Mega Posted October 5, 2011 Share Posted October 5, 2011 Hi Chaps, Are there any common issues that can impact fuel economy? I currently get around 17. This is around town but in no way hammering it everwhere. I tend to change up at 3k revs tops, other than perhaps 1 or 2 full blips of the throttle in a given journey, which I only do when the car is warm I was going to try the throttle adaptation and ECU reset as I am aware the car was sat for quite a while before I took ownership. I'll do this tomorrow/Fri. For ref my average speed is 15mph and I have a 1h15m each way commute from Harrow to Heathrow every morning. As such I'm not ruling out the mpg as being normal given the commute I do. Any opinions? Quote Link to comment Share on other sites More sharing options...
DaddyCee Posted October 5, 2011 Share Posted October 5, 2011 I commute 18 miles a day to and from work and its in a rural location. I'm at around 23mpg now.... it was 24 after a long journey. Haven't seen it above this, but I can cope with the low mpg considering its 3.5L of pure unadulterated power. Quote Link to comment Share on other sites More sharing options...
Mega Posted October 5, 2011 Author Share Posted October 5, 2011 yeah. if my numbers are normal I'm not moaning. I knew what I was getting into. I've just seen some people saying they struggle to get it BELOW 23/24 which I find ridiculous based on the numbers I've seen! Quote Link to comment Share on other sites More sharing options...
rabbitstew Posted October 5, 2011 Share Posted October 5, 2011 To be honest I think 17mpg is about right if your doing that speed. If i only use the car around town then i see similar figures. On my commute its about 45miles and I guess maybe half of that is cruising at 80mph, the rest is slow moving in traffic at about 30mph. My mpg is about 25mpg over a full tank. When I had my golf TDI I became an expert in mpg and trying to increase it. The best I saw out of that was 74mpg over a 30mile trip, incl stop / start, roundabouts, door-to-door, incl starting the car from cold. Typical average mpg per tank was more like 55->62mpg. Things you can do to improve it is to knock it out of gear and free wheel to a stop rather than braking, changing up as early as you can without making the engine labour. They reckon turning air con off saves 10% of fuel but I never found that made any difference. Really its all about predicting the road ahead to save you from wasting energy & fuel braking & accelerating. Also, cruising at 50mph or at least keeping it under 70 will help too. Quote Link to comment Share on other sites More sharing options...
Leeroy Posted October 5, 2011 Share Posted October 5, 2011 I only drive on recently re-surfaced roads which run down-hill and have calculated that it saves me 6.2 pence a month Quote Link to comment Share on other sites More sharing options...
Stew Posted October 5, 2011 Share Posted October 5, 2011 As with any heavy car, it's the stopping and starting that kill the MPG. Also the waiting time where the MPG is 0. I'd say that this is a fairly normal figure to be honest. Quote Link to comment Share on other sites More sharing options...
DannyBoy Posted October 5, 2011 Share Posted October 5, 2011 Things you can do to improve it is to knock it out of gear and free wheel to a stop rather than braking, changing up as early as you can without making the engine labour. They reckon turning air con off saves 10% of fuel but I never found that made any difference. Really its all about predicting the road ahead to save you from wasting energy & fuel braking & accelerating. Also, cruising at 50mph or at least keeping it under 70 will help too. Unless the VQ35 is a very unusual engine, it'll use less fuel (some engines even use none at all) under engine braking than it will at idle in neutral, so if someone is really wanting to hypermile then 1. why did they buy a zed, and 2. they're slightly better off engine braking rather than coasting. You're dead right about the cruising speed, the difference in MPG between 65 and 80 is huge, and it's much quieter and more relaxing too DB Quote Link to comment Share on other sites More sharing options...
lrh Posted October 5, 2011 Share Posted October 5, 2011 Slim chance a piston or two are stuck in the calipers but I doubt it... Brembo's are quality bits of kit. Quote Link to comment Share on other sites More sharing options...
