SPECIOUS SUPERCAR HISTORY: 1977 OLDS INDY ROCKET 88

 

Two Speeds Good Six Speeds Bad! or... Six Speed Supercar Suppositions Sunk

I pour over many a road test in my research on 60's supercars, and as the years wear on, I find it fascinating how well correlated 0-60 and 1/4 mile times are across the decades. Usually if you know the 0-60mph time, you can pretty well guess the ¼ mile time and trap speed. Recently I ran across this graph from the good folks at Lingenfelter performance. They offer a host of high-buck smog legal hop up parts for late model cars and trucks. Their most recent challenge comes in the form of the all new 2014 Chevrolet Silverado pickup. This revamped Cowboy Cadillac has an all new engine with direct fuel injection – “DFI.” With DFI super high pressure fuel lines run directly into the cylinders, bypassing the intake valves. Using DFI, the new Chevrolet “Ecotec 3” engine pulls an additional 40hp from the same 323 cubic inch displacement as used in the ’13 Silverado for a healthy 355hp. The ’14 model also features wider wheels and tires for greater off-the line traction, and is marginally lighter. Lingenfelter’s crew compared the ’14 with a ’10 Silverado that features the same six speed automatic. The laws of physics didn’t cheat the more powerful ’14 Silvy. It’s faster…

Now I’m not here to debate the merits of DFI or more horsepower, but rather I’d like to draw your attention to the alleged awesome-sauciness of another modern wonder: the six speed transmission. 

You can find many gearheads – running the range from the next guy at the bar to semi pros and pros who will tell you that thanks to our modern technological wonders like the (allegedly twice-as-nice as three speed) six speed automatic, current cars will use whatever power they have far more effectively than they did back in the olden days of the caveman, three speed transmissions, skinny tires and ethyl-lead gasoline.

Compare our Buck Rogers '14 Silvy with the dinosaur era '66 427 Caprice tested in the January ’66 CAR & DRIVER. It's a good comparison because this is a car with 2.73:1 rear gears, so wheel spin was absent - just like our current wonder with all those computers bearing gifts of torque management and traction control.

Despite the advantage of the new Silverado’s fat sticky tires and the ultra steep gearing of the six speed transmission, the high tech Silverado doesn't actually do more with what power it has.  The lbs/hp is surprisingly close if you figure 300 net horsepower from the 390 gross 427. (NOTE: This is necessary in comparing a ‘60’s car to the Silverado because the way horsepower is measured changed from the more optimistic ‘gross’ rating of the 1960’s to ‘net’ used from 1972 onward. If you compare net and gross ratings for the same engines from 1971, you get a typical conversion factor of .77x going from gross to net or 1.3x going from net to gross).   

With a test weight of 4553lbs we get 15.17lbs/hp for the 1966 Caprice. It's pretty close to the 355hp Chilvyrado's 15.7lbs/hp.  

The caveman Caprice actually beats our modern wonder -  just barely - with its slight HP/weight advantage. It has virtually the same 0-60mph and 1/4 mile times. 15.7 seconds @ 90mph and 7.6 to sixty for the Caprice. The Silvy's 0-90mph is exactly the same - it just arrives at the 1/4 mile marker 0.24 seconds later at 91mph. But here is the crux of the matter: Shouldn’t the extra gears in the Silverado make it faster, given roughly the same HP/lb ratio? Doesn’t the six speed allow the Silverado to use what power it has – more effectively?




More speeds more speed? 

Nope.  

But is this some kind of special case? Maybe a car with less traction off the line and even fewer transmission speeds will prove more speeds = more speed.  The coupe de grace is the 1963 Powerglide Impala SS 409. Spoiler alert: with a two speed automatic (yes, we used to have those – and Chevy sold its Powerglide for about eight years after the rest of Detroit went to three speeds), fifty fewer horsepower and even skinnier tires, it towel whips the ‘66 Caprice.

