C7 Corvette

[Gotta-Qik-C7]

Ruh roh spaghettios

What good is 650HP if u can only achieve it one time in a lab

I think GM doesn't want to be responceble for any engine failures on Z06s that are tracked/raced/etc. They know most of the guys that'll seriously race their car will flash that ECU thus voiding the power train warranty and letting GM off the hook unlike the valve train issues C6 Z06s had! Just my .02!

[GoCougs]

Ruh roh spaghettios

What good is 650HP if u can only achieve it one time in a lab

This has always been the downside of force induction cars, esp. supercharged. F/I is a cheap easy way to get big HP but this is the notable tradeoff.

These are not race/track cars so it's a non issue - these are street cars that see jaunts of a few seconds to maybe a few minutes, and then they get parked in the garage.

[SVT32V]

With the powdered metal rods in the LT4 it is not surprising the tune is very conservative, they are not going to take much abuse (detonation).
The LS9's titanium rods were better.

[GoCougs]

No F/I motor will take detonation though, and when that happens it's not rods that fail but rings and pistons...

Materials is not the be-all and end-all. The LT4 is by definition harder on rods - more torque, a bit more RPM - yet same as the LS9 has the 5 year/100,000 mile power train warranty. GM's not gonna spend big $$$ on an all-new motor, including more power, direction injection, pooprod VVT, and cylinder deactivation, and then give it less "better" rods.

[SVT32V]

No F/I motor will take detonation though, and when that happens it's not rods that fail but rings and pistons...

Materials is not the be-all and end-all. The LT4 is by definition harder on rods - more torque, a bit more RPM - yet same as the LS9 has the 5 year/100,000 mile power train warranty. GM's not gonna spend big $$$ on an all-new motor, including more power, direction injection, pooprod VVT, and cylinder deactivation, and then give it less "better" rods.

No, not at all.

While it is true that ringlands often break on pistons, rods are also a weak point and are prone to failure in FI engines.

Whether bending or snapping under detonation.

Forged rotating assemblies are generally better in such applications and they will suffer without fail from some level of detonation, much better than their non-forged counterparts.

GM screwed the pooch with a ten cent change to a key, hard to say what they might or might not do to save money and forged rods are $$$.

[GoCougs]

IMO you're over complicating it. The move to such rods is probably for lower weight - there is no such thing as screwing the pooch WRT rods these days. Either way a bit of googling says plenty of other Big Motors F/I and otherwise - Viper V10, GT500 5.4L, LSA - use powdered/sintered rods, and, to win the Internets for the night, so does the the 707 hp Hellcat 6.2L. In other words, since GM builds the best Detroit motors, if GM does it, it's a good thing to do.

[12,000 RPM]

In other words, since GM builds the best Detroit motors, if GM does it, it's a good thing to do.

So GM's inability to keep its engines cool is good design practice

[SVT32V]

IMO you're over complicating it. The move to such rods is probably for lower weight - there is no such thing as screwing the pooch WRT rods these days. Either way a bit of googling says plenty of other Big Motors F/I and otherwise - Viper V10, GT500 5.4L, LSA - use powdered/sintered rods, and, to win the Internets for the night, so does the the 707 hp Hellcat 6.2L. In other words, since GM builds the best Detroit motors, if GM does it, it's a good thing to do.

An opinion comparing a low revving naturally aspirated viper V-10 with FI motors hasn't much merit.


The Ford GT, terminator, and later GT500 all were completely forged, the first "low hp"GT500s had the same type of rods the LT4 had. Not surprisingly they were the weak point and replaced with forged units as HP went up.

Since GM can't even match the GT500 or hellcat HP levels in a brand new design it is hardly the best detroit engine builder.

LSA isn't offered in high hp ratings like the supersnake that actually used stock ford (overbuilt) internals and is why it could never even get close to GT500 hp levels in a warrantable package.

Once again cougs you are on the failboat.

[MrH]

So much goes into piston rod design besides just "forged" or "not forged".  Trying to boil it down to something like that is stupid.

[SVT32V]

So much goes into piston rod design besides just "forged" or "not forged".  Trying to boil it down to something like that is stupid.

Of course many other factors are taken into account, H-beam, cooled by oil squirters, length etc.

It is ludicrous to dismiss it is as not important.

[MrH]

It's not important when there are a million other things at play.

[12,000 RPM]

Dont obfuscate- for the most part forged rods are stronger than non forged

If non forged rods were OK the aftermarket would not go to forged rods for big builds

[MrH]

We can't say what's OK and not OK on this engine.  We don't have a fucking clue.  Let's all stop pretending we know more than hundreds of powertrain engineers at GM

[SVT666]

We can't say what's OK and not OK on this engine.  We don't have a fucking clue.  Let's all stop pretending we know more than hundreds of powertrain engineers at GM

Well, we certainly know more than those that created CUE.

[12,000 RPM]

We can't say what's OK and not OK on this engine.  We don't have a fucking clue.  Let's all stop pretending we know more than hundreds of powertrain engineers at GM

U have (and have always had) way too much faith in OEMs. GM is one of the worst too, they are still fucking up right nah.

[GoCougs]

So much goes into piston rod design besides just "forged" or "not forged".  Trying to boil it down to something like that is stupid.

I'm curious what's next - plastic intake manifolds?

GM has faults like any other automaker but their motors ain't one of them.

[FoMoJo]

I'm curious what's next - plastic intake manifolds?

