Can anyone help...

Following a few track day issues the cossie has screwed up fuel mixtures.

I need to adjust the fuel pressure to suit boost but I ahve forgotten the ratio's and thought it better to ask on here before finding 100 articles on the subject with 100 different figures.

Can anyone advise??

 

Most uses 3.5bar without vacuum around here

 

set fuel pressure to 3.5 bar atmosphric then it should drop to 3 bar when vacume pipe pluged back on.fuel and boost pressure should rise on a 1:1 ratio

 

only the person who wrote the chip can tell you what the base fuel pressure should be, dont guess as it can and often does end in tears.

Standard fuel pressure is set at 3.5 bar with the vac pipe off and blocked, the vac pipe on figure is really un important is it depends totally on the ammount of manifold depression present

 

What danny says find the chip make and ask them, most off the shelf ones are set around std 3 bar, but it is a lot cheaper to make a phone call to check than rebuild a melted engine!!
tabetha

 

What were the "issues" at the trackday and why has the fuel pressure been changed?

I would use an AFR guage to check it over first before making any guesses.

As above though, if you know who wrote the chip, they should be able to give you a ballpark figure to start from.