The Ongoing Tales of Red Zed

In February 2023 I bought Harvey's 2006 C6 Z06.  He recorded his history of the car starting in August 2016 so I thought "Why not start a thread to continue telling this car's tale?"

Why I Bought Red Zed

Around 1977, my six-year-old self accompanied my father to the local Chevrolet dealer in Middletown, Ohio for a test drive in a Chevrolet Chevette.  Dad wisely avoided purchasing the Chevette, but I remember seeing a Corvette in the showroom.  It might have been silver.  In any case, I was smitten at that time and Corvettes became something of an obsession.  When I pictured myself driving a car, it was in a Corvette.

In 1995 I was a struggling college student who needed to get out from under a car payment.  A church friend offered me his broken 1984 Pontiac Fiero for $250.  It needed at least a head gasket and a radiator.  I'd never done any major car work before but I was game.  I asked if I could fix it in his garage and he said "Take all the time you need."  I bought all the books, the tools, the supplies, and the parts and in 2.5 weeks, I drove home a properly functioning Pontiac Fiero.

Fieros became an obsession.  Around 1996 or 1997, I found Fiero.org, a listserv with a few hundred other Fiero owners and enthusiasts.  It's owner was an irascible, often irrational and rash admin of whom you could run afoul for the most meaningless things, but that was the state of the art and I found community there.  In 1999 I attended The First and Maybe Last All Fiero Swap Meet (or whatever it was called) at The Fiero Factory, a shop in Toney, Alabama owned by the inimitable and ever-helpful Ed Parks.  I attended every single Swap Meet in person for the next decade, until Ed sold the shop.  But by the end of that run, I no longer had running Fieros and I wasn't so interested in them any more: wife, kids, career.... you know.

In 2015 I told my wife I was having a mid-life crisis and wanted to solve it with a hot hatch.  She encouraged me to do it.  I researched for a few months prior to buying a 2015 Ford Forcus ST (trim level ST3).  It was my first new car and I've loved that car for eight years now.  It's a pure giggle machine and has made me happy every time I've driven it.  It's never been driven in winter.  While it's no Red Barchetta, I love its mostly pristine condition.

Once a year I and some car friends descend upon Deal's Gap to run Tail of the Dragon and surrounding roads for a few days.  These are not leisurely drives.  My Focus' Michelin Pilot Sport 4S's come back about 50% worn from each trip.  (Hey, tires are an entertainment expense!)  The Focus is an astonishingly capable car and I've gotten good at hustling it.

But, but, but... my friends and I refer to RWD as PWD or "proper wheel drive".  I began to want a PWD car.

A turn of events this winter had me driving a 2004 Corolla for work.  I've never hated a car like I hate this car, and I've had a lot of cars.  It runs well for a car with 230,000 miles but I hate, hate, hate it.  In December 2022 I came home from work and told my wife I wanted another car.  She rolled her eyes but she didn't say no.

My first thought was a new Civic.  My wife's daily is a 2019 Honda Civic Sport and it's a fabulous car.  I contacted my local dealer and spoke briefly about purchasing a new EX.  But then I had a thought: if I was going to spend that much money, why not make the Focus the winter car and purchase a PWD toy?  I had two cars in mind: an NC Miata or a C6 Corvette. We can fast forward to the end and note that the Corvette won.

I started thinking "3LT Z51 6MT".  Then I realized that I wanted Grand Sport just for the extra tire.  Then I thought "Why not a Z06?"  So that's what I bought.

The name Red Zed came from me messing with custom Ohio license plates.  "RED ZED" is available but while I've decided against the plate, the name has stuck.

Red Zed's Tales

I'll document what I do to and with this car in this thread.  I don't intend to autocross or track it, but I'll be making Triple Nickel and Hocking Hills runs in it with friends, and it'll be the new TotD car.

Red Zed has already resurrected that part of me that became expert in Fieros and worked on them.  When you buy a 17-year-old supercar with 70,000 miles on the clock, you get 17-year-old problems and I've had a few already. I don't mind spending the money or the time to work on it because when I close the door and take off down the road, I'm driving my Corvette.  My six-year-old self is pleased.

Very glad to hear you're loving it already.  
 

corvetteforum.com has a lot of info and stuff for all years vettes but  has a corporate feel - the opposite of this place.  
 

what are some of the issues you have found??

I know I love driving mine.  It feels like I'm driving an exotic super car. For some reason, moreso than when I move actually driven those exotics. 
 

as irrational as that is, I really enjoy these cars.   But I'd encourage you to take it to the track or an autox course.   They're amazingly fun. 
 

also, you should note what you would like to do to the car in case some here can offer advice or direction. 

The Pickup

Harvey lives in southern Connecticut.  I live in central Ohio.  I could have flown to Connecticut to drive Red Zed home, but it came with a shed load of extra stuff::
 

• 10 extra wheels, all with autocross-quality rubber on them, and some of it nearly new.
• Stock shifter assembly.
• TPMS tool.
• All the stock suspension components.
• Extra springs for the coilovers.
• Stock stereo.
• Stock swaybars.

I probably missed some stuff but you get the point.  So my buddy Ben agreed to drive with me in my 2016 Dodge Grand Caravan ("Caraturd3") to fetch the car.  We left Columbus just after 4 PM on Friday, 2023-02-24.  We arrived at our hotel in Shelton, Connecticut around 1:35 AM.  While Ben and I split the driving in terms of mileage, I had the easier route.  I managed to go 323 miles in exactly four hours through central PA.  Ben did the other half, which took him over five hours.

