Level8Drummer

I'll probably spend a lot of time in this section of the forums, so I also posted my intro here:

Hey everybody! I've been a BMW guy since 2001, and into performance driving since 2001. I started doing lots of track events in 2006, and became an instructor in 2009. I've had various BMW's as street / track cars, including an E34, an E30 (stripped out track car), and an E36 M3.

I'm joining the community by looking to purchase a C5 Z06 to use as a street car, and track car. Hopefully this will be more bang for my buck performance-wise, and the chassis will be less problematic than my E36 has been, namely as far as running reasonable temps on track without needing a head gasket every 25-50k miles.

Also I love engineering suspension setups, and I'm looking forward to ridding myself of McPherson struts, and getting a Corvette with A arms and a lower center of gravity!

I have spent quite a few hours reading up on this topic, going through the archives on Corvette Forums, but many of those posts are quite a few years old, and there may be lots of new options I have not heard about. Any tips or recommendations for setting up a bullet proof reliable C5 Z06?

I'm located in Greenville SC. I look forward to conversing with yall, and learning, and posting any valuable knowledge that I acquire along the way!


Level8Drummer

JerryTX

Welcome, you will enjoy it here and behind the wheel of our American M3 Buy a car with all the reliability mods done to it (engine/trans/diff cooling, big brakes, and a clutch bleed line installed at the slave) and you will have a heck of a time!

My son now drives my E46 M3 but I still love it.. the Vette is also a perfect 50/50 weight distribution car, just like an M3, just a lot faster.. but you already knew that.

Level8Drummer

Haha, I like it! I want to keep the creature comforts in the car as much as humanly possible, as I drive to and from the track (my E36 has 248k on the odometer and full interior). Clutch bleed line? Ok, more research to do.

I saw about the transmission and diff cooling, looks expensive. Are there a lot of failures without this?

And yes, vettes are much faster if driven properly! I'm looking forward to it, believe me.

Level8Drummer

JerryTX

Failures due to cooling: No.. you can simply back off and keep everything cool. Not fun IMO. I don't get a kitchen pass and make the effort to get to the track to go 7 or 8/10ths...

Clutch line: will be hard to find a car that is pretty stock that will have this: the owner will have to have experienced the overheated slave and soft clutch pedal, and then have dropped the driveline to get to the slave. Not a fun proposition.. but if they added an aftermarket clutch maybe they added the slave bleed line as well. There are other methods to bleed the clutch fluid more effectively: basically inserting a catheter into the line as far as possible and push new fluid in down low while sucking the reservoir of the old fluid. A bleed allows you to replace the fluid from the topside. There are OK workarounds so its not a deal breaker in my book but if you ever touch the clutch, you gotta add the slave bleed.

miracle_whip4130

Welcome! Read Zenak's sticky in this forum for a lot of good advice on prepping a C5 for HPDE, as most of the info is still relevant today. The C5 Z06 is a very popular HPDE car, so you'll find lots of good information. Given your experience, I'd recommend the following as a minimum for your first outing beyond just replacing all fluids and inspecting wheel bearings, ball joints, etc:

-add larger radiator
-add oil cooler
-install cheap rotors, track pads (Raybestos ST-43s work great) and new brake lines

Since you have a lot of track experience, you'll also want a better seat, brake ducting, diff and trans coolers, and a BBK ........but I'm not sure how aggressive your mod budget/schedule is.......

Level8Drummer

Great info! Doing trans diff cooling research now.

Yes JerryTX, I can't just drive 7/10ths either man. Gotta take it to the limit.

Definitely getting a remote clutch bleed line.

miracle_whip4130, good info. I already planned on a radiator upgrade and an oil cooler install. Is it much easier to install separate units than a combination radiator? I read one post where the guy had to lift his engine up to install the oil cooling lines...

LG motorsports has a kit, but it sure is expensive.

DRM kit? Other options?

Level8Drummer

Dan H.

Welcome!
Just getting started with a c5z and love it

There is a great sticky topic that covers a lot on different areas regarding track upgrades. It's a couple years old but still pretty relevant.

This forum is quite active and a great help!

Olitho

I recommend the larger radiator, engine oil cooler, trans cooler and diff cooler if you run often in the warm climate of your area. Doing so let's you run a lot of laps while thrashing on the car. Without those items the car will eventually protest and go into limp mode and you must exit the track.

