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Old 04-03-2012, 10:04 PM   #47 (permalink)
jtbo
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Join Date: Apr 2011
Location: Europe
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ZX - '97 Citroen ZX Monaco
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Quote:
Originally Posted by Old Mechanic View Post
Higher RPM
Low throttle
Without vacuum

Not sure how you would accomplish that combination, assuming I read the intent of your post correctly. High RPM and no vacuum can not really be accomplished with low throttle positions. Low vacuum is high load which means the engine is working harder. It's not really possible to have a high load and high RPM with a low percentage of throttle opening, unless you went from a high percentage of throttle opening to a low percentage, which would raise the vacuum reading for a short period of time until the inertia of the vehicle depleted and the load increased.

regards
Mech
I have no throttle butterfly, so no vacuum either, oddities of diesel

So I guess my initial thinking must be right that with diesel it might be better to use higher rpm instead of lower when getting up the hill, which makes driver need to adapt to car he is driving and that is good to know.


Here I present my shopping route, it is bit of challenging route for fuel economy, this is just 20 miles from shop to home, when I start driving engine is of course relatively cold, but that first hill (right in graph) will get engine up to temp quickly, however it is taking lot of fuel climbing that at warmup cycle.
My last fill up was 5.1l/100km (around 46mpg) and it had mostly driving that route, some short trips and coast down testing quite a bit, I can get bit better mileage on that route at summer.


Good thing is that to other direction I can get miles of engine off coasting as there is good combination of hills, almost from 577 to 401, there is need to use engine around 20 seconds at hill near 449, but only because there is 60kph limit and school without those I could coast whole way from 577 to 401. Each datapoint is between around 42 meters, which is almost 138 feet, so that is over 7km or rather would be. So certainly not the worst kind road, but it would be easy to burn a lot more fuel on these hills.
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