We met Havey at his home at 11 AM on Saturday morning.  A minivan is a UUV: ultimate utility vehicle.  When you need to haul a lot of people or stuff, they're commodious and Caraturd3 is sufficiently large to fit a 4' x 8' sheet of anything between its rear wheel wells.  It was mostly full after loading 10 Corvette wheels and two extra tires plus the stuff listed above.

The three of us had lunch together and Ben and I set sail westward.  Just our luck: it was snowing and salt was everywhere.  Shortly after I left the diner the dashboard lit up like a Christmas tree: TC, ABS, and ESC were all disabled.  Probably something affecting a wheel sensor.  I shrugged and kept going.

The first time we stopped, I filled it with fuel and Ben took the Corvette and I drove Caraturd3.  The electronic gremlins didn't return, which is good, but the starter cranked *really* slowly.  Ben drove the Vette for 210 miles and we stopped a final time.  I refuelled it again and this time it barely started.  I told Ben that we weren't going to turn it off the rest of the way to my house, but we didn't stop again, so it didn't matter.

The next day I got out my waterless wash and cleaned it up.  My 14-year-old son, the youngest of three teenage boys, approves:

The Shakedown

Whenever you buy a used car that isn't close to new, you spend a lot of time getting to know it.  You're especially interested in its warts, foibles, and troubles.  As noted in an earlier post, I've had a lot of cars and nearly all of them have been closer to the end of their lives than the beginning.  I'm familiar with them.

But Red Zed is a completely different class of car.  It's 220 HP more powerful than anything else I've ever owned, and its power-to-weight is off the charts.  This particular car has 700# coilovers in the rear and 550# coilovers in the front, Penske double adjustable canister shocks, and aftermarket sway bars.  The power combined with the modified suspension can overrun what my senses have experienced heretofore, and it clouds the discovery process.

So far, here are my observations:

• Starting problem.  I noticed this upon starting the car for the first time in Harvey's garage: it cranked very slowly, much more slowly than I expected and far more slowly than any Corvette I could hear on the Web.
• Engine clatter.  Within about three seconds of starting it for the first time, I noticed that the engine had an astonishing level of clatter.  I know the LS engines aren't quiet, and the LS7 might be the noisiest of them all, but this engine REALLY clatters.  There is a particular distinct part of the clatter prominent between 1500 RPM and 2500 RPM.  The noise doesn't vary with load, so it's probably in the valvetrain.  So far, it hasn't been a problem.
• Possible charging problem.  Within a couple days of driving it routinely, I had my first no-crank condition when commanding a start.  This always happened when the starter was hot, after a shutdown.  A week ago, my colleagues (amusedly) pushed it in the parking lot so I could bump the clutch to start it when it no-cranked.  A minute later, I had a "Service charging system" message on the DIC and the voltage was around 11.6 with the engine running.  I rev'd the engine and this seemed to bump the alternator into business.  System voltage returned to 14.5 and I was able to drive it home.
• RR wheel bearing.  Harvey told me it was bad and had already purchased the replacement.  It makes quite a bit of noise.
• Busted HUD hinge.  Also communicated before the sale, I'll pull the instrument cluster and cut the duct to pull the HUD and repair it. It hasn't fully fractured yet.
• Blown speakers.  It has at least one, and maybe two blown stereo speakers.  I don't have a plan for those yet.  The car is so noisy - road noise, wheel bearing noise, muffled engine noise - that music loses its midbass and midrange punch unless you turn the volume up really high.
• Degraded seat.  Corvette seats SUCK. I knew they were unsupportive so this isn't a surprise, but good golly are they awful.  My driver's seat sucked when new.  Now it's got 70,000 miles on it and the bottom cushion is worn enough that when I lower the seat I can feel the bottom cushion come up when it contacts the floor.
• Brutal ride at highway speeds.  See the springs and shocks.  North of 70 MPH, expansion joints lubricate your spine in fine, fine fashion.
• Misfire at idle.  The misfire is not rhythmic but it's constant.  The harder you drive the car, the worse it gets until things cool back down.
• Runs a little rich.  I've got some soot around the tailpipes.  It sometimes smells rich at idle and especially when you really get on it.
• Faded floor mats and cargo area mat.
• Moves left under hard acceleration.  When smashing the fun pedal and holding a constant steering angle, the car moves left.  It doesn't move an equal amount to the right after lifting, which is expected since coasting doesn't create as much dive as acceleration creates squat.  I'm going to see how much this behavior changes after the RR wheel bearing is replaced.
• Occasional TPMS problems.  Surprise!  I'm almost surely going to replace the Micheling Pilot Sport A/S 4's on the factory wheels with MPS4S's.  I'll have the TPMS sensors addressed at that time.

Not all of these are problems, of course.  But some are and I've started the process to make Red Zed into what I hope will be a reliable daily driver.

I've begun addressing some of the things listed above.

New Alternator

I bought a remanufactured alternator from a local parts store and last Friday night (2023-03-24) my 14-year-old son and I installed it.  It is one of the easiest "major" repairs I've ever done to any car.  It took me a lot longer to complete than planned because the belt got hung up on the lip of a lower pulley and I couldn't get it back on the alternator.  It took me a little bit to sort that out.

The old unit is a GM Remy unit.  It makes no noise when I spin it.  I'll have it tested and if it's good, keep it since the core charge is only $54.

