Quote:
Originally Posted by Frank Lee
I'd think that "set speed" would be different all the time- constantly varying grades, winds, temps...
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Yes you are correct this statement is only valid on a flat road with zero head or tail wind.
From my own experience driving with this I have never noticed the difference from wind alone, but I dont live in a very windy part of the world I am sure you would notice it at the coast. When you go up a slight incline it will loose 5 km or so, you get it back on the down hill side though if you willing to allow it to happen. Only on a massive incline like when you go into the mountains then you have two choices either:
1) Change down and maintain the setting on the accelerator or
2) Just apply more accelerator, in most cases applying more accelerator doesnt actually feel very impressive compared with the optimal set position, this applies to small engined cars, by adding more fuel you mess up the 14:1 fuel air mixture and the power doesnt feel proportional to the accelerator input you get a bit more but not much if you dont change down.
Of course on the bigger engines things do happen, I fitted a 400 cubic inch 6.9L Chevy into a 1988 Toyota Supra it had gas flowed heads, 10:1 compression, racing cams, and was statically and dynamically balanced.
At 160 km/h if I stomped on the accelerator the bonnet used to lift up 4 inches..... it was a beast.
That vehicle used to consume 25L per 100 km or 9.4 miles per gallon if I was in a hurry. I changed the diff ratio to 2.9:1 and fitted one of these fuel saving devices and I got it down to 12L per 100km or 19.6 miles to the gallon at at a set speed of 140km/h or 87 mph it wasn't fuel injected it had a big Holley double pumper on it. For a big engine like that I was happy with the fuel consumption as it was comparable with a 3 Liter standard car.