Fuel economy!

24th March 2011, 09:35

i know there is a sticky for fuel saving, but i have been following it and i am still struggling!

i put half a tank in the other day, i am well into the red, and i have covered 130 miles. thats like 26 mpg!

i change gear at 2k revs, and drive in 5th everywhere

i just dont understand it

my clutch is on its way out, so you think this could be playing a part?

also, will have to get my brakes checked to make sure there not dragging. i hardly ever use my brakes, just engine break to slow down, but i am gettin mega brake dust, so that could be a contributing factor

i have all unessentials out of the car for weight saving. i do have my amp and sub in the boot though, and again, this isnt helping.

i drive from the edge of manchester to the centre 4 times a day (there twice and back twice), 5 mile there and 5 back, and i know city centre driving is a killer.

but i still thought i would be getting more than 130 to half tank...

is this right?

24th March 2011, 10:32

When you say you put half a tank in, do you mean you put 20ish litres in or the fuel gauge was halfway ? Also is the car due a service ?

I always get less miles out of the second half of the tank then the first going on the fuel gauge as shape of the fuel tank holds less in the second half, plus you can get the extra bit in the filler hose. usually get 225ish out of the first half and 145ish out of the second half befroe the light comes on.

24th March 2011, 11:06

Quote:

Originally Posted by Jonny52002

When you say you put half a tank in, do you mean you put 20ish litres in or the fuel gauge was halfway ? Also is the car due a service ?

I always get less miles out of the second half of the tank then the first going on the fuel gauge as shape of the fuel tank holds less in the second half, plus you can get the extra bit in the filler hose. usually get 225ish out of the first half and 145ish out of the second half befroe the light comes on.

WOW

thats good economy!

the cars been serviced 6 months ago, new oil, filter, new induction, new plugs and fuel filter.

i put just over half a tank in, the needle was half way when i reset the counter.

if i fill the tank til it clicks i do not get 300 miles driven...

i do seem to get less out of the bottom half of the tank aswel. must be the shape of it

just got a quote to replace the clutch, £200

so this needs doing, will do it next month see if that makes a difference.

i wanted to buy a TDi, for the economy. but now i have to replace my rear axle and clutch, so will have to keep the VT for another year. so need more MPG, fuelling it is killing me. i could have a Subaru for that economy!

24th March 2011, 11:11

city centre driving is a killer though, thats where my MPG goes i reck. constantly stop start, stuck in traffic etc

also, i am in the red now, light is well and truely on. how many miles do you usually get out of that? i dont wanna fill up coz i wanna see how many miles i actually get out of it, but on the other hand i do not wanna break down!

24th March 2011, 11:42

I'm getting good milage at the moment as its freshly serviced and I dont do city driving, just country roads mainly.

When the light comes on I think the rule of thumb is you've got another gallon ish, so another 40 odd miles usually.

24th March 2011, 11:58

so another gallon, so 26 miles for me then! lol

i reck if i did country miles i would get better.

26-30 i am guessing isnt the end of the world for city centre daily driving is it?

24th March 2011, 13:16

30 sounds about right, have you check your tyre pressure's too mate ?

24th March 2011, 13:22

for a vtr I'd say thats bad my old gti on £25 iirc which was about half tank again filling from empty I managed 125miles reguarly and that was driven hard

24th March 2011, 13:22

yer i was getting 23 mpg, so checked my tyre pressure, was running 22 in fronts and 24 in rear!¬ lol

changed it to 36 front and 32 rear as manufacturers spec

now its gone up by 3.8 mpg's

i reck when i get my clutch sorted it will jump up again. fingers x'd

thanks for the help Jonny!

24th March 2011, 13:22

I got a MK2 Decatted VTS, I dont go over 3000 revs unless on a steep hill and I get 320 miles to £50 oh and its backfiring like a bitch these days

24th March 2011, 13:25

with my gti6 i now get 24mpg which is really noticeable in the wallet! but my jp4 hybrid gti was averaging 35mpg! i drove up to cambridge 150miles from here and averaged 45mpg for the trip. not too sad really.

