RedM Posted December 31, 2007 Share Posted December 31, 2007 I'm not sure if that makes sense as a title but here's my question in more detail. Auto JDM Supra TT Is the Supra more fuel efficient at a certain speed/rev range than at others? I've just done a 250 mile each way trip and filled up to the first click-off at the pump before each leg. The first 250 miles were done between 04:00 (don't ask!) and 08:00 and I stayed between 70 and 80 mph. Yes it was a chore. The return journey was done in the evening (17:00 to about 20:30) but with light traffic and speeds varying from 70 to 'interesting' with some hard acceleration and higher sustained speeds than the outward journey. On the return leg I used visibly less fuel. About three sections on the fuel gauge! The route was identical. This got me wondering whether the Supra is more fuel efficient (or whatever it's called) at speeds above our speed limit. Anyone? Quote Link to comment Share on other sites More sharing options...
Whitesupraboy2 Posted December 31, 2007 Share Posted December 31, 2007 all cars are more efficent at a certain speed. its a comprimise between speed and how fast you get somewhere. Years ago I read in a mag when you go over 56mph cars become more inefficent. Also its more efficent bewlow 50mph to have your window open then aircon on, above that its the other way round. Quote Link to comment Share on other sites More sharing options...
RedM Posted December 31, 2007 Author Share Posted December 31, 2007 all cars are more efficent at a certain speed. its a comprimise between speed and how fast you get somewhere. Years ago I read in a mag when you go over 56mph cars become more inefficent. Also its more efficent bewlow 50mph to have your window open then aircon on, above that its the other way round. Thanks but that's not really answered the question. Is the Supra more efficient above 70 than below it. ie, would it be better to drive down a m-way at 85 rather than 70? If not can someone explain how driving faster used less fuel than driving slower? Quote Link to comment Share on other sites More sharing options...
Fifty Posted December 31, 2007 Share Posted December 31, 2007 isnt 56 mph said to be the norm for a cars best mpg? Rich Quote Link to comment Share on other sites More sharing options...
Tones Posted December 31, 2007 Share Posted December 31, 2007 My guess is in 6th gear at 2700rpm Quote Link to comment Share on other sites More sharing options...
gaz1 Posted December 31, 2007 Share Posted December 31, 2007 i cannot see how if you were going at say 60, it would be better at 70, if the car is in the same gear at those speeds then at 70 the engine will work harder thus more fuel needed Quote Link to comment Share on other sites More sharing options...
Wez Posted December 31, 2007 Share Posted December 31, 2007 Idle Quote Link to comment Share on other sites More sharing options...
mplavery Posted December 31, 2007 Share Posted December 31, 2007 parked up Quote Link to comment Share on other sites More sharing options...
Tones Posted December 31, 2007 Share Posted December 31, 2007 When its like this Quote Link to comment Share on other sites More sharing options...
Max Headroom Posted December 31, 2007 Share Posted December 31, 2007 0mph! can't get more fuel efficient than that Quote Link to comment Share on other sites More sharing options...
jevansio Posted December 31, 2007 Share Posted December 31, 2007 Uphill the way there, down on the way back Quote Link to comment Share on other sites More sharing options...
michael Posted December 31, 2007 Share Posted December 31, 2007 56mph is just a standard, it's not the most efficient speed in the world in every car in every type of condition, that would be madness And RedM - no idea on your question, it's thirsty most of the time, that's about as far as my research goes. Quote Link to comment Share on other sites More sharing options...
Fifty Posted December 31, 2007 Share Posted December 31, 2007 wind direction and velocity , road gradients would all affect consumption would they not? people seem to post up all sorts of mileage results on here, from a tank of gas, but even the gas itself is not standardised? just drive the bleedin thing will you lol Rich Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted December 31, 2007 Share Posted December 31, 2007 MMM to be fair I found with my TT no matter wether I tried my hardest to stay at daft low mph or ragged the ass off it when capable the MPG was all the same a pretty much 19 mpg Quote Link to comment Share on other sites More sharing options...
RedM Posted December 31, 2007 Author Share Posted December 31, 2007 I'm not bothered about using fuel. I'm just curious about why it should be that a more spirited drive used less fuel. TBH, this isn't the first time I've noticed that a steady drive seemed to use more fuel. My stepdad thinks it might be that the ECU or gearing or something works better at a higher speed than you'd think. Quote Link to comment Share on other sites More sharing options...