ioneabee Posted October 5, 2011 Share Posted October 5, 2011 To be honest I think 17mpg is about right if your doing that speed. Things you can do to improve it is to knock it out of gear and free wheel to a stop rather than braking, changing up as early as you can without making the engine labour. They reckon turning air con off saves 10% of fuel but I never found that made any difference. Really its all about predicting the road ahead to save you from wasting energy & fuel braking & accelerating. Also, cruising at 50mph or at least keeping it under 70 will help too. I think I'd have to disagree with you on freewheeling - correct don't use the brakes, because you have wasted the energy getting there, just use natural engine braking. Also when freewheeling the engine will use fuel to turn the engine over and keep firing, however, keep it in gear going downhill, just take you foot off the accelerator - the momentum keeps the engine turning ie use gravity to power the engine not petrol I am no mechanic/engineer - so feel free to shoot me down Quote Link to comment Share on other sites More sharing options...
Chris`I Posted October 5, 2011 Share Posted October 5, 2011 I'm guessing going from Harrow to Heathrow has a hell of a lot of stop/start driving. As Stew pointed out this is what kills MPG. This seems to be backed up with your average speed of only 15MPH. Going from that I'd say its normal. Not a lot you will be able to do with that, even with using engine braking, keeping momentum and trying to minimise start/stop. Quote Link to comment Share on other sites More sharing options...
Mega Posted October 5, 2011 Author Share Posted October 5, 2011 It seems I've sparked some kind of greater debate!! lol Quote Link to comment Share on other sites More sharing options...
slimjim Posted October 5, 2011 Share Posted October 5, 2011 Things you can do to improve it is to knock it out of gear and free wheel to a stop rather than braking, changing up as early as you can without making the engine labour. They reckon turning air con off saves 10% of fuel but I never found that made any difference. Really its all about predicting the road ahead to save you from wasting energy & fuel braking & accelerating. Also, cruising at 50mph or at least keeping it under 70 will help too. Unless the VQ35 is a very unusual engine, it'll use less fuel (some engines even use none at all) under engine braking than it will at idle in neutral, so if someone is really wanting to hypermile then 1. why did they buy a zed, and 2. they're slightly better off engine braking rather than coasting. You're dead right about the cruising speed, the difference in MPG between 65 and 80 is huge, and it's much quieter and more relaxing too DB I asked THAT question a while back... about using engine breaking vs knocking it out of gear... General consensus on our engines was that it used LESS fuel under engine braking then being knocked out of gear. Quote Link to comment Share on other sites More sharing options...
rabbitstew Posted October 5, 2011 Share Posted October 5, 2011 To be honest I think 17mpg is about right if your doing that speed. Things you can do to improve it is to knock it out of gear and free wheel to a stop rather than braking, changing up as early as you can without making the engine labour. They reckon turning air con off saves 10% of fuel but I never found that made any difference. Really its all about predicting the road ahead to save you from wasting energy & fuel braking & accelerating. Also, cruising at 50mph or at least keeping it under 70 will help too. I think I'd have to disagree with you on freewheeling - correct don't use the brakes, because you have wasted the energy getting there, just use natural engine braking. Also when freewheeling the engine will use fuel to turn the engine over and keep firing, however, keep it in gear going downhill, just take you foot off the accelerator - the momentum keeps the engine turning ie use gravity to power the engine not petrol I am no mechanic/engineer - so feel free to shoot me down Hmmm. you learn something new every day. What I found with the golf was that under engine braking the car would slow down quicker, whereas if free wheeling, you could happily freewheel for a much greater distance - so if i saw cars braking up ahead of me on the road I could just time it so id freewheel up to them, whereas with engine braking, the car would end up stopping too soon, and id have to accelerate again. You can cover quite a long distance sometimes through freewheeling, esp if down hill - so in effect you could be travelling at 60mph, but engine revs are just idling at 600rpm - compared to whatever revs you`d normally be pulling travelling at 60mph. I know on my golf it made a huge difference, but maybe on the zed things are different. As someone else said, at any rate, the zed isnt the car to have if your worried about saving a few mpg! Quote Link to comment Share on other sites More sharing options...
John tarantula Posted October 5, 2011 Share Posted October 5, 2011 Mega, seems normal to me, my dial says 18mpg around London with probably slightly less stop start than you as I try not to drive in rush hour(s)... though managed 32 mpg on the motorway! Quote Link to comment Share on other sites More sharing options...
