May 02, 2011
After nearly 60,000 miles of fun the brakes on our 2002 Chevrolet Corvette Z06 sound like this.
April 07, 2011
New cars are our thing. We only delve into the used car world from time to time for something fun like a 1985 911, 1984 308 GTSi or in this case a 2002 Chevrolet Corvette Z06. So it isn't common that our registration renewals include a smog-test due notice. That's just what happened with the Z06. Do you think it passed?
March 31, 2011
We dropped off our 2002 Chevrolet Corvette Z06 to address the "service active handling" threat scrolling across the IP and asked for your diagnosis. From there the guesses came rolling in. They covered just about everything:
"Wheel speed sensor."
"EBCM module... $1500-$2200 at the dealer."
"Steering wheel position sensor."
"Battery acid on the ECU."
Our service advisor called us a few hours after we delivered the Z06. He explained, "We found fault code C1287, which is a problem with the steering position sensor. We checked for any shorts or bad grounds in that circuit. Everything looked good so we are going to replace the faulty sensor and clear the code. Your car will be ready to pick up tomorrow."
Did you call it? Well, pat yourself on the back.
Total Cost: $290.54
Days out of Service: 1
Mike Schmidt, Vehicle Testing Manager @ 58,249 miles
March 30, 2011
Well, this has been going on for some time now, and after driving it over the weekend, including 30 minutes in dark, rainy conditions, I'd had enough of the Service Active Handling warning message. Vehicle dictator, Mike Schmidt, charged me with dropping it off at Santa Monica Chevrolet, Infiniti, Oldsmobile, Saturn, Peugeot, Maserati, Skoda, ATS and whateverelsetheyservice, and I did just that.
Owing to personal experience with the exact same warning in another C5, I'm going to predict a wheel speed sensor. Any of you care to take a guess?
Kurt Niebuhr, Photo Editor @ 58,281 miles
March 23, 2011
After viewing Mr. Oldham's video in which our longterm 2002 Corvette Z06 flashed up two communiques, I became curious.
Recall that the first message was "Service Active Handling" and the other was "Service Vehicle Soon."
Now, neither of these alerts lit up the check engine light, but perhaps a code or two was stored. So I placed the Z06 into 'diagnostic mode' by threatening to yank off its intake manifold again (actually I followed the instructions here).
It vomited up sixteen 'history' codes (15 of which pertain to 'loss of communication' among the various subsystems) and no 'current' codes. The remaining code (28-TCS C1287 H) for steering sensor rate malfunction mightcouldpossiblymaybe have something to with the "Service Active Handling" message.
My guess: a ground wire is loose somewhere. We'll have it checked out.
Jason Kavanagh, Engineering Editor
March 17, 2011
Scott Oldham, Editor in Chief @ 57,976 miles
February 23, 2011
About a week ago I posted about this slight damage on the nose of our Corvette Z06. Well, sure enough, it did buff out. Mostly. This is as good as I could get it.
And now it looks like we're missing a valve stem cap on that front wheel. Maybe I'll fix that tomorrow.
Scott Oldham, Editor in Chief @ 57,114 miles
February 17, 2011
The culprit? A crapped-out water pump.
When Bothwell first attempted to replicate the drip, of course, the sucker wouldn't leak. They pressurized the cooling system with the engine off and cold. Nothing. Checked it while warming up. Dry. Then ran it up to operating temp and pressure and checked again. Wouldn't leak a drop.
They called me up to double check the conditions during which we observed the leak. It was always after a long period of running. So they left it running for a good long time where it could fully heat soak. Then the river finally started flowing out of the pump, the accessory drive belt slinging coolant all about and generally making a mess.
Our pump had 57k miles on it. According to Bothwell, it's not unusual for them to see Corvette water pumps give up the ghost at this point in their lives.
It was about time for an oil change so we had them perform that, too, while they were in there.
Once again, dealing with Bothwell was a smooth, professional and courteous experience . The repair did however take about a day longer than expected since they were down two guys at the shop on Friday and had a full house. Seems we're not the only ones to discover a good shop.
Total bill including pump, 2 gal Dexron coolant, seven quarts of synthetic oil & filter, labor and tax- $601.86
Jason Kavanagh, Engineering Editor @ 57,028 miles.
February 11, 2011
Our beloved 2002 Corvette Z06 is still in the shop. As soon as we know how the patient is doing, we'll pass it on to you.
But a funny thing happened while I was standing next to the Corvette as it bled coolant all over my driveway: I noticed it is without a single door ding. Not one. And that's after 57,000 miles of driving.
February 09, 2011
Scott Oldham, Editor in Chief
February 08, 2011
Remember when our Long Term 2002 Corvette Z06 puked coolant all over Oldham's driveway? Well, turns out sudden, enormous leaks don't fix themselves and by the time the Corvette made it the few miles back to the office the coolant smell was as strong as ever, as was the smoke filtering in from the vents. Neither of the temperature indicators moved a hair.
Still, once we got it to the office, we weren't sending it out again. We called the flatbed to bring it to Bothwell Automotive. You'll remember Bothwell as the shop that helped us diagnose the knock in our Z06 when we first bought it. These guys know what's up and we don't have to babysit or nitpick over pointless things like unnecessary tire rotations or wiper replacement like we would with a dealer. Plus, the chance of them diagnosing and fixing the problem first is infinitely higher.
