Blue Bullet Blog-The C6 Ownership Experience

[catbert]

And it will be called.......

Z28

At least that's what I've heard.

GM made it official today! The production LS7, complete with dry sump, will be the power plant for the Camaro Z28. The LS7 lives - at least for awhile.

Hib, that's great news for your Z.....the more they make, and the longer they sell them, the longer they will support the 427 small block from the factory!

 

[Hib Halverson]

GM made it official today! The production LS7, complete with dry sump, will be the power plant for the Camaro Z28. The LS7 lives - at least for awhile.

Hib, that's great news for your Z.....the more they make, and the longer they sell them, the longer they will support the 427 small block from the factory!

They gave the secret away...at least to those who researched the Internet carefully and could think like GM engineers and marketing folks...when the 2014 VIN Card showed up on-line just before Christmas last year.

The Camaro LS7 is slightly different, however. It has a different exhaust manifold and a different air filter assembly. Also GM is only giving an estimated power number, but it's about 5-hp down on the C6 version. I'll guess that the Camaro exhaust system is the reason for the slight power hit.

My guess is it will be one year program. At the reveal in NYC they didn't say anything about how many will be built but I'll bet 500 is the number.

Chevy press info claims a Z/28 is 3-sec a lap quicker than a ZL1 which has 80-more horses. That speaks volumes about how light-weighting a car, adding huge carbon brakes and a better chassis can be an advantage.

 

[Tuna]

The show's Z28 is white. Maybe GM will paint a few in Penske/Sunoco colors as a Donohue Special.

 

[catbert]

The show's Z28 is white. Maybe GM will paint a few in Penske/Sunoco colors as a Donohue Special.

With gold yellow trim and the number 6 or 66 on the side. I wonder if the new one is faster than the dual quad, cowl inducted Z28 from the TRACO shop. Probably not. That thing was a bullet.

 

[Hib Halverson]

With gold yellow trim and the number 6 or 66 on the side. I wonder if the new one is faster than the dual quad, cowl inducted Z28 from the TRACO shop. Probably not. That thing was a bullet.

That'd be kinda hard. Traco built engines not race cars.

It would be interesting to test an accurate vintage racing 67-69 Z/28 against the new Z/28.

Old Z/28 race car: lighter, on modern race rubber.
New Z/28 street car: more powerful, much better brakes, handles better on rough track, better aero, better off slow turns

 

[catbert]

That'd be kinda hard. Traco built engines not race cars.

No s..t - I think everyone who knows the name TRACO knows they were an engine shop.

The fact that the little 302 was putting out 420 horsepower in race trim (Popular Hot Rodding Magazine, June 2007 figure) still amazes me. I too would like to see the new and the old go at it. TRACO's chief engine builder is now in North Carolina at his shop, TRA-CO. Oddly enough he's doing engine development work for Callaway. Seems stuff goes in circles, Hib.

 

[Tuna]

The '65 327 FI engine was rated at 375 HP in the "stock" Corvette.
Take away 20 cubic inches replace the FI with twin 4-barrels and let TRACO do the work and you have 420 HP. Seems reasonable.

Wikipedia says:

"The (Z/28) engine was designed specifically to race in the Trans Am series (which required engines smaller than 305 cu in (5.0 L) and public availability of the car. Advertised power of this engine was listed at 290 hp (216 kW). This is an under-rated figure. Chevrolet wanted to keep the horsepower rating at less than 1 hp per cubic inch, for various reasons (e.g. insurance and racing classes). The factory rating of 290 hp occurred at 5300 rpm, while actual peak for the high-revving 302 was closer to 360 hp (268 kW) (with the single four barrel carb) and 400 hp (298 kW) (with optional dual-four barrel carbs) at 6800-7000 rpm."

Maybe TRACO didn't have to do that much to the 302 after all.

 

[Hib Halverson]

The '65 327 FI engine was rated at 375 HP in the "stock" Corvette.
Take away 20 cubic inches replace the FI with twin 4-barrels and let TRACO do the work and you have 420 HP. Seems reasonable.