I don't actually know if the alternator was a problem.  My goal is to make this car a reliable daily driver and this is, in my opinion, and inexpensive way to provide peace of mind.

New Starter

I ordered a new starter from RockAuto plus a blanket in which to wrap it.  A local Corvette friend referred me to a mechanic who works in his garage, and last night I delivered Red Zed to him.  He'll install the starter and the blanket.  I know that the positive connection at the starter can be a problem, so I'm hopeful that his work installing the new starter will ensure a return to proper operation if there's a deficiency.  It's possible that the connection at the starter is the problem, not the alternator.  <shrug>

New RR Wheel Bearing

As noted, Harvey provided the new wheel bearing when I bought the car.  I've changed quite a few wheel bearings in the past 30 years, but none as beefy as this rascal!  Harvey told me it was the ZR-1 bearing.  I did a little check on the name and part number on the box.  It is, and it's not cheap.  Thanks Harvey! 

The mechanic will install that too.  Since he has to remove the knuckle to change the bearing, I asked him to assess the three ball joints on that corner of the car.  If they're less than optimal, I'll know I will probably need to do all six on the back, though perhaps not right away.  I'm mulling a winter project to replace all of the factory bushings with delrin.  Since it would all be apart, I can replace the joints at that time.  I'm not committed yet to that project, but this car has 70,000 miles on it and has signs of being driven *very* hard, probably tracked.

jfryjfry said:

Very glad to hear you're loving it already.  
 

corvetteforum.com has a lot of info and stuff for all years vettes but  has a corporate feel - the opposite of this place.  
 

what are some of the issues you have found??

I know I love driving mine.  It feels like I'm driving an exotic super car. For some reason, moreso than when I move actually driven those exotics. 
 

as irrational as that is, I really enjoy these cars.   But I'd encourage you to take it to the track or an autox course.   They're amazingly fun. 
 

also, you should note what you would like to do to the car in case some here can offer advice or direction. 

I'm also on CorvetteForum under the same username. I've found it helpful already, especially since that's where I found the car.

I want to use the car as a daily driver and a weekend corner carver.  My car friends and I love SE Ohio: Hocking Hills and the Triple Nickel.  And once per year I make a multiday trip to Deal's gap to run Tail of the Dragon and other surrounding roads.  Some quick back of the envelope math says that in four days we do between 10,000 and 20,000 turns, at least half of them very aggressively.  My ST's tires come back significantly worn, and I'm looking forward to seeing what my Z06 does.

Engine Health Data

Given the misfire and (what I call) extraordinary engine clatter, I wanted some data about engine health.

Harvey replaced the OEM heads with AHP ported and polished replacements.  The engine seized several thousand miles after that but the block was undamaged so it was rebuilt with a new crank, steel con rods, new pistons and rings, and a new camshaft.  When the AHP heads were removed for the rebuild, the guides were worn again so now the heads have bronze guides.  The factory tune still runs the engine.

In the world of once-supercars, replacing the engine in a Z06 is comparatively inexpensive.  In the world of Dave's wallet, it's not.  If it's got a problem that should be addressed, I want to know about it now.

Stethoscope

I've never used one, but I ordered one from Amazon.  Wow.  I spent about 10 minutes listening to multiple points on the valve covers above the intake and exhaust valves.  I listened to the manifolds.  I did this at idle, at 1500 RPM, at 2000 RPM, at 2500 RPM.  It really DOES clack a lot in there, but the clacking was consistent everywhere.  A couple of cylinders were louder than others but not by much, and the type of sound was the same everywhere.

I didn't raise the car to listen to the pan.

Conclusion: good.

Compression Test

I purchased a compression tester.  This past Saturday, I drove to the house of my Corvette friend Thomas. He details cars professionally, so while I started pulling plugs and wires he gave me a gift by removing the residue from Harvey's autocross stickers.  

I pulled the first plug wire and then noticed plastic in the end that connects to the coil.  Whaaa?  Oh, the coil has broken.  In fact, most of the coils cracked or broke when I pulled the plug wires off, due to embrittlement.  Some of them were so brittle that I could easily remove plastic with a gentle scrape of my fingernail.

Then, one of the plug wires would not separate from its plug.  When we finally got it loose, the steel core of the wire pulled out of the silicone and remained on the plug.

The plugs came out without drama.  All of them look good, and they should since they're aren't very old.  A couple of them had a little bit of black liquid at the top of their threads but I don't know why. 

I checked the gap of the plugs.  Eight of them were around 0.037 per the cheap gauge I used.  One was at 0.028.  I set them all to 0.040.

The compression tester I bought is a good kit and it was easy to use.  The test took a lot longer than expected because the battery quickly wore down even though I only used six to eight compression strokes for each test.  Thankfully, I remembered to bring my 30-year-old 2A/10A/50A battery charger so it ended well.

I retested the first two cylinders I did after I did all eight.  All eight cylinders were within a few psi of each other, which was the hoped-for and expected outcome.

Thomas drove me to an auto parts store where I picked up eight Delco spark plug wires.  We installed them on the coils despite the missing plastic.  They all stuck, and the engine started and ran as it normally did.

I didn't solve the misfire, but I gained confidence that the pistons and valves operate as expected.  Perhaps the clatter I hear is a lifter.  It's not a tick, more like a chuffing sound between 1500 and 2500 RPM.  Anyway, I had fun and I got to know my Vette better.

New Foglamp Bulbs

Thomas likes to tinker, so he bought some ridiculously bright 5000K LED bulbs for his C6's fog lamps.  He then wanted something yellow, so he put them in a box.  He sold them to me on Saturday for a significant discount and we installed them.