February 07, 2011
This is wierd one. I was running around town in our long-term Z06 yesterday, when my wife called and asked if I would bring home In and Out Burger for dinner. So I hit the drivethru for a Double-Double Animal-Style and two plain cheeseburgers.
The line was long, so the Vette was idling for a while, and when I was leaving with the food I smelled something I shouldn't. The car was running fine and all the gauges read normal, but I got a short whiff of something.
"Clutch?" I thought. "Nope, smells more like coolant."
But the smell went away quickly, so I drove home without a thought.
January 22, 2011
I get a kick out of our Corvette Z06's old-school pop-up headlamps. Sure, pop-up setups don't make a whole lot of sense anymore, what with the added mechanical complexity, the severe lack of aerodynamics during night driving and the fact that manufacturers can produce sleek front ends using exposed lights (including the C6 Vette). But not everything has to make sense, and I enjoy watching the lights flip up and down, especially since we might never see them again on a mass-produced car because of pedestrian impact regulations.
On another subject, I have yet to experience the "service active handling" indicator that Editor-in-Chief Oldham witnessed the other day. Maybe I need to drive it harder...
I also checked the engine oil (not to imply that's a great feat on my part), and it's just fine; the Z06 seems to be using the stuff sparingly, which is good to see, although the car's readout says the oil's life is at 17 percent remaining.
Mike Monticello, Road Test Editor @ 56,628 miles
January 20, 2011
This morning I was driving our Z06 at speed on an L.A. freeway and this notification appeared on its instrument panel. And it stayed on until I reached our office nearly an hour later. It did go away, however, after I cycled the key and rebooted the car. Hmmmmm...
We'll keep you posted and let you know if it comes back.
Scott Oldham, Editor in Chief
December 29, 2010
You might remember that our Z06 has a gimpy trunk lid popper -- JKav posted a workaround video for it way back in February. You also probably thought that we had long since fixed it. Well, we didn't. But as of today it's gimpy no longer. I finally got tired of the thing and fixed it. We've had the car 11 months. Total fix time? Thirty minutes.
December 07, 2010
While I had our 2002 Chevrolet Corvette for my Buttonwillow trip, the "Check Oil Light" came on. And when that light comes on you can't check your trip or odometer. The odometer comes on for a second when you start up the car and then gets wiped away by "Chevrolet" and "Corvette" and then the oil warning light stays there no matter which buttons you press.
Fortunately as editor John DiPietro noted back in March, pouring oil in the large oil fill opening is a cinch. The only minor issue is that twisted dipstick. Makes it a bit of a bother to try and wipe away the oil for a clean read.
Here it is showing that the Vette was down a quart.
November 15, 2010
So there's this turn I take every night on my way home. It's just past my freeway offramp and it's a sharp hairpin left with a yield sign. The last time I sliced through it in our long-term 'Vette, the back end got pretty squirelly. Maneuvers like that tend to have those results when you're on worn-out tires. With the new Bridgestone RE760s in place, though, the Z06 had a very different reaction...
It tracked through -- quickly, and without any tire screeches. It's not that I try to break cars loose in this turn, it just tends to point out when a car doesn't handle well. "Wow," I muttered to myself, "that was different."
I was stuck at the next signal, eyebrow raised. I gave it a little more juice off the line, expecting a tiny bit of wheelspin. Nothing. The rear tires dug in and shot me out the other side. I never drove the Corvette when the previous tires were in their prime, so I can't really say if these new Bridgestones are a step up. What I can say, however, is that these new tires are up to the task of handling the wallop of torque coming from the driveline.
On a side note, I noticed the Z06 got quite a few looks over the weekend. Granted, in one instance I was in first gear and hopped off the throttle to get that wonderful burble. A pack of Japanese tourists on Melrose stood on the corner slack-jawed, frozen in place by the wonderful growl and pop. Then a very attractive limousine chauffeur was pacing me on Sunset Boulevard. She gave me a very sweet smile as she overtook me on the right. Who knew? I thought that in car-jaded L.A., where Corvettes are a dime-a-dozen, our Z06 wouldn't be able to turn heads unless it was scraping its splitter in a dip or high-centering on my driveway.
Mark Takahashi, Associate Editor
November 11, 2010
A couple of weeks ago, we broke the news that our 2002 Corvette Z06 had been damaged by Mark Takahashi's driveway. (No, really.) Six business days later, our Corvette was back in our hands.
But not for long. The driver side fender didn't quite line up with the door in the same way as the passenger side. At least, I didn't think so and as I had the guy's number at Golden Hammer, I called them up to see what they could do.
As you can see, the panel gap wasn't horrible, but it wasn't the same as on the passenger side (I could fit my pinky in this side) and it wasn't the same as when we dropped it off. And for what we were charged, it should've been.
The mark of a good service shop, as you've read me say a billion times, isn't perfection-- perfection is impossible -- it's willingness and attitude to fix things that go wrong when they do.
And to that end, Golden Hammer did a spectacular job. We weren't on the phone for 30 seconds before he appologized and said that whenever we could free up the time, they'd get things straight. Obviously for free.
November 02, 2010
Mufflers. I don't much care for them and neither does The Brunette.