Mike B Posted January 1, 2008 Share Posted January 1, 2008 MMM to be fair I found with my TT no matter wether I tried my hardest to stay at daft low mph or ragged the ass off it when capable the MPG was all the same a pretty much 19 mpg dude.. that's harsh I've had 32 out of my tt's... are you towing another car? or forgot to take the handbrake off? all your tyres gone flat? lol driving with you eye on the boost guage and not letting it get past -0.5 bar will get you decent mpg. I drove my single to CW last time, filled up at home, drove 200 miles in rush hour (60-80mph) and the needle was still above 3/4 full when i got there. I bought the G/F a golf gti with a fuel computer on...; nightmare; whenever I drive it I have to beat the last score; so far I have not bettered 46mpg for a 2.0 4 pot... 2008 I will get it to 48.. lol I hear if you acccellerate to 70, then turn the engine off and coast to 30 and repeat the cycle it gives you 70 mpg.... I tried it on a car which cracked the oil filter 100 miles from home and i think it works! Used more oil than petrol. Quote Link to comment Share on other sites More sharing options...
Syed Shah Posted January 1, 2008 Share Posted January 1, 2008 The engine is most efficient at peak torque. The Jap TT makes peak torque at what - 2800-3000rpm? So whatever speed that translates to in top cog. 85mph ish IIRC. *Note that the engine is most efficient at peak torque, but that does NOT mean it will be using less fuel than at a lower speed. But simply that you are getting more 'bang for your buck'. Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted January 1, 2008 Share Posted January 1, 2008 dude.. that's harsh I've had 32 out of my tt's... are you towing another car? or forgot to take the handbrake off? all your tyres gone flat? lol driving with you eye on the boost guage and not letting it get past -0.5 bar will get you decent mpg. I drove my single to CW last time, filled up at home, drove 200 miles in rush hour (60-80mph) and the needle was still above 3/4 full when i got there. I bought the G/F a golf gti with a fuel computer on...; nightmare; whenever I drive it I have to beat the last score; so far I have not bettered 46mpg for a 2.0 4 pot... 2008 I will get it to 48.. lol I hear if you acccellerate to 70, then turn the engine off and coast to 30 and repeat the cycle it gives you 70 mpg.... I tried it on a car which cracked the oil filter 100 miles from home and i think it works! Used more oil than petrol. Ah well there's the thing I found it impossible to stay off boost in my BPU motor as it reached zero before 1500 rpm and was up to 1.0 bar well before 2500 rpm. I also didn't manage a whole tank of driving "slowly" ever oops. I know what you mean about the trip computer thing. I aero-tow trucks now in my range rover. I managed a whopping 22.1 mpg in it once which is a real achievement Quote Link to comment Share on other sites More sharing options...
Thorin Posted January 1, 2008 Share Posted January 1, 2008 88mph is the most fuel efficient... of course then there's the small issue of the 1.21 gigawatts of electricity needed. Quote Link to comment Share on other sites More sharing options...
RedM Posted January 1, 2008 Author Share Posted January 1, 2008 *wonders what date it'll be before the question is understood and answered* Quote Link to comment Share on other sites More sharing options...
Thorin Posted January 1, 2008 Share Posted January 1, 2008 *wonders what date it'll be before the question is understood and answered* Time is relative. Quote Link to comment Share on other sites More sharing options...
MrRalphMan Posted January 1, 2008 Share Posted January 1, 2008 *wonders what date it'll be before the question is understood and answered* Dunnow, pick one. Quote Link to comment Share on other sites More sharing options...
Chewie Posted January 1, 2008 Share Posted January 1, 2008 As previously mentioned by Syed Shah, it's at peak torque in whatever gear. But sadly at 85 mph you're dealing with tyre rolling resistance which is linearly proportional to speed and worse than that, wind resistance which increases with the square of the speed. Quote Link to comment Share on other sites More sharing options...
Mike B Posted January 1, 2008 Share Posted January 1, 2008 Ah well there's the thing I found it impossible to stay off boost in my BPU motor as it reached zero before 1500 rpm and was up to 1.0 bar well before 2500 rpm. I also didn't manage a whole tank of driving "slowly" ever oops. few! I thought we have a MKIV caravan tower for a moment there! Quote Link to comment Share on other sites More sharing options...
suprafan72 Posted January 1, 2008 Share Posted January 1, 2008 I am managing 20mpg arround town at the moment and 25mpg on the motorway doing 85.... But i've past caring... thats with afr's in the late 14's early 15's... Quote Link to comment Share on other sites More sharing options...
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