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*Originally posted by Anthracite *
5) They ran them at crazy valve and ignition timings, using something he always called “Purple Aviation Gas” (I have no idea what that is, BTW).
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Aviation gas for piston engines used to come in four grades, dyed different colors so you could tell them apart. Purple was the highest grade, 130 octane IIRC. I did a quick web search to refresh my memory and I found one page that says that standard is obsolete.
OK, that makes sense, but is it even better to have a smooth, tapered rear end? Or is a ‘spoiled’ surface still better? Aerodynamic drag is extremely important in HPV (human-powered vehicle) races and yet I’ve never seen a single HPV with spoilers. The Virtual Edge page talks about carefully designing the body of their HPV to preserve laminar flow.
Over 99% of these sparrow strainers and balogna slicers serve only one function. If properly mounted, on a good day, they might stop backflow of exhaust into an open rear window.
Sure, winged Indy cars could drive on an inverted track, but the Highway Patrol has got to have some sort of rule against us mere mortals doing it.
A polymer gas additive know as Polyisobutylene is reported to decrease emissions by 70%, increase mileage by 20% and improve horsepower 10%. I submit for your approval that externally mounted rigid polymer structures (even the 3,000 pound ones, Sofa King) are no match for internally applied polymer compounds.
Please refer to the Science News, edition of 9/2/2000 (Volume #158, No. 10, page 149). The compound equalizes the ignition point / burn rate of both short and long chain hydrocarbons. Read it and weep guys. Sure, these aliform appurtenances improve performance for the top 10% of cars at the top 10% of their speed ranges. Other than that, these wing-dings are no more than automotive hairdos.
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*Originally posted by Gunslinger *
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No thanks to Ohio George, right? Didn’t Ford want him to build a turbo system for that engine?
Anyone else been reading the stories in Motor Trend and Hot Rod about the “Gasser wars” and Ohio George? Cool shit.
–Tim
100/130 Avgas is not 130 Octane - I think it’s closer to 100. But I can’t remember the real amount offhand. It’s what the ‘purple’ gas used to be, but it is no longer available because of its high lead content. Aircraft engines that burn it are fairly low compression and don’t need a particularly high octane - in fact, when 100/130 was phased out, airplanes that used it all converted to either 100LL (low lead), or 80/87. There are no detonation problems or anything else even at 82 Octane. In fact, most aircraft engines can also be certificated to use standard auto gas.
Anthracite: I came up with the 425 number by doing the math, and I believe I was being conservative.
The engine started out as a 375 HP 327 from a Corvette. I took it from there and bored the cylinders out, changed the compression from 11:1 to 12.5:1, had the heads ported and polished, mechanical lifters, water injection, and a huge Holley carb. I could run the quarter mile in 12.2 seconds in street trim, with the headers uncorked. If you want to see how that compares to modern cars, check the quarter-mile times for comparable cars like the new Corvette.
Well, I would then ask how much the car weighed, and relative to the new Vette we could probably come up with a decent estimate.
Still - let me do some math here. Guessing a '67 Camaro at 3200 lbm (I really don’t know, but that seems good) and a 12.2 quarter…hmm…maybe you are up around 400+ or so after all. Esp when I compare with the VO6 Corvette. What sort of transmission are you running with that? If it’s a “traditional” automatic, then I would have to admit you probably are actually above your 425 you say (maybe 430-440), according to my calcs. If a manual, then I would guess about 390-400. Still pretty damn good…
But your car isn’t exactly stock either (for which I imagine you are quite pleased 
)- did you get a quarter mile run before any of the mods?
I had a Turbo 350 Transmission when I ran the 1/4, but that thing only lasted a couple of months before it was pretty much shot. So I replaced it with a Turbo 400. I had a 12-bolt posi-traction differential with 454 gears.
I never ran it in the 1/4 mile before the mods, because it had a wimpy little 283 in it. I bought the motor and did the mods all at once. I also had to run octane booster to keep it from detonating even with the water injection, and I used to say that it was a 1/4 mile racer because that’s about all it could get on a tank of gas. It was a real gas hog.
And I think 3200 lbs is about right for the weight, with the small-block Chevy. The Big Block Camaros were probably around 3500.
Great car. After I put that engine in, I blew up the transmission, the differential (original 10-bolt), the shocks, the leaf springs… I basically had to rebuild the car from the ground up to handle the power.
I did a bit more checking into the changeover from Gross to Net horsepower ratings. The big changeover happened in 1972. Most people agree that the change in measuring resulting in a reduction of about 16-18% in advertised horsepower. Thus, a 1971 GTO with a 455 was rated at 330 HP, and a 1972 GTO with the same engine was rated at 275.
So, it’s not THAT big a difference. 300 HP today would be about 350 HP in the good old days.
I’m looking at some published numbers for some 60’s Muscle cars, which would indicate that their horsepower numbers, if anything, were under-reported. I mentioned that GM intentionally did that with the LS-7 and L-88 motors. Remember that it was a big deal for car companies to win stock races with their cars, and one of the requirements for ‘stock’ cars is that they had to run with components available to the public. So the auto makers would offer some wild engine options to the public for no reason other than to qualify them for use in their race cars. We’re talking $4000 engine options in a $3000 car, with 427 aluminum block engines that are ridiculously impractical on the street.
Anyway, here are some published 1/4 mile times for some 60’s muscle cars. Remember, these are using old tire and suspension technology, in very heavy cars by today’s standards:
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[li]1966 427 Cobra 12.20@118 427 8V 425hp[/li][li]1966 Corvette 427 12.8@112 L72 427 425hp[/li][li]1969 Road Runner 12.91@111.8 440 Six BBL 390hp[/li][li]1970 Hemi Cuda 13.10@107.12 426 Hemi 425hp[/li][li]1970 Chevelle SS454 13.12@107.01 454 LS6 450hp[/li][li]1969 Camaro 13.16@110.21 427 ZL1 430hp[/li][li]1968 Corvette 13.30@108 427 6V 435hp[/li][li]1970 Road Runner 13.34@107.5 426 Hemi 425hp[/li][li]1970 Buick GS Stage I 13.38@105.5 455 Stage I 360 automatic 3.64 MT 1/70[/li][li]1969 Charger 500 13.48@109 426 Hemi 425hp[/li][li]1969 Super Bee 13.56@105.6 440hp Six Pack 390hp[/li][/ul]
In Comparison, here are a couple of later-model cars
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[li]1996 Camaro Z28 SS 13.46@106.48 350 LT-1 310hp[/li][li]1996 Corvette GS 13.7@105.1 350 LT-4 330hp[/li][li]1987 Buick GNX 13.70@102 231 Turbo V6 300hp[/li][/ul]
To me, they look pretty close, when you consider the 16.7% HP reduction from Gross to Net, coupled with the tremendous improvements in tire and suspension technology.
Something not shown here - the lower-horsepower Muscle Cars used to post 1/4 times almost the same as the higher-horsepower ones, indicating that the real limit was traction.