Jump to content
SAU Community

Recommended Posts

14.7 is what the factory ECU would target for anything but high load. Sometimes leaner is OK provided the EGTs are under control. However 14.7 is perfectly safe, and also will give you very good economy. There shouldnt be any reason why you should go richer under vacuum conditions.

My yellow light normally lights up quite early about 40l used then I just fill it up on the E , I will fill around 45-47l max haha.

I thought I was doing bad with those 350km (I'm a student so not much highway driving) , since BP Ult petrol price went up to 126 cents per litre!!! ridiculous (In Perth)

haha did you read my post, I'm paying 132 cents per litre for normal premo 95RON. I'd give anything to be able to get 98RON for 126cents pl

well i feel better now atleast i know i am not alone. If i fill my tank to the point of overflow. Even if i drive like a granny the best i can get out of the tank is 350. before i put exhaust airfilter fmic i used to get 450. ah well the price we pay for owning PHAT cars hehehehe

I've had mine checked out.

The std pfc map & light load up until around load point 12-13, it was reading spot on 14.7:1.

I had a vs v8 common whore, it had a mild cam that you could only ever so slightly hear lope over. It was remapped.

I remember the bloke saying light load was tuned to 16-17:1.

It still had sh*t economy around the city.

Driving nicely the most it would get around the city was 430-450km's per tank, but on the open road whoahhh.. an easy 650. lol

Its tank was big, I remember with cheap petrol back then (0.72-0.79c) it was costing $55-$60 to fill.

When tuning for a leaner mixture you not only have to change the afr, you also have to change the ignition timing.

A leaner mixture will require more ignition timing as it burns slower, you need peak combustion pressure to occure ~10degrees ATD.

Advancing the ignition timing also lowers the EGT, so I would think if its done correctly the egt would be very similiar to the richer mixture will less ign. timing.

Edited by Cubes
Is Julian Edgar quoting 16:1 for a nissan?  Is that cruise or lean cruise?  Most cheap (non sequential) aftermarket computers wont cope with those kind of numbers.  We continue to run lean cruise in most holden v8's with durations up to about 220deg at 50 thou as a rule of thumb.  But this is only with sequential ECU's.

"Light-load cruise conditions permit the use of lean AFR's. Ratio's of 15-16:1 can be used in engines with standard cams, while engines with hot cams will require a richer 14:1 AFR. If a specific lean cruise function is available, air fuel ratio's of 17:1 or 17.5:1 can be used, normally at standard light-load advance. The cruise air/fuel ratio can be leaned out until exhaust gas temperature becomes excessive for these conditions eg. 600+ degrees C" =)

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Don't even try to run it on the stock ECU if you're going to have the boost controller bring boost above ~10 psi. I've already told you that. If you use the Nistune ECU, you will need to CAREFULLY read the available documentation for Neo tuning, and read some threads on the Nistune forums, to discover the various things you have to do to prevent the ECU from going bananas when the boost is too high. The is a table associated with th boost sensor that must be modified to prevent it from shitting the bed. This is just one of the things that you will need to do to the tune in Nistune, because the Neo turbo ECU will be expecting to see a number of things (such as the TCS) that are not there, and you have to block the DTCs on those. It is totally not surprising to me that you are having the problems that you are, but the solutions to these problems have been known for >15 years. So just get it done.
    • Hi. Sry iam not a mechanic and iam not at the car atm so i dont know 100% but they told they measure those and even try to change those. AFM they have two. Coils are new a they have my old one too. Plugs too. ECU...we have 25 NEO stock and Nistune 25 NEO.   But i dont know if any one those could be the problem and why/if/what can cause this, Only thing they did not check is fuel...but that walbro 255 is new(like 1,5 years)... That fuel pressure gauge idk...but i let them know Any suggestions?   EDIT: how can they know if it is like you say he ECU pull power when it reaches a specific boost level that is too high? Tha car has boost controler
    • Can you clarify what you mean by boost cut, do you mean it misfires both when under load (driving) and when stationary and out of gear? Or does the ECU pull power when it reaches a specific boost level that is too high (boost control issue)? Does it occur at idle with no throttle? When you say "the ECU is OK", what ECU is it and why do you think it is OK? Have you used the NEO ECU, and if so do you have a MAP sensor attached? Same for the AFM, why do you think it is OK? Do you have any way to put a fuel pressure gauge on it (even just a mechanical one between the fuel filter and fuel rail)?
    • Hi.. Just another problem. So maybe you can help. I(my mechanic) done swap from my RB20DE NEO to RB25DET NEO. Everything is OK but we have a boost cut. Coils/Plugs are ok...AFM is ok. ECU is ok. I have Walbro 255 but it "changed" sound few months ago(you can hear it ouside) you did not hear that when it was new(maybe faulty?) Sooo...what now? What can cause this boost cut? It is even when you standing still...
×
×
  • Create New...