Hey guys, I'm looking for a Z06 which will be mainly used for track (road course) duty. I run hard, about 20-25 days per summer, and sometimes do back-to-back sessions.

I'm looking at a few cars that have already been modded for track use, and since they usually have modded engines as well, I'm wondering about the strength of the stock transmission and differential.

One of the cars I'm looking for, for example, is pushing close to 500rwhp. It has a tranny/diff cooler, C6 Z06 clutch and strengthened output shafts, but the rest of the driveline is stock. Will it break? What else needs to be done to make it bulletproof?

I'll be driving to and from events so I need reliability... I'm hoping to tap into the pool of collective knowledge here since I'm new to the 'vette world (have read all the FAQs).

Thanks!

 

I say most reliability is in a Stock drive train Z06 (C5 or C6) On C5 Add Coolers for oil and maybe trans / diff and a accusump. Not sure what a C6 needs to be more reliable but ya can find a 2007/8 at decent prices with a 5 year 100K warranty. These cars stock you can beat the crap out of and they keep going. Tweak the suspension and you will be hard pressed to find a car who can keep up with ya.

To answer your questions directly though .... 500WHP sounds like part of the trans is in good shape but to make it bullet proof I would talk to RPM ... they can build the trans as strong as you want. Same with the diff. Make sure the brakes are upgraded as well since ya got quit a bit more power. As far as that motor for road course use make sure it does not have a huge cam.... These motors hate the high HP cams that are great for High HP numbers but death to a valve train.

sorry for rattling on ....

 

The car already has a Wilwood Superlite brake package, engine oil cooler as well as tranny/diff cooler. It's got coilovers too.

I know about RPM and their packages, I'm just not sure if I absolutely need that for the car at that power level.

How can I tell if the cam is "huge"? I don't understand this cam business... here's the info I have re: cams on this car:

Ls6 Rockers 1.7 Modified By Harland Sharp Rocker Arm Conversion Kit On Trurion Bearings

Comp Cams Moly Push Rods
Lg Motorsports Gx3 Camshaft On A 114 Lsa
Gm Performance Race Lifters

What's that tell you?

 

I just realized this would probably belong in the tech section. Moderators, feel free to move it there. Sorry!

 

With that cam there should be upgraded springs. Valve springs were a weak link on these motors. If it has the stock springs you will want to upgrade for sure.

 

At that Power level I would just run it and see how things go. If not abused she should hold up ok. It just may be the "weaker" link in the setup by by no means is fragile. G5X3 is a big cam with super power on the top side of the RPM range. Lots of drag racing guys love that cam and it may not be the best road race cam but like another post said I am sure it has new stronger valve springs ya just may want to replace them after a good hard year of racing. Also stay off the rev limiter as that big of a lift cam puts allot of stress on a valve train especially on a road course.

I do speak from experience... I have a G5X2 and 2 years of running broke a spring. Now my spring break could have been just a normal failure but do believe if i had replaced them things would have came out better.... I ended up bending valves in my setup. But sure there is stock cam guys who have broken a spring just saying with big cam ya may want to take a little bit more caution.

Check out this post and read his CAM section has some good info
http://forums.corvetteforum.com/auto...e-learned.html

 

This post should be moved to the autocross/road racing section. That's where the track rats hang out and can answer your question from experience.

 

Then would you advise I go back to a more "conservative" cam? I'm not looking for ultimate power but I need reliability. Maybe easier than changing valve springs every year...

 

change trans and diff fluids every 3-4 events. Put in good synthetic fluids.

Just like your oil change, every few events. Dont plan on 5000 mile oil changes with a track car. 500-1000 miles is more then enough.
Send the oil for analysis each change so you know what is happening

Both are very strong. it is the Drop clutch launches or so called power shifts that break things.


Change your valve springs yearly is a very good idea. I run a smaller 224 cam and 918 springs. change them each winter.

road track events, are very hard on the car and valve train. Keep the valve train light wt and working is key to longevity.

