing to do with peak piston speed its all about delta speed over delta time multiplied by piston weight. and because a f1 engine changes direction so many more times per second it is going to pull higher g forces than the nascar engine, but the actual force on the is
less than an 1/8 of the time a rod actually sees pulling force its almost in compression all the time
and aluminum rods are much more preffered for drag racing engines is because they can absorb some of the shock if detonation happens instead of blowing out bearings right away
but this still doesnt answer the question, what limitations are people seeing with these?
less than an 1/8 of the time a rod actually sees pulling force its almost in compression all the time
and aluminum rods are much more preffered for drag racing engines is because they can absorb some of the shock if detonation happens instead of blowing out bearings right away
but this still doesnt answer the question, what limitations are people seeing with these?
08-27-2006, 10:49 PM
#72
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Originally Posted by Quickin
At the power levels and rpm's the LS7 was designed for they serve ZERO purpose.
Ferraris don't need'em either.
Ferraris don't need'em either.
.....not to mention, the reduced weight of the titanium rod means less specific impulse and dynamic kinetic force on the rod.
I would have to say that they (GM) were after a lower MOI for the threashold RPM range of the LS7. I myself, totally agree..... I am after the same thing.
I also agree with 11 Bravo's contributions to this. Gm's Ti rod has its place, in its application.... for its purpose. And one thing not really talked about is rod angle. A rod doesnt need to be as strong as humanly engineered. It only has to be as strong as the application it is designed for, plus a margin saftey factor.... and GM's effort, I can assure you, was a factor of 10+.
But I have one question though..... Who the *** cares about a rod that can handle 2000hp ?? Not me. How many people here even make 1500hp ?? I think ZERO comes to mind.
Ill take a 480g rod weight and keep my low MOI. Versus a rod that takes another 200g for the strength to weight ratio to come back around for saftey factor. Not to mention that it much much easier on the clutch and transmission...... and for the accleration rate increase.
08-28-2006, 12:07 AM
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Originally Posted by chicane
Well, I guess you answered your own question with this.........
I would have to say that they (GM) were after a lower MOI for the threashold RPM range of the LS7. I myself, totally agree..... I am after the same thing.
I also agree with 11 Bravo's contributions to this. Gm's Ti rod has its place, in its application.... for its purpose. And one thing not really talked about is rod angle. A rod doesnt need to be as strong as humanly engineered. It only has to be as strong as the application it is designed for, plus a margin saftey factor.... and GM's effort, I can assure you, was a factor of 10+.
But I have one question though..... Who the *** cares about a rod that can handle 2000hp ?? Not me. How many people here even make 1500hp ?? I think ZERO comes to mind.
Ill take a 480g rod weight and keep my low MOI. Versus a rod that takes another 200g for the strength to weight ratio to come back around for saftey factor. Not to mention that it much much easier on the clutch and transmission...... and for the accleration rate increase.
I would have to say that they (GM) were after a lower MOI for the threashold RPM range of the LS7. I myself, totally agree..... I am after the same thing.
I also agree with 11 Bravo's contributions to this. Gm's Ti rod has its place, in its application.... for its purpose. And one thing not really talked about is rod angle. A rod doesnt need to be as strong as humanly engineered. It only has to be as strong as the application it is designed for, plus a margin saftey factor.... and GM's effort, I can assure you, was a factor of 10+.
But I have one question though..... Who the *** cares about a rod that can handle 2000hp ?? Not me. How many people here even make 1500hp ?? I think ZERO comes to mind.
Ill take a 480g rod weight and keep my low MOI. Versus a rod that takes another 200g for the strength to weight ratio to come back around for saftey factor. Not to mention that it much much easier on the clutch and transmission...... and for the accleration rate increase.
.
08-28-2006, 01:26 AM
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Originally Posted by Quickin
typo...4 second 1/4 mile times...4.4 to be exact.
08-28-2006, 03:23 AM
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Originally Posted by Quickin
typo...4 second 1/4 mile times...4.4 to be exact.
08-28-2006, 03:25 AM
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Originally Posted by RussStang
Isn't this example a moot point anyway? Are nitro engine funny cars even allowed to use titanium? Kind of defeats the purpose of using them as an example.
08-28-2006, 01:31 PM
#78
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Originally Posted by Quickin
Oh well, I guess it boils down to an engine that for the price it is, as a crate engine, is a joke, compared to what you could have built to destroy it in hp/tq as it comes in crate form for the same money or less. And the fact they use $2,000 plus Ti rods doesn't help it in price or power.
So. Lets take away the Ti rods and valves, the dry sump and put on a lesser cylinder head. Is this what you talk about when you say "for the same money or less" at the same CID ??
And since when doesnt a lower MOI help in horsepower production.... regardless of the price tag ?? Id like an explaination on that one.
08-28-2006, 05:27 PM
#79
Originally Posted by Quick1998Z28
they use 358s made from destroked 400 blocks, so the stroke is the same as a 327, 3.25" IIRC. I don't understand where people can say titanium is weaker than any type of aluminum.
There are also alloys of steel that behave this way too. Case hardened steel is also very brittle: once its threshold is reached it shatters. There's a reason why fighter aircraft bulkheads are made out of titanium alloys, and it's not cause they like to several weeks machining them. Sorry but it's not a marketing ploy. Tensile strength and a less crystalline structure is what matters for rods survivability and forged titanium FAR exceeds aluminum and even steel in tensile strength. not to mention, the reduced weight of the titanium rod means less specific impulse and dynamic kinetic force on the rod. Doesn't mean they are invincible, forged aluminum or 4340 steel is preferred cause it's considerably cheaper. Only steels used for industrial cables and other heavy load lifting exceed titaniums tensile strength. Carbon fiber is far better than both, but it's brittle crystalline nature in current forms only makes it a durable performer externally. If you can afford titanium rods, use them. Don't kid yourself and think they are junk, a quality titanium rod made by a reputable company, could and should far exceed steel or aluminum in durability and reliability.
There are also alloys of steel that behave this way too. Case hardened steel is also very brittle: once its threshold is reached it shatters. There's a reason why fighter aircraft bulkheads are made out of titanium alloys, and it's not cause they like to several weeks machining them. Sorry but it's not a marketing ploy. Tensile strength and a less crystalline structure is what matters for rods survivability and forged titanium FAR exceeds aluminum and even steel in tensile strength. not to mention, the reduced weight of the titanium rod means less specific impulse and dynamic kinetic force on the rod. Doesn't mean they are invincible, forged aluminum or 4340 steel is preferred cause it's considerably cheaper. Only steels used for industrial cables and other heavy load lifting exceed titaniums tensile strength. Carbon fiber is far better than both, but it's brittle crystalline nature in current forms only makes it a durable performer externally. If you can afford titanium rods, use them. Don't kid yourself and think they are junk, a quality titanium rod made by a reputable company, could and should far exceed steel or aluminum in durability and reliability.
I would choose a set of quality Ti rods over anything on the market. Can you say Pankel??
