1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

maf readings to bhp conversion

Discussion in 'A3/S3 Forum (8L Chassis)' started by djdougalno1, Oct 17, 2010.

  1. djdougalno1
    Offline

    djdougalno1 Member

    Joined:
    Oct 22, 2008
    Messages:
    189
    Likes Received:
    1
    hi anyone know how to do the conversion from maf readings to bhp cheers
    #1
  2. Alex C
    Offline

    Alex C Well-Known Member

    Joined:
    Jan 26, 2010
    Messages:
    2,633
    Likes Received:
    152
    i think i have seen 0.8 metioned before
    #2
  3. Prawn
    Offline

    Prawn My other car is a MINI!!!!

    Joined:
    Dec 8, 2006
    Messages:
    9,440
    Likes Received:
    1,281
    to convert MAF readings into approximate BHP figures divide the g/s value by 0.8, or multiply is by 1.25, both give the same result.

    120 g/s divided by 0.8 gives 150bhp for a standard A3. 160g/s or there abouts for a mapped A3

    168 g/s divided by 0.8 gives 210 bhp for a standard S3. 200g/s or there abouts for a mapped S3

    You usually won't see those exact figures of course, but that's the ball park you're after
    #3
  4. DJ_Troopa
    Offline

    DJ_Troopa K1 Driver

    Joined:
    Oct 30, 2008
    Messages:
    1,741
    Likes Received:
    13
    1.25

    When my car was down on a bit of power and done a couple dyno runs on my liquid gauge i was getting 258bhp. My air readings were 208g/s. 208 x 1.25 = 260. So not far off really!
    #4
  5. dannyh
    Offline

    dannyh Nogaro S3

    Joined:
    Jul 4, 2009
    Messages:
    786
    Likes Received:
    11
    when do you collect the G/S value, will it increse and decrese ad you put your foot down, at which point do you take the figure??,

    I have been speaking to my mechanic (as in one of my threads i cant decide if my car is mapped or not) and he said he thinks he has some software that can measure this. I can probably use this to work out if it is mapped or not
    #5
  6. s3dave
    Offline

    s3dave TFSI Hybrid

    Joined:
    Nov 11, 2009
    Messages:
    10,120
    Likes Received:
    728
    Ideally 3rd gear to the redline ...if safe to do so of course.
    #6
  7. dannyh
    Offline

    dannyh Nogaro S3

    Joined:
    Jul 4, 2009
    Messages:
    786
    Likes Received:
    11
    is this correct, i think i can hit 90 in 3rd so i will have to take it to the motoway lol
    #7
  8. badger5
    Offline

    badger5 RIP S3dave Site Sponsor

    Joined:
    May 28, 2004
    Messages:
    7,263
    Likes Received:
    668
    if logging, look at 115 and 003 and you will see what boost (unless its an agu) and what airflow.
    std 150bhp airflow is 120g/s, 210/225bhp is 180g/s as a guide
    #8
  9. JD09
    Offline

    JD09 I'm not modding, I'm improving

    Joined:
    Dec 20, 2009
    Messages:
    3,080
    Likes Received:
    35
    I still need to buy the VCDS upgrade... You can't log half the required blocks with just the lite version :(
    #9
  10. dannyh
    Offline

    dannyh Nogaro S3

    Joined:
    Jul 4, 2009
    Messages:
    786
    Likes Received:
    11
    Thanks, my mechanic has a scanner, not VAG COM so we will have to see if it gives MAF reedings and btw mine is AGU
    #10
  11. Welly
    Offline

    Welly VX220 SC Driver :)

    Joined:
    Aug 5, 2009
    Messages:
    10,699
    Likes Received:
    117
    You can do the air flow logging though dude. Doesn't the shareware give you up to block 025?

    Anyway, either /0.8 or x1.25 your g/s figure gives an estimated BHP output.
    #11
  12. Welly
    Offline

    Welly VX220 SC Driver :)

    Joined:
    Aug 5, 2009
    Messages:
    10,699
    Likes Received:
    117

    Scanners don't normally do logging mate, they tend to just read/clear fault codes...
    #12
  13. Prawn
    Offline

    Prawn My other car is a MINI!!!!

    Joined:
    Dec 8, 2006
    Messages:
    9,440
    Likes Received:
    1,281
    I'm fairly sure the liquid gauge uses airflow to calculate bhp anyway, so no wonder they were similar numbers!
    #13
  14. dannyh
    Offline

    dannyh Nogaro S3

    Joined:
    Jul 4, 2009
    Messages:
    786
    Likes Received:
    11
    he said his scanner offers Live Data, we are going for i spin tomorrow to get the figures, i havent told him the full extent of the test lol, he doesnt know we will be at the redline in third lol,


    is it the peak figure i am looking for???
    #14
  15. metricspaces
    Offline

    metricspaces Member

    Joined:
    Jun 4, 2007
    Messages:
    628
    Likes Received:
    1
    Yep, take the max g/s value from a run up to the redline.
    #15
  16. dannyh
    Offline

    dannyh Nogaro S3

    Joined:
    Jul 4, 2009
    Messages:
    786
    Likes Received:
    11
    in third gear????/
    i can hit 90 in third
    #16
  17. Prawn
    Offline

    Prawn My other car is a MINI!!!!