24th March 2011, 13:26

i used to get 350 miles to a tank on my vtr then i had a dodgy idle everyone on here said it was the icv turned out it was the lambda sensor and was over fuelling

changed that now im getting 420 to a tank at least and i fill up as soon as the light comes on....have a look at your lambda sensor

24th March 2011, 13:27

Quote:

Originally Posted by Newtz07

city centre driving is a killer though, thats where my MPG goes i reck. constantly stop start, stuck in traffic etc

also, i am in the red now, light is well and truely on. how many miles do you usually get out of that? i dont wanna fill up coz i wanna see how many miles i actually get out of it, but on the other hand i do not wanna break down!

Fill up a fuel can for when you do run out

Just make sure your on a flat surface otherwise it sill wont start after 6 quid of fuel..

24th March 2011, 13:48

Quote:

Originally Posted by Ramigojag

i used to get 350 miles to a tank on my vtr then i had a dodgy idle everyone on here said it was the icv turned out it was the lambda sensor and was over fuelling

changed that now im getting 420 to a tank at least and i fill up as soon as the light comes on....have a look at your lambda sensor

wow!

i was getting the same strange idle aswel, removed and cleaned lambda and then reset my ECU, now its runs smooth as fuck. gonna squeeze the rest of the tank!

Quote:

Originally Posted by tisandy

Fill up a fuel can for when you do run out

Just make sure your on a flat surface otherwise it sill wont start after 6 quid of fuel..

Yer, thats the plan! will see how it goes.

gotta another run to go in a bit, back to manchester centre, about 5 miles there and 5 back. will see if i can make it without cutting off!

24th March 2011, 14:06

Cool, enjoy

24th March 2011, 14:23

Quote:

Originally Posted by Newtz07

thanks for the help Jonny!

No probs fella.

24th March 2011, 16:46

I put in 10 or 20 litres at a time and measure it till it is bone dry- 71 miles from 10 litres thats only 32 mpg, a mix of town and caning. I got a lambda from a scrappy and it gave 80 miles every time, that one melted eventually though

24th March 2011, 17:07

I get about 150-160 in my vtr to 20 quid (half a tank) and thats with some hard driving aswell, i reckon it probably is the city driving doing it on yours

24th March 2011, 17:18

Quote:

Originally Posted by Ben_SaxoForte

I get about 150-160 in my vtr to 20 quid (half a tank) and thats with some hard driving aswell, i reckon it probably is the city driving doing it on yours

I make that 44mpg [at 125p litre] which is bollox

24th March 2011, 17:22

50 mpg is dooable in a VTR.

24th March 2011, 19:00

Quote:

Originally Posted by adsayer

50 mpg is dooable in a VTR.

Its doable in mine too but it doesnt!

24th March 2011, 19:25

Quote:

Originally Posted by Brettles1986

I got a MK2 Decatted VTS, I dont go over 3000 revs unless on a steep hill and I get 320 miles to £50 oh and its backfiring like a bitch these days

Whats the point of fitting performance mods if you have to drive like a Vicar? Only asking..

24th March 2011, 19:46

Use my saxo for a week and see how how much fuel it uses!! ir drinks it.

24th March 2011, 20:46

Quote:

Originally Posted by Railroader

Whats the point of fitting performance mods if you have to drive like a Vicar? Only asking..

Usually because optimising a component, particularly with the inlet and outlet improves volumetric efficiency i.e. more air flow. Any efficiency improvements can relate to hp when you boot it and mpgs when you're pootling.

24th March 2011, 20:56

Put a full tank of petty in mate and you will get better mpg, so say it's 45 to put a full tank it's better to put that in in one go than keep putting tenners in i think it lasts longer to

24th March 2011, 21:14

don't see how its bollocks as I have no reason to lie pretty easy to get 44 mpg in a vtr unless you thrash the hell out of it everywhere

25th March 2011, 08:38

Quote:

Originally Posted by adsayer

50 mpg is dooable in a VTR.

Ad... i know you are the MPG king

you taught me everthing i know about squeezing the extra mile out!

but seriously dude, i am struggling here.

going looking at a nice white mk2 VTR at 12, so if its any good, will get him to take mine in PX and away with the problems!

and hopefully this one is better on fuel

25th March 2011, 09:09

Quote:

Originally Posted by skitts

Put a full tank of petty in mate and you will get better mpg, so say it's 45 to put a full tank it's better to put that in in one go than keep putting tenners in i think it lasts longer to

Agreed and also get a better judgement when doing this

25th March 2011, 09:12

Quote:

Originally Posted by tally2425

Agreed and also get a better judgement when doing this

Yer, see, maybe this is just me, but when i fill the tank, say £60 or something, then i always end up driving everywhere, and run it out in a week!

where as if i put tenners in i always think "nah, cant go here i got no fuel"

maybe thats just me though

25th March 2011, 09:17

Quote:

Originally Posted by Railroader

Whats the point of fitting performance mods if you have to drive like a Vicar? Only asking..