Great googly moogly!  They surely don't produce as much light as the laughable and outrageous claim on the box, but their intensity on the fence in my backyard is similar to what the HID headlamps produce.  But unlike the headlamps, these rascals have no sharp cutoff at the top so they're useless in traffic because they'll blind everybody coming toward me.

I like them because on those dark nights when some of us are carving up SE Ohio roads or TotD, these may help me see apexes a lot better.  Of course, as soon as I flick my brights on, the fogs turn off.  I wonder if I can do something about that...

I just picked up Red Zed from my trusted backyard mechanic.

He replaced the RR wheel bearing, supplied by Harvey when I bought the car.  He said the old one had considerable play.

He also replaced the starter and wrapped it in a blanket.  It cranks *very* quickly now and I doubt I will ever have trouble with it again.

The mechanic checked play in all four corners.  Both rear corners are solid.  The LF is solid too. The RF has play, and I wiggled the tire while he looked.  The RF outer tie rod is worn, so I know what to attack next.

I slithered around under the car in the mechanic's garage.  The control arm bushings show no evidence of displacement or bulging.  That's good.  Maybe I won't do the winter project to replace the bushings with Delrin.

I wish I'd taken some pictures of the new and old parts, but I didn't.

What are the chances that the engine noise is an exhaust manifold leak?

They can sound like all sorts of engine problems.

It could be pushrods that are too short.  I had to get slightly longer ones when I had my heads rebuilt by ahp. 

In reply to wvumtnbkr :

I think the exhaust as a cause is small.  The reason is that the most prominent part of the clatter is not related to throttle.  Between 1500 and 2500 RPM, the sound is prominent regardless of whether the throttle is open or closed.

I meant to take my stethoscope with me to my mechanic's shop last night, and use it underneath the car.  Sadly, I forgot.

When he started the car and backed it out of the driveway, he commented on how much it clatters.

In reply to jfryjfry :

I'm convinced the sound is at camshaft speed and not related to exhaust.  Since the compression test and the stethoscope have led me to believe I don't have a problem with a valve, valve seat, or rocker arm, my thoughts have turned to lifters and pushrods.

Dave, when my friend rebuilt the motor he opened the piston bore and used a short skirt piston with a long rod. These changes definitely create more noise from the motor itself, but it should not be an issue for performance. It's definitely noisier at idle, but the motor should last forever. The specs for all of the parts used are either in the spreadsheet or in one of the docs saved to that folder.

------------

Piston

Part # WD-09994

Chevy LS7;4.130" x 1.110"ch;11:1 cr

Rods

Part# CSC6125DS2A2AH

COMPSTAR ROD LS1 6.125 2.100 .927 PIN

Crank

Part# AWO-31Q-CS

COMPSTAR 8 CTWT LS1 CRANK

--------------

Why do you think you have a misfire? If you have a misfire the computer would throw a code and you would get a check engine light. 

I'm glad you have the car now. Sorry about that driver seat, I honestly did not notice how bad it was getting because it was gradual, but in hindsight I can see looking at the pics I took when I put it up for sale how the leather is slightly loose on the seat indicating the padding has given up.

The starter had always been a bit slow and I'm betting at some point they updated the part and you are getting the benefit of that, but at the same time it was original and undoubtedly age also compromised it.

I am pretty sure that center speaker in the dash is no good, I totally forgot about that with everything else. When I looked at people talking about modifying the stereo system even before they did anything most of them pulled out that speaker, because it's very small and tends to get overwhelmed by any aftermarket system. I think I mentioned when we talked about the car that the stereo head unit is probably one of the best at the time it was installed, but the install itself seemed to me to be kind of hamfisted, for one thing they didn't actually put anything in to account for the factory chimes, which could be intentional because the chimes are annoying or could be just them taking shortcuts. I was going to have a complete stereo refurbish done, but never got around to it.

Regarding the suspension and how stiff it is. It is relatively easy to swap the springs to something less aggressive, but you can also add compression and rebound to soften it up a bit more. The settings I had it on are literally the settings I used for autocross. I just became used to them. To be fair to this setup, the stock suspension is pretty damned aggressive. It was noted by reviewers at the time it came out that it was pretty brutal and I felt that was true when I drove on it. At least with this setup when you hit a bump on one side it doesn't transmit across a leaf spring to the other side as well. 

Also, with regard to replacing the suspension bushings with Delrin. If you don't like the ride now, you really don't want to do that.

I wanted to note also with regard to how it pulls to one side, if you haven't driven a car with tires this large before they will tramline given any imperfect road surface, but it's not impossible that the alignment needs checking. I did have them do it right before you picked it up, but you took a long drive and something could have gotten out of wack.

Harvey said:

Dave, when my friend rebuilt the motor he opened the piston bore and used a short skirt piston with a long rod. These changes definitely create more noise from the motor itself, but it should not be an issue for performance. It's definitely noisier at idle, but the motor should last forever. The specs for all of the parts used are in one of the spreadsheets I linked you from Google sheets.

Why do you think you have a misfire? If you have a misfire the computer would throw a code and you would get a check engine light. 

I'm glad you have the car now. Sorry about that driver seat, I honestly did not notice how bad it was getting because it was gradual, but in hindsight I can see looking at the pics I took when I put it up for sale how the leather is slightly loose on the seat indicating the padding has given up.