Wikipedia says:

"The (Z/28) engine was designed specifically to race in the Trans Am series (which required engines smaller than 305 cu in (5.0 L) and public availability of the car. Advertised power of this engine was listed at 290 hp (216 kW). This is an under-rated figure. Chevrolet wanted to keep the horsepower rating at less than 1 hp per cubic inch, for various reasons (e.g. insurance and racing classes). The factory rating of 290 hp occurred at 5300 rpm, while actual peak for the high-revving 302 was closer to 360 hp (268 kW) (with the single four barrel carb) and 400 hp (298 kW) (with optional dual-four barrel carbs) at 6800-7000 rpm."

Maybe TRACO didn't have to do that much to the 302 after all.

Traco did a stuff to those engines–probably more than "that much" but, because of SCCA rules, less than "a lot". A 302 in Trans-Am race trim made about 450-hp, probably less in '67 and '68 and maybe more in '69, '70 and '71. In the late 60s, 70s and early 80s a Traco engine was serious bragging rights...sorta like Katech is, today. "Traco" was a contraction of the owners two last names, Jim Travers and Frank Coon. When Travers and Coon retired, they gave the business to Travers' daughter who was married to Jim Jones and Jim kept the Traco name going through the mid/late-80s until the mid-1990s when he sold the business and went to work for several different NASCAR Cup teams. Jones currently is associated with Callaway Cars. I did a lot of work with Jim Jones and Traco during the mid-80s to early-90s. Jones was one of the first aftermarket guys to fool with chips in 85 Corvettes with port injection and I remember using his calibrations in my 88 Beretta GT and in an 89 Firebird project car I built for a magazine. But...I digress.

As for the old Z/28s in the Trans-Am, not only did Chevrolet release a 2x4 low cross ram manifold which used two Holley double pumpers, but it also has a special valve train package, centered around the famed "Service Cam" and later got roller rocker arms homologated.

As you can imagine, a 302 with racing heads, a killer camshaft and two big Holleys, made for a very peaky engine. I think the useable RPM range was about 5000 to about 7500. Imagine running that with a close ratio four speed.

 

[Hib Halverson]

Cheap but functional exhaust mod!

Finally got the exhaust on my '12 Z06, the "Blue Bullet II" the way I want. Did it with a buck or two worth of hardware and maybe an hour of work.


When the exhaust valves were closed, it was too quiet. I'm not the only one who thinks this because, since the C6 Z06 was introduced in 2006, NPP was offered on coupes and convertibles in 2008 and the ZR1 got it in 2009, a cottage industry has grown up around products which change the way the dual mode system works. Examples are the "Mild2Wild" and the "Exhaust Commander" and there may be others. These products override the Exhaust Tail Pipe Flow Control Module (EFCM) allowing manual opening of the exhaust bypasses.


Problem is, when you leave the bypasses open in all driving situations, unless you're the type of person who needs to let everyone to know you're nearby or you're hard of hearing, the noise at idle, part throttle and, especially, the 1700-RPM exhaust resonance typical of V8s at highway speeds can be obnoxious. If you don't like that, you're frequently going to be stepping on the switch (if you have a wired system) or looking for your remote (if you have a wireless remote)


I've driven a car with the Mild2Wild and, once the novelty wore off, being that my hearing is good and I prefer mostly to keep a somewhat low-acoustic profile, except for when I really need the car's power, he sound when the bypasses were open was pretty loud and ugly when driving around town. I found myself fumbling with the M2W remote often.


But then…when driving around town, the Blue Bullet II is actually too quiet–likely becuase of the four-cat exhaust used on '12s and '13s.


Too annoying when open. Too quiet when closed. What to do?


A while back, I noted that the folks making Mild2Wild offer an "Z06/NPP Mild Adjustable Control Kit". Intrigued with the long name, I wondered, "WTF is that?" The web site described it as a pair of stainless steel, slotted collars each with a set screw. You use them to limit the travel of the bi-modal exhaust actuators and hang the bypasses slightly open–say ⅛-¼–when the EFCM commands them closed. It's a clever idea, but you pay 25 bucks plus tax and shipping for these two little collars.


The cheap-skate DIY that I am, I got curious if there's a "better" way. I spent 10 minutes removing the exhaust bypass valve actuators. There are no instructions in the Service Manual for this but the removal procedure is obvious and quite simple. Unplug the vacuum hose, pop the actuator rod loose from the valve, remove three nuts and take out the actuator.


