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Fuel Consumption after Mods

Discussion in 'A3/S3 Forum (8L Chassis)' started by MickM, Oct 13, 2010.

  1. MickM
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    MickM Member

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    Hi guys,

    Could someone confirm if this is right for me. Got a 99 A3 1.8T (AGU) with the following mods:

    K03S Turbo
    Forge TIP
    Miltek Cat Back
    Forge 007
    Air Filter
    Custom Remap

    Remap graph shows it running about 245BHP. Now i have a feeling something is wrong somewhere. I am getting roughly 70 miles to £15 of fuel on a motorway run (sitting at 70MPH)

    This sounds wrong to me?? If you guys agree would be first things to check?
    #1
  2. Duktor
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    Duktor Member

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    Hi Mick strangely enough i was just about to post a milage thread , to determine if my 01 plate S3 is running properly Ive just bought the car a cpl weeks ago and so far filled the tank three times and twice recorded the milage till the fuel light comes on, heres my findings

    total milage covered = 577 miles
    total litres fuel used = 111 litres
    average cost per L = £1.25.5 in my neck of the woods :banghead:
    average cost per mile £ 0.02412478336221837 = 25 pence per mile
    my calculations aint exact but based on one tank of tesco 95 ron that the dealer supplied then a tank of tesco 98 ron ive calculated that it costs 25 pence per mile

    which equates to £17.50 for 70 miles regardless of driving style condition etc

    my old buggy has done 126k had new oil filter n timing belt last week, as far as i know its a (standard ) amk which has limited service record which i will endevour to investigate as soon as i get the v5 through .

    all in all i dont think 0.25 pence per mile is bad for an old bus with large miles on her with relatively good performance :ninja:

    be good to hear what milage other folks get from standard or modded buggies :whistle2:
    #2
  3. s3dave
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    s3dave TFSI Hybrid

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    I too think 25 mpg is quite fair for an s3, i can only manage.... 21mpg..mainly 20min runs to work, so to be fair its only just got up to temp both ways,
    Always V Power@ 1.23 a litre.
    245 BHP on a ko3s.....?
    #3
  4. jojo
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    jojo S3 Drift King! Staff Member Moderator

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    I average 25mpg or there about with mixed driving in my remapped S3, I have seen 30mpg+ with long haul drives on the motorway only also.
    #4
  5. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Sat on the motorway at an indicated 80 our A4 will return 32mpg, and round town it drops to 25-26.

    If your A3 is using more fuel than that then your driving around with a lead foot, or its broken, as the A4 is heavier and has permanent 4wd.

    Saying "70 miles per £15" is useless. Fuel can vary in price hugely. Brim the tank, drive, then brim the tank again, and compare your mileage with the actual number of litres of fuel you put in.

    First thing to check is simple, does your coolant temp come up to 90 quickly and stay there? It should be at 90 within 2-3miles, and shouldnt ever move from there. If it does, your thermostat is probably gubbed.
    #5
  6. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    If its taking 20mins to warm up your thermostat is knackered. The A4 gets up to temp in about 5 minutes.
    #6
  7. S3 Paul
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    S3 Paul Moderator Moderator

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    With mixed driving i see about 400 miles per tank (60 ltr )
    To and from work though i dont realy get the car fully up to temp. so never going to see a good figure there.
    #7
  8. Welly
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    Welly VX220 SC Driver :)

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    I see 26.4 MPG on the DIS if driving reasonably with a truck load of mods...

    Where the hell did you get that car dyno'd anyway? 245 BHP from a K03S is, IMO having had one with that setup, a bit out of reach. But that's besides the point...
    #8
  9. MickM
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    MickM Member

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    My mistake, the RR Graph is showing 230HP - Seems a little more realistic for the K03s!?

    I'll try Brimming the tank, doing the trip and then filling again to get an exact amount but the 70 miles to £15 was at 117.9p and fuel light to fuel light so it shouldn't be far out if at all.

    It generally takes around 10-15 mins for the temp to get to 90 degrees, i have a spare thermostat so I'll get that changed at the weekend. As always thanks for your replies guys!
    #9
  10. MickM
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    MickM Member

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    My mistake, the RR Graph is showing 230HP - Seems a little more realistic for the K03s!?

    I'll try Brimming the tank, doing the trip and then filling again to get an exact amount but the 70 miles to £15 was at 117.9p and fuel light to fuel light so it shouldn't be far out if at all.

    It generally takes around 10-15 mins for the temp to get to 90 degrees, i have a spare thermostat so I'll get that changed at the weekend. As always thanks for your replies guys!
    #10
  11. s3dave
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    s3dave TFSI Hybrid

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    5 minutes from cold, are you straight on a motorway?
    I was saying 20 mins so people can get a picture of my circumstances ...21 mpg. It rises slowly from off, my thermostat is fine, always dead centre on the button...once warm
    By the way the 20 mins is all downhill going hence the possible slow warm up :thumbsup:
    #11
  12. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    Fuel consumption is very subjective.... I get on average 24mpg which I prob could get a bit higher but I have country roads, town traffic and hills to contend with on my journey to and from work...