That's why, when there was a C5 Corvette parked in our garage, we ditched the stock sissy pipes and shoved the above SLP Loud Mouth onto our Vette. It was beautiful.
Children wept, old people spat and emasculated men did whatever emasculated men do.
Because of our Z06's titanium exhaust (it actually sounds halfway decent as opposed to a stock C5 Corvette), I've let it slide for a while. But now, for two reasons, I want to fit the SLP pipes on our car.
Reason number one, it's awesome.
Reason number two, we can strap it to the dyno at MD Automotive and see what kind of power a muffler-less Corvette exhaust actually makes.
Who's with me?
Kurt Niebuhr, Photo Editor @ 53,195 miles
October 27, 2010
I noted a while back that my driveway has become less Corvette friendly with my neighbor's tree uprooting a section of the concrete. Well, the situation has become downright hostile. I had the Z06 for a weekend and was skirting around the offending bump as I was departing and WHAM! A litany of expletives followed immediately thereafter.
As I surveyed the damage, I felt that sickening feeling in my gut. It's moments like this that make you wish you had a Tivo skip-back button that worked in life. Maybe I could've driven further away from the hump. Maybe I should've taken a motorcycle. Maybe I didn't need to run this errand.
Then I looked at the offending piece of driveway concrete. It was no longer a moderate hump, it now sports a jagged edge protruding above the hump. It looked to me like the slab on the downslope side of the hump cracked under the weight of the front wheel. This forced the peak to jut upwards, right into the Corvette's rocker panel (see the animation below).
October 26, 2010
Put my first miles on the Corvette after getting its new tires. As you can see, the new Bridgestones have an asymmetrical tread design and some pretty deep grooves that should displace a fair amount of water should we need it. They're not exactly all-seasons, but they're not on the verge of being barely legal track tires either.
Other than the fact that all four tires were holding air, I didn't notice an immediate difference. Then again, I wasn't really expecting to in the grocery store parking lot. Getting anything out of this new rubber is going to take a serious run up Angeles Crest Highway, or a track day at Willow Springs. Looking forward to one or the other very soon, will report back then.
Ed Hellwig, Editor, Inside Line
October 21, 2010
The results from our vote, Which tires should we get for our Z06, were overwhelming. Ok, not overwhelming, but the Bridgestone Potenza RE760s took the top spot. Plus, they were the ones we wanted. So after Jacobs drove the rear tire smack into a flying truck tread, the time for procrastination was over, it was time to spend some money.
October 17, 2010
Around here, we communicate via Post-It notes on a regular basis. So when a Good Samaritan left this note on our 2002 Chevrolet Corvette Z06 we almost walked right past it.
You see, ever since the tire was compromised last week the Vette's been parked while we wait for a new set of tires to arrive. In the meantime, it's good to know there is a total stranger out there that has our back. Nice people still do exist.
Mike Schmidt, Vehicle Testing Manager
October 04, 2010
As I was refueling our Corvette, I decided to check the oil level while I waited. I usually wrap a rag around the top of the dipstick tube to squeegee the oil as I pull the dipstick out, but all of the twists in the 'Vette's metal blade complicated my usual routine. No big deal, though, as there was little to no oil until I got down to the last couple of inches. Manufacturers put these twists in dipsticks to allow it to snake its way past bends in the dipstick tube on its way into the oil pan. With as many twists as the Corvette's has, I'm assuming it has to follow a pretzel-shaped path. Re-instering the dipstick is a bit like feeding a wet noodle into a keyhole. The level was fine, though the oil was starting to look a little dark.
On a side note, the Forza 3 Hot Lap standings have not changed since the last post, though I have improved my lap time to 1:34.188.
September 16, 2010
Back in April I wrote this about our 2002 Chevy Corvette Z06. Now, 6,383 miles later you can see the result of all that scraping.
Scott Oldham, Editor in Chief @ 51,205 miles
September 15, 2010
After ripping our Z06 home last night I was reminded that it once had a nagging engine knock. I mostly remembered this because I was the one who bought the thing and would likely never hear the end of it should it spontaneously self destruct.
After an extensive fact finding mission by our resident engineering staff, the problem was eventually found and fixed. Since then, it's been flawless. Haven't heard a ping since. Okay, maybe a random one here or there, but our M3 sedan used to do that on occasion too. When you wind up a street engine to such a degree, it's bound to happen once in awhile.
That said, the LS6 in our Corvette is an amazing piece of work. It not only sounds great through the titanium exhaust, it makes great noises from inside too. There's just enough valvetrain noise to remind you there's a serious V8 sitting not too far from your feet. It's a sound that's rarely heard in modern cars these days, so much so that passengers sometimes think something is wrong. Nope, it's just fine I tell them. In fact, it's just about perfect.
Ed Hellwig, Editor, Inside Line
September 10, 2010
I've had it with the shifter in our long-term 2002 Corvette Z06. Time for some new hardware. But which one should we buy?
To figure it out, today we fired up the forums and did a little research. This is what they spit out on the subject.
B&M ($260), Hurst ($180) appear to be similar throw/effort. Noisy, especially at WOT.
MGW is another option. Lots of enthusiasm for it including from many on IL ($250). Very quiet.
All three of the above sound like they're pretty unforgiving for daily use.
