Then there’s this comment:
I’m fairly sure that sweeteviljesus’ point still stands – complying with NASCAR’s stated rules (i.e. without additives), I don’t think there’s a way to achieve an octane rating higher than 100. Am I missing something?
The other issue is engine development. I’m not sure about specifics but my understanding is that racing has been a spur to the development of lighter, more efficient engines. Perhaps not so much in some of the more rigid formulas of racing, but in the more technologically sophisticated styles of racing like Formula One.
If racing development results in tiny increases in efficiency for one car, that can be a big saving if it trickles down to the average car in the world fleet.
I guess the flipside is that racing probably increases the popularity of waaaay overpowered cars on the street.
None, nor does av-gas. High octane fuel allows engines designed (or modified) to have high compression ratios or high levels of induction boost (supercharging or turbocharging) to operate without detonation. It is the high compression ratio or boost that creates the extra horsepower, the high octane fuel just keeps such an engine from self distructing before the end of the race (usually).
Yep, he has a very tricked out Audi S4, with many aftermarket engine parts (upgraded turbo, headers, downpipes, water injection [flashes to steam, increases compression], and custom ECU chip). His ECU had a setting for “race gas.” As I understand it, there are few Audi S4s that are modified to the level that he has taken it. He is well over 400HP in full race configuration. See here for specs
He doesn’t actually race, but does do many “performance driving schools,” which is racing without the competition part. See
here for what I’m talking about.
Otherwise, it wouldn’t make any difference to most passenger cars.
Formula One has been responsible for huge advancements in engine development. Variable valve timing is one good example. First deployed on the V10 in the McLaren-Honda MP4/8 (I think- it was the '91 season car, at any rate).
However, to a Formula 1 engineer, “efficiency” refers to developing as much power and torque as possible given the engine size constraints (3.0 litres, normally aspirated, these days); fuel efficiency doesn’t really come into it, although teams may run slightly detuned engines at race X in order to drop a pit stop.
Or the first link in my thread above, about High Performance Driver’s Ed.
Well, this link to it might work better. 
But yes, same thing. I missed your thread.
Lots of fun to watch, I’ve never ponied up the money to actually attend on as a student, but I’ve been a groupie, and a paid corner worker for one at NHIS (NHMS post SMI).
I’ve had this debate before and I am unconvinced by your position. The goal of a race engine engineer may be as you say, but many of these sorts of developments scale downwards.
In other words (taking figures out of the air) lets say the public expects a normal small street car to have 100hp, and they are usually fitted with a 2 litre engine to achieve that.
Then race engineers develop a technology that gets 120 hp out of the same size and weight of engine.
Scaled backwards, car manufacturers can then start fitting 1.8 litre engines (which are lighter) fitted with this new technology that still produce 100hp. Result: less weight, greater fuel efficiency.
Your comment doesn’t take into account the fact that getting more power out of the same thing is often going to be permit you to get the same amount of power out of a smaller thing.
No, it doesn’t work that way. The things that allow a smaller engine to develop more power usually (though not always) result in it drinking more fuel too.
The other fundamental misconception here is that displacement - the cylinder volume swept by the pistons, is perfectly correlated with weight. Most car makers manufacture families of engines with different bore and stroke dimensions. Given the same engine block design, a larger displacement engine will always weigh less - air weighs less than metal, and bigger displacement = more air and less metal.
You could, in general, say that a very small displacement 4 cylinder engine will weigh less than a very large V8 engine, but even in that extreme case, the difference is probably less than you think. Just drawing a few numbers off the top of my head, modern Chevy small block engines displacing 5.7-7l weigh around 435 to 450lbs, compared to ~350lbs for a 2l Honda K20A engine. Sure, the Honda engine is lighter, but the truth is that if you replaced the engine in a Honda Civic Si with an engine out of an old Camaro, the difference in weight is probably less than 200lbs. Not very much for a car that already weighs almost 3000lbs already.
Talking about horsepower as a factor of displacement may be relevant when all the engines in your racing league are the same size anyway, or if the engines are somehow airflow restricted (like WRC) but it’s much less meaningful when it comes to normal cars for normal people. The reality is that if you measure HP as a factor of weight, big American V8 engines almost always come out ahead.
:smack: Thanks. What went wrong with my links?
You shifted into 3rd rather than 5th on the straightdope, and dropped a couple of characters. 
You miss the point, although Thoatwarbler reckons weight doens’t make much difference anyway.