BHP calculating

[caveo]

I think i read that vag-com can calculate your bhp , which blocks to i use and how do i work it out??

 

[wild willy]

a good guesstimate is to multiply air mass reading by 1.25.

 

[caveo]

Right mate iv been and done it and the best i can get is 227 g/s which is 280 bhp ( x 1.25 ) so now im worried . No fault codes and i cant see any loose hoses or split ones.

 

[Daz_gibbo]

MAF x 1.25 is a rough guide so don't get hung up on it. I think the vagcom was was to derive it from a block which gives you a torque reading iirc. But this goes out the window once remapped etc.

 

[ibizacupra]

block 120 was the original torque figure. log that and rpm and you back calculate bhp
( as said, meaningless once modded)

 

[caveo]

i used block 77 rpm and mass air in ( best was 227 @ 6400rpm )

 

[Daz_gibbo]

forget calculating it from MAF for an accurate reading. Found a post from Bill a while back, plenty of threads out there on this.

Quote:
Originally Posted by Feel
Sorry Bill - I've read this post a good few times and I don't understand...

Are you talking about the 1.31 * g/sec = HP calculation, or something else?

kinda the same thing... scaling in factory ecu's is not the same, so comparisons with x g/s = a power output can at best only be a guide.

internal scaling of maf being different between ecu's, let alone various "tune" ones

 

[caveo]

well im having a service on friday so i'v asked em to take a look.

 

[jcc-gttdi150]

The formula I was told to use for bhp using vagcom is below but you'll need to log rpm and torque as a minimum from the blocks. torque in Nm is block 020 on mine.

First, you'll need to convert the Nm torque to lb/ft, which is done by multiplying Nm by 0.738

Then you use this:


bhp= (rpm) * (lb/ft) /5252

I did and then used the excel graphing to create this graph

207bhp and 302lb/ft, which is nice