    I do have a fair few mods too it must be said :)

    <tuffty/>
    #12
  13. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Ye maybe its more like 10mins to get to 90.

    Not quite streight onto a motorway, looking at a map theres about 1.4miles of streets then a mile of 60 limit (though its usually full of morons doing 45-50) , and by the end of that the gauge is about 70-80c. Then its back into 30 limits the rest of the way to the missus work.

    Total trip from the house to her work is about 4 miles, and takes about 10minutes, and the gauge is always at 90 when she gets there.
    #13
  14. bennn
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    bennn Member

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    The S3 seemed to be quite frugal on the motorway on the way back from picking it up (saying that i was going no more than 60 as it was pissing it down and id forgot my glasses so couldnt really see much)

    Since then ive brimmed it from empty with tesco 99 and have done 330 miles with the computer saying ive got 50 to go. Ive mainly used the car a fair distance at a time (about 40mins drive) but have done a few town journeys and given it a bit of beans every now and again.

    The Astra GSI Turbo its replaced used to give me over 400 miles on a 50L tank of super unleaded so was significantly better on fuel, that said the S3 is faster and heavier.

    My S3 does take a long time to get to temperature and wont sit on 90 (unless in traffic) so i belive the thermostat is knackered.

    I presume when the thermostat is replaced and its been through a few tanks of super unleaded allowing the ECU to adjust that my fuel economy should improve?
    #14
  15. JD09
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    JD09 I'm not modding, I'm improving

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    I see 23 most of the time, because work is a mile or 3 away. But on motorway runs, I've seen 38 ( 4hours driving to London at night).
    #15
  16. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    It will improve immediately.
    #16
  17. Welly
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    Welly VX220 SC Driver :)

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    Although not by enormous amounts in my experience.... And I've had 3 of them and replace thermos on them all...
    #17
  18. mk1chopper
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    mk1chopper Missing the S3

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    I'm getting on average 30mpg, I get 400 miles out of a tank of sainsburys super unleaded. I've just filled up with a tank of shell V power and i've done over 200 miles and not used half a tank yet. I've never seen any differance in mpg between fuels before but the V power seems to be returning better mpg at the mo. The other thing to take into consideration is the clutch. My slave cylinder falied early this year and the clutch and flywheel were replaced at the same time, the clutch being worn and the flywheel having excess play. I was averaging 330 to 350 out of a full tank before the clutch was replaced.
    #18
  19. S3KO4
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    S3KO4 Member

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    I agree with mk1chopper, after replacing my clutch kit I saw better MPG.

    At 70mph when warmed up I see average of 39MPG :)
    Town drive when warmed up I only get 26MPG at best. :(
    Mixed drive when warmed up I get 33PMG. :unsure:

    thermostat has a lot to do with it as well as leaks in exhaust, faulty lambda etc... and when I changed one of my coil pack last week, that help as well.

    I always wait at least 2 minutes to warm up regardless of the season(longer in winter) and I drive under 2K rpm until the temp reads 90 and the oil reads 90C. option 51 :)

    This will takes care of the engine internals and the turbo.

    When I see people getting into their cars and stepping hard on it from a cold start! I think they either have no feeling for the poor thing or they haven't worked for it or just not educated enough!
    Last edited: Oct 15, 2010
    #19
  20. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Depends how broken it is!

    Our first A4 the coolant guage wouldnt climb much above 70 unless stuck in traffic, and it returned 24mpg on the drive home. Changed the stat and economy went up to about 32 for the next tankfull.
    #20
  21. devan
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    devan Member

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    My S3 with a stage 1 Revo remap gets 30mpg average, running on Shell V-Power.

    Think i need to change the stat though, as its not sitting and staying ay 90 degrees.
    #21
  22. Prawn
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    Prawn My other car is a MINI!!!!

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    the figures you gave give exactly 25mpg, which to be honest, is pretty poor.

    My old stage 2 ko3S agu used to get 38mpg cruising at a steady 70mph on the motorway. I generally averaged 27mpg from it with a mix of town and A road driving fairly briskly, and I get 28mpg ish from my ko3S AUM now too.

    Comming back from germany last month with the A3 loaded to the roof is returned 38.8mpg again, with a stage 1 map, CAI, TIP and 3'' DP/decat, so a similar spec to yours.

    have you checked all the vac lines and everything for leaks? if it's got a boost leak somewhere you'll be running rich and using more fuel
    #22
  23. TimG
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    TimG Member

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    My stat needs changing, although I still average around 28mpg with it broken. I do suspect it will go up though once fixed as most of my 11 mile journey is motorway & I think I should be getting more than 28. Should be sorting it next weekend.
    #23
  24. Kave
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    Kave Member

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    My unmodded a3 agu was returning around 30mpg on my 80mile motorway commute, was killing me filling up twice/week. Now in a pd130, 60mpg and 650miles per tank. £££ woot.
    #24
  25. Duktor
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    Duktor Member

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    thats exactly what i did currently seeing 23.6 mpg with mixed brisk driving , temp hardly gets above 75 unless gunning it or sitting in traffic so stat being changed tomorrow,
    have also checked all vac hoses and all seems well

    does anyone know if the temp sensor in the expansion tank will affect fueling at all if its at fault ??