GM has faults like any other automaker but their motors ain't one of them.

Why not plastic pushrods...reduce the weight of all that reciprocating mass.

[MX793]

I'm curious what's next - plastic intake manifolds?

GM has faults like any other automaker but their motors ain't one of them.

Not sure if serious.  GM did plastic intake manifolds.  They had issues with warping.

[FlatBlackCaddy]

Don't know why anyone even reads his BS anymore.

[Soup DeVille]

Dont obfuscate- for the most part forged rods are stronger than non forged

If non forged rods were OK the aftermarket would not go to forged rods for big builds

Aftermarket is generally much lower volumes. The tooling for forging is tried and true and widely available, which means they are going to be cheaper to tool for than powdered sintered forged stuff.

Not that, a H points out, it's as simple as that; but its a big factor.

[Soup DeVille]

U have (and have always had) way too much faith in OEMs. GM is one of the worst too, they are still fucking up right nah.

All things being considered; if i have to bet on a GM motor versus one made by even the best aftermarket company; I'm going to bet on getting more out of he GM motor.

Of course they make mistakes.  Both of them; but when GM messes up everybody hears about it.

[FlatBlackCaddy]

All things being considered; if i have to bet on a GM motor versus one made by even the best aftermarket company; I'm going to bet on getting more out of he GM motor.

Of course they make mistakes.  Both of them; but when GM messes up everybody hears about it.

Reminds me of the C6 Z06 guys, funny thing is that when they "bet" on one it isn't GM.

[GoCougs]

Not sure if serious.  GM did plastic intake manifolds.  They had issues with warping.

Uh, plastic intake manifolds are common the industry over, and it's a good and right thing.

[Raza]

C6 wont hang with the C7 Z06 on a road course

*If the C7 driver has the stones to commit to turns enough to utilize the grip of the aero

Who are we kidding though. Here is how most races between C6/C7 drivers will play out

Two Turkeys on Thanksgiving Wrecking their Corvettes in The Woodlands

Haha, that video never gets old. 

[MX793]

Uh, plastic intake manifolds are common the industry over, and it's a good and right thing.

Indeed they are.  But GM did have significant and well-documented issues with the plastic intake manifolds on their V6s from the late '90s thru mid '00s.

[SVT666]

http://api.viglink.com/api/click?format=go&jsonp=vglnk_141829909608112&key=5e9e33f20bf41d5a669cc4838c2690e9&libId=6d7a1718-3005-4310-b0a6-7d58fc891006&loc=http%3A%2F%2Fwww.corvetteforum.com%2Fforums%2Fc7-z06-discussion%2F3574423-it-s-not-heat-soak.html&v=1&out=http%3A%2F%2Fwww.autoevolution.com%2Fnews%2F2015-corvette-z06-owners-report-heat-soak-power-loss-its-actually-a-conservative-ecu-setup-89790.html&title=It%27s%20not%20Heat%20Soak!!%20-%20Corvette%20Forum&txt=http%3A%2F%2Fwww.autoevolution.com%2Fnews%2F20...tup-89790.html

[Gotta-Qik-C7]

[url=http://api.viglink.com/api/click?format=go&jsonp=vglnk_141829909608112&key=5e9e33f20bf41d5a669cc4838c2690e9&libId=6d7a1718-3005-4310-b0a6-7d58fc891006&loc=http%3A%2F%2Fwww.corvetteforum.com%2Fforums%2Fc7-z06-discussion%2F3574423-it-s-not-heat-soak.html&v=1&out=http%3A%2F%2Fwww.autoevolution.com%2Fnews%2F2015-corvette-z06-owners-report-heat-soak-power-loss-its-actually-a-conservative-ecu-setup-89790.html&title=It%27s%20not%20Heat%20Soak]http://api.viglink.com/api/click?format=go&jsonp=vglnk_141829909608112&key=5e9e33f20bf41d5a669cc4838c2690e9&libId=6d7a1718-3005-4310-b0a6-7d58fc891006&loc=http%3A%2F%2Fwww.corvetteforum.com%2Fforums%2Fc7-z06-discussion%2F3574423-it-s-not-heat-soak.html&v=1&out=http%3A%2F%2Fwww.autoevolution.com%2Fnews%2F2015-corvette-z06-owners-report-heat-soak-power-loss-its-actually-a-conservative-ecu-setup-89790.html&title=It%27s%20not%20Heat%20Soak!!%20-%20Corvette%20Forum&txt=http%3A%2F%2Fwww.autoevolution.com%2Fnews%2F20...tup-89790.html[/url]

Like I said earlier. GM doesn't wanna be responsible for replacing blown engines on tracked Z06s. SMH.....

[FlatBlackCaddy]

Haha, that video never gets old. 

It's a classic, would have been even funnier if they crashed in front of a denny's because they were racing to beat the deadline for the early bird special.

[SVT666]

Like I said earlier. GM doesn't wanna be responsible for replacing blown engines on tracked Z06s. SMH.....

They're is a problem with the cooling of this engine if there is a 20 degree differential in intake air temps after a couple hard runs.  Also, for GM to build in such a conservative tune that cuts power as soon as things get a little hot says to me they're really concerned about the longevity of this engine and it must be maxed out.

[SVT666]

If I had just dropped 100 large on this car and then found out it only makes max power for one highway blast and it loses a bunch because GM programmed a big ignition retardation to protect an engine that is obviously not up to the task, I would be pissed.