0-60 in 6.6 seconds? In 1963? With only one geared ratio? Yep. Well OK you might think, but the ¼ mile probably won’t be well correlated to the sixty sprint – not in the same way as three speed automatic. In the 1/4 mile it's going to fall way behind because of no intermediate 'passing gear’ and the commensurate bigger drop in RPM for its single up-shift…right?

Sorry.

Wrong again. The supposed ‘slushbox’ Powerglide in the 409 scorches through the ¼ mile traps with a 15.1 e.t. at 90mph. In terms of trap speed in relation to elapsed time, the 409 could be thought to lay down what power it has even more efficiently than our smart phone-era Chilvyrado.

Why? Consider 340 'gross' hp x .77 gives us only 262 'net' HP. With a 4120lbs test weight, the real fine 409 has the same exemplary lbs/hp ratio as...

Our spankin’ new ‘14 Silvylet: 15.7lbs. Yet the Silvy is nearly a second behind with three times the speeds!

(NOTE: A 15.1 second e.t would easily qualify for the definition of 'supercar' when it was coined in the May '65 issue of CAR LIFE. This ‘softer’ 409/Powerglide Chevy competed with the similar ‘de-tuned’ '63 Dodge and Plymouth 426 street wedge engine. All three employed Super Stock drag racing engines that had been transformed into far more docile beasts for useable consumer performance for the street rather than the ¼ mile strip. They shared agreeable traits like quick warm-up, decreased maintenance and yes, even better gas mileage. This ‘pragmatic power’ is the signature trademark of the 1960's supercar. The brightest lights from the supercar era - men like Roger Huntington, Marty Schorr and Joe Oldham - would all agree on that. They would also all agree that the '64 Pontiac GTO is the undisputed first supercar. In spite of having similar pragmatic power, and even special trim and sexy bucket seats, there are a host of reasons – mostly intangibles – why the 426 Plymouth and Dodge and the 409 Chevrolet didn’t start a trend of copycat models the way the GTO did.)

So for chrissakes, why? Why oh why does all this awesome technology – superior six speed and all – not absolutley slice the Paleolithic 409 to shreds?

First off, despite having lower engine power, that Powerglide transmission actually…yeaaahhh… wastes fewer horsepower. It stands to reason, since the PG doesn’t operate as many clutches and turn as many gears.  Just to run itself, the Powerglide consumes only about 20hp. The three speed automatic in the Caprice needed more than double that - http://www.442.com/oldsfaq/oftrn.htm#TRAN Auto Transmission Comparison - to run itself.

We also must consider the low rpm torque multiplication of a torque converter made the first speed work more like two. As rpms increase, torque multiplication is gradually eliminated and engine revs per mile goes down. The ‘63 409 would easily spin the tires, with less traction than the Caprice, yet with an inferior HP/weight ratio, it soundly trounced the wider tire-d ‘66 Chevy. Also keep in mind the ‘mild’ 409 still made its power at 5000rpm – 200rpm higher than the Dodge/Plymouth 426 models. Peak torque is at 3200rpm, so the wide drop in rpm just gets you back to the torque peak.

In most road tests, the 426 Wedge Mopars, which were more powerful ‘on paper’ actually tested slower than the 409. In the May 1965 CAR LIFE issue devoted to the coinage of the word supercar, a new, ‘standard sized’ Dodge Coronet “426-S” with a 4 speed manual transmission and a steep 3.55 axle ratio made it to sixty in 7.8 seconds with a 15.4/89mph e.t. and a 120mph test top speed at 5100rpm. That’s slower all around than the CAR LIFE ’63 409. 

But maybe the Powerglide 409 is just a black swan – a well tuned test car with plenty of break-in miles run on a perfect day. The typical two speed supercar should run much less efficiently. And we would see that tight correlation in 0-60 times and ¼ mile times go away.

Well…interesting story: in the same May ’65 supercar issue, CAR LIFE tested a Buick Skylark GS with the 325hp 401cid engine hooked to a Super Turbine 300 two speed automatic. It employed ‘switch pitch’ torque converter stator blades that multiplied torque by either a 2:1 or 2.5:1ratio, depending on throttle position (by this logic it would actually be a pseudo four speed since the switch could happen in either low or high gear).