The starter had always been a bit slow and I'm betting at some point they updated the part and you are getting the benefit of that, but at the same time it was original and undoubtedly age also compromised it.

I am pretty sure that center speaker in the dash is no good, I totally forgot about that with everything else. When I looked at people talking about modifying the stereo system even before they did anything most of them pulled out that speaker, because it's very small and tends to get overwhelmed by any aftermarket system. I think I mentioned when we talked about the car that the stereo head unit is probably one of the best at the time it was installed, but the install itself seemed to me to be kind of hamfisted, for one thing they didn't actually put anything in to account for the factory chimes, which could be intentional because the chimes are annoying or could be just them taking shortcuts. I was going to have a complete stereo refurbish done, but never got around to it.

Great to hear from you!  No apologies are necessary for anything!  You've been the best imaginable seller and the whole affair was, and remains, a pleasure.  I'm a "buyer beware" kind of guy and I know that when you buy a 17-year-old car, you get 17-year-old car problems.  It's a grand adventure!

Regarding the pistons, I reviewed the sheet you provided but I missed that the pistons are shorter and the rods are longer.  Why did the rebuilder choose this? I'm aware from Hib Halverson's article about the LS7 that the stroke is so long that the OEM pistons were shaped to provide support when the piston is exposed below the bore at the bottom of the stroke.  Was the rebuilder's combination chosen to overcome this issue, given that he needed pistons with an increase in diamater of 0.005"?

I think it randomly misfires for the following reasons:
- I can feel the engine shake in the car.
- I can feel the engine shake when I hold my hand on the intake.
- I can hear a disruption in normal combustion at the exhaust outlet.

As for the stereo and speakers, I'll probably not do anything about that right away.  I'm still listening to the car.  Getting a new-to-you car is like getting a new lady for a dance partner. You have to learn how she moves, what she likes, and how she sounds.  I confess I'm not much of a dancer, but I've loved many four-wheeled ladies.

Dave, I'll ask my builder for exactly why on part choice, but the increased bore was because he felt the stock clearance on these motors is way too tight. The rest is probably down to having to balance the assembly given the change in piston size, rods and crank. Remember the stock engine has titanium rods and this motor does not. Having held the rods that went into this motor and one of the old titanium rods side by side the titanium rods are noticeably lighter than the steel ones used in this motor.

If you are getting a lot of engine shake I would check the motor mounts. They are fluid filled mounts and even though I replaced them at one point, they do not hold up well over time. If you go to anything other than the fluid filled mounts though you will end up with a lot more noise from the engine being transmitted into the cabin.

If you are just getting some engine shake then I would say that is normal. This is not a smooth running motor, even in stock form, it brutalizes you with the power and makes itself felt all the time and again the motor mounts are fluid filled so there is some give there. Their priorities in building this car were light weight and power. Most aspects of comfort were secondary.

If you were actually getting a misfire you would get a code.

Dave, here is what my friend said about the motor.

"Long rod with a short piston revs faster, plus the rod ratio is better."

"Short pistons rock in the cylinders until warmed up."

Those were just his texts to me, when I called him on the phone he basically confirmed what I already knew. He built the thing to be a race motor that revs to 7000rpm and lasts forever and because of that its not gonna be quiet, but it will be more reliable than any stock LS7 motor.

My best advice for when you are bothered by the engine noise is to flip that little switch I put in the console and open the exhaust so that it drowns out the noise the motor is making. Hit the gas a few times while you are at it. 

My friend and I both agreed that some sort of insane people at GM got the reins when they made this car. 

They took a truck motor whose basic design is 30+ years old and made it into a race car engine that revs to 7000 rpm and puts out 505hp, put the cheapest dry sump system they could find on it and slapped it into the car and then took out most of the comfort features, removed all of the sound deadening and gave it a brutal ride that is only really happy on track and still managed to sell almost 30,000 of them.

It's brilliant.

Harvey said:

Also, with regard to replacing the suspension bushings with Delrin. If you don't like the ride now, you really don't want to do that.

I have no complaints about the harshness of the ride, and I've had lots of cars with rough rides, like pre-88 Fieros.  My specific note about this car is how vicious it can be at highway speeds over expansion joints and similar large inputs.  I don't even notice the ride quality until about 70 MPH but above that, it moves up and down quite rapidly, especially as the speedometer swings farther clockwise from 70 MPH.

"Doctor doctor!  My Z06 compresses my spine when I drive 85 MPH over expansion joints!"
"Well don't drive 85 MPH over expansion joints."

I've been doing some research about spring rates, wondering how the coilovers in the car compare to the factory leaf springs.  I found this page that states the following spring rates:

C6 Z06 front: 531 lb/in
C6 Z06 rear: 782 lb/in

This means that the springs you installed (700 lb/in rear, 550 lb/in front) are close to the factory rates, ignoring any progressive rate tendencies of either spring.  (Some reading I've done indicates that the leaf springs have a progressive rate, though I can't find any information about the rate ramp.)

If the spring rates are similar, then playing with the shock damping is what I might try next.  You told me when I picked it up that I could and should play with the damping.  Now that I know the difference in rate between the leafs and coilovers aren't hugely disparate, your advice seems even better.

But not yet.  I need more seat time as-is to get to know it better.

Screenshot of the spring rate page I linked, just in case the page ever goes away:

Harvey said:

My friend and I both agreed that some sort of insane people at GM got the reins when they made this car. 

