air to fuel ratio, is 14-15 too lean? Options

[skogs]

My GT4 with a jap-spec 3sgte and euro ecu is showing typically 14-15 on my air/fuel gauge. Is this too lean? My mechanic said that i shouldnt use the jap-ecu on 95 octane... Im running 15 psi turbo pressure.

Going on a road trip tomorrow, and i dont want to mess up my car again.

This post has been edited by skogs: Apr 11, 2014 - 3:15 AM

[lagos]

I grew a pair and did some runs while having an eye on the a/f-gauge. And the ratio drops to around 10 when flooring it. Very safe then:)

When at idle or cruising you want to be at 14.7 because there is not much load on the engine and the turbo is not really doing anything. Once you floor it and boost builds, you want that ratio to get richer to supply more fuel to the extra power you are making. Normally when people talk about what afr their car is running, they are referring to the afr under wide open throttle and at full boost.

Here is a good visual example of the type of look up table your ecu uses. The 100 load on the left is 0 psi, and the 200 load is about 15 psi.

http://www.miataturbo.net/attachments/mega...-afr_tablez-jpg