Engine requirements for 100 mpg

[retrorocket]

-High speed race cars are generally at near peak efficiency because the force due to aerodynamic drag is maybe 40 times greater than when cruising at 60mph, if they were to cruise at 60mph, engine efficiency would drop, but vehicle efficiency would increase, and they'd probably be in the 20-40mpg range imo.


I was meaning more like if you changed the cam timing so the engine could run
effectively at the new lower rpm

If a Nascar engine can get almost 5 MPG (more on some tracks) at 189 miles per hour then how does that efficiency translate to 60 mph.

You mention drag being 40 times higher at the high speed does that mean that it takes almost 40 times more energy?

If the cam timing and gearing were optimized for WOT at 60 mph would it get 40X5 miles per gallon?

Just thinking. the engines run at wide open throttle and have very high compression ratios.

[omgwtfbyobbq]

Not quite 40x5, more like half that. And because they run really sticky tires I don't think 40 times more force due to aerodynamic drag translates to 40 times more overall force. It's likely lower due to way higher CrrW. I'd guess that if the cam timing/gearing were optimized for efficiency (keeping in mind it doesn't have to be WOT, anything from a half throttle on up is usually way better than the bottom half of a BSFC map) about 60-70mpg would be doable. Peak thermal efficiency is peak thermal efficiency, and there's minimal differences in peak efficiency between most engines. Otoh, the car will still have obscenely sticky tires on, so that would take the largest chunk out compared to a normal car, not to mention there are limits to displacement. I don't think we can fill (air) a 500ci engine up enough to get decent BTE at something like 60mph, a 302ci may be doable, and a 226ci would be probably be np.

[Jay2TheRescue]

Great, now you're bringing up threads from 15 months ago to talk about the Pogue carb. Don't you realize it was a hoax? He wouldn't let anyone examine it up close, no independent lab was allowed to test it, and when it was mysteriously "stolen" he was able to colect investor money, but not able to create another carb.