dapopa9

Great question. I've often thought of that myself.

If you take out all of those items you mention above I think essentially it comes down:

- Aero
- Cooling (based on the body and available space/positioning for coolers)
- Weight
- Weight distribution
- Vehicle dimensions
- Suspension geometry

With that being said the lightest one would be a good start. I don't have expertise on the rest of those items as far as how the effect performance or the differences(if any) between the models.

This would also be a great conversation to have with Tage to see what his thoughts are on it.

chpmnsws6

Just remember the factory race teams used the steel tubs

Bill Dearborn

I wouldn't bother with NT05s. They are not all that great of a tire when it comes to going around a corner.

Bill

C5inWV

I cut my track teeth on a C5 fifteen years ago. It was a Z51 car but I upgraded the swaybars and could pretty much run w/ the stock Z06's. I moved to a C6 in '07, also a Z51 car. Changed the swaybars on it, and put on some longtubes and x-pipe, Borla attack etc. The C6 made all the right noises but didn't charm me like the C5.
So I bought a '99 FRC last summer and I'm preparing it for dedicated track use. After half a dozen track days it showed it can really hold it's own.
Driving the C5 with the 345HP base motor teaches you to drive it like a momentum car, and that is quite entertaining.

Metalgearsolid_x

Just curious, what are you building?

Interesting. Do you guys run into any cooling issue? oil or trans cooler needed to track base c5/FRC? I have a FRC. I'm debating if I should turn it into track car. Just not sure what cooler do you guys use

C5inWV

After thinking about it more, the decision betw C5 and C6 would be more difficult if the cost of the cars are the same. Most C6's cost about $5,000 or more than a comparable condition C5, and that money can be the budget for refreshing, modification, and safety equipment.

Bill Dearborn

C5 needs engine oil cooler, transmission oil cooler and differential oil cooler. I had the GMPP T1 trans/diff cooler on both my 97 and 03Z and I had a Ron Davis Racing Radiator with built in EOC which kept the engine cool. With a remotely located 1 quart oil filter it held 9 quarts of oil. Some people ran Accusumps as well.

C6Z51, C6Z along with C6GS came standard with a better engineered trans/diff system than the C5 GMPP T1 kit which seems like it was offered as an after thought shortly after the C5 was introduced. GM's 2009 and newer dry sump design was a good track setup. It held about a quart and half more oil than the pre 09 system which worked fine in most cases.

When I went from my C5Z with the add on radiator and trans/diff coolers I didn't have to add those things on the 08 C6Z. The stock cooling system worked really well and I never came close to overheating the car in 6 years of track use.

Bill

SunnydayDILYSI

If you are going to mod all the important stuff anyway, C5 base is the way to go. Leaves more budget for mods. Agree with others above that already modded C5 is the best bang for the buck. I bought a caged ST2 1999 FRC last March. I had previously modded (on my dime) a C5Z. Speed / dollar definitely goes to the base C5.

chpmnsws6

For a track car, I'd be looking at a C5z, C6 Z51, or a manual GS.

The Z's have a shorter range gearbox. The c6z51 has a factory cooler for the engine and trans. Wilwoods for both are roughly 1600 using stock style rotors.

The GS adds a dry sump setup and a diff cooler to the mix, along with better brakes.

SunnydayDILYSI

If you get into tracking to the point of requiring mods, the "upgraded" parts from these models will not work. Brakes, coolers, dry sumps, etc. that are designed for the track assume the car is either 100% throttle or 100% brake ALL the time. Factory cars are made to be at operational temp even if they have been rolling down the highway at constant speed for 20 minutes. What works for one does not work for the other.

carefulnow

Yes. Very many considerations and compromises involved and several ways to go awry. Be especially wary of shops who are trying to weld attachment pads/boxes to the Al frame.

The frame is factory hydro-formed, which is cold worked. Welding anything to it anneals it locally, softening it substantially at that point, exactly what you do not want to achieve.

(I say this as a warning because there is a vendor on this forum who is selling such an approach which I'm sure you can find if you look.)

So, you are left with fabricating big surface area plating around the frame, bolting through, and sleeving inside or around to prevent collapse. You then will also need to address galvanic corrosion (minimally wherever moisture/water can occur, which is realistically everywhere) which means zinc coating at least, probably in addition to adhesive.

So all of this mucking about = about double the time/labor.

strano@stranoparts.com

What's better, Pepsi, Coke, Dr Pepper?

That's a BIG spread of cars from a base C5 to a C6Z. 1997 to 2013. All the submodels. Yikes.

I think it comes down to money, pure and simple. What can you afford to buy. What can you afford to leave wadded up in a ball (god forbid). What do you have to upgrade. Etc.

If you start with a C5,hard not to say Z06 given the extra power and better gearing vs. a "normal" one. Again unless cost is a big factor then the base cars do get you in the door for less. All the C5 and base C6 brakes suck. I mean they work, you won't die, but you tear up pads pretty badly. And they need coolers added.

A C6 Z51 is a little better. Same better gearing and an LS2 or LS3 depending on the year. Crappy brakes still but at least a little bigger rotor. Grand Sport is maybe the sweet spot. LS3 is reliable. The bigger brakes (which are not nearly as badly in need of upgrading as the 'normal' brakes. The larger oil tank and the shorter gearing too.

I have a C6Z, so does my girlfriend. We've more than once slapped better pads on and run on tracks with out autocross setup. Nothing more done (we do run good fluid anyway). I've run Laguna, Thunderhill out west, PittRace and Summit and others here in the east. No issues with the smaller oil tanks, oil temps weren't outrageous. We both fixed out heads, which again is a non issue in the LS3... but the LS7 is just more likeable for me. So it a roof that doesn't drive me nuts.

You are going to mod them all some I'm sure. How far do you want to go? That might tell you where you want to start.