Be careful Guy or you could go too far the other way with just as drastic results. 3.1kg/cm2 this is a smidge over 3 bar which is 43.5 PSI. loads of converters on the web. This would be without the vacuum pipe connected I would expect. When connected it will then vary this when the engine is running and under load or sudden throttle opening. Rolling road and a way of measuring your exhaust gasses with an analyser or wideband lambda is the only sure way of getting this mixture right. Generally a standard ECU will cope with minor performance changes, however there is a lot of discussions about 12v injectors being near their limits hence people upping fuel pressure to richen mixtures or swapping injectors but often ending in tears, only a rolling road session will confirm what the engine needs. Until you confirm this I'd not do any high speed runs a running lean will have just as dire consequences