Can you really guess BHP from peak MAF readings?

Can you GUESS BHP from peak MAF G/S?

Answer = Sort of yes and sort of no

Armed at my disposal is over 350 datalogs i've carried out over the past 3 years, which disproves that theory.

The first thing to know, is that yes, MAF will go up when there is a power increase, but this is dependant on load/boost, temperatures, air density/humidity and even your induction kit.

Got an ITG? It has slightly different scaling between V1 and V2, so your peak MAF will also be different (higher in the case of V2)

Let's go back to the days I was trying to make CP4X work.. 

The best I managed to get from the car, was a peak of 287bhp, tested on the Dastek Dyno in braked mode.

Revisiting the same dyno recently in hotter conditions, with all the software and hardware progressions in 12 months, it hit 330bhp. At the same peak boost.

CP4X Peak MAF 222 g/s
MaxD 3R Peak MAF 226 g/s

Same turbo. Same induction kit. And even the same peak boost. 

WHAT?! 43bhp has been gained, but MAF has only increased by 4 g/s? Correct!

Its a similar story no matter where we look.

Customer 1's X47R made 322bhp, Peak MAF was 221 g/s.

Customer 2's X47R made 335bhp, and hit a peak of 231 g/s using the newer V2 ITG tube (which gives a higher MAF output due to its different scaling)

Customer 3's X47R, on a Stage 2 Intercooler and hitting 48c charge temps, made 312bhp with MAF of 220 g/s.

I could go on, but as you can see, there isn't a fool proof, direct formula for converting MAF into actual power, at least not in this application.

It will show if any changes you make actually increase power, but for a direct conversion to bhp? There are too many variables. 

When it comes to measuring power, you should use a dyno, and my preference of using loaded dynos that heavily stress the cars may not produce the higher numbers that others claim from the same set up, it is however,  honest!

And far more important is how the car performs on the road, rather than trying to prove anything to impress your mates or some randoms on a Facebook group..