Once I had an actuator on the bench, I quickly developed my own exhaust valve travel limiting device. I visited a local industrial hardware store and bought six aluminum sleeves. They had a #10 I.D. (about 0.190-in.), ⅜-in. OD and were ¼-in. thick.


I removed each actuator's rod end, dropped three of these sleeves on each shaft, put the ends back on and reinstalled the actuators. I could see this modification was holding the valves open about 3/16-in on the left and about 5/16-in on the right.


I went for a test drive and noted a big change in sound. In fact, it was now a little too loud when the valves were closed. The sound I wanted was just a little bit louder than stock–about the same as the titanium exhaust on my C5 Z06. I rolled the car back in the shop, removed and disassembled the right actuator, then took about .050-in off one of the spacers with my Eastwood bench grinder. I reassembled the right side, noted that when "closed" both were now open about 3/16-in, and went for a second test drive.


The sound was perfect! All for $1.50 plus tax for the spacers and 45-min. of my time. Plus there's no set screw to come loose. And, the system was still fully-computer controlled.

 

[navy2kcoupe]

Ingenuity......Field Expediency.......Innovation.........Whatever you decide to call it,
THAT'S ONE GREAT SOLUTION TO YOUR PROBLEM!
Andy

 

[carlc1c3c5]

Traco did a stuff to those engines–probably more than "that much" but, because of SCCA rules, less than "a lot". A 302 in Trans-Am race trim made about 450-hp, probably less in '67 and '68 and maybe more in '69, '70 and '71. In the late 60s, 70s and early 80s a Traco engine was serious bragging rights...sorta like Katech is, today. "Traco" was a contraction of the owners two last names, Jim Travers and Frank Coon. When Travers and Coon retired, they gave the business to Travers' daughter who was married to Jim Jones and Jim kept the Traco name going through the mid/late-80s until the mid-1990s when he sold the business and went to work for several different NASCAR Cup teams. Jones currently is associated with Callaway Cars. I did a lot of work with Jim Jones and Traco during the mid-80s to early-90s. Jones was one of the first aftermarket guys to fool with chips in 85 Corvettes with port injection and I remember using his calibrations in my 88 Beretta GT and in an 89 Firebird project car I built for a magazine. But...I digress.

As for the old Z/28s in the Trans-Am, not only did Chevrolet release a 2x4 low cross ram manifold which used two Holley double pumpers, but it also has a special valve train package, centered around the famed "Service Cam" and later got roller rocker arms homologated.

As you can imagine, a 302 with racing heads, a killer camshaft and two big Holleys, made for a very peaky engine. I think the useable RPM range was about 5000 to about 7500. Imagine running that with a close ratio four speed.

One of my h.s.,rvn,friends,had one w xram,holley s, also some sort of factory cast iron headers,he had 2 rev-up approx. 33-3500rpm dump the clutch!!then all HELL BROKE LOOSE !!it was a screamer !! then he got married.end of story!

 

[Hib Halverson]

(snip)then he got married.end of story!

(sigh)

I'm lucky, my Wife, the Fairest Sandra the Red, Duchess of Goleta, is into the Corvette hobby almost as much as myself. She's not a gearhead by any means, but loves the car, the people and the Corvette mystique. When we were engaged, she had one, I had two then we bought one together. A-year-and-a-half ago, we sold one and bought the Blue Bullet II.

I'm, like...way lucky that I got married and my Corvette "story" didn't end.

 

[Hib Halverson]

Love much, hate a tiny bit

Don't get me wrong, I love my '12 Z06 but sometimes, in working on this car, I've found that GM cuts corners here and there.
ad(maybe a little)

I changed the coolant yesterday, mainly because I wanted to look at the thermostat for learning purposes.

Following the "static refill" procedure in the FSM, I began to notice coolant leaking onto the left frame rail in the area below the surge tank. In the past my experience, all the way back to C3, has been that when you're filling the tank, no matter how careful you are, some coolant spills onto the cap sealing ring, then flows into the overflow hose inlet and, from there, down the hose and onto the shop floor.

Well–not with this C6.

