I just read where the C6 does not use forged internals but cast parts (ie pistons, rods, and crank). Is this true??? Seems silly to me that Chevy wouldn't use decent internals in a 50 grand sports car. Not downing the car in any way but for the money you are paying I think they should give you a stronger bottom end.

 

I am afraid it's true. The LS2 in the C6 does not have forged parts in the bottom end.

 

Well it doesn't have a toilet in it as standard equipment either but I hear very few complaining about that.
My point being that it doesn't need forged internals (that are often heavier meaning they make LESS power, are potentially less fuel efficient/emissions friendly and add substantial costs) to get the job done.
Now I'm sure many of those with plans for nitrous and/or forced induction would love to have the supposedly 'stronger' bottom end but in most cases one would need to go in there (lower compression, ring work etc.) and rebuild anyway so why should the rest of the market have to pay for all of the negatives that come with it.
The stock LS1/LS6 bottom ends have proven to withstand some serious abuse (up to 750+ crank horsepower in some cases) just fine and so far so has the LS2....I like my internals (light and reasonably priced) just the way they are.

 

Well I for one would not be running nitrous or FI. Once I get my car I plan on doing basic bolt ons. I'd like to be able to match the 500hp crank rating of those pesky new GT500's once they hit the streets. (I'm a Ford guy, did I just say that )

 

Why would they need forged internals if they aren't supercharged or turbo equipped? Do you know why specific materials are used or aren't used?

Hypereutectic pistons have less expansion properties compared to forged pistons, and maintain a better piston/bore tolerance. They are also lightweight and inexpensive.

The non-forged crankshaft in these LSX engines is strong as hell. In fact, there have been NO reported factory crank failures in the LSX racing world. There are guys pushing 1000+ hp with these factory cranks.

The rods in the engine have been pushed to over 800 hp in many cars, without failure. Seems to be fit for the purpose on a 400 hp engine.

So, I think the main reason is to keep costs down, but its clearly evident that the components are more than fit for purpose.

 

I never knew that, thanks for the info. Guess I should worry less and just save save save so I can have money for mods once I get my car. We all know how expensive modding can be

 

I wouldn't worry about the Shelby Mustang. Those cars are 600 lbs heavier than these Corvettes. They *need* the extra 100 hp just to keep up. A simple cam swap and headers will put you close to 500 hp crank yourself.

 

With full bolt ons and tuning you should be able to come very close to 500 crank horsepower (high 300s at the wheels) in a manual C6.
Add in a decent heads and cam/tuning package and you could even be knocking on the door of 600+ (high 400s at the wheels).
I usually prefer to reference rear wheel power numbers only but I know some look at the crank ratings and it's how the factory rates things.

 

The GT500 test mules have been putting down around 435 - 440 at the wheels which is 500 hp at the crank. Car won't be under rated like the 03/04's as this is a certified rating. Nice to know that with heads and cam/tuning I can exceed that number with the Vette. I'll probably just stick to the basic bolt ons and not go that extreme though.

Thanks!!!

 

I think that the LS2 will be fine. Things tend to break when we get a little greedy with making horsepower. One thing leads to another and the conservative tune goes bye bye to make the extra horse power (with power adders). We all know that you have to "pay to play".

In any case there are enough bolt on parts to make our cars very fast. In my opinion we should be much more concerned with the drive train (several 6 speed cars have lost their rears at the track) as well as getting the additional power to the pavement.

 

Any one know what the "safe" power level is for the rear??? I guess it all matters on how you drive the car too. Drive stupid and your going to break stuff.

 

Yeah the GT500 was originally going to be rated at only 450hp, then it got bumped to 475 which was big news and just recently it was announced that it would be rated at 500. But like you said I will assume that it will be right at 500 and not anywhere over it like the '03s/'04s which were almost dynoing their 390hp crank rating but at the wheels in some cases.

 

Stock. I believe there have been failures to stock cars. I'm just glad that I'm not into drag racing, so I don't repeatedly put my rear at risk.