Because at one point it was 18 miles to work and back and now its 60 miles

25th March 2011, 10:08

i drive like a vicar, because only cunts drive like cunts. an am not a cunt. see?

also, if i choose to plant my foot down it feels good because i rarely do it.

plus, fuel is expensive enough without driving like a bell end.

25th March 2011, 14:46

Quote:

Originally Posted by adsayer

Usually because optimising a component, particularly with the inlet and outlet improves volumetric efficiency i.e. more air flow. Any efficiency improvements can relate to hp when you boot it and mpgs when you're pootling.

Its usually the opposite thats the case. The engine is designed to a standard manfold pressure and exhaust back pressure. Its all integrated in the valve timings and head design. Although you can modify the engine to be freer breathing at maximum output, this is at the cost of optimum gas flows at partial throttle, which is where most of your driving is done.

In other words- HP mods worsen fuel economy.

25th March 2011, 14:51

Quote:

Originally Posted by Newtz07

i drive like a vicar, because only cunts drive like cunts. an am not a cunt. see?

also, if i choose to plant my foot down it feels good because i rarely do it.

plus, fuel is expensive enough without driving like a bell end.

I think there is something in between a Vicar and a cunt. You have chosen the two extremes. But is is a valid question what I asked Brettles. If you are just going to trundle along what is the point of performance modificationing?

btw is a bell end the same as a cunt or are they different?

25th March 2011, 15:00

Quote:

Originally Posted by skitts

Put a full tank of petty in mate and you will get better mpg, so say it's 45 to put a full tank it's better to put that in in one go than keep putting tenners in i think it lasts longer to

How can it make any difference putting a full tank in? Thats ridiculous! In fact it will use more because you are carting about extra weight.

25th March 2011, 15:15

Quote:

Originally Posted by Railroader

Its usually the opposite thats the case. The engine is designed to a standard manfold pressure and exhaust back pressure. Its all integrated in the valve timings and head design. Although you can modify the engine to be freer breathing at maximum output, this is at the cost of optimum gas flows at partial throttle, which is where most of your driving is done.

In other words- HP mods worsen fuel economy.

You have to be careful in what context, hp mods worsen fuel economy at WOT true - that is where restrictions and inlet and outlet tuning is critical. More air + more fuel = more bang yada yada. But at partial throttle maintaining a given velocity, the volume of air and consequently the gas flow velocity is relatively speaking, very low; pulse tuning, runner length, bore is of much less importance since the conditions are not appropriate to exploit specific component states of tune.

I've got 55 mpg in my VTS once before - that was with a completely non standard exhaust system, xsi box, CF air box.

25th March 2011, 15:19

Quote:

Originally Posted by Railroader

How can it make any difference putting a full tank in? Thats ridiculous! In fact it will use more because you are carting about extra weight.

I think he meant to say you get a more accurate figure for your mpg, because you have a constant reference point. Whereas stuffing in a random half a tank will give a pretty large error margin.

25th March 2011, 15:53

Quote:

Originally Posted by adsayer

You have to be careful in what context, hp mods worsen fuel economy at WOT true - that is where restrictions and inlet and outlet tuning is critical. More air + more fuel = more bang yada yada. But at partial throttle maintaining a given velocity, the volume of air and consequently the gas flow velocity is relatively speaking, very low; pulse tuning, runner length, bore is of much less importance since the conditions are not appropriate to exploit specific component states of tune.

I've got 55 mpg in my VTS once before - that was with a completely non standard exhaust system, xsi box, CF air box.

Cant quite understand your paragraph, wot is a WOT? is it an acronymnm? working optimum temp or something?

One way to describe what I am getting at is if your exhaust starts blowing then your mpg worsens noticeably, it is a well known fact. That is simulating the reduction of back pressure you get with a large bore sports exhaust or a decat. Some of the fuel mixture tends to flow through the overlap in valve timings if there is reduced back pressure.

Obviously you are going to state you got a high mpg with a non standard exhaust, because it goes to prove me wrong and you are always right and perfect.