Rather than spending the money for a longer overflow hose which will vent coolant in manner that it exits the underhood area, all GM did was stick a four-inch long, corrugated elbow on the overflow hose connection at the surge tank. It vents, straight down, onto the inner fender under the tank and from there, it drips onto the top of the frame.

I'm all, like....no big deal to clean up, but sheesh, guys–you couldn't have spent five bucks for a little more hose??!!


On the other hand, it's not like GM didn't warm me. The FSM does say, "Rinse away any excess coolant from the engine and the engine compartment."

In any event, I'm off to Jerry's Auto Parts over in the other part of town to get some hose and make a proper overflow vent line.

After that, the next job is to wrap the exhaust from the cats back to the axle. I got a decrease in center console heat from that insulated tunnel close-out plate I installed earlier and I'm going for another decrease by insulating the exhaust with DEI Exhaust Wrap.

Next weekend, were taking the BB2 up to the ALMS at Laguna Seca. It'll be a good test of the mods I've made to decrease exhaust heat into the interior.

 

[Hib Halverson]

Didn't get a chance to wrap the exhaust before The Fairest Sandra the Red and I left on the long run up to Northern Cal for the ALMS race in Monterrey, but the trip made it clear to me that, while the insulated close-out plate I ordered from Zip Products decreased peak temps of the center console, there is still more work to be done on that front. I'd like to get the temps around the console down another 10°F beyond the improvement I got with that close-out plate.

Interestingly, one of the questions Corvette Chief Engineer, Tadge Juecter, took at the Corvette Racing banquet on Friday night was from a C6 owner who complained about the heat which comes off the floor of the center console compartment and other parts of the console, then asked what the Corvette Team had done with C7 to reduce that problem. Juechter briefly discussed some new thermal management technology GM is rolling out on C7. On the tunnel in a C7 there are sections of a aerospace-derived product called "aerogel". The stuff is supposed to work better than traditional thermal insulation materials long used by the automotive industry. There are some types of aerogels which are said to be 5-10 times more efficient than existing insulation, with a quarter-inch-thick sheet providing as much insulation as three-inches of fiberglass. Not sure if the product used on C7 is the same as that type of aerogel, but if it is; C7 ought to be a lot better than C6 was as far as hot center consoles. Maybe some aftermarket vendor will start selling that aerogel stuff.

At any rate, the next big job I do on my '12 is to get the DEI Exhaust Wrap on the exhaust system under the interior.

We had a blast at the Corvette Coral and watching the ALMS race. The Coral was next to the Porsche and Viper Corals. Too bad the weather wasn't hotter we all could have had a big water balloon fight.

The race itself was another victory for Corvette Racing. They're 2 for 3 going into LeMans. Here's sort of an abbreviated race report I pulled off the Corvette Racing site then edited...

A well-executed team effort returned Corvette Racing to victory lane at Laguna Seca for the second consecutive year. Jan Magnussen and Antonio Garcia, in the No. 3 Compuware Corvette C6.R, scored their first American Le Mans Series GT Class win of the season to match the 4-car team of Oliver Gavin and Tommy Milner, who won the season-opener at Sebring.

Gavin qualified fourth at Laguna Seca while Garcia posted the sixth-fastest GT time in his No. 3 Corvette.


Early in the race, the 4 made contact with another car but was able to continue with no damage. After both Corvettes stopped for fuel and tires just over an hour into the race, the No. 3 car, driven by Magnussen, went to the front of the GT field, but trouble struck the No. 4 Corvette when its transmission stuck in sixth gear. A full course caution coincided with the gear box problem and the crew brought Gavin in under yellow. The Team quickly identified the problem as a cracked hose in the gear box. Unfortunately, repairs cost five laps and the No. 4 fell to the rear of the GT ranks, eventually finishing 10th.


At the halfway mark of the race, Magnussen had built a two-second lead over second place until the track went yellow, again, for a car stuck in the sand. The No. 3 team decided to bring Jan in for tires, fuel and a driver change. It was another lightning-fast stop for the Corvette Racing crew which kept the car at the front of the field.

With Garcia behind the wheel, the 3 would not relinquish the lead again. The margin was tight most of the race and varied from three-tenths to almost two seconds. The crew and drivers had no room for error . The 3 Team spent four seconds less on pit road than the second place Porsche Team, no doubt a key factor in Corvette's win.

