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Full Version: Rpm For Max Torque In 1.6 Petrol?
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GSM
Hi all,

My Haynes manual has a wee section with tips on economical driving. It says you should change up the gears as soon as possible, and when cruising, try to cruise at the rpm for max torque, as that's the most fuel efficient rpm.

It says you can usually find this rpm in the owner's manual - but I've searched through the manual for my Focus (1.6L Petrol Ghia (100ps) 2006), and I can't find it anywhere.

Do any of you know what the figure is or where it can be found?

Also, I usually change up at 2000 revs, which I've decided upon by experiment - anybody agree that this is the best rpm to change gears?? (the needle falls to usually 1500 in the next gear when I change at 2000).

P.S. I've read elsewhere the max torque isn't necessarily the rpm for best efficiency - only the best efficiency for the engine on its own, but not when inserted into the car and hooked up to the transmission, etc. If that's the case, then what do you YOU think is the best rpm for cruising? What do you personally go at?
Haz93
I read somewhere that the max torque for the 1.6 Ti VCT is at 3800 - 4000 rpm as that is the point where the cams change position. Not too sure on the standard 1.6 but I imagine it to be about 2500 - 3000
I know 2500 is recommended shift up rpm for efficiency in petrol cars. However I rearly shift up lower than 4000 rpm and my average mpg is normally around 35 - 40. Have got 60 mpg before when really trying, i was quite suprised really
reprised
Hi,

Not sure about the rpm for max torque but I normally change at about 2800-3000 rpm. 2000 seems very low to me as this engine revs high. The power seems to kick in at 2800rpm.
artscot79
1500-2000 rpm is a bit early assuming its flat road youre driving on the ti-vct is max torque at 2000rpm so on flat roads you can change then with all petrols i find 2500 rpm is the base line for most
raskL
these are the graphs for power / torque on 100 bhp model and 115bhp model i presume yours is 100 ? but not sure so heres both (obviously just ignore the superchip figure, you want; original max) :) :

100bhp mk2 1.6 : [url="http://superchips.co.uk/curves/FocusMk21.698bhp.pdf"]http://superchips.co...Mk21.698bhp.pdf[/url]

115bhp mk2 1.6 vvt : [url="http://superchips.co.uk/curves/Focus16VVT115PS.pdf"]http://superchips.co...s16VVT115PS.pdf[/url]

looks like its quite high up in the rev range on the 100 so i doubt changine gear there is gonna help
GSM
Yeah mine is the 100ps engine... just about bang on 4,000 rev/min... seems a tad excessive.

I know the car does around 60mph in 5th gear at 3,000 rev/min, so no doubt 4,000 rev/min takes you just a tad over the limit, and I know for sure that the car loses fuel efficiency pretty rapidly once you advance from 55mph through 80mph.

So... maximum fuel efficiency at max. torque... MYTH BUSTED.

What would be really helpful would be if Ford bothered their arse activating the instantaneous fuel consumption on the trip computer. Avg. is fairly useless after a short while.
raskL
yeah somehow i cant see that saving fuel :D screaming round in 2nd doing 35 haha
GSM
Took it out for a spin to test the theory.

4000rpm is just a smidgeon over 80mph on the dial (so probably about 77mph in actuality), and after a 5 minute run the avg was about 33mpg. Tried the same at just under 3000rpm, which was about 60mph on the dial (so probably about 56mph in actuality) and drove the same route - avg was about 47.
Rh1no
I usually change up at around 2800 on my 115bhp 1.6 Petrol......is this correct then for most efficiency?
artscot79
the 115bhp petrol has the same torque at 1800rpm as a standard focus at 4500rpm so anywhere from 2000-2500 is best
jordan_macgregor
i usually change at 3000rpm but im only 5 minutes to work and dont think i'll get better than 31-34mpg in any car tbh


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