MTI said to be a bit more livable effort/slightly longer throws than the above ($194). Not quite as quiet as the MGW.
C6 Z06 shifter is apparently a middle ground in terms of effort and throws. As of late '09, the C6 Z06 parts appear to have been superceded by regular C6 shifter parts.
My vote would be for the MTI (pictured above). Sounds like a decent all-rounder. What do you think we should buy?
Scott Oldham, Editor in Chief
September 03, 2010
The Z06 just got a pretty thorough detailing. It's the best money you'll ever spend on a used Corvette.
Over time, a kind of veneer of neglect builds up on a Corvette. Because this car is so easy to use, you start to take it for granted. Its simple practicality kind of smudges your whole idea of the car.
Then you commission a detail and suddenly everything about the car is crisp and clean.
What you see might not be entirely to your taste, but you sure know that it's really something -- a car worth owning.
Michael Jordan, Executive Editor, Edmunds.com @ 50,489 miles
August 17, 2010
The need to replace the tires on our aging Corvette has led to some conversations about other parts of the car that might be worth upgrading.
Rest assured, the seats have been discussed. We're working on it. As far as the wheels go, your comments suggest we shouldn't change a thing, so we probably won't. Well, we might powdercoat the stockers a darker shade of gray, but that's about it.
The other most often discussed issue is the shifter. It's not terrible, but not graceful either. And it's a little on the tall side. So, do we go aftermarket? If so, which setup? Another possibility is switching to a C6 setup. One of the cars we test drove during the buying process had such a setup and it wasn't bad. Suggestions?
Ed Hellwig, Editor, Inside Line @ 50,302 miles
August 12, 2010
It's been time for new tires since the introductory test on our 2002 Corvette Z06. It's not that it's dangerous now, but there is a mild, crippling fear of freak rain storms or puddles or really damp squirrels.
In any case, these meats are overcooked, and it's time for some fresh ones.
The C5 Z06 is a sports car and sports car guys like to change things up so there must-- MUST-- be options: Dunlop, Sumitomo, Nitto, Michelin-- anything. Everything!
Well, there aren't. Without going +10mm or with bigger rims, we're staying with stock sizes, there are 5 tires available.
Follow the jump, tell us which one you want to see us test. Which you'd buy with your hard earned money. And we'll buy them. (Probably. Maybe.)
Tire 1: Goodyear Eagle F1 Supercar
Tire 2: Michelin Pilot Sport PS2
Tire 3: Firestone Fireawk Wide Oval
Tire 4: Continental Extreme Contact DW
Tire 5: Bridgestone Potenza RE760
Your call. Which should we buy?
August 02, 2010
One would think that there was plenty of room between our Corvette and the bike lane to prevent such unpleasantness, but no.
When I came out to the car on Sunday morning I found the Corvette's driver's mirror tweaked in a most awkward manner along with a lovely scrape of the paint on its outer edge. No note, no nothing.
Here's hoping that the unrepentant hipster jackass who caught the mirror with his brakeless fixie went down in a blaze of mangled spokes and shredded skin.
Ed Hellwig, Editor, Inside Line @ 50, 083 miles
July 29, 2010
This morning I pulled into the EZ Lube on Washington Blvd. in Culver City and bought an oil change for our long-term 2002 Chevy Corvette Z06. It was a smart move. The facility was well kept and Manny and the EZ Lube guys could not have been nicer or more professional. They performed the service quickly and cleanly. They even knew what oil was right for the car before I mentioned it or popped the hood.
I climbed from the Corvette, walked up to Manny, asked for an oil and filter change and he said "Mobil 1 right?."
The entire process took about 20 minutes and cost $104.51 including tax. That price includes a 3 month/3,000 mile free top off service, which is nice.
Manny and Co. also filled our windshield washer fluid, gave the car a once over, checked and topped off the tire pressures, vacuumed the Vette's carpet and even cleaned the windshield. I would go back in a heartbeat.
July 28, 2010
It has been 7,000 miles since we put new oil in our 2002 Chevy Corvette Z06. And some of those miles have been on the racetrack. Today the car told me that has been nearly long enough. It wants fresh oil soon.
July 12, 2010
I'd dare to say the most abused part of our Corvette is not the engine, the brakes or the recently replaced tires. I'd say it's the air dam.
With every sound of scraping plastic, I clenched my teeth and white knuckled the steering wheel, wishing for the sonic misery it to end as soon as possible. My weekend in the Corvette was stressful.
I guess for people who drive cars this low to the ground, looking for clearance and ways to get into parking garages and over speed bumps is a way of life. After my weekend in the Corvette, it's no everyday way of life for me. Sure you might say "It comes with the territory" or "Stop being a panzy and suck it up." Do you drive a low slung car like this all the time? I'd bet most do not.
I scraped the plastic more than I care to remember this past weekend. Even when I thought I was being super careful going through a rain run off trough in an intersection, it scraped. Taking the angle over a speed bump at low speed, it scraped. Just driving down the road and hitting a small bump, it scraped. Ok, it might just be a piece of plastic, but sound it makes me think I'm about to rip off a piece of suspension.
