Bokononblue22

Hey guys,

I posted this in the general forum, but was told to come here. (Should have looked around before posting. My own darn fault.)

Anyway, I'm looking at a C6, either as a dedicated track car or a modded road car and I'm looking for some insight.

I've built several racers in the past, but nearly all have been M3s or 911s. I know very little about Corvette technicals, so be patient if some of these questions are obvious.

My big decision is whether to pay extra for a used Z06 or buy a base C6 and spend the rest on parts. Based on a quick look at the specs for each, I feel I could better the Z06's performance without paying extra up front.

In fact, I'd likely replace most of the features that make the Z06 unique anyway. (Not the aluminum frame or engine, obviously, but, for my purposes, those features alone aren't enough to justify the extra cash.)

However, the big question I have is about the targa roof on the base model. How does that affect structural rigidity.\? Obviously, it'll be less rigid than the Z06 but my experience is that some makes can pull it off better than others (For instance, the M3 cab vs., say, the Elise. The M3 cab is a tub of lard and the elise, well, isn't.)

If the difference isn't enormous, I might opt for the base. I'm fairly certain I can run the targa in my class with some safety modifications. Never tried to run a targa, but I'm pretty sure.

Feel free to throw out any numbers, newton meter tolerance or what have you. I can take the jargon. Also, if you have any other big reasons why I should pony up the extra cash for the Z06, feel free to point them out.

Next is with the engine. I know the Z06 runs a different block, but I'd like to know more about your experience with the strength of each engine.

Here's my point with this question: Buying used M3s is something of a minefield. Inevitably, you end up with an off-lease copy that belonged to some hack who didn't maintain it properly, wound the engine before it was up to temp, etc... That's a big problem with Ms because their engines are very, very high strung. In the past, I've had to do full rebuilds before taking an M to the track.

By contrast though, the modern 911 blocks are surprisingly stout. It's difficult to hurt them, even if you're a moron. I usually blueprint eventually (usually after having some fun with HPDE, when I want to get serious with it), but it's more by choice than necessity. I can pick up a used copy without worrying too much.

So, given that I'm looking at a used C6 for the track, should I be worried? Is the block fairly idiot proof? Obviously, any high performance engine will be a little delicate, but should I plan on swapping in a new lump or doing a full tear down to make it track/race ready?

Final question: the gearbox.

As mentioned, I'm deciding between a modded road car and a dedicated track car. I'd never take an auto to the track unless I knew the brand really well (I run a DCT M3 right now, but that's a little different...), but I might buy an auto road car if the paddle shifting is quick. What are the shift times like for the C6's autobox? Are the paddles fairly responsive? Will it upshift at the redline or hit the limiter? And finally, how much torque will the auto tolerate?

Thanks in advance for any insight,

Bill Dearborn

C5/C6 chassis is very stiff. The car was designed as a convertible so the targa top isn't that much of an issue as far as chassis stiffness. Some of the members who race their Corvettes have had oil starvation issues with the LS3 and maybe the LS2. That is one of the reasons the Grand Sport was developed. The manual shift GSs get the dry sump from the Z06/ZR1. My experience with LS engines has been with the LS1 and LS6 in two C5s and currently the LS7 in my C6Z. The LS1/6 were both bullet proof and I put a lot of track miles on both cars with the engine maintenance on both being oil changes. The LS7 had a pretty heavy oil leak for a couple of months while it took the service department 3 visits to get the problem fixed. Transmissions seem to do well as long as you keep them cool. The Z06 and the GS come with trans/diff coolers directly from the factory. I have been beating the crap out of various versions of the T56 for 14 years now and haven't had any issues.

Bill

Greywolfe

My vote would be for a base model C6 especially if you are going to make it a race car or dedicated track car. It will be much easier to weld in a cage with the steel frame of the C6 and you can use the money you saved on a dry sump oil system and other race parts your gonna upgrade to anyway.

Or better yet buy someones SCCA T1 car all set up and ready to race. There seems to be alot of good deals out there.

I'd stay away from autos for the track. I don't think the GM autos are up to par with the euro and japanesse quick shift autos yet.

Bokononblue22

Thanks, that answers my questions. I'm really excited about this build, but I still need to do some research. This helped out a lot.

To the second poster, that's a really great point. Steel vs. Aluminum frame with the roll cage issue had completely slipped my mind, but you're absolutely right. I've taken a look at used racers, but for me, the build is half the fun. (That's sort of why I keep moving makes.) Also, you're absolutely right about the gear box, I wouldn't think of taking a torque converter auto to the track. I was thinking of that as a possible road car, but I'm leaning more toward racer at this point.

On a side note, I just wanted to say that this forum is an absolute class act. In the past, when I've tried a new make and approached other groups with technical questions, I've gotten a bit of flaming in response because I'm coming from a different automotive background. You guys have been really open.

Thanks again guys, hope to see you at the track

Short-Throw

There is a huge difference between a dedicated track car and a modded car.

If you're open to the idea of a dedicated track car I would suggest you worry about what you're going to put a cage into. Also, do you want this car to fit into a specific race class for future possibilities? If you build strictly a track car with no intended class it will be much tougher to sell (although any track car is money gone), find a class to race or mod it back so it will be legal to race.

The weight difference in the Steel vs AL frame is about 110lbs. By the time you add materials (read weight) to properly install a cage in an AL frame, the difference is less.

My car is more of the extreme, but I went with a base C6 over a Z06. Although a costly project, the concepts of what you're debating are the same.