 

Personally, I'd like to see stronger internals. I don't think that forged internals would add more that $500 to the cost (unless GM decided to gouge, who'd think??) and knowing that I have the best avilable parts would give me some piece of mind. Plus, I will be modding this summer, with a goal of 550rwhp, and good internals would be a plus. At the C6 Bash last month, a few engineers eluded that a forged engine is in the future, aimed specifically at owners who plan to mod their cars. Horsepower around 435, but with the potential to handle a consertive 650 reliabily.

 

A cast hypereutectic piston's density (of the aluminum) is less than a forged piston which is where the main advantage is. With the casting being less dense, its' rate of heat transfer is less than a forging. From a thermodynamic standpoint, that means three things (with identical engines except for the pistons): the engine with cast pistons will make more HP, have less emissions, and get better fuel economy than the engine with forged pistons. This is because it transfers less of the heat from combustion (BTUs) through the piston head thus allowing the heat to act on the piston head (BTUs/heat is HP). Of course, this is up to the structural limitations of the cast piston. And cast pistons will not tolerate shock loads (like detonation, they'll crack in an instant) where a forging will (to a point). With more HP, less emissions, and better MPG, it was the best choice for GM to make.

 

I think it would be silly for GM to put parts in the car which the factory Hp and Torque levels do not require. Doing that would just add cost for the vast majority of Corvette Owners who leave the motor and drive train pretty much stock.

Even if they used some "forged" pieces there are lower quality forged parts from China such as the Eagle stuff and then there are top of the line forged parts such as Callies Magnum cranks for about 1600, Carillo rods for about 1300 and JE pistons for about 700. In other words good forged parts are a 2500-3600 cost adder. Chinese stuff would be about 1500 or so extra. Why pass this cost onto the normal Corvette owner? If you require this higher strength stuff for your modifications spring for the extra bucks yourself.

 

Ford will be lucky if those turds even put out what they say they will. The latest test showd them being VERY slow in both 0-60 and 1/4 mile times. Like others said, it will need every ounce of power it can get because of how heavy it is.

 

Most of the breakage is attributable to excessive wheel hop. Guys with six speeds who did not realize they were experiencing wheel hop/ or realized it too late to let up on the throttle. Then some guys with slicks/drag radials got too good a bite and boom. You can do a search on the forum.

Please see below post from DTE

"We have noticed quite a lot of folks breaking driveline components regularly lately at various power levels regardless of the driveline upgrades one has, so we thought we would chime in here to offer our expertise on the matter based on our direct experience, as we've seen it all at one time or another....many times over.

FYI:
Just so we're on the same page here before all of this is written~ If you are going to go racing with the C5/C6 Corvette, you *MUST* strengthen the driveline to support the abuses and stresses of racing....period. It doesn't matter who you are or how lucky you think you are, you cannot escape the Laws of Physics and you *WILL* break something sooner or later, no matter how well something is built. No one is exempt from this and the sooner you realize that, the easier it will be to accept when something breaks at some point. Even professional NHRA drag racers break the most exotic driveline/engine parts day-in and day-out, but they expect the inevitable and accept it as a by-product of going faster...faster...faster.


The first and foremost best way to avoid any type of driveline failure with the C5/C6 Corvette regardless of what fortification level your driveline is currently at, is to incorperate simple common sense with your foot... Contrary to what folks would like to believe, the C5/C6 Corvette is a street car *NOT* a tube-chassis, solid-axle, full-tilt drag car that can withstand John Force-type punishment round after round without incident, therefore don't drive the car that way thinking you have something you don't.

However, the C5/C6 Corvette driveline/chassis/engine can be built *VERY* strong and the engine's in these cars obviously produce exceptional power, but in the end, it is still an IRS-driveline with stock-type suspension, relatively heavy, stock chassis and a rather unusual power delivery path from the engine to the wheels; therefore there will always be some form of limitations with regards to the driveline when compared to a full-tilt, purpose-built, solid axle racing car.


Wheel Hop:
Oversimplified- Professional race cars have it and it's called tire-shake; C5/C6 Corvettes have it and it's called wheel hop.

This condition is *EXTREMELY* destructive and will fracture even the best of parts offered from whom-ever, so don't think that you can simply "drive through it" and not fracture the driveline in some fashion eventually.. If the car tramps.....*LIFT*! Your ego might be temporarily bruised for not making a good showing at the track in front of your buddies, but your wallet with thank you later when you don't have to repair a severly damaged driveline.

