A/F ratios....what should i be tuning for?
 

hi guys.....

Currently (i got it back from a shop like this)
it will idle at 12.1 when i start to slowly rev (no boost) it will slowly climb up to a high point of 14.7.....and in data logging i have recorded a highest measurement of 15.9

What should i try to keep the A/F at, on cruise, idle, and on WOT.


btw, its a Microtech MT8
s4, stock turbo

on boost over 5000, no leaning than 11.5:1, its the stock restricter opps i mean turbo, which is you biggest bottle neck at the moment.

14:1 crusing without idle sounds a tad too lean aswell.

>14:1 crusing without idle sounds a tad too lean aswell

No, that's fine, although he said 14.7, not 14.1. If you have closed loop operation, cruising should be close to 14.7:1 (average, it'll bounce above and below that). If it's open loop it doesn't matter much, but making it richer than 14.7:1 just wastes fuel. You can lean it out up to the point that it begins to misfire, then that's too lean.

update...
after data logs i found this out :


On idle its averaging around 12.9-13.5

On cruise its 14.7 (closed loop i guess)

On boost its 12.5-13.0

Im guessing THATS why its blowing black smoke..

Im going to get some new plugs, take it to my tuner d00d guy, actually ill get two sets of plugs =D and we will get it running better....


thankyou for ur help


oh ps, i really need that intercooler, i had a 100 degree celcius intake temp on a big burnout =D
(simulated burnout of course..... :) )

If you are going off the reading of your Microtech I would not trust them for even one second. They are a guesstimation on a non-temp corrected O2 sensor. You should only trust the figures from an accurate and dedicated wide band Air Fuel ratio meter.

Microtech MT-series do not do closed loop, nor is it programmable for closed loop features to select a target voltage from the sensor to aim for under different conditions.

If you run true 12.5 to 13.0:1 under boost at WOT it should not blow smoke and would infact be hours away from needing a rebuild. :-) Being a Microtech you should be aiming for at least 11.5:1 as HWO has said correctly. Idle around 12.6:1 and cruise at 13.8 to 14.5:1

lol.....c'mon MICROtech is one of the world leaders in rotary engine managment systems isn't it ?

I love the screwdriver adjustable series of computers, I think they were on a good thing back then.