They took a truck motor whose basic design is 30+ years old and made it into a race car engine that revs to 7000 rpm and puts out 505hp, put the cheapest dry sump system they could find on it and slapped it into the car and then took out most of the comfort features, removed all of the sound deadening and gave it a brutal ride that is only really happy on track and still managed to sell almost 30,000 of them.

It's brilliant.

I love how GM powertrain uses racing to figure out what works well, then they productionize it.  Nowhere is this technology better applied than in the heads.  

• The LS6 in the C5 made as much power as the LT5 did in the C4 with only one camshaft and only two valves per cylinder, given identical displacement.
• The LS7 in the C6, well, we know what it does.  505 factory-conservative HP out of 7.0L in a small block package.

20+ years ago, I had the following argument repeatedly with friends (and strangers).

Them: "Those GM engines are low tech.  My Honda is high tech."
Me: "So your 150 HP engine is superior to the 400 HP in the Corvette because... it's a "higher tech" lower power?"
Them:  "Well, no. I'm just saying that GM has to use all that displacement because the engines are so low tech."

You know when somebody says "I'm just saying..." that they've run out of details.  But I digress.

Me: "What makes your Honda engine higher tech than a Corvette engine?"
Them:  "Just look at it!  It's got DOHC and four valves per cylinder and VTEC, yo!"  (You *always* have to say "yo" after you say VTEC, yo.  I don't even know how to spell it any other way than VTEC, yo.)

VTEC, yo was pretty darn good technology in its day.  Every time I drive my buddy's S2000 AP2 I'm thrilled again and again by its VTEC, yo.  It's a high tech engine, for sure, but that doesn't make the GM pushrod engines low tech, does it?  My 2019 Honda Civic Sport has a K20 in it with VTEC, yo and it's also a fine mill.  By today's standards, I think it's somewhat low tech.  It's normally aspirated and has SPFI instead of DI.  Pffft.  Those jokers over at Honda.  Who do they think they are?  GM?

Me: "So your Honda is higher tech than the GM engines because it has four valves per cylinder and twice as many camshafts for half the cylinders?"
Them: "Yes."

The overly curt, mildly insulting response could be "If your ability to judge engine technology is limited to your ability to count the number of valves per cylinder and the number of camshafts on top of the head, you should have the good grace to exit the conversation."  My younger self might have said this a couple of times.  My older self prizes people a lot more and frowns upon my younger self.

The heads on the LSx engines are magnificent pieces of technology.  Starting with the LT1 in 1992, GM left Ford small blocks in the 1960's and Dodge, well...  It took Ford two decades to catch up and when they finally did, they used four valves per cylinder and four camshafts to do it.  Disclosure: I greatly admire the Coyote and it shines in the S550 Mustang.

One of the things that attracted to me to the Z06 is its high tech engine.  Only now, with the C8 Z06's FPC has GM outdone it.

Yeah, you can get some of that out of the car by tweaking the shock settings. If you add compression it will soak up bumps at high speeds better. Give the knobs on the canisters one full turn clockwise and see how that works for you. Unlike some adjustable dampers these are noticeably different for every small adjustment you make. If that doesn't do it, just add some more.

You could also remove some rebound (turn counter clockwise), but the adjusters for that are harder to get to and it's the sweep adjuster that they describe in the doc I linked below so you need to use an allen wrench or a small pick to sweep the adjuster around. You'll probably need to remove the wheel to get to them unless you can get it off the ground a fair amount.

I probably don't need to tell you, but make sure when you change the settings you change each one the same amount.

With the settings it is on now it's dialed in for a generally smooth surface. I made a habit out of dodging potholes and holding on to the wheel when hitting higher speed on the highway.

https://www.penskeshocks.com/hubfs/Resources/Manuals/8300-DA-SHOCK-Manual.pdf

My buddy that built the motor said if he had the cash laying around he definitely would have bought my car, but he just built a race car.

What's new with the car??

I haven't done any work on the car lately.  Given a new alternator, new starter, and new RR wheel bearing, it starts and runs reliably so I've been driving it.  Well... not the past couple of days.  In central Ohio it got frickin' freezing, Mr. Bigglesworth, and rain has been falling, so Red Zed sits under a cover in my driveway.  My fallback is my beloved 2015 Ford Focus ST, and that ain't bad.

Most of Ohio is flat and straight.  But SE Ohio is a driving paradise.  One hour from Columbus is the Car and Driver Loop.  Twice in five days I and friends ran this loop in the evening, multiple times, both clockwise and counterclockwise.

First Trip
I was all out of sorts.

• Not turning in quickly enough.
• Not trusting the lateral loading of the car, so not running tight enough lines.
• Not on the power soon enough around the apex.
• Not using enough power.

That last bullet needs some explanation.  I've been hustling a 250 HP Ford Focus ST since April 30th, 2015.  When you spend so much time in one car, you meld with it.  In effect, I'm calibrated for 250 HP, which means my butt says "Hey, that's enough" when driving the Vette.  Red Zed got really good gas mileage running the loop, which told me I wasn't pressing the go-fast pedal nearly as far as I should.

Second Trip

I had four days to mull my poor driving on the first trip, and I picked three things on which to work:

1. Turn in faster.  The Vette's slow steering (especially compared to the Focus, which is like driving a video game) combined with the way the front end loads up means "Turn the wheel more and turn it more quickly."
2. Apply power sooner through the turn.
3. Apply more power.