I also recommend the clutch bleed line, but in my 10 years of tracking and racing C5s, I have found with the stock clutch setup you can avoid almost all of the slave cylinder problems by shifting late in the brake zone. If you brake and depress the clutch right away while still at high speed and high revs, you can replicate the stuck clutch problem within a few laps. If you brake hard and then shift just before you need the gear as the RPMs have dropped I doubt you will get the stuck pedal. That is my experience.

miracle_whip4130

Yeah, the struggle is real if you opt for the Dewitts combo cooler and Aluminum oil cooler lines. This is the thread I started about that setup, and it was a bitch to install and included removing the driver side exhaust manifold and then disconnecting the rest of the exhaust as well as lifting the engine a bit: https://www.corvetteforum.com/forums...post1589561291

If you're going to add slicks and more power to the car then I would just go with the standalone unit. I think if you stay on street tires, like I plan to, you'll be fine with the Dewitt's combo cooler. One downside of the standalone for me is that I would also need to add a thermostat for this setup, as my car is my DD and I want the oil to warm-up on the street. My plan when I was considering the standalone was to buy the oil cooler itself, the Improved Racing oil cooler adapter with built in thermostat, all the AN plumbing for the oil lines and then make a oil cooler mounting bracket myself. This saves about $100 over the DRM kit and I get the thermostat, which DRM doesn't offer, and it lets me get the lighter and more stealthy Aeroquip Startlite AN hose. However, then I decided that I would just use the Dewitts combo unit, for the reasons stated in the thread above.

The C5Z is a popular track car for good reason and is pretty damn robust. The oiling system is particularly good for a wet sump and contributes greatly to engine reliability by not loosing pressure in most high G situations. The only major areas that the car is lacking in from the factory in my opinion are:
-cooling
-brakes
-seats
There are a couple engine issues to be aware of, although the actual failure rates from these are very low:
-valve springs - the stock valve springs have been known to break on the '02 and '03 Zs, even under normal operating conditions. This is easily remedied by replacing the valve springs with the updated part used in the '04 cars or aftermarket units using a special tool that lets you do it with the heads still on the car.
-timing chain - some bad harmonics can lead to timing chain failures. The fix is to use the beefier LS2 timing chain and add a timing chain damper. However, I think this issue takes many hours of high RPM use to manifest itself, but someone else might be able to provide more info here.

argonaut

Welcome. Echoing what everyone else has said - cooling is one of the car's biggest issues for serious track work. Motor (both oil and water), trans, power steering and diff cooling are all important. Personally I burned up two diffs and one transmission before installation of the DRM coolers. Likewise the clutch can be an issue and most serious track guys have a remote bleeder installed and many also have gone with a racing master cylinder for the clutch. Improve the overall cooling and then you are ready to bang on it. The LS6 engine in the C5 Z06 has proven to be very reliable - near bullet proof.

After cooling the next weak point is brakes. Stock the car will use pads and rotors at a prodigious rate (as it will tires). Calipers spread, pads taper something awful. Many, if not most, serious track junkies have installed an aftermarket BBK. Then we have the problem of pushing out upper front A-arm bushings...the list goes on. Every car has its share of issues when stressed to the limit. Overall the C5 is very reliable and a good sight cheaper to maintain than most with equivalent performance (I'm looking at you Porsche).

One thing you will find about this forum and the Corvette community in general as compared to BMW is we are a WHOLE lot more civil, more helpful and more welcoming. (I own an M5, I hang out on E39 M5board and bimmerforums and as anyone who has done so knows - the two communities are from different worlds).

Have you driven a C5 Z06 on track already? I'm curious of your thoughts vs. E36 M3. Over the years we've had a couple guys make the switch from M3 to Vette and, for a time, become very active on this forum. But to my knowledge they all seem to have slipped away. In fact I know one guy well who rode in a C5, really liked it, went out and bought one, drove it one year, sold it and went back to a M3. Said he missed the 'feel' of the M3.

Bill Dearborn

For a street and track car the things that should be addressed first are reliability items such as added cooling for the engine, transmission and diff. When I had my C5s I installed a Ron Davis Racing Radiator with built in Engine Oil Cooler. It really gets the engine temps under control. I also had a GM Performance Parts T1 Transmission/Diff cooler installed. I did that after a particularly hot track day when the diff suddenly started howling on my first C5.

The C5s brakes can stand an upgrade. Stock brakes tend to taper the pads quite badly, have some cooling issues and crack rotors about every three track days. The good thing about the rotors is they are fairly cheap compared to BMW rotors. I used to use the NAPA Premium rotors and got them on a special purchase deal I had at the local NAPA store (they let me use a local government discount code as long as I didn't try to charge anything against the account). They were considered consumables due to low cost and frequency of replacement.

One issue with C5s is the ABS system. Pre 2001 C5 EBCMs are practically unobtainable and 2001-2004 C5 EBCMs have a failure mode that hits quite frequently.

If you follow GM's recommendation to run an extra quart of oil when on track the LS1 and LS6 engines are pretty close to indestructible except when run at high rpm through long high G left hand turns. The C6 dry sump system resolved that issue in its 2009 version with a larger reservoir. C5 people used Accusumps. I depended on not doing the long high G left hand turn deal and with my RD radiator, remote oil filter and the added quart ran with 9 quarts of oil in the system.

Some people say the Vette steering doesn't have as much feel as BMW steering does but I have been driving Vettes since 1972 and when I drive a BMW I really don't notice that.

Seats will be another issue. For the Gs that can be pulled they really don't provide enough lateral support and you should plan on upgrading them. That is pretty much the same thing you would do with an M3 since their seats really don't provide that much support either.