 

You are probably running about 425-435 rwhp with headers. You aren't going to approach 500 rwhp without some major head work or aftermarket heads plus FAST intake and aftermarket TB etc...


There are typically two kinds (perhaps 3) of owners

Group A does most of their own work, understands the car, pays attention to the wear of the tires, brakes, checks the ball joints/wheel bearings etc. makes mods to improve reliability: oil/tranny cooler for example.

Group B that has the dealer to all the service and they drive the car until a symptom appears. Only buy appearance mods, chrome license plate for example. Don't know what a DIC is.

Group C would get the brakes, belts, hoses and tires but wouldn't know when to change the fluids. Would only change the spark plugs if the car started making an odd sound.


Group A people think the Z06 is reliable.
Group B people think the Z06 is expensive to maintain ($250 for a new battery for example) but enjoy the weekend car shows and poker runs.
Group C people are upset their car broke on their third pass at the drag strip launching their stock Z06 at 4000 rpms using a drag pack from a buddy at work.

So what group are you??


If it were me, (having owned a G5X3 cam), I would replace it with something more mild for a reliable track car... AU N EGL knows his stuff on road racing...listen to him..

 

Paul is right on here.

and 500 is just a fricken number. Big numbers dont go fast around corners. Road course are mostly sweeping corners connected to sharp corners with short straights in between the corners. With an OCCASIONAL LONG STRAIGHT, then back to lots of corners and short straights.

Handling, brakes and cooling ( engine, oil, trans, diff and brakes ) are more important.

Have driven many cars with the G5X3 cam. Bloody rocket ship over 4000 rpms, kind of so so under 4000 rpms.

Getting out of CORNERS quickly and UP to speed is far more important then top speed.

Heck look at the NASA ST2 corvettes with stock LS6 motors at 380-385 rwhp. and they can run with the best of them and in many cases put down lower lap times, then big hp cars.

i run a small cam 224/224 581/581 on a 112+4 and thinking of going to an even smaller cam ( 218/224 595/595 110+4 ) if not back to a new crate LS6 or crate LS2 ( with different springs and LS6 valves) if I can not find an LS6.

 

OK, perhaps I should have given you guys a bit more info, but I didn't want to make too long a post, I know it often discourages people from answering.

1) ME: I have a bit of track experience. I'm currently running a stock E36 M3 and I instruct with several organizations here in the region. I wanted a faster car that would be more of a challenge for me, and also a car that was track-prepared and fit for purpose. After thinking about various models (STi, S2000, 350Z, E46 M3, making my E36 a track car, etc.) I settled on a C5 Z06.

I realize 100% power isn't everything and am not looking for crazy amounts of it (although you can never have too much, reliability is factor no.1 for me). I know that straights are only the boring parts in between the fun stuff, and that powere only gets you so far.

I want something that's already track-prepared with the right mods to lower the total expense and headache. I would actually prefer a lower-powered, more stock car but any track-prepared car I see always has some engine mods. This one has A LOT of nice mods and is almost local...

All I want to do is drive, I'm not mechanically inclined at all and anything related to modifying or maintaining or repairing a car is a pain in the proverbial for me, although I recognize the importance of such things (hence why I'm here).

I change the oil every 3 days of track in my completely stock car and was planning on doing the same + tranny, diff and clutch fluid on this car. I will also get someone knowledgeable to look it over regularly. Changing the valve springs every year, however, seems like a pain to me.

I guess I would be in Group A except I don't do the work myself because I hate it and suck at it (both being fully related of course).

2) THE CAR: Let me give you an idea of what the engine is: it is a Callaway fully forged 383 based on the original LS6 block,TEA LS6 heads, G5x3, LG long tubes/x-pipe, Callaway Double D exhaust/insert, Doug Rippie tranny&diff.coolers, Ron Davis rad/oil cooler.

I can copy/paste more detailed specs but some of those things may have changed since then:

This engine was dynoed at 485whp when it came out of Callaway's shop, and then had more head and cam work done (but without a tune). It seems the nitrous WAS actually installed at some point, probably not for long, don't know how that would affect things.