    how much did it cost for you guys who had a clutch change ??

    and how would you know if your lambda sensor was faulty ??
    #25
  26. finesse
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    finesse Active Member

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    get a thermo from Audi,

    coolant sensor at two places,
    #26
  27. Duktor
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    Duktor Member

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    Opted for the £4.50 unit from motor factors Audi unit was £23,

    as posted previously 2 x brimmed tanks gave 23.6mpg after 111 liters of fuel , my temp guage never reached 90 unless gunning it etc and even then it would sit at around 75 @ the ton

    so took the car to a m8 who has own garage less than a gdiver for the stat and about a tenner for 5 litre comma X stream G30 coolant , flushed the entire system and boy did it need it ( oil pick up deffo nxt job )

    we pressurised the system with air to check for leaks all was well so proceeded to top up with the coolant thats where the fun started :banghead: no heat from the matrix :banghead: pc was down so elsawin was out the window :banghead: couldnt find a bleed screw anywhere :banghead:

    BIG THANKS to all u guys on the forum :readit: we loosened off the expansion tank put a block of wood under it too raise it as high as poss then pumped the trolly juck under the coolant side filled the tank and revved the car at 2500 rpm for approx 20 mins whilst pumping all the pipes within 5 mins we had full heat from the matrix and no more air bubbles. Job was a good un .

    went and filled the fuel tank to brim:thumbsup:


    covered 55 miles since and the temp didnt move from 90 deg at any point all the time testing different driving modes :weight_lift2: :icon_thumright:

    65 mph on dual carriageway 32 mpg as indicated by the dash
    average on dash = 28 mpg

    I will run the tank untill fuel light comes on then post findings :wacko:


    ps had a cpl of fault codes relating to temp sensor and the engine was knocking when cold :sadlike:so we cleared the codes and fitted the stat started up no knocking or pinking will get it tested on the vag again after this tankfull :Flush:

    heres hoping all goes well :unsure:
    #27
  28. crazychris
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    crazychris Member

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    sorry silly question but im new..... option 51 would that by any chance be something to do with vag com and switching on some extra function if so is it possible on my 1999 a3 1.8 t sport

    sorry to hi jack cheers lads
    #28
  29. crazychris
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    crazychris Member

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  30. s3gazz
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    s3gazz Active Member

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    i get 22.4 mpg and only got forge tip, and forge dump valve, and remap whats going on taking piss e
    #30
  31. Duktor
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    Duktor Member

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    I just ran 28.8 liters after my thermo and fluid change and got almost exact same milage 22.4mpg as you s3gazz ( must admit its been short journey town driving mostly and less than half a tank of juice and my avarage before stat change ect based over 2 full tanks was 23.6 mpg ) so ive put in a whole tin of BG 44K and filled up again.

    Untitled Document now this could well be snake oil I dunno , but my m8 who runs a mot station swears it has fixed many a mot failure due to emmissions !!, and if it does what it says on the tin then i thought why not give it a try so threw in the extra £20 notes then refillied the tank, and lets face it when your buggy is returning these figs its worth a chance even if it returns 1 mpg better it will soon pay for itself , so im gonna follow the instructions on the bg site then change my plugs and refill :thumbsup:
    #31
  32. s3gazz
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    s3gazz Active Member

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    looks good lad myt have to try some of this changing spark plus soon anyway and new injectors seals as they are all leaking lol joys of motoring ha
    #32
  33. finesse
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    finesse Active Member

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    I get 41mpg with a bumpy needle a idle... Revo S3. :p

    Need to find the vac leak asap
    #33
  34. s3gazz
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    s3gazz Active Member

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    my injecters are leaking i kno that and sorting them out tomoz with new rings god now what elso it can be will spark plugs help tar
    #34
  35. finesse
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    finesse Active Member

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    1. Give your MAF a clean if it is old or replace
    2. sort the injectors
    #35
  36. Duktor
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    Duktor Member

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    better spark should be more efficient whether we will notice any difference in mpg i dunno but im goin for the same plugs as u gaz ngk iridium BKR6EIX as per the advice in the spark plug thread no idea when mine were last changed so wont do any harm to change em , how do u know your injectors are leaking ??

    finese how do you clean the maf is it ok to spray it with carb cleaner and if so do you need to remove it for the job or just spray it in whilst running ?
    Last edited: Oct 28, 2010
    #36
  37. finesse
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    finesse Active Member

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    #37
  38. Duktor
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    Duktor Member

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    ill give that a go and at same time change plugs and clean the throttle body , also have a new fuel filter to fit , now i should only have to wait another 3 months for a dry day
    #38
  39. finesse
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    finesse Active Member

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    errrrm go steps to follow

    change plugs, clean throttle body with carb cleaner, new fuel filter and air filter would be good, clean the MAF

    cold rainy weather? dont be soft
    #39
  40. s3gazz
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    s3gazz Active Member

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    sorting injectors tomoz and u can see petrol coming out and drippind down the pipes around the injectors changing spark plugs for sakes of it anyhow tar going to get new fuel filter 2
    #40

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