© by Hib Halverson
No use without permission, All Rights Reserved
Steven Stringfellow, a Hughes engineer with a background in aircraft instrument panels, lead the project and one of the first attempts at putting an economically-feasible, head-up display in a GM car was done on a Corvette. While this development version was well-received, the production, C4 structure behind the instrument panel would not accommodate a useful HUD. The idea was shelved for Corvette and rolled into the development of the GM10 program, which arrived in 1988 as the then-new, W-platform. Both the Pontiac Grand Prix and the Olds Cutlass had HUD's designed by Hughes and manufactured by AC Delco. In 1992, a "Gen2" HUD debuted in the Pontiac Bonneville.
By 1993, Stringfellow was working directly for GM in an advanced electrical design group. A Chevrolet marketing executive, Dr. Fred Gallasch, approached Dave Hill with information supporting Chevrolet's position that customers wanted an HUD in the car. The case for a HUD was further reinforced when the digital vs. analog speedo debate (another one of those differences of opinion and frank exchanges of views, perhaps?) at the Corvette Launch Center resulted in an almost 50/50 split- the cluster went analog and the HUD would provide digital speed. It was put on the list for the 1999 model year (MY99) and Stringfellow was brought into the C5 development group to work, initially, on the Instrument Panel Cluster (IPC) and the Driver Information Center (DIC) for MY97 and subsequently on the HUD.
C5's Head-Up Display is the fourth generation GM HUD. It is brighter and can display more information than previous versions. The unit was designed by Stringfellow's group and Nippon Seki, the manufacturer of the car's IPC, was awarded the manufacturing contract after ACDelco's bid was rejected due to high cost.
The hardware resides in a small well ahead of the instrument panel and projects its image, via a vacuum fluorescent display, on the inside of the windshield. The HUD is positioned such that the display reflects off the front glass and into the driver's field of view. It appears to hang in space just below the driver's line of sight. Its basics are: digital speed, graphic RPM display, a choice of 3 gages, turn signals, high beams, a check gages warning and a shift light. The unit can be formatted, by holding down the page button, to show: 1) speed only, 2) speed and gage, 3) speed, gage and RPM 4) speed and RPM or 5) just RPM. Tapping the page button switches between oil pressure, coolant temp and fuel gages.
|Latest 1997 - 2004 C5 Corvette Forum Topics|
You can judge the HUD two ways, as a convenience option and as a performance driving aid. For convenience, it's easy to get used to the HUD as a constant driving "assistant". There it is, seeming to floating out there about 100 feet in front of the car. You never need to look down at the IPC to see your speed, rpm or to check if your blinkers are on. All you do is drop your line of sight a tiny bit and you see that bluish display. One thing we like about the HUD is, while a lot of data is available, only the basics are default-displayed, the rest is user-selectable. We, also, like the controllability of the HUD. The user can set the display's format, position within a moderate range and the brightness, all with controls that are easy to reach. They are located on the left of the IPC trim where, since 1997, there was a styled plug.
If the C5's HUD has a weakness, it is the shift light feature. At the media program at Indianapolis, after introducing the '99 Hardtop, Chief Engineer Hill discussed the HUD. He emphasized the shift light feature as a performance driving aid, similar in nature to shift lights used in road race or drag race cars. Our evaluation later that day, in a performance driving situation of the type deemed by Hill as ideal for the HUD shift light, found the feature lacked visibility.
We tested the light in the default choice of HUD data by accelerating in second gear. We intended to upshift when we saw the light in our peripheral vision, however, we never saw it and the LS1 hit the rev limiter. We tried it again, looking directly at the HUD as the engine neared redline. This time we saw the light, but couldn't find it until too long after it came on and the motor tagged the fuel cut-off, again. The light is so small, it seems to get lost amongst the other data. We found out later that the HUD can be set to show the shift light without the graphic tach display and it stands out more when not nestled up against the tach bars, however, in our opinion; it still needs to be a contrasting color or at least made several measures brighter than the surrounding parts of the display.
Putnam Park is a road race venue about half an hour west of Indianapolis and was the track Chevrolet rented for a few hours so Vette and other media outlets could test '99 Hardtops. Like Buttonwillow in California and Grattan in Michigan, Putnam Park is one of many fine road race courses in this country about which many motorsports fans know little because they hold no professional races. It's mainly an amateur racing, race driver school and a test facility.
Putnam Park is attractively landscaped and neatly-kept. It's main course is 1.76 miles long and has 10 turns. There is one fairly long straight and a couple of shorter ones. The track has several different kinds of turns and, thus, is a good choice to evaluate performance handling. The only thing lacking was some slow-speed, sharp-turn stuff typical of autocross. We were unable to instrument any of the cars we tested, so all we have to offer is subjective data.
After running hard at Putnam Park for nearly 20 laps we've no doubt that the Hardtop is the Corvette for the aggressive driver. It's mix of slightly less mass, manual trans and Z51 chassis tuning makes for race track performance that is just a slight measure better than any C5 we've tested to date.