Now what do you think? Should I hold off and get another car with a more stock-ish engine, although this one is quite attractive?

Another one is this one but I think I'd run into many of the same problems and the overall package isn't as impressive (brakes, suspension, etc.)

Thanks for your help!

 

Personally, I think the cooling and forged internals are the most impressive parts of this package. Just run it and do normal maintenance for a race car.
With this car, seat time, and TIRES (A6??) are going to make the most improvement.

 

As said by others, the GX3 cam is too much but the rest of the package sounds nice. If you think the car is good shape and is not being sold because it has some sort of issue, why not buy it and change the cam to something more moderate? Or else just live w/that cam and change springs every year (maybe sooner?)

 

Good write up with more details .... this thread has had me coming back looking for updates every day. Good to see you have the seat time in a M3 that is my favorite car of all times one heck of a machine for many years running. Out of all your choices the C5 is the best choice but I am partial.

Looks like your car is quite stout with that built motor. I do not think any of us could say "dont buy" as it seems like it was done right and with the exception of that cam seems to be a solid track car. Get it go have fun and see how things go after one season. Just keep an eye on those springs and maybe short shift it before redline.

 

I found out that the motor is running "double valve springs" (whatever that means, haha!) and that they meet the cam's requirements, apparently.

The FAST intake is gone, now the motor is running LS2 intake, injectors, rail and throttle body.

The "vacuum pump" is also gone, don't know what that is or what purpose it serves.

NOW what do you guys think? Should I still pull the trigger? What would you do?

One possibility would be to ask Callaway what the exact engine specs/mods were when it came out of their shop were and bring it back to that exact configuration... they remember the car or have it on file, since they were able to confirm they did build the engine originally.

I just don't want to have the car break at a track and be stranded... I guess I should buy it, run it "easy" for a few days, then change all fluids and have them sent for analysis, see what's up. And get a CAA (same as AAA) membership!

I never hit the redline in the M3 (I think I probably hit it like 3 times the whole time I've had the car, and never on track), so it won't be a problem.

Anything else you guys can think of?

 

I got your email in regards to the same question. So I will post here because everyone may enjoy the info.

Transmission. Yes it is strong enough for the power level, in every gear. Now what happens in between gears is a different story. They are wearable items and will wear out. When will they go away is anybody's guess. We have seen stock transmissions last 10 years on track without issues. Then we have seen them last a day. Why is that you may ask. There is some factory blemish (very rare) and the driver has a ton to do with the equation. If your clutch is working right and the driver is easy on them, they will last. I'm glad that the car has our coolers on it. That really rids the transmission of many failures from bearings.

Rear end. The rear end is a interesting setup in a car. It's doing many functions. First of it transfers power 90 degrees in rotation, changes the ratio and has a LSD (clutch style). Heat is a major killer on rear ends the cooler will help a bunch. But after that is preventive maintenance. Once a year one should replace the clutch packs running 20-25 events a year. That is a ton of track miles. It also depends on the driver and track. Smaller, ,bumpier,tighter tracks will wear on them faster then a long smooth track.

Good luck to you, drive fast and smooth and life will be good. Minus a few headaches along the way.

Randy

 

Dont think any of us can say stay away ... Car sounds good long as work was quality which is what Callaway is known for. If it is a good deal go for it ... since ya may have to change a few things to make it the track car you want you may want to build that into your cost..

 

Thanks a lot Randy, that is great info. I like to think I am a pretty smooth driver, never hurrying shifts, but I do like some level of oversteer, often power-on oversteer, which I guess will take its toll on the diff. I'll change the oil often and see if there is anything in it that is worrying.

Thanks a lot guys; now there's the matter of price, I'll see where the negotiations take us and take it from here. I guess with heavy duty track work even a stock engine would have taken its toll on the driveline at some point...

I'm glad to have found this community, seems like a good place to share.

 

Slight used T1 car. Race prepped