A newcomer joined the run, in a 2016 Mustang Shelby GT350.  (I call that car "Ford Sex on Wheels."  Much want.)  He's an older man who said he was still getting reacclimated to the car after it spent winter in the garage, so he wanted to be the last car.  In front was a young friend in a newly-acquired 2008 Mazda Miata NC1.  Being young, he's not got enough experience to be afraid so he goes quite quickly indeed.

I felt a little pressure at first.  With the Miata ripping up the road in front of me, and the highly potent Ford Sex on Wheels behind me, I wanted to keep up.  Pressure is bad if it leads you to do dumb things, but I'm old enough and experienced enough to avoid that pitfall.  Intellectually, I knew Red Zed had far more in it, so I decided to trust it a little more, especially laterally.

Well... we were going quite quickly indeed.  I successfully worked on my three objectives.  Toward the end of the run, I had one of those magic moments that will forever alter the way that I drive.  I'd gotten a lot better at turning in more quickly, so the lines were much tighter.  But I was still not satisfied with how early I was applying power, so I was focusing on that.  I had the Vette under heavily lateral load and when I squeezed the throttle... my butt felt the back end rotate.  My brain screamed "That's it!"

I think the first thing to learn when hustling a car around corners is how to make it rotate.  To be honest, I wasn't even aware that I didn't know how to make the Vette rotate until I accidentally did it.  This experience mirrored exactly what happened in 2015 when I bought the ST, specifically, I accidentally induced trailing-throttle oversteer in the Focus, which is how you make it rotate.

I was able to get Red Zed's rear end to rotate on power repeatedly after my discovery.  The next fun trip, I'm gonna try to dial that in.  I want to be able to do it on command, and even manage the degree of rotation I induce.

What else?

• It understeers very little off throttle.  This is either because it's neutral or because I'm not as close to its lateral limits as I think I am.  I suspect it's neutral.  Very well set up.
• It has immense grip, even with A/S 4 ZP's on it.  This week or next I'm going to purchase MPS4S's because... summer rubber.
• It moves around *a lot*. Remember, this is my first powerful RWD car.  I'm learning to ignore the little movements as noise in the signal of what the tires are really doing.
• The front end loads up progressively and more slowly than the Focus.  I'm still calibrating myself to the car.
• So. Much. Power.  It just never ends.
• The seats suck.  Harvey may chuckle if he reads this. My right knee is now adding to the missing paint on the center console.  I follow in the tradition of the drivers before me.
• The wind behavior in the car with the windows open is unpleasant.
• Harvey added insulation to the tunnel.  But it still got plenty hot forward of the shifter!
• People notice the car.  They may not notice a Miata or even the Ford Sex on Wheels, but they always notice the Z06.

On Wednesday and Thursday of this week I replaced the foam in the driver's seat bottom cushion.

Materials

• Bottom seat foam.  Many vendors sell seat foam. Since nearly all of them had the same stock photos, I figured they were all the same product.  Since the prices diverged widely, I bought one for the lowest price, or almost the lowest price, I could find.  Even if the products are really different, anything is better than the degraded factory foam.
• 3M Spray Adhesive.
• 1" wide masking tape.
• Hog rings.  These came with the hog ring pliers I purchased.

Tools

• Trim removal tools.
• Hog ring pliers.  Came with hog rings.
• Cutting tool.  Knipex makes good stuff.
• 15mm socket plus extension, adapters, ratchet, power tool, whatever.
• Philips head screwdriver.
• Tiny flathead screwdriver.
• Torque wrench.

I watched several YouTube videos before starting the work and I consulted at least one during the work.

Seat Removal

The seat mounts to the car's frame with four 15mm nuts. The forward two are covered by a plastic trim piece. I used the trim tools to remove the Christmas tree fasteners that hold them in place. Please note that these slide forward for removal.

Next I pulled the four 15mm nuts that bolt the seat to the car and the 15mm nut that holds the seat belt to the outboard seat frame.

Then, I disconnected three electrical connectors under the seat.  The large connector with the purple piece on it wasn't intuitive despite having markings intended to tell you how to disconnect it.  I watched a video to figure it out.

The seat is out.  

She's listing a little to port, Captain!

Those fries on the carpet are recent.  Hey, I'm using Red Zed as a daily driver and sometimes <gasp!> I even eat in the car! 

Once on an 8' table in my basement, I was able to see the dingaling design of this seat.  Because there's nothing between the wires and the foam, the wires cut into the foam.  You can see that here:

Here is what a part of the seat looks like where the wires haven't cut the foam:

Disassembly

I used the trim tools to remove the switch cover.  I used a tiny flatblade screwdriver to remove the wire clip that holds the seat back recline lever onto the seat, which took a little while.

I used a philips head screwdriver to remove the plastic trim plate around the power seat switch.  Then I used it again to remove the steel plate underneath the trim plate.  I then disconnected and removed the switch.

The seat cushion has a string tie that pulls it taut around the bottom of the foam.  You're supposed to untie it, but my string was broken.

I disconnected the electrical connector for the seat heater.

I cut hog rings, removed staples, etc and pulled off the seat cushion, which is the foam plus the pleather cover.

Here's the foam and seat heater sitting next to the pleather cover:

You can see the damage the wires cause to the foam:

The outboard side of the foam is degraded by all the butts sliding across it getting into and out of the car.  Since Red Zed is a well-used Z06 (>71k miles right now), there have been a lot of butts on it.

