Ok everyone,

after reading in another thread that the boost preset and actual readings could be read in vag-com I decided to have a look at mine for curiosity's sake.

Took me a while to find but in engine, measuring blocks no. 115 I saw two values in mBar - set was 1000 and actual was hovering around 950ish on idle and going up to 1000 on blipping the throttle (peaked up to 1050 then back again).

I did a quick conversion and that equates to around 14.5psi so I'm confused now :confused: .

I thought standard octy boost was accepted to be about 9-10psi ???

I'm certain mine hasn't been mapped (not yet anyway ) so I wondered if anyone else could comment on this or try it themselves and report back?

Iirc you have to subtract normal air pressure which is a 1000mbar

Try it leathering down a private road

Second or thrid from as low revs as possible all the way up to the blood and log it

Right, I've done some logs on my conveniently local private air field .

Still confused as the peak boost is 1730mBar (25.1 PSI) :eek:

I'm obviously doing something wrong here.......... :D

I've attached the excel file (hope that works!), converted the k/mh to mph and added a PSI column, any comments welcome!

[ATTACH]15526[/ATTACH]

Knock off 1100 mbar then try this PSI BAR Converter

The 1100 is normal air pressure at sea level, with your boost your adding 730mbar to that natrally aspirited cars run at 1100mbar

i just did it with the above site and got 10psi which it think is right

i'll look into your file closer in a bit i must smoke then shower first

Thanks for that fatty (That's hypoticritical from me , no offense intended!), that gives me a peak of 10.3 PSI at around 5500rpm which would tie in with what everyone says.

Funny that the max value of 10.6 was at 3300rpm but then it was done while not constantly accelerating. (I subtracted 1000mbar so I didn't end up with negative values to confuse my formulas.)

Roll on remap time eh.......

Why's it have to be so flipping complicated???!!!!:grumpy:

If you look at rows 77 to 101 coloums CDEFG you have booted it and and the turbo is spooling then in row 85 its at its peak and holds its up to row 90 where you back off the gas

Good to see you coasted for a bit after booting it lol

Your next assignment is to do a third gear run as i said above and log that, ideally get a mate to do it with you

FYI the hotter everything is the less boost you will get and air pressure varies from day to day and at alltitude

edit. you need to knock 1100Mbar off for it to be correct

HTH

Good to see you coasted for a bit after booting it lol

There was a good reason for that - it was dark and there were other vehicles nearby

Your next assignment is to do a third gear run as i said above and log that, ideally get a mate to do it with you

Now I have an idea what I'm doing and looking at I'll try it again in 3rd, as also recommended by the petrol head tuner who sits behind me at work and said "quote" you could blow more pressure than that!

you could blow more pressure than that!

I get stick off my mate with S2 RS turbo with a huge garret item strapped to it. He's always on about my measley boost and the size of my turbo

'Standard' atmospheric sea level pressure is 1013.2mb but actual air pressure varies with weather systems - eg high or low pressure systems - and elevation above sea level also needs to be allowed for. A good barometer will give you the reading you need to factor in to your calculations.

Thanks for the reply denis , I've since downloaded the excel examples from the ross tech website (which have calculations that bear out exactly the figures you've suggested!) so I'm going to try a few runs sometime over the next week, weather permitting!

Will be nice to have some rough guides on what the engine is producing etc, especially as I am definately planning to look at remapping it in the next few months.

Most noticeable thing so far is how poor the on-board boost controller is - this is something that a work mate who's extremely knowledgeable on tuning cars (not so much vag but plenty of others, even has a self built near 400bhp kit car :eek: ) has been saying for some time. Will be definately interesting to see some figures of a remapped ecu and how the "standard" valve copes etc. (I know that the recirc valve is usually replaced by the mappers though.)

I did a boost run on my car in 3rd gear and got the same results: peaked at 1730 mbar standard car apart from a carbonio cai.