Magnussen was happy with the long awaited win in a tough race. "I have to say, today was one of the most perfect races we've had with Corvette Racing," he said. "We were under pressure the whole way. We never had a big lead, we really had to work through traffic and not get stopped by the slower cars and lose too much time. It was a matter of being precise the whole race. The pit crew made perfect stops. We didn't have any issues in the pits. We did the driver change during only a short fuel, so there wasn't a lot of time to make it. I am so happy we finally get a win over a year and a half. With this one, if you can't win driving like this, you can't win. It is a lot of pressure, but we have a great crew behind us the whole time."

Garcia, who drove the final laps under intense pressure, gave much credit to this team. "It was brilliant," said Garcia. "Even the driver change was amazing. Even if it was 11 or 12 seconds on fuel, we made it out on time and I could hardly even do my belts before taking off. So basically that is the main thing. The Corvette crew did a great job out there and all the pit stops were under yellow and even if we were coming in bumper-to-bumper, every time we were going out of the pits, nobody was behind us. They were behind, but they were further back than when we came in. You need a fast Corvette race car, but just as important is having a crew that performs like these guys did today."

Corvette Racing has 79 ALMS class victories, including four in 2012, making it the most successful team in American Le Mans Series history.

At Laguna Seca I had a reunion of sorts with an old friend, Dan Binks, who's one of Corvette Racing's CrewChiefs. Danny Binks comes from a road racing family. His Mom and Dad were both long-time San Diego Region SCCA race workers. Back in the '80s I, also, was an SCCA worker with the CalClub Region's fire-rescue crew. I first met Dan Binks at Holtville, a dusty airport course out in the desert east of San Diego. His Mom and Dad were working the race. A group of us from Cal Club went down to Holtville to help out. I met the Binks family Phil, Marge and their (at that time) little kids of which
Dan was one. All the cool people camp out at Holtville and we all worked the race and partied together at night.

In later years, as Dan got older, he became a race worker himself, sometimes working with our Cal Club Emergency Team at old Riverside International Raceway and other venues such as Willow Springs and Long Beach. Several times, I had the honor of working on the same firetruck or towtruck crew with Dan.

Back then, Dan was into seriously hot rod Volkswagens but then, the times when I drove my 71 Big-Block Coupe out to the track for race weekend, he was always interested in what new mods I'd done to the car as part of the old Big Block from Hell project. So, it might be a bit of a stretch but, maybe, I had some small part in getting Dan Binks interested in Corvettes...and interest he, obviously, still, has today.

Sandy and I stopped in at the Corvette Racing garage before the race and spent a little time with Dan talking about the Team's qualifying effort and its confidence about performing well in the day's event. We even talked about those old days at Riverside, Holtville and other tracks.

Best of luck to Dan Binks and the entire Corvette Racing operation at LeMans at the end of next month.

 

[ltmax]

LS7 Write-up Follow-up

Hib, not to throw this thread somewhere else, but GREAT write-up on the 427! Nice detail that filled in my thoughts on this mill when I first saw it in Detroit, NAIIS.
So how do ya throw a guy props? Ask for more! Ya have any thoughts of doing something similar for the LS9? That they got that blower/cooler packaged under the hood of a Vette is still amazing, and taking the 430 hp LS3 to 640 hp HAS to be a story for sure!

Either way, thanks for the 427 story

...and good to hear ya watched yet another Vette victory at Seca - where ZR showed SRT how smallblocks run.

 

[Hib Halverson]

Hib, not to throw this thread somewhere else, but GREAT write-up on the 427! Nice detail that filled in my thoughts on this mill when I first saw it in Detroit, NAIIS.
So how do ya throw a guy props? Ask for more!

NP, dude. We got ya covered.

Ya have any thoughts of doing something similar for the LS9? That they got that blower/cooler packaged under the hood of a Vette is still amazing,and taking the 430 hp LS3 to 640 hp HAS to be a story for sure!

See: Corvette Action Center | Model Center | C6 | 2009 ZR1 | Ruthless Pursuit of Power: Supercharged Edition - Page 1 of 7

Either way, thanks for the 427 story

...and good to hear ya watched yet another Vette victory at Seca - where ZR showed SRT how smallblocks run.