There is no one-silver-bullet fix for this negative condition and it is caused by unusual suspension wind-up deflection during acceleration. In order to *completely* eliminate destructive wheel-hop in these cars, you'll have to upgrade the soft, stock shocks (all 4 not just the rear) with adjustable units, use the proper racing tire with correct tire pressures for the application, (and no, a drag radial is not that...) replace the overly-soft rubber suspension bushings with high quality polyurethane components, (all 4 corners, not just the rear) and have the chassis dynamically aligned while placed under a suspension load that simulates the wheel position during a launch event.

Don't skimp!!!! You *MUST* perform *all* 4 of these upgrades to your Corvette car to maximize the true benefits of the modification, which rewards the driver with fewer broken driveline components overall, greater success at the track and a car that lanches much straighter/cleaner. I don't know how many times I've seen or been told that someone "thought they didn't need that" for whatever reason and then they are scratching their heads when their car shatters the driveline...

If you cheap-out on any one of these 4 upgrades to your car, you will only be cheating yourself and increase the likelihood that your car will expereince complete, catastrophic driveline failure. No one is exempt from the Laws of Physics, so don't think that you can "get away" without any one of the recommendations described above for very long, as the the Laws of Probability will also eventually catch up you...

Maintainance:
IRS-equipped cars will inherently require more maintainance to sustain durability over time, by design. If you neglect the driveline, it will fail you....period! Change the burned lubricants *VERY* frequently, inspect the nuts/bolts for tightness regularly and always keep on the look out for hairline cracks that form because of metallurgical fatige. Many times a potential problem can be found *BEFORE* a catastrophic failure occurs if the owner will just be viligent in checking these areas.

Misc.:
Install a line-lock!! There is nothing harder on a driveline or overheats the differential/transmisison more than smashing the brakes down while trying to do a full-power, big burn-out.... Those are two opposing forces that induce a *LOT* of driveline stress when paired against each other. The by=product of this is eventually burning up the brakes up on the car and/or burning up the differential/trans from excessive heat. Install a line-lock that allows a free wheel burn-out of the rear tires, so that the only item that experiences any real heat are the the intended tires.

Allow sufficient vehicle cool-down between runs. Even professional racers allow their cars to cool between rounds and their cars are built purposely for racing! You need to do the same for your street car... Hot-lapping rounds is neat, but you car suffers for it eventually.


This is long-winded, my fingers are sore from typing and it's about all that I can think of off the top of my head at the moment. There are countless other tips to prolong the life of any race car, as I'm sure some will chime in with additionally.

The bottom line: There are some folks racing the C5/C6 Corvette that can go round-after-round through nearly the entire season without hardly ever breaking one thing; but then there are those that will consistantly break anything, built by anyone, no matter what it is, at their first few times on the track.. Chances are the guys that aren't breaking things reguraly are the guys that have done what is described above to their car and excercise common sense while racing their Corvette to prolong its life. Their racing efforts don't cost them as much, they don't break as often and they have fun week-after-week.

To those that break parts consistantly~ follow their successful lead and you'll have a lot more fun overall. Most of all, racing is racing and you *WILL* break parts, so the sooner you accept that, the easier it will be to accept the reality of fixing your car when it goes down. If you can't afford to repair your car when parts eventually break....don't go racing in the first place, as there are *NO* gaurantees for anything in racing...

A lot of this was oversimplified for time purposes, otherwise I would be here for days typing, but I hope this helps some of you understand a bit easier. Happy motoring gents and if any of you have any questions, please call to ask and I cover it further."


Best Regards,
Phil
Dynotech Engineering Inc.

 

Pick up the new Car and Driver. They compared the GT500 to the Vette and the Vette won and I'm not talking Z06 either. The GT500 weighs 615 more pounds than the Vette and no where near as agile.

 

LOL, if you think the C6 torque management and programming is bad, just wait until you do some research on the GT500. Why they would saddle the car like that from the factory makes no sense to me.

One of the experts over on SVTPerformance said,

"Vehicles using Ford's new ETC have a built in delay from pedal WOT to TB WOT of between .7-1.0 seconds--even between shifts."

Oh well, can't get everything right. A little weight loss wouldn't hurt either.