I moved to Charlotte from Upstate NY about 18 months ago and have been a BMW DE instructor since 2009. I currently instruct at Tarheel Chapter events. I am hoping to get a chance to drive and instruct at Road Atlanta in the next year or so. Have you ever run at Carolina Motorsports Park?

Bill

froggy47

Interesting.

Level8Drummer

Great information guys, I've got some reading to do!

L8D

Level8Drummer

Olitho, thanks for the info about the shifting, I've always double clutched when I heel toe, so that should make it easier since I can easily and smoothly skip gears when I shift. And I've heard of the ST-43's. Deciding between them and the new (last year) EBC orange pads...I'm used to running Performance Friction 06's on my M3.

miracle_whip4130, does the updated valve spring part fix the issue with them breaking? Or is it still a wear item even with them installed. Also, that was your article that I read! Holy cow man, talk about a deterrent.

Argonaut, Good info man. Yes, you all are much more helpful than the people on BF.com are. I have not driven a vette on track, but had students with a C6 Z06, and a C5 Z06 at my last 2 events. I've got to try one out!

Bill Dearborn, Were you at VIR 3 weekends ago with Tarheel? I was there! If you want to instruct at Road Atlanta, I'd recommend Hooked on Driving. I'm not a big fan of Peachtree BMWCCA (the club that runs Road Atlanta). I go to CMP every year with the Mustang club. Great club to run with.

Froggy47, I was watching your videos the other night, fantastic walkthroughs. I learned what the underside of a C5 looks like thanks to you!

I'm leaning towards getting a dewitts (only coolant cooling) radiator, and a seperate oil cooler with the Improved Racing oil cooler adapter with built in thermostat, plumbed in with an 2 quart accusump. There is a place that fabs hoses, and I can get the fittings.

What's the cheapest effective and reliable trans diff cooling setup? Apparently it's a must...Also, do any of you track guys run Redline MTL in the tranny, and Redline 75W90 in the diff? That's what I ran in my BMW, never had any issues other than have to replace the head gasket all the time.

Level8Drummer

miracle_whip4130

Changing the valve springs should fix that for good if you're using stock cam and valvetrain. This thread I started has links to the guides I used to change mine, if you're interested:

https://www.corvetteforum.com/forums...e-springs.html

Haha and yeah, installing those oil lines is no joke on the Dewitts. However, they also offer a hose kit with braided steel lines that wouldn't be any harder than installing any other oil cooler lines. However, you lose the pressure bypass that's part of the hardline kit if you go with the AN hose kit.

Olitho

What is a Level 8 Drummer?

Do you know this guy? http://www.daveweckl.com/bio.htm.

fatbillybob

Dang! Last month I raced at VIR and my 1st session ever seeing the track was in qualifying. I could have used your track knowledge and I could have told you lots about racing a C5Z. I'm racing SCCA T2 which is like a spec vette class restricted with lots of ballast. The car is driven like a spec miata momentum car. It is bullet proof, needs coolers like all have said, brakes fantastic with Stoptech's T1 brake kit. I'm still on a 10 year old engine I have never rebuilt! I would like to race an E90 or E46 M3 and would have liked to hear about that. Those BMW's can be made to be very fast. Fall-Line is making the BMW and Porsche very very competitive in class. Depending on mods a C5Z can fit in many racing classes. How fast do you want to go and how deep are your pockets?

crimlwC6

I'm a fellow bmw convert as well (E92 m3,330i,X5d). Welcome! To stir the pot, I've run for several years with no diff or trans cooler in Arizona. My car is a race car and about 350 lbs lighter than stock so ymmv. Imo, you don't need to rush out and get $3k diff/tran coolers. I run wilwood sl6 calipers and I'm quite happy with them. You can buy a kit for under $1500. You'll save money in pad costs your first or second year and save hours swapping out pads. Imo no need to get a z06 and tear the top end down to replace springs unless it is high mileage. When I switched to a spec clutch (flame suit) I installed a remote bleeder but never had to bleed it because it is always very clean. I'm not saying to not install one though just that better material seems to sove the dirty clutch fluid for me.

klodkrawler05

Welcome! I recognize your SN from BF.C where I mostly lurked but occasionally posting under the same username as here.

Level8Drummer

olitho, I know who he is, great drummer. I used to play many years ago. The name just stuck.

Fastbillybob, I'll check out some bbks. Would love to have taught you vir. great track

Crimlwc6, thank you as well.

Klodkrawler05, people are very helpful here, I can't complain!

Ok, more questions:

If I get this:
http://www.improvedracing.com/oil-pa...kit-p-493.html
And an accusump, would that solve the ls2 oiling issues In a c6 non z?

And separately, would a non z c5 (ls1) come with a bat wing oil pan?

Also would an accusump solve the oiling issues the non z c5 ls1 would have?

I'm having trouble finding a c5 z06 That would make a suitable dd/track car. I'm finding either highly priced garage queens, or wrecked salvage cars, nothing in the middle.

L8d