Corvette Racing's engine program has the Viper beat hands down. When I was chit-chatting with Dan Binks he says to me, "The Viper guys told me, 'We have a million dollar engine program.' Heck, I have a million bucks worth of engines just in my trailer outside."

I'll guess that GM Powertrain's engine program for Corvette racing is three times what Dodge spends on trying to make a truck engine into a racing engine. I'd love to do an article about the C6.R's 5.5L race engine, but GM is very secretive about that program. It might be tough to convince them to go public with some aspects of that engine.

 

[Rob]

if you want to read any of Hib's articles here on the CAC - just scroll over the Tech Center tab up above and click on Featured Articles.

 

[Hib Halverson]

I've put a lot of miles on the Blue Bullet II in the last week or so, driving around the southwestern U.S. speaking to Corvette Clubs about the 2014 National Corvette Caravan. A week ago last Wednesday, I met with Color Country Corvettes in St. George, Utah and, the next night, with the Las Vegas Corvette Association in Las Vegas. This week I was at Inland Empire Corvettes in San Bernardino, California. All these clubs have members who will join us on the '14 Caravan. Inland Empire has volunteered to host our Departure Events the night before and the day we leave Fontana, California for the six-day trip to Bowling Green.

In all this driving, I made some observations about my C6 Z06.

First, my two dollar answer to expensive exhaust bypass disablers–"Mild-to-Wild", "Exhaust Commander" and etc. With my cheap exhaust mod, below 3500, BB II is just the right amount louder than stock–ie: "authoritative" but not obnoxious and, once I go past 3500, the Exhaust Control Module commands the bypasses open, allowing the engine to make maximum power. For two bucks worth of spacers, I have louder (but not too loud) exhaust with the valves closed, full computer control of their opening, no foot switches or fobs to fool with and 78 extra bucks to spend on beer.

Another characteristic of the car which really came to light on these last two drive trips was the effect of RPO F55, Magnetic Selective Ride Control, or as the GM guys say, "MR". Basically, it's a set of ride-adaptive shock absorbers, controlled by a computer, which can change their damping characteristics in near-real-time such that they can alter the car's ride while the suspension moves. Back in '03, when the system was introduced, I wrote an article about it and, while MR is now in its third generation, the basic principles by which it works have changed little. For more technical info see: Magnetic Ride - Star Wars Meets the 50th Car

California has the worst roads in the country because politicians and misinformed voters have run the State to near bankruptcy with huge voted indebtedness, costly entitlement programs and half-a-century of wage and pension giveaways to public employees, leaving little or no money to spend on highway maintenance–in spite of some of the highest gas taxes in the United States. Especially bad are the freeways in the Greater L.A. area. Common are sections of broken/cracked concrete slabs in the two right lanes used by heavy trucks, tilted slabs in any lane, dips at transitions between normal road way and bridge decks and undulating road surfaces resulting from ground settling, poor construction or heavy truck traffic. All that makes frequent and sometimes significant low-frequency ride movements at highway speeds.

My Wife, the Fairest Sandra the Red, and I own two Z06es, an '04 C5 and the '12 C6. On roads like that, the difference in ride quality between the C5 Z, with its fixed-valve shocks and the C6 with its MR shocks during big low-frequency ride movements is just amazing. I don't know what the MY04 FE4 and MY12 FE4 wheel rates are. I suspect they are comparable, but the better ride of the MR-equipped '12 during really makes a difference on long trips.

Let’s examine what Magnaride does when one traverses a dip at highway speed. At 70-mph, you’re covering a bit over 100 feet a second. MR takes several milliseconds to respond and, in that time, the car only moves forward maybe six inches. As it moves forward, MR tries to maintain body movement in a plane in space. When you enter the dip, MR's wheel position sensors, seeing the wheels dropping into the dip, signal the controller that a large body event is taking place. The controller determines the next thing the body will do is pitch down, but, before much of that movement takes place, MR's rebound damping goes very soft, not only to let the wheels fall into the dip, but to let the springs actually push the wheels into it. Without MR, in this situation, you’d have heavier rebound damping pulling the front end into the dip. Once the tires near the bottom of the dip, the body wants to fall into it, too, so MR's compression damping goes very stiff. It takes much longer for the body to move down on the suspension, because compression damping is, now, stiff.

