I searched without any luck. I think it would be a good idea if it already has not been done on a small guide to tuning with an FMU.

I realize most of you dont use them because you have better ways of fuel management that are not overly expensive. I on the otherhand can not get away that cheap with a Jbody.

Anyways could someone explain to me the best way to tune these. How to look for lean and rich conditions. I realize my AF gauge will not be that accurate.

When I do finish I want to be as tuned as possible so when I go to the dyno there is little adjustment to be made. Also will the dyno place allow you to make adjustments there between runs or just run with what you have?

 

Basically they are what they are. Unless you are running a B&m regulator that would be the only way to adjust fuel but it will do very little. The best way i think to check on any motor without the aid of gauges, etc. is plugs. That is what I have always done with my nitrous motors.

 

I have a cartech 2025 FMU which is adjustable quite a bit...maybe I misunderstood. I should be able to make it richer or leaner with the turn of a dial.

 

ya but its not rpm adjustable (ie tuneable).. you can richen or lean out the whole band by increasing the fuel pressure multiplyer dependant on boost level.. buy an afc or standalone if you want to tune.

about all you can do is read the plugs and turn it up till you run the engine rich.. sure you will lose power but you have less chance of leaning out and burning a piston.
thats why fmus suck.

dyno shops will let you run as many times as you pay for. you can tune in between runs.

 

ZexRex,

Yes I realize why the fmu is not the best thing to run. I'm limited with what I can do... I'm saving up for a unichip which will work well for my car. Probably run some sub injectors that are controlled by it.

You pretty much aswered what I wanted...not looking to tune for max hp just reliability for now. Thank you