# DIY: Simple BHP test using VagCom



## youngg (Jun 15, 2006)

Heres perhaps one for the newbees as im sure some of the longer members will already know this but i found it out not long ago and it is a good tool and is also very fun!!!!

Heres some simple instructions on how to get a ESTIMATE of your current BHP!! without all the sums...

You will need to do some power runs to get a figure for your air mass flow g/s reading.

You do this with the following steps...

Go to Meas. blocks (8 )









And now you have to log block 003 to file (the top one)









Now go out and do some power runs in 2nd and 3rd gear up to red line (6500 rpm) be careful, empty roads and wear your seatbelt!!

once you have loged the file open it up in excel and you will see something like this..









Look in the row called *AIR MASS FLOW*.. and find the highest reading..

For a stock 180bhp this will be about 135 - 145 g/s
For a stock 225bhp this will be about 170 - 180 g/s

and simply divide this figure by 0.8

so say your best was 143.7..

143.7 / 0.8 = 179.6 BHP!!!!

Simply hey...... have fun...

(thanks wak for the info and use of piccys!!!!)


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## Nem (Feb 14, 2005)

Interesting.

My highest air mass figure is about 200 which /0.8 is 250. I got 260 bph on the rollers at AmD so I think the calculation may get off sync the higher the figures.

Nick


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## youngg (Jun 15, 2006)

depends when you got that 200? could of been different conditions that when on rollers with air fans pumping into it??!!

Like i sayed just a estimate!!! put my mind at rest as i thought the car was in limp mode, but it did add up and just re enforced my intentions of getting a remap!!


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## Wak (May 6, 2002)

its "ballpark" and many things can effect the air mass figure for power calcs, load on the car, elevation of the road surface and the colder temps may mean you need less to make the power.

Its a calc from Ross-techs site to give you a means of getting an idea of bhp but in practice it can only be considered estimate, a rolling road run is the only way of getting a more accurate calculated figure from the torque measured at the wheels.


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## KammyTT (Jun 28, 2006)

can you buy a vag com thingy?


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## freegeek (Aug 26, 2005)

Yes, you can get them cheap on ebay, do a search on my posts to find out where.

My best reading was

Marker	STAMP /min g/s	% Â°BTDC	BHP
Group A:	'003 
7.21	5880	213.67	100	10.5	267.0875

In case that didn't work, it was 267.0875 BHP using vag com


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## barton TT (Nov 13, 2004)

KammyTT said:


> can you buy a vag com thingy?


Free download from http://www.ross-tech.com/index.html and cable from ebay.


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## xxknifeprtyxx (Jan 20, 2009)

whoa just did this and my 180 pulled 158.42g/s @ 6440RPMs

saying my 180 has about 198.025bhp with just a BOV?

funny...i wish lol


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## xxknifeprtyxx (Jan 20, 2009)

whoa just did this and my 180 pulled 158.42g/s @ 6440RPMs

saying my 180 has about 198.025bhp with just a BOV?

funny...i wish lol


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## KammyTT (Jun 28, 2006)

where the hell did you find this thread


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## xxknifeprtyxx (Jan 20, 2009)

KammyTT said:


> where the hell did you find this thread


google my friend, google

hahaha bringing back memories of the n00b days?


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## KammyTT (Jun 28, 2006)

yeh :lol: , we were all noobies at some point eh.


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## CHADTT (Jun 20, 2007)

Any ideas what the airflow should be for a stage1 remapped V6?


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## xxknifeprtyxx (Jan 20, 2009)

very true :lol:


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## viakruzis (Feb 18, 2013)

Hi guys,

I know this is an old thread, but maybe someone with more vagcom skills than me can help me.

I made a couple logs, but the maximum air mass that i get is 120 in 5400 rpm. I have a 225 so there may be some problem.

I did some other logs to see if the requested boost and the actual one were different but no. I get 1 bar (14.5 psi) and constant boost.

Any idea?

PS: I don´t have any error on the Vag com


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## Hoggy (May 8, 2002)

Hi, You need to do 2nd or 3rd gear up to red line to get max MAF flow reading & then divide by 0.8.
If you MAF reading is 100% correct you may get the correct BHP reading, but can be subject to many variables, but useful as a guide to future changes in performance. A MAF flow of 180 gives 225 BHP, but it's only a calculation.
Hoggy.


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## viakruzis (Feb 18, 2013)

I did a 2nd and 3rd gear to redline, and the most i get is that 120 g/s at 5400 rpm, so it seems my car is running now at 150 bhp... (it is a 225 ttr)

The boost pressure is correct (1 bar) so i don´t know where the problem can be.

Any thought?


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## brian1978 (Jul 10, 2013)

viakruzis said:


> I did a 2nd and 3rd gear to redline, and the most i get is that 120 g/s at 5400 rpm, so it seems my car is running now at 150 bhp... (it is a 225 ttr)
> 
> The boost pressure is correct (1 bar) so i don´t know where the problem can be.
> 
> Any thought?


Your maf may be buggered, giving a false reading. A 225TTR at 150bhp would be as slow as hell considering a TT weighs about the same as a church. :mrgreen:


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## jamman (May 6, 2002)

Hoggy said:


> Hi, You need to do 2nd or 3rd gear up to red line to get max MAF flow reading & then divide by 0.8.
> If you MAF reading is 100% correct you may get the correct BHP reading, but can be subject to many variables, but useful as a guide to future changes in performance. A MAF flow of 180 gives 225 BHP, but it's only a calculation.
> Hoggy.


2nd is no good Hoggy 3rd okish but 4th better if it's safe to do so.


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## Hoggy (May 8, 2002)

jamman said:


> Hoggy said:
> 
> 
> > Hi, You need to do 2nd or 3rd gear up to red line to get max MAF flow reading & then divide by 0.8.
> ...


Hi, Yes, Sorry my error, 3rd & the 4th if poss.  
Hoggy.


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## Hoggy (May 8, 2002)

Hi, 5400 rpm is not the Red line, take it to 6k.
Hoggy.


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## viakruzis (Feb 18, 2013)

Hi guys, i think i found the root cause of my lack of power.

I am 90% sure that the previous owner had problems with the maf sensor, and he bought one from an AUM code engine (GTI IV), that maf sensor maxes out at 130 g/s... I suppose the last owner did this because those maf sensors were cheaper... :evil:

So i was limited to 170 bhp this all last 4 years by the Maf sensor without even knowing it...

I didn´t get any error code since there was no error at all.

Thanks to the torque app i realized that i was getting so low maf readings, that app is awesome!


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## viakruzis (Feb 18, 2013)

I replaced my MAF and boom 190 g/s



Thanks for your help buddies


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