The first thing we noticed is the car accelerates just a bit harder, undoubtedly because of lower mass. Compared to a Z51 Coupe that was available, Hardtops reach just a bit higher rpm at braking points prior to entrances to turns at the ends of straights. We are not sure how much that will knock off the car's already quick quarter mile times, but we tested a C5 manual Coupe last spring that ran 13.14 and 13.11. Initially, we were skeptical of the car's "tuning" but other tests we read or heard about have shown different C5 Coupes with stick-shifts capable of low-13-second passes. We think some Hardtops, run in good air and driven with skill will go 13-flat and maybe the very high-12s. That's ZR-1 country, my friends.
The word "tossable" was dreamt-up by GM to describe the Hardtop's claimed increased forgivingness when run past the limit. Several times during the two days Editor, Rich Lentinello and I spent at the '99 Corvette media program, we heard Dave Hill and other GM folks answer, when asked about the Hardtop's handling, "Well, it's more tossable."
If a car is "forgiving", one thing it does when pushed real hard is let a driver get more in over his or her head and still save the car, before it spins. Generally, we feel the quality of forgivingness is not something fast drivers should exploit. Drivers who consistently run past their cars' limits, that is: lots of sliding and gathering it up at the last second, are usually not as quick around the track as a driver-road race champion and former Assistant Corvette Chief Engineer, John Heinricy, for example-who's very smooth and runs on the near side of the limit or right on it.
I did not spend time in Hardtops deliberately getting over my head then trying to save it, as a measure of the car's "tossability," but I will tell you that the C5 in general is a better balanced car than C4. It lacks most of the quirks at the limit that were imposed upon C4 by a trailing arm rear suspension and less robust structure. Those two qualities would tend to make C5, Hardtop included, more forgiving and there was one instance in my testing at Putnam Park where that was demonstrated.
A technique we use on the race track, sometimes, is "trail-braking". With an understeering car that sometimes resists turn-in, trail-braking can be an acceptable strategy to improve turn entrance performance. In short, when you trail brake, you carry your braking into the first part of the turn. In most cases, this tends to induce a bit of oversteer and rotates the car sooner.
Our "bud" Mike Neal, the C5's ride and handling development engineer, told me several times over the last year or so to get out of the habit of trail-braking when driving a C5. Because the new car is more neutral than even the best, production C4s; trail-braking actually degrades lap times and, in extreme cases, can cause the back end to really step-out. I decided to see this for myself. During one of my laps in a Hardtop at Putnam, I came flying up to a turn and trail-braked it pretty good, like I'd do with a nose heavy car (such as a '93-'95 ZR-1). Sure enough, the back stepped right out-in fact, it stepped-out a bunch and suddenly, I found myself a bit crossed up. More astonishing was that I saved it. In most other cars, I surely would have been embarrassed with a spin and slide into the weeds. OK. The car is more tossable.
After after 10 laps in different Hardtops to get familiar with Putnam Park, I picked one that felt best and went out to really run it hard. I noticed two things: 1) I was able to brake just a bit deeper in several of the turns. That is probably due to the new model's lower mass and, perhaps, a small shift in its weight distribution. 2) In transitions, compared to a Z51 Coupe, Hardtops are noticeably (but not significantly) quicker or "crisper" in transitions. Transitions are "ess" turns in which the car is driven in a rapid, zig-zag fashion. The lighter a car is and the better tuned its suspension is, the quicker and more responsive the car will be in transitions. That the C5 Hardtop is both better under braking and quicker in transitions make it capable of better lap times. Again, we had no timing at Putnam Park, but considering the track's length and our estimate of the Hardtop's improved performance over a Z51 Coupe, we are fairly sure the new model would be the quickest C5 by about 1/3 to 1/2 a second-per-lap.
The only thing we regret about our preliminary test of the 1999 Corvette Hardtop was that none were available with the car's only performance option, Active Handling and we did not have more power. It will be interesting to track-test a Hardtop with a 375-400hp engine some day.
The 18-month introduction of the C5 has been a memorable time for anyone working at a Corvette magazine. A group of writers who regularly cover Corvette and some GM people have become a "family" of sorts through our attendance at all four of the C5 media programs. Having those events go smoothly not only helps we writers, but it helps you, the reader too, because you get better coverage of a product you want to learn about. A lot of people at Chevrolet made the C5 media preview series happen, but one person had overall responsibility for the planning and execution of the events and that was Tom Hoxie, Assistant Director of Chevrolet Communications.
Dealing with scores of writers, each with varying needs, descending on the program venue from all over the world, also requires a "travel agency/tour management" operation and ChevyComm contracts to a Michigan firm called Marcom for that. Every time we turned around, there was a smilin' Marcomer there to answer questions about travel arrangements, dig-up press kits, conjure up a snack after we missed a meal while on a photo shoot, give us a ride to the airport, along with other, more outlandish requests. The people at Chevrolet Communications and Marcom made our trips to C5 media events something special. We appreciated their efforts.
Well, there you have it. The Launch of the Fifth-Generation Corvette is complete and Chevrolet saved the best for last: The Hardtop-the Corvette for Hardcores. At this point, let's recall some of the first words heard about the C5 at the '97 Coupe preview, way back in November of 1996, it was Lead Exterior Designer (and sometimes amateur road racer) John Cafaro talking about his car, "It's a great car and it's got a great future. This car is gonna kick ass."