JetSet Posted October 5, 2011 Share Posted October 5, 2011 Very low reference speed there, mine's reading 29 with an MPG of 27.9. That's not a one off reading as I've never reset the computer since I had to change the battery 7,700 miles ago. All that mileage around town really hits MPG on a heavy car like The Zed. Pete Quote Link to comment Share on other sites More sharing options...
nzr350z Posted October 5, 2011 Share Posted October 5, 2011 To be honest I think 17mpg is about right if your doing that speed. Things you can do to improve it is to knock it out of gear and free wheel to a stop rather than braking, changing up as early as you can without making the engine labour. They reckon turning air con off saves 10% of fuel but I never found that made any difference. Really its all about predicting the road ahead to save you from wasting energy & fuel braking & accelerating. Also, cruising at 50mph or at least keeping it under 70 will help too. I think I'd have to disagree with you on freewheeling - correct don't use the brakes, because you have wasted the energy getting there, just use natural engine braking. Also when freewheeling the engine will use fuel to turn the engine over and keep firing, however, keep it in gear going downhill, just take you foot off the accelerator - the momentum keeps the engine turning ie use gravity to power the engine not petrol I am no mechanic/engineer - so feel free to shoot me down Hmmm. you learn something new every day. What I found with the golf was that under engine braking the car would slow down quicker, whereas if free wheeling, you could happily freewheel for a much greater distance - so if i saw cars braking up ahead of me on the road I could just time it so id freewheel up to them, whereas with engine braking, the car would end up stopping too soon, and id have to accelerate again. You can cover quite a long distance sometimes through freewheeling, esp if down hill - so in effect you could be travelling at 60mph, but engine revs are just idling at 600rpm - compared to whatever revs you`d normally be pulling travelling at 60mph. I know on my golf it made a huge difference, but maybe on the zed things are different. As someone else said, at any rate, the zed isnt the car to have if your worried about saving a few mpg! Think diesels run a higher compression than petrol so have greater engine braking! Quote Link to comment Share on other sites More sharing options...
Daryl Posted October 5, 2011 Share Posted October 5, 2011 To be honest I think 17mpg is about right if your doing that speed. Things you can do to improve it is to knock it out of gear and free wheel to a stop rather than braking, changing up as early as you can without making the engine labour. They reckon turning air con off saves 10% of fuel but I never found that made any difference. Really its all about predicting the road ahead to save you from wasting energy & fuel braking & accelerating. Also, cruising at 50mph or at least keeping it under 70 will help too. I think I'd have to disagree with you on freewheeling - correct don't use the brakes, because you have wasted the energy getting there, just use natural engine braking. Also when freewheeling the engine will use fuel to turn the engine over and keep firing, however, keep it in gear going downhill, just take you foot off the accelerator - the momentum keeps the engine turning ie use gravity to power the engine not petrol I am no mechanic/engineer - so feel free to shoot me down Hmmm. you learn something new every day. What I found with the golf was that under engine braking the car would slow down quicker, whereas if free wheeling, you could happily freewheel for a much greater distance - so if i saw cars braking up ahead of me on the road I could just time it so id freewheel up to them, whereas with engine braking, the car would end up stopping too soon, and id have to accelerate again. You can cover quite a long distance sometimes through freewheeling, esp if down hill - so in effect you could be travelling at 60mph, but engine revs are just idling at 600rpm - compared to whatever revs you`d normally be pulling travelling at 60mph. I know on my golf it made a huge difference, but maybe on the zed things are different. As someone else said, at any rate, the zed isnt the car to have if your worried about saving a few mpg! Think diesels run a higher compression than petrol so have greater engine braking! Not to mention a heavier flywheel and probably clutch assembly. That will slow you down a treat. My commute is 30 miles each way. Thats with a few milton keynes round abouts, abit of town driving through Towcester,and some A roads (43+5). My average consumption is 24-25 MPG over a full tank. (Which lasts 7 days) Quote Link to comment Share on other sites More sharing options...