25th March 2011, 16:10

Quote:

Originally Posted by Railroader

Cant quite understand your paragraph, wot is a WOT? is it an acronymnm? working optimum temp or something?

One way to describe what I am getting at is if your exhaust starts blowing then your mpg worsens noticeably, it is a well known fact. That is simulating the reduction of back pressure you get with a large bore sports exhaust or a decat. Some of the fuel mixture tends to flow through the overlap in valve timings if there is reduced back pressure.

Obviously you are going to state you got a high mpg with a non standard exhaust, because it goes to prove me wrong and you are always right and perfect.

Wide Open Throttle dude.

Nearly, I'm Right, Perfect and Awesome. You forgot Awesome. There's a difference between the theory and real world, we could arsemunch forever about various theoretical examples that support or contradict each others view points, but at the end of the day it's what happens when you're on the road. You can click on the link below with all my fill ups since I owned the car. That's every single journey I've ever done, including track days and spirited driving on the dales/moors. You'll find a few that exceed the official EU Extra Urban figures for a VTS, even with the XSi box that reduces my motorway mpg by around 5-10%.

regards,

25th March 2011, 16:16

Quote:

Originally Posted by Newtz07

Ad... i know you are the MPG king

you taught me everthing i know about squeezing the extra mile out!

but seriously dude, i am struggling here.

going looking at a nice white mk2 VTR at 12, so if its any good, will get him to take mine in PX and away with the problems!

and hopefully this one is better on fuel

Anywayyyy, back on topic.

Firstly dude, your accuracy with your mpg is probably quite low, you ought to fill the car completely, drive about and then fill to the brim again. Half way is not very helpful. That'll give you the most accurate mpg available to you without fancy techno toys. You could find that the car is actually okay. That said it could be worse and you do have some sort of issue with the car. But it's hardly worth replacing the car... just systematically work around the car, tyres & brakes firstly checking everything is good and then working into towards the engine. Checking for leaks/gaps in the exhaust and inlet systems etc etc

Ads

25th March 2011, 16:26

Quote:

Originally Posted by adsayer

Anywayyyy, back on topic.

Firstly dude, your accuracy with your mpg is probably quite low, you ought to fill the car completely, drive about and then fill to the brim again. Half way is not very helpful. That'll give you the most accurate mpg available to you without fancy techno toys.

+1 agree can work out your mpg more accuratley using a full tank.

25th March 2011, 16:26

£20 gets me 80-100 miles depending on my driving
Thats at about £1.30 a litre

25th March 2011, 16:45

Quote:

Originally Posted by devilsadvocate

£20 gets me 80-100 miles depending on my driving
Thats at about £1.30 a litre

Thats 26.5 mpg for 90 miles, yikes

25th March 2011, 18:06

Quote:

Originally Posted by Railroader

Thats 26.5 mpg for 90 miles, yikes

Yup, I think mines running slightly lean
It's decatted so that won't be helping

25th March 2011, 21:52

I really really notice a nosedive in MPG in winter. I think a combination of no bonnet heat insulation on 106s, and a tiny 8v block which loses heat so quickly after being turned off, so engine is always running cold unless on a long journey, are the two main problems.

In summer though, I have to say my MPG is excellent. I worked it out at about 48mpg, and considering the journeys I do consist of mostly urban driving, is good.

25th March 2011, 21:55

Quote:

Originally Posted by Meto

I really really notice a nosedive in MPG in winter. I think a combination of no bonnet heat insulation on 106s, and a tiny 8v block which loses heat so quickly after being turned off, so engine is always running cold unless on a long journey, are the two main problems.

In summer though, I have to say my MPG is excellent. I worked it out at about 48mpg, and considering the journeys I do consist of mostly urban driving, is good.

I would love mine to get anywhere near 48mpg lol

25th March 2011, 21:57

Quote:

Originally Posted by devilsadvocate

I would love mine to get anywhere near 48mpg lol

I'd quite happily sacrifice that MPG for a 106 gti though! I'm itching for one, the insurance is a rip off though.

25th March 2011, 22:05

Quote:

Originally Posted by Meto

I'd quite happily sacrifice that MPG for a 106 gti though! I'm itching for one, the insurance is a rip off though.

Luckily mine is just a weekend car so MPG isn't that important
I have had like 6 less powerfull cars before I got the GTI so I know how it feels lol

25th March 2011, 23:37

£10 gets me 50-60 miles in my VTR.