    Joined:
    Dec 8, 2006
    Messages:
    9,440
    Likes Received:
    1,281
    You can hit over 90 in 3rd mate. Rev limiter in 3rd is over 100mph
    #17
  18. dannyh
    Offline

    dannyh Nogaro S3

    Joined:
    Jul 4, 2009
    Messages:
    786
    Likes Received:
    11
    is that how fast i need to go for the test?????
    #18
  19. dannyh
    Offline

    dannyh Nogaro S3

    Joined:
    Jul 4, 2009
    Messages:
    786
    Likes Received:
    11
    also, if you can hit 100 in 3rd why is the top speed 135??
    #19
  20. Welly
    Offline

    Welly VX220 SC Driver :)

    Joined:
    Aug 5, 2009
    Messages:
    10,699
    Likes Received:
    117
    No-one is going to say yes and encourage you to go 90+ on a public road matey....

    However, on a private track, then yes, 7200 in third FTW!
    #20
  21. DaveA3
    Offline

    DaveA3 Audi A-Trizzle!

    Joined:
    Feb 25, 2010
    Messages:
    2,374
    Likes Received:
    14
    motorway juction should be fine to do ur "77mph" lol if ur lucky enough to be close.

    i have a m1 junction 13-14 running accross the backend of milton keynes so thats a good place for me
    #21
  22. Prawn
    Offline

    Prawn My other car is a MINI!!!!

    Joined:
    Dec 8, 2006
    Messages:
    9,440
    Likes Received:
    1,281
    The limiting factor in top speed is power not gear ratios. In theory, if you could get to 7200rpm in 5th gear you'd be doing about 180mph, but the power simply isn't there.

    I managed to get my stage 2 agu to 6600rpm in top on the kerpen autobahn, which was 163 according to the satnav
    #22
  23. S3KO4
    Offline

    S3KO4 Member

    Joined:
    Aug 15, 2009
    Messages:
    850
    Likes Received:
    2
    I think you are referring to the 5 speed box to get 100mph out of 3rd. the 6 speed is a lot shorter ratio, good speed there but what was it showing on the dash? I bet over 165! I was once in a fully stripped A3 with K04 that reached way below the clock. if only the head permitted, there was still tones of torque coming from the engine which I think would have taken it over 170mph
    #23
  24. badger5
    Offline

    badger5 RIP S3dave Site Sponsor

    Joined:
    May 28, 2004
    Messages:
    7,263
    Likes Received:
    668
    easier said than done..
    IHI'd back in 2003, 320bhp, seat ibiza @ bruntingthorpe 2 mile straight, 160mph was its gps timed Vmax. speedo was off the clock.

    I did a Vmax day with pistonheads back then, and what a crack it was.. ickle seat ibiza going side by side and head to head with proper fast cars, and M3, M5's loosing in a rolling start and slower terminal.. funny as :)
    #24
  25. Welly
    Offline

    Welly VX220 SC Driver :)

    Joined:
    Aug 5, 2009
    Messages:
    10,699
    Likes Received:
    117
    Cos I bet that didn't make you smile at all..... Much. :thumbsup:
    #25
  26. Prawn
    Offline

    Prawn My other car is a MINI!!!!

    Joined:
    Dec 8, 2006
    Messages:
    9,440
    Likes Received:
    1,281
    I was indeed refering to the A3 5 speed box, as DannyH who asked the question has a 150bhp 5 speed A3 :)

    Speedo on the A3 was well off the clock on 6600rpm, showing roughly 170 indicated speed, 163 on the satnav
    #26
  27. dannyh
    Offline

    dannyh Nogaro S3

    Joined:
    Jul 4, 2009
    Messages:
    786
    Likes Received:
    11
    Weel guys i wen out last night and got my data.

    firstly whe i was driving the G/S value incresed when i let of the accelarator,

    well i diddnt hit 7500 but i took it to 7000 in third and i recorded 127.5g/s
    so..
    117.5 x 1.25 = 146.88 so 147bhp

    is this normal, i am guessing so
    however when i let off to change gear i recorded 124g/s

    why does it increse when i let off.

    any way conclusion..... Remap Time
    #27
  28. s3dave
    Offline

    s3dave TFSI Hybrid

    Joined:
    Nov 11, 2009
    Messages:
    10,120
    Likes Received:
    728
    it may have over revved when you put the clutch down
    #28
  29. badger5
    Offline

    badger5 RIP S3dave Site Sponsor

    Joined:
    May 28, 2004
    Messages:
    7,263
    Likes Received:
    668
    that airflow matches cars which I see and dyno at around 150bhp, so looks normal for stock car

    Remap time now then :)
    #29
  30. dannyh
    Offline

    dannyh Nogaro S3

    Joined:
    Jul 4, 2009
    Messages:
    786
    Likes Received:
    11
    yes just booked it in, cant wait lol
    #30

Share This Page