Chris`I Posted October 6, 2011 Share Posted October 6, 2011 Think diesels run a higher compression than petrol so have greater engine braking! Not to mention a heavier flywheel and probably clutch assembly. That will slow you down a treat. Surely a heavier flywheel with its greater inertia will reduce the effects of engine braking? Lighter flywheel will give you more engine braking. Or when you say slow, do you mean its harder to get up to speed? That will take more power and thus fuel if start stopping all the time Quote Link to comment Share on other sites More sharing options...
Hammer Posted October 6, 2011 Share Posted October 6, 2011 I've averaged between 24 and 24.2 in the month I've had mine and that's with a fair amount of showing it off when I forst picked it up. Commute to work is a stop/start 8 miles each way and that's the furthest it has went as well. Quote Link to comment Share on other sites More sharing options...
goodatcrashing Posted October 6, 2011 Share Posted October 6, 2011 Unless the VQ35 is a very unusual engine, it'll use less fuel (some engines even use none at all) under engine braking than it will at idle in neutral, so if someone is really wanting to hypermile then 1. why did they buy a zed, and 2. they're slightly better off engine braking rather than coasting. You're dead right about the cruising speed, the difference in MPG between 65 and 80 is huge, and it's much quieter and more relaxing too DB Am I the only one who finds the most fuel efficient speed around 80 - 85? Dropping to 70 seems to reduce fuel economy by 2mpg. Designed as a grand tourer, I thought it would have been optimised for higher speeds. *obviously, tested on a private road * Quote Link to comment Share on other sites More sharing options...
marzman Posted October 6, 2011 Share Posted October 6, 2011 about 59mph is my most economical speed... i got 35mpg onto a trip from Manchester to Durham which was all motorway... Quote Link to comment Share on other sites More sharing options...
Beau Posted October 6, 2011 Share Posted October 6, 2011 The highest I ever got and I commute everyday from Milton Keynes to London, and occasionaly use the 350z I manage a solid 33mpg averaging a speed of 78mph, about 70% of that on the motorway. So overall I can easily manage a good 450 miles off the tank Quote Link to comment Share on other sites More sharing options...
DannyBoy Posted October 6, 2011 Share Posted October 6, 2011 Unless the VQ35 is a very unusual engine, it'll use less fuel (some engines even use none at all) under engine braking than it will at idle in neutral, so if someone is really wanting to hypermile then 1. why did they buy a zed, and 2. they're slightly better off engine braking rather than coasting. You're dead right about the cruising speed, the difference in MPG between 65 and 80 is huge, and it's much quieter and more relaxing too DB Am I the only one who finds the most fuel efficient speed around 80 - 85? Dropping to 70 seems to reduce fuel economy by 2mpg. Designed as a grand tourer, I thought it would have been optimised for higher speeds. *obviously, tested on a private road * I do Cambridge-London and back pretty much every weekend, and between 60 and 65 sees the least fuel used, i go by what the fuel tank says, not what the DTE and MPG readouts say, as they're suspicious at best, lol. The other week i managed to convince the DTE that London to Cambridge was about 25 miles DB Quote Link to comment Share on other sites More sharing options...
nzr350z Posted October 9, 2011 Share Posted October 9, 2011 Just done a round trip of 380miles from home to Longleat and back,averaged 32.3mpg,mostly 75/80 on m'way ,also quite a bit of A road stop /start too.Noticed at motorway services,litre of Super 150.9p Quote Link to comment Share on other sites More sharing options...
goodatcrashing Posted October 9, 2011 Share Posted October 9, 2011 I do Cambridge-London and back pretty much every weekend, and between 60 and 65 sees the least fuel used, i go by what the fuel tank says, not what the DTE and MPG readouts say, as they're suspicious at best, lol. The other week i managed to convince the DTE that London to Cambridge was about 25 miles DB I do alot of Newcastle to Manchester trips and the little dials like DTE help keep me entertained (for a couple of seconds). I'll try 60 on my next trip if it doesnt drive me insane. I think the DTE changes depending on your immediate average fuel consumption. ie. if your getting 10mpg the computer calculates the remaining distance based on that. If you then go from 10 to 30mpg, the computer re calculates the remaining distance using the new figure. Hence your DTE 25 mile difference between London and Cambridge was because you improved your fuel consumption. I have seen my DTE go up as im driving! Quote Link to comment Share on other sites More sharing options...
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