You can read about it here:

http://forums.corvetteforum.com/c6-z...r-support.html

As far as HP, you sound somewhat seasoned and should know that suspension and aero is far more valuable than HP (but yes having all 3 is the best).


Mike

cdbmathews

I suggest a 2008+, C6, Z51. Build it to SCCA T1 specs and you will have one fast and safe car that has decent resale value along with a place to race it if you so desire.

redtopz

A lot of T1 people will eventually be moving to base C6's so if you build one you will have potential buyers down the road. You can do the same with a Grand Sport, but not a C6Z. You would need a copy of the current SCCA rules pertaining to T1 specs for C6 corvettes. Good luck and I agree this forum is a great one .

fatbillybob

With Vettes there is no BMWCCA or POC/PCA to race with. To race there is really only NASA and SCCA and in SCCA at least there is no such thing as the "PCA chop". So really you need to decide if you want a dual use trackcar OR a racecar to race. If you want to race then what class? I don't know much about NASA but I think vettes fit into st2, st1, and another unlimited class mostly. In SCCA they fit in T1, STO and more unlimited classes. Your choice of model to start with really depends on your target. The most popular SCCA class is T1.

Regarding cages there should not be any real difference if your cage is built to the best specs on an aluminum or steel frame. The primary reason for my statement is that the safest cages have seat frames integral with the rollcage not seats bolted to stock floors sitting inside a rollcage welded to the steel frame. If you believe in the cage design of "seats as part of the cage" then your steel capsule cage could float unbolted in your aluminum frame and be totally safe but of course those steel cages are bolted to the aluminum frame. It is alot easier of course to design a lesser cage to stiffen a steel frame which can be a handling advantage. Additionally you can use less steel by cheating and using the sill of the vette chassis to say support your nascar bars instead of a sill tube like you would in an aluminum frame or unibody like you would in the M3.

Personally, I'm waiting for the C7 body hoping that the LS3 engine will die with the C6. We racers want the LS3 or better performance but the LS6 of the C5's bullitproofness. So for now I'm sticking with the C5 as a racecar. The absolute minimum entryfee to run a C6 LS3 car is a $5000 homebuilt drysump and testing the growing pains of that. It pains me to hear the storied of my race brothers who blow motors routinely due to oil issues in just a few laps which should never have been an issue. The GS while a great C6 is really a bandaid added Z06 drysump to make up for a bad design sold to us as an upgrade. Nice marketing I'm not buying.

Bokononblue22

Thanks Short-throw, I'll definitely take a look at that thread.

As for road car vs. track car, my eventual goal is a dedicated track car. However, given that this is my first time working with a corvette, I might benefit from getting to know the car on the road.

I race NASA PT, etc so I'm fairly open with modifications. I've been racing ST1 on and off (as often as I can get away from work), and am looking for a different sort of challenge. The M's DCT is great, but it's made me lazy. I need to start heel toeing again.

Classing will likely be what pushes me to a pre 08 base C6 in the end, now that I think about it. More flexibility. It starts in PTA while every other C6 is in SU, which doesn't appeal to me at this point.

Thanks again guys, sounds like I've found a great resource as I plan the build. I'll try not to bug you guys too much.

96CollectorSport

I definatly agree with the guys above about the LS3/C6/Grand-Sport (GS). That is the T1 car of the future and will always have a good amount of potential buyers, you can de-tune it to run in ST2 which is growing all the time. I'm not sure what NASA region you're from but the upcoming NASA-SE race at Rd Atlanta has 15 ST2 cars registered and I bet we'll get over 30 at Nationals. And you don't need to start with a 08+ car to make it into an LS3 car, really you can start with any 06+ and add the body work and engine yourself - if the build is half the fun.

Even buying a C6 LS2 T1 car would be a good start, they are kind of the red-headed step child of T1 right now so you should be able to get a fairly good deal on one, if you can find one that hasn't been converted to an LS3/GS.

exracer28

Even buying a C6 LS2 T1 car would be a good start, they are kind of the red-headed step child of T1 right now so you should be able to get a fairly good deal on one, if you can find one that hasn't been converted to an LS3/GS.[/QUOTE]

Why is the LS2 a red-headed step child in T1. We get a weight break from the LS3 and it looks like weget all of the tire/body mods from the grand sport. l don't understand why everyone is saying the dry sump system is so expensive. Are you paying someone else to do your work? I bought some of my stuff used but I have undert 2k in it. Hardest part was the lines but where do these 5-10k numbers come from.

96CollectorSport

I didn't mean to insult any LS2 T1 drivers, it just looks like they kinda got the short end of the stick by the SCCA. The LS3 does weigh more but it also has a lot more grunt - around 430 rwhp worth give or take a few (3450/430= a hp/wt of 8.0 to 1). The LS2 makes around 390 rwhp give or take a few (3280/390= 8.4 to 1) - at a track like Road America hp is king and the extra grunt of the LS3 is pretty hard to match.
Even the C5 gets help from headers and a lower minimum weight, I've heard numbers in the 410 rwhp area so (3180/410= 7.75 to 1).
This is what I was refering to, I don't want to start another thread about the differences between all of the different T1 Corvettes I was just simply saying that by the numbers the LS2 looks like it has a uphill battle in T1, plain and simple.
The dry sump is around $5k if you have someone else do the work. If you buy the parts new from ARE your looking at around $3500, plus lines and installation it can easily come in above $5k. A dry sump is not cheap, can it be done cheaper heck yeah but it's usually not easy to find used dry sump parts.

I was just trying to try to help the OP with what I have seen on the market.