When you start coming up, out of the dip; the controller sees the suspension starting to be shoved up into the body. To keep the body from pitching upwards, the MR controller sets the shocks very soft on the compression side, so the suspension will easily move up, but not pitch the body up as you come out of the dip on the other side. In that fraction of a second, between the bottom of the dip and the end of the dip, Magnetic Selective Ride Control as switched through nearly its full range of compression damping, from very stiff to very soft. As you finally clear the dip, there may be some, secondary, cyclic motion taking place which pitches the body. The controller sees that, then applies whatever appropriate level of compression and rebound damping to properly damp those motions. It does all this in a few hundred milliseconds while the car, traveling at highway speed, moves, maybe, 70 feet. Amazing!

Needless to say, on crappy roads in California and other places with old, bumpy highways, Magnaride is really a plus on a car like a Z06 which has high spring rates and big stabilizer bars. MR can't do as much with the harshness which comes from stiff control arm bushings and low-profile run flats, but harshness is a function of high-frequency suspension movement and it's the low-frequency stuff that usually makes for an uncomfortable ride. Bottom line: I'm really glad I ordered MR.

The trip to St. George and Las Vegas took me though hot country. On the way up to Vegas in I-15, it was 109 in Baker California. The mercury got to 105-108 on the drive to St. George and it was around 106 in Las Vegas. So–how did the Blue Bullet II do in keeping it's cool? Quite well, in fact. I never saw higher than 214 for coolant temp and it was at 190-194° most of the time. I bet with a 170° thermostat (which no one makes right now) and a different calibration with lower fan-ons would reduce that.

While the radiator stayed pretty cool from the second day of that trip, the driver was wasn't cool because the car's air conditioning quit working. As I drove up I-15 to St. George, the outside temp was 108. All I could do is run with the windows down and that was like standing next to a pizza oven right when someone opens the door. Needless to say, I was pretty pissed about that. ad

When I got back home, I took the car into the local dealer. Under warranty, they checked the A/C, found it low on refrigerant but couldn't locate any leaks. They topped it off with more R134a and, also, put a tracing dye in the system which shows up under ultraviolet light. They told me to come back in a few weeks and they'd inspect the A/C with a UV light in an attempt to find the leak.

Another little quirk I noted on the longer stretches of the trip on I-15 is, starting about 80-mph, I'd feel a medium-frequency vibration that was cyclic in it's intensity and could be felt in the steering. It would fluctuate in severity from almost nothing to a peak in about 1-Hz. It was awfully high-frequency for a wheel imbalance, but too low a frequency to be a bad wheel bearing. C6's do not have a large prop shaft or half-shafts like C4s did so a driveline imbalance was unlikely. I was thinking it was a slight wheel balance problem.

When I got back home I pulled the front tires off and took them to Bob Woolever's Tire Shoppe for balancing. While Woolever had the front tires, I carefully inspected the brake rotors and hubs for anything that looked as if it could cause an imbalance. I found nothing.

At Woolever's I was told they rebalanced one wheel but the weights ended up in exactly the same places the factory weights had been located. The second tire was perfectly balanced.

Back, at my shop, I sat looking at the tires while sipping a Pepsi. I put the fronts back on the car, but while handing the lug nuts, I noted the McGard wheel locks were quite a bit heavier than the lug nuts. I put the lugs and locks back on and went for a road test and the above-80 vibration was the same.

Then, I removed the wheel locks from each front wheel, replaced each with a stock lug nut and went for a second road test.

The vibration was gone. Even at 90-mph, I couldn't feel a thing. I called Bob Woolever and told him. He said in 30-years running a tire store, he'd never heard of wheel locks causing an imbalance.

On Monday morning, I'm going to contact McGard and ask if such a situation can occur.

My gut feeling is that it can in cases when locks weight a lot more than lug nuts and the vehicle speed is 80-mph-plus.

I'll let you know what I find out.

 

[froggy47]

Continue the test, put wheel locks back on, maybe just 1 front side & see if it comes back.

 

[Hib Halverson]

I've decided that, before I do any more testing, I'm going to ask McGard about the situation and, I'm going to weigh one of the locks and one of the stock nuts.