Old and new side-by-side:

Sometimes the wire ends are detached from their anchor.  Mine weren't. Edit: I just took a closer look.  One of the wires is dangerously close to the end of the rod to which it attaches, and I failed to notice this with my Mk 1 Eyeballs.  <shrug>

Bottom Cushion Preparation

The seat heater is glued to the foam cushion.  I pulled it off.  Next, I placed masking tape on the velcro on the new foam to protect it from the spray foam used to put the seat heater on the new foam:

I sprayed adhesive onto the foam, and onto the seat heater, shown here:

After a few minutes for tachification (I like inventing words) I put the heater on the new foam:

Reassembly

Time to put the new foam onto the seat.  Others have installed a piece of fabric between the foam and the wires to remedy Chevrolet's oversight.  I'd forgotten to get some, so I went to my local Walmatucky to get some jute.  But while there, I bought this intead because it was cheaper:

Not only will it separate the foam and the wires, but when I pee in the seat, I have something to help with the mess!

Here's the diaper cloth on the wire frame:

I admit that I struggled getting the foam back onto the seat.  I first tried by putting the pleather cover onto the foam.  This was problematic, so I removed the edges of the seat cushion and flipped them up prior to reinstallation.  That helped a lot.  It still took me a long time before it was fully seated on the frame:

The replacement foam can be used on either the driver or passenger seat, but you have to cut the outboard part of it to get around the switch and lever.  One YouTuber cut holes in the foam for the switch and lever.  I noticed that the factory foam was bespoke for the driver's side and was missing all of the foam on the outboard side of the seat so I used a carpet knife to remove it.

Next I put the edge of the pleather cover back into place.  I was unable to tie the bottom back down since the string was broken.

I reconnected the switch, reinstalled the steel plate, and reinstalled the plastic trim cover.  Installing the steel plate was not easy because at least one of the screws goes through a hole in the seat cover.  The cover's shape is different after so many years of use, and I had to pull and use foul language to get everything to line up.

Many years ago, one of my brothers told my mother that he sometimes used bad words when working on cars.  She turned to me in shock and said "Do you do that too?"  I said "Yes.  Everybody who works on cars knows that profanity is as effective for stuck bolts as any lubricating penetrant." 

Here's the reassembled seat from the bottom.  The diaper cloth is visible:

I reinstalled a few hog rings.  It's a little asymmetrical but I've got no experience reupholstering anything.  Perfect is the enemy of good, and this is good enough.

Here it is, ready to go back into the car, or so I thought:

Welp, I noticed something:

See that frayed wire?  That's been abraded by the seat pivot and the frame.  Worse, it was stuck between those two pieces because I sit with the seat as low as it can go, and tilted with the front upward as far as it can go.  I'll just pull it out... oh, no it's stuck.  Hey, I need to move the seat... awww drat, it's a power seat.

Sigh.  I put the seat back in the car, plugged in the connectors, moved the seat, took it back out of the car, and worked on the harness. I used a zip tie to make sure it couldn't go back to the same place:

The zip tie wrapped around the seat spring at the top of the pic pulls the factory zip tie that locates the harness.

I put the seat back in the car.  I plugged it in, reattached the seatbelt to the frame, reinstalled the four mounting nuts, and reinstalled the front trim.

What Do I Think?

The seat no longer lists to port.  I suppose this is good though I hadn't really noticed it until one of my brothers noted it while sitting in the seat.

The new foam is much firmer.

I sit a lot higher in the car and I don't like that at all.  I like to sit really low in a car.  The height is sufficiently greater that the steering tilt which I used before I removed the seat causes my hands to hit my legs when I turn the wheel.  Of course, I adjusted the seat and the tilt, and I'll get used to it quickly.  I figure the foam will compress a little with the first few 10's of hours of use.

The seat is still no more supportive, and I didn't expect it to be.  I know I'm a broken record in this thread, but these seats are awful.  If all you do it cruise in a straight line, maybe they're sufficient.  But I actually throw my Corvette around corners.  I expect the seat to hold me in place and it doesn't.

This work has allowed me to know that I can probably get a Corbeau A4 and make a "quick-ish swap" installation.  I figure 30 minutes to change seats is possible, and maybe far less.  When I want to carve corners, I can put the Corbeau in the car.  For daily driving, I'll keep using the factory seat so I have a side-impact airbag, which I prize. 

Very nice Dave! 

Yes, that rubbed off area on the console was my knee rest as well. I tried finding some sort of leather pad I could stick on there, but the one I ordered ended up being too big and then I gave up on the idea.

That tunnel heat. I got the carpet to sit up higher and put insulation in there around where the center console compartment is, so now it doesn't boil whatever you put in there, but I couldn't really fit much towards the front and the stock insulation behind there at the front has fallen down, so in some small areas there is just a thin coating of carpet over the bare metal. That should be something to look at improving. I was going to get a new shift boot since the stock one is kinda crappy and at that point I was going to look at replacing some of the insulation up front.

On the outside underneath it does have all the tunnel insulation one can put on the car, both on the sides and on the tunnel plate, but there is still a lot of heat coming in despite that.

Don't forget to use the ratcheting seat belt when you go around corners fast as it can help (pull all the way out and let it back in and it will lock in place), but yes, those seats are just not for a car that pulls .98g on the skidpad in stock form. They even have adjustable bolsters in the regular C6, but they removed that in the Z06 for lightness.

They changed the seats slightly in later years of the run to make them better, but they never really got particularly good. They are godawful heavy too as I'm sure you now know.

Also, come on Dave, you saved a lot of money getting a used Corvette! https://www.caravaggiocorvettes.com/c6-daytona-race-seats-with-headrest-logo