C6 Z06 Info

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C6 Z06 Info

Post by disneyd »

So... I was chatting with Kristo at the last event and found out that the price on C6 Z06's has fallen into a range that is doable for me.

Over the years I've tinkered with the idea of putting an LS engine in the Miata, but every time I run the numbers on it and consider the amount of time I'd have to put into the project to do it nicely, I've come out thinking I'd be better off just buying a 'Vette. Yes, there are cheap ways to V8 a Miata (and I'm a big fan of sleepers), but I'd want the car to be structurally strong (FlyingMiata subframes), use the stock dash electronics (conversion hardware $$) and so on.

With that said, I think I'm going to sell the Miata and pick up a 2009/10 Z06. I know a C5 would probably be wiser from an autocross perspective, but I like the looks of the C6s a lot more.

However, I don't really know jack about Chevrolets. I've been into Mazdas and Subarus for ages and the last Chevy I had was a '72 Chevelle about 25 years ago (and it was a pain the ass).

So, what can anyone tell me about C6 Vettes? From googling around, it sounds like the early (or all?) C6s could have some valve train issues. I've also read about delaminating roofs and broken axles and transmissions. Anyone know any details on that stuff and what to look for? Any other things to consider just from the general ownership perspective and the autocross side of things?
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Re: C6 Z06 Info

Post by jpvette »

In 2009 the dry sump system was changed to address a starvation problem in long turns. Probably wouldn't matter for a/x. They definitely have a valve problem. If you plan on really flogging it? Look into some valve train work. As far as the transaxle pretty tough unless you're going to the drag strip. I would suggest looking at the grand sport also, dry sump hand built motor and z06 suspension. On street tires it's almost impossible to put all the power down anyway. Oh and tires are expensive!
The c6's are a lot nicer car to drive and don't have all the electrical issues the c5's have. Most vettes are babied to the max. You will enjoy any of them.
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Re: C6 Z06 Info

Post by disneyd »

What exactly is the valve train issue? If it's caught before any catastrophe, can you upgrade/correct it from the top without pulling the heads, or do the heads need to come off?

I've heard about them dropping a valve into the cylinder resulting in a grenaded engine and I've also seen something about an exhaust valve problem. Not sure if they're the same issue or different, nor have I found any solid info (yet) on exactly what the valve issue is.
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Re: C6 Z06 Info

Post by 01badz28 »

The stock dry sump can be problematic in autocross situations, especially with R Compound tires. The stock tank didn't contain enough oil and it would still oil starve with extreme G loading (that's mostly because the stock system is more a "semi - dry sump" system than a true dry sump). I had looked at cannibalizing that system to use in the Camaro, but disregarded it pretty early due to the fact it didn't really seem to solve the problem.

Lingenfelter and ARE both made upgraded tanks that would help, and I think GM made some changes to the system later in the production run but its something to be aware of if you go the Z06 / GS route. Bone stock LS3 cars had serious oil starvation issues, especially in sustained left hand turns. Keep in mind this was such a problem, that the SCCA allowed the Corvettes to use an aftermarket dry sump system (pretty much the same one I'm running) in showroom stock racing.

The early LS2 cars were more reliable (they used the LS6 heads on the 6.0 block) and the LS6 heads have much better oil drainage. Oil starvation is just generally an issue with LS cars though.
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Re: C6 Z06 Info

Post by thrdeye »

Dave,

Since you have mentioned getting a car that is good for an autocross class, my advice is to reach out to Sam Strano. He knows all there is to know about the intricacies of these cars. He can tell you why a GrandSport is better in some circumstances than the Z06 and vice/versa. Either one can really shine in A Street or SSR. If you want to tinker with the car, you'll soon find yourself in SSP/SSM again ($$$$$$$ prep).
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Re: C6 Z06 Info

Post by disneyd »

Thanks Chris. I wasn't aware of the GrandSports... they look pretty interesting. Anyone know if the LS3s of that vintage are less prone to problems? Did they improve the oil starvation issue in the LS3's by 2009/10/11?
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Re: C6 Z06 Info

Post by 01badz28 »

disneyd wrote:Thanks Chris. I wasn't aware of the GrandSports... they look pretty interesting. Anyone know if the LS3s of that vintage are less prone to problems? Did they improve the oil starvation issue in the LS3's by 2009/10/11?
Dry sump was really the only way to solve the oil starvation issues. I was an early LS3 adopter, so I wasn't keeping close tabs on the changes they made after I ordered my dry sump system. The GS dry sump system may be better than the early LS7 systems I was looking at.

The main problem with the oil starvation problem is the oil drains slowly out of the heads. The square port heads (L92 / LS3) are worse about it than the earlier cathedral port heads (LS1/LS6). Big R compound tires and courses with sustained left hand turns exacerbate the problem due to the location of the oil pickup.
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Re: C6 Z06 Info

Post by jpvette »

Guides and exhaust valves so yes the heads have to come off. In 2009 they increased the dry sump volume and a couple of other things but I don't know if it was a complete fix. As far as oil starvation in the ls2 the manual tells you to add half quart above full. Not all ls7 have dropped valves but like I said most have been babied. I personally would rather have a ls2 or ls3.
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Re: C6 Z06 Info

Post by MARKP »

With the C6, the Z06 has the valvetrain issue and the heads have to come off. The valve guides wear and so do the valve stems. The end result is they drop a valve and you are looking at an engine. In Street class, there is no good fix other than doong the heads as a wear item.

The Grand Sport doesn't have the issue but the suspension is different, particilarly the front spring. The Grand Sport gearing is generally considered to be better.

Sam is an excellent resource on these cars. Be sure to support him with purchases if you are going to ask for his help with stuff. He is a one man show.

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Re: C6 Z06 Info

Post by disneyd »

Thanks guys, I will definitely give Sam a call. Maybe he remembers me from an Evo school years ago.

What kind of power can you get out of the LS3 in the GrandSport without going into the bottom end? I'm talking mostly bolt on stuff, tune, maybe cams.
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Re: C6 Z06 Info

Post by jcox07 »

Most numbers with what you are wanting to do is just over or right at 400 rwhp.
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Re: C6 Z06 Info

Post by thrdeye »

disneyd wrote: maybe cams.
Welcome to CAM.

Or Prepared.

:D
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Re: C6 Z06 Info

Post by 01badz28 »

disneyd wrote:Thanks guys, I will definitely give Sam a call. Maybe he remembers me from an Evo school years ago.

What kind of power can you get out of the LS3 in the GrandSport without going into the bottom end? I'm talking mostly bolt on stuff, tune, maybe cams.
My LS3 put 430 to the wheels. Only significant power mods are a .621 lift cam (singular), LT headers and a tune. There are cam only cars that make bigger numbers, but I wanted a flat torque curve.

I never had her dynoed after the dry sump went in, but it should have caused a power bump.
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Re: C6 Z06 Info

Post by MARKP »

The stock GS is just over 400 and the stock Z06 is 505.

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Re: C6 Z06 Info

Post by disneyd »

Is Dan Popp still in the Corvette business?
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