The high point of stress was going into a parking structure I'd never been to before late Saturday night. I didn't notice the entrance had a ridiculous change of angle until I was right on top of it. I entered the parking structure at a meticulously slow pace, hoping not to drag the nose. The guy behind me decided he could beat the light too. He took the left turn and tucked in close behind me. The fact I was trying to be careful didn't bode well for him as the oncoming traffic let him know he was being a jerk by honking at him, which he in turn started to honk at me. If I knew of another entrance to the garage I would have taken it, but I was stuck in the situation and had to deal with it. Despite the careful speed, the angle of approach, there was a sickening thud as some chunk of metal hit the cement. Garage entrance FAIL.
There is no doubt that the 'Vette is a blast to drive on flat, predictable surfaces. But the real world responsibilities are more than what I'd want for my day to day lifestyle. I guess if I was really into our Z06, I'd find ways to get around and minimize the abuse. This just makes me realize I'm not that into our 'Vette to overcome those difficulties.
Scott Jacobs, Senior Photographer @ 49,670 miles.
June 04, 2010
Managed to snag a pic of this alert in our 2002 Corvette Z06 just before pulling out of our parking garage. It came on about 20 seconds after key-on and shortly thereafter was replaced by another alert reporting that everything was just peachy, or something like that.
A brief check suggests that this alert has nothing to do with warming up, per se -- logical, since there's nothing to warm up. Rather, the system, once you're rolling, does quick check of various chassis sensors including the steering angle sensor. It needs a brief straightaway to check this guy.
Since our garage is a series of slow 90-degree turns immediately after another, the system couldn't get a proper read on the steering angle sensor in the allocated amount of time. Owner's manual says this is normal and that the Active Handling is not operational during this period.
No worries here. I usually go full stability-off commando-style but hadn't yet hit the buttton this time. Anyway, I don't beat on cars til the coolant is fully warmed up (and then some -- that way the oil can get warm too), which takes far longer than it took for the Active Handling to be ready in this case.
Jason Kavanagh, Engineering Editor
May 28, 2010
Cammed Z06? Yes please.
Turn up your speakers. Watch. Repeat.
Ours needs to sound like this. Now.
May 15, 2010
That's too much information. But no, the heads up display on our Z06 isn't broken-- well, it's broken, but it's functioning as intended so it's not more broken-- that's just what it does when the sun hits it in just the right spot. And just the right spot happens to be my entire morning commute.
There doesn't appear to be a way to avoid this without putting something -- I used our Long Term Fuel Log-- over the hole on the dash. Of course, this results in the reflection of a fuel log on the dash to fly over the IP and hit me in the face when I get a chance to use the big V8.
"Sorry, officer. As you can see, my gauges are broken. I was going less than 188, right?"
Mike Magrath, Vehicle Testing Assistant
May 07, 2010
After my softball game last night, I was standing around the Z06 with our right fielder when he mentioned he'd never been in a Vette before. I told him to get in and he plummeted into the squishy driver seat with a declaration of "it's so low." As a former M3 owner, I don't think he was impressed. As he climbed out, though, he must've used the steering wheel as leverage to get out and activated the steering column lock.
When I started the car, the gage cluster read-out ominously said something to the affect of "Pull Key; Wait 10 Seconds." I was going to ignore it (probably not the best idea), but when I went to move the wheel I found it was locked. This engaged a new read-out saying "Service Steering Column Lock." Uh-oh. So I pulled the key, waited 10 Mississippis and tried again. No luck, still locked. I tried it two more times, waiting longer each time. No luck.
At this point, good buddy and catcher SubyTrojan entered the scene. "Vette's broken," I declared through the window. We chatted for a few moments about possible causes, solutions and just abandoning the Z06 at Cheviot Hills to become a bird sanctuary. Then I said, "OK, let's just try this all over again." I got out of the Vette, locked the door, waited a few seconds, unlocked the door, got in and fired it up. Low and behold, the steering column lock was disengaged. No service (or tow truck) required.
To double check, I locked the steering column again this morning, but it unlocked once I started the engine. Go figure. Though I have to wonder how common this issue is when the trip computer has both a specific warning and solution for it. Hmm.
Oh well, I guess this just proves once again that if you want to fix something -- anything really -- just unplug it and re-plug it back in.
James Riswick, Automotive Editor @ 46,562
May 01, 2010
Before we send out 2002 Chevy Corvette Z06 out to the test track, we wanted to make sure this 45,978 mile Corvette was aligned properly. We haven't experienced any driving anomalies, but crazy things happen at 10/10ths. Plus, those tires are big and look expensive, might as well make sure we're good.
So we took it to Stokes Tire Pros here in Santa Monica. They know us and let us cut in line (take that, guy with the Subaru wagon)-- we just wish they'd give us a price break. An alignment there cost $110.
Follow the jump for some nerdtastic alignment numbers!
Front Caster: L: 7.80 L: 6.97
R: 7.72 R: 7.36
Camber: L: -0.91 L: -0.81
R: -1.16 R: -0.79
Toe: 0.10 0.01
Rear Camber: L: -0.60 L: -0.84
R: -0.80 R: -0.85
Toe: 0.19 0.01
Mike Magrath, Vehicle Testing Assistant @ 45,978
April 26, 2010
I've been wanting to take our long-term 2002 Corvette Z06 to the dyno since day one. A certain detonation issue sort of sidetracked our plans, though, as you really need to avoid full throttle in those circumstances... unless you like engine salad.
