maf readings to bhp conversion

[djdougalno1]

hi anyone know how to do the conversion from maf readings to bhp cheers

 

[Alex C]

i think i have seen 0.8 metioned before

 

[Prawn]

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

 

[DJ_Troopa]

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!

 

[dannyh]

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

 

[s3dave]

Ideally 3rd gear to the redline ...if safe to do so of course.

 

[dannyh]

Ideally 3rd gear to the redline ...if safe to do so of course.

is this correct, i think i can hit 90 in 3rd so i will have to take it to the motoway lol

 

[badger5]

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

 

[JD09]

I still need to buy the VCDS upgrade... You can't log half the required blocks with just the lite version

 

[dannyh]

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

 

[Welly]

I still need to buy the VCDS upgrade... You can't log half the required blocks with just the lite version

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.

 

[Welly]

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

Scanners don't normally do logging mate, they tend to just read/clear fault codes...

 

[Prawn]

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!

I'm fairly sure the liquid gauge uses airflow to calculate bhp anyway, so no wonder they were similar numbers!

 

[dannyh]

Scanners don't normally do logging mate, they tend to just read/clear fault codes...

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???

 

[metricspaces]

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???

Yep, take the max g/s value from a run up to the redline.

 

[dannyh]

Yep, take the max g/s value from a run up to the redline.

in third gear????/
i can hit 90 in third

 

[Prawn]

You can hit over 90 in 3rd mate. Rev limiter in 3rd is over 100mph

 

[dannyh]

is that how fast i need to go for the test?????

 

[dannyh]

also, if you can hit 100 in 3rd why is the top speed 135??

 

[Welly]

is that how fast i need to go for the test?????

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!

 

[DaveA3]

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

 

[Prawn]

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

 

[S3KO4]

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

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

 

[badger5]

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

 

[Welly]

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

Cos I bet that didn't make you smile at all..... Much. :thumbsup:

 

[Prawn]

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 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

 

[dannyh]

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

 

[s3dave]

it may have over revved when you put the clutch down

 

[badger5]

that airflow matches cars which I see and dyno at around 150bhp, so looks normal for stock car

Remap time now then

 

[dannyh]

that airflow matches cars which I see and dyno at around 150bhp, so looks normal for stock car

Remap time now then

yes just booked it in, cant wait lol