I often drive a V8-Mustang and I think the difference between a gas tank of 'jack rabbit' starts and regular starts is less than ten percent of total mpg. That doesn't seem like a 'solution' to me.

There are comparisons that indicate that a brisk acceleration (not a drag-start) may be approx equiv. to a 'snail' start in mpg for some cars, because you achieve the desired top-gear in shorter time and distance.

Also, when I do start this way intentionally, this 'device' would negate the value of having extra horsepower, which costs money and is fun.

Once I had a truck that broke the throttle linkage so that it would only go to half-throttle. It didn't get significantly better milage, but was dangerous during towing.

Is this 'device' you're talking about a block of wood under the pedal?

Seriously, I think limiting stops would be a better way to save, ie. more coasting, hypermilling, etc.

dear hrench,

ive figured out that this device could possibly make your car 5% more efficient. but for the reasons you mention above, i agree that it is extremely unpractical.

i think anyone who have make a safe car accessory that makes it 5% or more efficient will be an instant millionaire.

One of the recurrent delusions at this site is that an idea, good or otherwise, is a quick road to wealth. This site is probably useful to business oriented people who have the intelligence, contacts, know how and mostly the determination to see an idea through to get some compensation. I have an occasional reasonable idea but the rest of it holds no interest for me at all. I have other interests and it might be more practical to buy lotto tickets than to hope for real money out of an idea since even the best ones fail most of the time in a commercial market.