But that's all behind us now. We've since been relishing the ability to hoon the Z06, which we've found has an aptitude for powerslides and can slither its rear end on a straight road with nothing more than a third-gear roll-on.
This car certainly feels strong. Always has. Without further ado, here's what we learned at the dyno.
Hit the jump for the dyno chart and photos. And pardon the video quality above, which was done not by our usual crack video team but by some hack with a tempermental and sub-par point-and-shoot.
March 29, 2010
I finally got in our long-term Corvette Z06. Though I could've had the car earlier, I wanted to wait until its pinging problem was cured. Now that it has a clean bill of health, I figured I'd be able to enjoy it as the creators of its 405-hp V8 intended. I'm sure I'm not shedding any light here when I say "Damn, this thing is fast!" but I'll say it anyway.
Blasting down freeway on-ramps and out of corners reminded me just how great an old two-valve-per-cylinder, pushrod V8 can be. The vocals (sorry, too much American Idol) from the exhaust are cool too -- quiet enough when you're just tooling around and downright rocking with a gutteral roar when you're leaning on it.
Follow the jump for other observations, some of which aren't as well, obvious.
-- I checked the oil and found the 'vette was down a quart. Though two quarts of Mobil 1 were secreted in the trunk (see below) I stopped by Pepboys and got the vital synthetic fluid (cost: $7.49). Thankfully, the LS6 V8's dipstick and oil fill cap were very easy to access. The oil fill opening is dead level and large enough so I didn't spill a drop. Conveniently, it's also just larger than the bottle's neck, so I stuck the bottle in there upside-down for a few minutes to get the last bit of oil out (and minimize the hurt to the earth).
-- This being the top-dog performance Corvette, I expected a stiff, bone-jarring ride but my finicky back was glad to discover that wasn't the case. The Z06 was actually pretty compliant over the crappy roads in and around L.A. (La Cienega, I'm looking at you). And it sticks like a cat to a drape in the corners -- there's more capability here than I was willing to exploit on public roads.
-- When I went to put my gym bag in the trunk, I discovered the lid barely moves when you hit the release. As the trunk is open to the passenger compartment, I saw that there were a few quarts of Mobil 1 stashed in its rearmost left corner, but I couldn't get to them unless I crawled back there, hence the trip to Pepboys. Later in the day, it dawned on me to try shutting the door quickly (with windows up) to pop up the lid, the theory being that if the car is airtight enough that would do the trick. It did. My "Nice going Johnny!" moment was short-lived -- I found out later that Jay Kav already discovered this method and even made a short video on it.
-- The center console lid can't be opened all the way if the parking brake is up. So after parking the car and pulling up the p-brake, my instinctive flip-the-lid-and-grab-my-wallet action was thwarted time and again, until I remembered to open it first and then set the brake. Furthermore, it gets pretty warm in that compartment so I wouldn't advise stashing any chocolate bars there.
-- I love the meaty feel of the shifter but dislike the 1>4 skip-shift (big surprise). I got around that annoying "let's lug the engine to drive up our fuel economy estimates" feature by either accelerating a bit more briskly in first (so it didn't kick in and thus really defeating its purpose) or, if I took off more gently and it did kick in, giving it a throttle blip mid-shift to cancel its action.
John DiPietro, Automotive Editor @ 44,773 miles.
March 10, 2010
Is our long-term 2002 Corvette Z06's detonation spell drawing to a close? It appears so.
Bothwell Automotive checked out the MAF sensor and found some damage -- one of the sensing elements was tweaked. Rather than just throw parts at it, Steve Bothwell figured he'd first try to repair the MAF sensor. He did so, and then re-checked the fuel trims. Lo and behold, the fuel trims came down from their previous 14% down to low single digits. The knock had vanished too.
Basically, the tweaked sensor dongas of the MAF made it tell lies. The MAF was reporting to the ECU that less air was entering the engine than in reality. This fib had two very significant side effects -- it made the air/fuel mixture leaner at full whack than it should have been, and the ignition advance more aggressive to boot (sounds kind of like a non-adjustable SAFC...). Just the sort of conditions that are ripe for a ping.
Now, this still doesn't explain why the Z06 apparently can't hear knock, but if the source of the knock is eliminated (as it appears to be), then we're fairly okay with it.
Also, the MAF damage was caused by a thing, and that thing may have kicked the snot out of the MAF on its way into the engine. Seems unlikely. Our Z06 feels quite strong, and such a snot-kicking thing would cause it not to be so. The damage was more likely done by mishandling. Perhaps the previous owner's mechanic was some kind of ape.
I'll be giving the Z06 a good rogering today to fully convince myself of its knock-free-ness, just to be 100% certain. You know, in the interests of science.
Jason Kavanagh, Engineering Editor
March 03, 2010
As RC Engineering's injector flow test report suggested, the cleaned injectors made little improvement once reinstalled.
Keep in mind that if the detonation had gone away as a result of this, it still wouldn't explain why the ECU refuses to recognize any knock activity. Even physically rapping the block doesn't register knocksum on the scan tool.
This is really the oddest part of the Z06's knock situation. As I mentioned earlier, there are no readiness codes, no DTCs, no knocksum -- absolutely nothing anomalous according to the ECU. It thinks everything is just awesome even as the engine pings audibly.