On paper the Dodge should not just beat the Buick, but blow it into the weeds since the GS had a 16.2lbs/hp test weight (325hp x .77 ‘net factor’ = 250hp divided by 4030lb test weight) while the 426-S had a 4174lb test weight and its 365 ‘gross’ hp converts to 282 net for 14.85lbs/hp. The Buick worked with 40 fewer rated horsepower fed through a ‘slushbox’ 2.5 speed automatic and a ‘highway’ 3.08:1 axle ratio. Yet David Buick, with his two speed sling, doth slayeth (marginally at least) the Dodge Goliath. 

The ‘65 Skylark GS (described in print ads as a “Superbird” – you’re welcome Plymouth http://en.wikipedia.org/wiki/Plymouth_Superbird) raced to 60 in 7.4 seconds, to the ¼ mile e.t. in 15.3 at 88mph and finally to a 121mph top speed at 5000rpm. One might imagine the two speed automatic paid the price in wasting more fuel – after all, the Dodge was a manual transmission with no hydraulic slippage. Except that the Buick actually got better gas mileage according to CAR LIFE: 13-16mpg vs. 12-15mpg for the Dodge. The Buick had fewer horsepower, fewer gears and higher overall gearing – but it was able to lay down what power it did have more effectively and efficiently, just like the ’63 409 Impala SS.

We focus nearly all of our attention on numbers – the higher the better. That goes without saying in bench racing circles. For us fans the fetish is speed – and higher HP/torque numbers and higher multiplication of that torque should mean greater speed – isn’t that the point of higher numbers? More speeds, more power. But in some respect, every auto test we read isn’t a test of the mighty engine, but merely an ongoing contest of better and better tires pitted against the rate of gravity and the aero resistance on mother earth.

We're justly proud in our age of complicated phones that the 2014 Heavy Chevy Silverado rates 16mpg city. Yet CAR LIFE made 16mpg with the Buick GS supercar in 1965 – going on fifty years ago. Fifty years! The '63 409 was pushed to 124mph in the road test, while our 2014 Silvy computer cuts the fun off at 110mph. If the electronic nanny is bypassed, it could probably match the 409 in top speed. This time its superior coefficient of drag helps compensate slightly for its much larger frontal area, but of course the top two gears in the vaunted six speed transmission would be useless in getting to 124mph. 

Yes, the Silvy makes it quick to 60mph, tows 8000lbs, hauls 3/4s of a ton and can carry a family. The sixties Chevrolets could tow about half of that; they came without the 1500lb hauling capacity but could also carry a family. And let’s face it: just carrying the driver is what most Silverados will do most of the time.

Let’s remember that spec sheet numbers mean nothing if the power can’t be effectively hooked to the tarmac. All those computers and gears and direct fuel injection involved in making a ’14 pickup almost as fast and slightly more fuel thrifty (and it must be said, with a tiny fraction of the smog forming tailpipe emissions) than a fifty year old ’63 Chevy 409 or ’65 Buick Skylark GS is there to allow another 1500lbs of body weight. 

And most important to remember - even then all those speeds actually don't allow the Silvy to use what power it has - any more effectively. If anything, the two speed transmissions of the 409 and Skylark put what power they had to the ground in a more efficient manner.  In the case of the 409, exactly the same power to weight ratio gave us a car that's about a second quicker in both the 60mph sprint and 1/4 mile. In the case of the Buick GS, an *inferior* power to weight ratio 16.2lbs/hp vs 15.7lbs/hp for the Silvy, but thanks to the awesomeness of its two speed transmission, it overcame the hp/lb deficit and beat the '14 Silverado.  Two speeds good, six speeds bad! Remember that. 

So when we thrill to our contemporary wonders - all those *speeds* man! - We have to remember exactly where we are progressing. We’re not going faster, we’re just growing fatter. Thanks computers!