Aware of this, Bothwell was planning on scoping the knock circuit while the injectors were out at RC, but he became deathly ill and was home sick those days. So he's doing that electron work today along with cleaning and checking the MAF in an effort to bring the fuel trims down to a more reasonable level. This fuel trim activity is separate from the knock detection/correction thing above, but the former isn't helping given the latter's current situation.
As for intake leaks allowing in unmetered air, we found none while reassembling the intake when we performed the TSB.
A word on the local Corvette specialists, since you asked: one of them doesn't service cars anymore, another took four days to respond to our inquiry, another was actually a Chevy dealer and not a specialist like we were led to believe, and the last one only does basic routine maintenance.
Jason Kavanagh, Engineering Editor
February 26, 2010
What you see above is a flow report from RC Engineering of our longterm 2002 Corvette Z06's injectors. Not only is it a converted scan of a fax of a fax, but it looks like a bunch of alphabet soup. Here's a translation:
Our injectors were in pretty good shape.
Recall, Bothwell Automotive's diagnostic work suggested that a bum injector or two was causing a lean condition and making the engine ping.
The left column in the table above lists the flow of each injector on RC Engineering's flow bench rig, which applies a current to open the injector and delivers a pressurized test fluid for a specified amount of time. The fluid's volume is measured to determine the injector's flow rate. Here, the worst injector was only down about 5%.
After cleaning the injectors, RC re-checked the flow (right column) and they had all come up to spec (260 cc/min).
I'd love to be proven wrong when Bothwell reinstalls these injectors on Monday, but I'm skeptical that the cleaning process will solve the detonation issue. Even if the four worst injectors somehow managed to find themselves in same cylinder bank, it'd only be 4% lean on that bank and not the 14% reported earlier by the ECU. This suggests to me that the MAF is underreporting the actual airflow.
But I was wrong about the knock sensor TSB thing being the culprit, so don't listen to me.
Jason Kavanagh, Engineering Editor
February 23, 2010
You're probably as tired of reading about our longterm 2002 Corvette Z06's ongoing detonation saga as we are dealing with it. Here's the latest.
This morning we brought it in to Bothwell Automotive in Torrance, CA. These guys are not Corvette specialists per se, but they do service about 20 'Vette customers and countless other makes and models. Oh, and they know plenty about how to go fast, too -- their lobby's trophy case is bursting with about a dozen and a half NHRA Wallys.
First, Steve Bothwell confirmed the detonation. Then he checked the fuel pressure to ensure that it doesn't have a bum fuel pump or clogged fuel filter. Fuel pressure checked out okay.
Then he hooked up the scan tool and checked the engine calibration to be doubly sure we didn't get snookered by the GM dealer. The calibration checked out too, so that's not the source of the problem, either.
With the scan tool, Steve observed the long-term fuel trims and noticed something that might be telling -- the fuel trim for the right bank of cylinders is +8%, and the left bank is +13%.
Basically, over time, the ECU has "learned" (based on feedback from the oxygen sensors) to compensate for a general lean condition by commanding the injectors of each bank to stay open longer than normal. Apparently the LS6 can only trim banks of cylinders and not individual cylinders. This is a 2002, after all.
Anyway, a lean condition is a prescription for detonation. An underachieving injector (or two) per bank is the leading candidate as the cause of the lean condition, but at this point there's no way to know exactly which injector(s) is the culprit.
His recommendation is to have the injectors flowed and cleaned, which might be enough to bring a lame injector(s) up to par. If not, we'll at least know which one(s) is frumpy and can replace them accordingly.
Why the ECU doesn't acknowledge and/or correct the plainly audible knock activity remains a mystery. For whatever reason, it thinks everything is just peachy -- no trouble codes, no knocksum on the scan tool. Go figure.
Jason Kavanagh, Engineering Editor
February 16, 2010
Click to next page and follow the drama, that is, if you dare.
February 14, 2010
At the conclusion of Part 1 we left you with Josh Jacquot vacuuming up the rat poop we found after we removed our Corvette's intake manifold. .
Well, lets pick up the action with the image above, which is illustrating a key moment in the repair of our Z06. It's Josh asking Jay whether or not he likes his Grave Digger hat. What you don't know is that Jay is a hardcore Tom Meents fan and this exchange caused friction for the remainder of the day.
February 12, 2010
This will be part one of a three-part series as Jay Kavanagh, Josh Jacquot and myself attempt to change the knock sensors on our long-term 2002 Chevy Corvette Z06. The goal, of course, is to solve the Vette's chronic detonation problem.
Just in case anyone out there thinks this job is a walk in the park, let me remind all of you that this procedure includes the removal of the Corvette's intake manifold. Not exactly complex, but it isn't airing up the tires either.
The photo above is step 1: Remove the useless plastic valve cover covers.
February 11, 2010
We've had enough of the run around. We are going to fix our 2002 Chevy Corvette Z06 ourselves. At least that's the plan.
We're convinced (mostly) that our detonation problem is due to a faulty knock sensor. In the last Z06 post Mike Schmidt mentioned that our research turned up GM Technical Service Bulletin No. 02-06-04-023A, dated June 2002. Condition: Some customers may comment on a mild to severe engine ping, usually worse during acceleration. Cause: This condition may be the result of corrosion of the rear bank knock sensor due to water intrusion into the sensor cavity. Correction: Replace the rear bank knock sensor and build a dam around the sensor using RTV to divert water away from the sensor.
So we're going for it. Tomorrow morning at 9 am the Corvette, myself, Josh Jacquot and Jay Kavanagh are meeting at my house. And the wrenches will fly. Before he arrives Jay will buy two new knock sensors and a couple of intake manifold gaskets. I will also make a purchase; beer, which I plan on drinking while Josh and Jay fix the car.
By noon, the Corvette will either be fixed, on a flatbed, or just as sick as it was when we started this stupidity.
Wish us luck, we'll let you know what happens. In the meantime, enjoy this awesome David Kimble cutaway of the 2002 Corvette Z06 that I found on GM's media site today.
Scott Oldham, Inside Line Editor in Chief
February 10, 2010
By now you know the story behind our 2002 Chevrolet Corvette Z06 and its engine knock. We dropped it off at Cormier Chevrolet as a starting point, expecting the Corvette-centric dealership could mend our ailing LS6. We expected too much.
Office chatter on the day we picked up the Z06 went something like this:
"Is the Vette fixed? What did the dealer say?"
"The tech drove it while hooked up to his computer. He recreated the ping but even at the moment of detonation his equipment showed no signs of error. The knock sensor did not relay a fault. The tech elaborated. He said this ping was an issue he'd seen on numerous occasions and would consider it characterisitc of this engine. Some are cured by the ECU recalibration we had. Others are not."
"Screw the dealer. They are apparently completely incapable of performing even the most basic diagnostic tests on not just a car, but their flagship freaking sports car. The fact that their scanner shows nothing is really odd though, especially as the car has a GM calibration in it and not some aftermarket tune. Cars should not ping like this -- bottom line."
We've racked our brains trying to diagnose the problem ourselves. Fuel filter? A clogged filter could cause fuel pressure to drop, making the car run lean... ping. Knock sensor? If the tech's computer showed no recorded knock but we've confirmed audibly that it is in fact there, maybe the sensor is bad.
Our research turned up GM Technical Service Bulletin No. 02-06-04-023A, dated June 2002. Condition: Some customers may comment on a mild to severe engine ping, usually worse during acceleration. Cause: This condition may be the result of corrosion of the rear bank knock sensor due to water intrusion into the sensor cavity. Correction: Replace the rear bank knock sensor and build a dam around the sensor using RTV to divert water away from the sensor.
Corvette owners should be able to go to their dealer for diagnosis and repair of this sort of issue. So we wanted to give ours a shot at fixing the problem. We wanted to give them the the benefit of the doubt. But they let us down. We've done our research. We'd like to find a shop that will do the same. This dealer isn't cutting it. We're headed someplace else.
Mike Schmidt, Vehicle Testing Manager @ 42,430 miles
February 02, 2010
We dropped our 2002 Chevrolet Corvette Z06 off at Cormier Chevrolet yesterday, as planned, to address the ping. No word yet. But we expect an update by the end of day today. When we know more, you will too.
Mike Schmidt, Vehicle Testing Manager @ 42,888 miles
January 29, 2010
You've probably been wondering where our 2002 Chevrolet Corvette Z06 went for the past week. It's been on the road. As Jay mentioned, we decided to run 100 octane through the system to confirm the ping issue. Once that was official, we tried to burn off the good stuff.
We chose to put two tanks of 91 octane through the Z06 before handing it back to the dealer for further diagnosis. Our math figured two refills would dilute any remaining 100 octane mix and make doubly sure it was back to 91. The last thing we wanted was the dealer to test it with a higher octane fuel and give us the old, "problem cannot be recreated at this time" response.
Where do we stand now? We've transformed the last of our diluted mixture into ozone and we're back to full 91 octane. So we made an appointment with the dealer for Monday. We'll let you know how that goes.
Mike Schmidt, Vehicle Testing Manager @ 42,888 miles
January 19, 2010
Z06: Knock, knock.
Me: Who's there?
Me: Oh, s#&@.
Two days after he picked up our longterm 2002 Corvette Z06, Senior Editor Ed Hellwig thought he heard engine knock at full throttle around 4000 rpm. I took it for a drive and confirmed that, sure enough, it was definitely detonation Ed was hearing.
The previous owner didn't pile on the miles. We figured maybe the fuel in the tank was old and had become octane-deficient. So we ran three tankfuls of fresh 91 octane through it. It made no difference -- the Z06 still pinged like crazy.
We brought it to the dealer last week to have them check into it. They reflashed the ECU with an updated calibration and separated us from $98. Again, no difference.
At this point we thought maybe we were nuts. To be doubly sure that what we were hearing was in fact detonation and not something mechanical in nature, we added octane. Yesterday I mixed five gallons of 100 octane with the few remaining gallons of 91 still in the tank. The pinging vanished.
We'll bring it back it back to service once all the 100 octane fuel has been replaced with 91. Maybe this time they'll check the timing and verify that the knock sensor(s) haven't crapped out.
It's anyone's guess as to how long the engine has been running in this state. Though it runs strong according to the ol' butt dyno, a basic compression and leakdown test would be a good first step in determining whether prolonged detonation has caused any engine damage.
Jason Kavanagh, Engineering Editor @ 42,340 miles.