!

My question is about fueling. I want to richen the AF mixture and am thinking about the Apexi S AFC. My current car is running 14 psi boost. The ECU was cutting fuel/ignition when the boost went too high, as you already know. I have temporarily remedied the cut by using an HKS FCD, but I want to keep the AF mix rich enough etc.


My questions are :

1.With an Autometer AF gauge, what readings should I have? ( I am getting about half way with WOT)
2.Will the S AFC unit enable me to stop the stock fuel cut off due to high boost AND increase the fuel air ratio or does it just increase the MAP sensor reading into the ECU.?


I have asked question 2 because I have seen some units which richen fuel by increasing the pressure signal from the MAP sensor.

a. I thought the stock ECU had RPM based fuelling curves. i.e. A system which just modifies the MAP sensor signal would not affect fueling.
b. By increasing this reading, wouldn't the the stock ECU think boost was higher, and hence cut ignition?



I hope I have made some sort of sense!!



Thank you

Trevor Lam
1994 Black Type R2.

 

Don't put too much faith in to the autometer gauge. It really just tells you your O2 sensor voltage. And they are very easy to get an incorrect reading, by simply having the power wire tapped in to the wrong source.

You'll get different #'s depending on where you get your power source inside your car.

 

You're lucky you haven't blown a motor. You can pick up a used Pettit ecu for $400 and be pretty safe up to 13 psi or so. Above that, you really should have larger injectors and fuel pump -- which require a stand-alone ecu such as the PFC.

The fuel-cut defenser is a very bad idea for an FD, and so is the S-AFC.

EDIT: Also, as the previous poster pointed out, the A/F gauge you have is next to worthless. You cannot use it for tuning. You need a wideband o2 sensor, either your own, or the one at a dyno, to tune.

 

Fuel maps are all 3D.&nbsp They are based on both RPM and "load".&nbsp Your map sensor is your load sensor.


It depends on your FCD design.&nbsp Most modern FCD designs are voltage clamps which prevent it triggering under any circumstances.


-Ted

 

I second that. The SAFC doesn't work well, if any, with the FDs but it seem to work with other vehicles. Please do not waste your hard earned money on this device. The Pettit ecu is pretty much the best bang for the buck depending on your set up.

 

Hi,

thanks guys for your info. I will wind down the boost until I get hold of either a Power FC or a pettit ECU. In fact, since I posted the first message I broke 2 apex seals anyway. Rebuild is in progress....

Now I got 2 questions...:

I bought apex seals for my first rebuild which was about 2 months ago. They were 1 piece items which seemed strange to me because I thought they should be in 3 pieces. Now inspecting them, they fractured along the line where usually the 2 long pieces meet. I will have a picture of this on Monday because my explanation is not clear.
Do you think the break is due to this being a bad/poor quality apex seal, or more likely due to detonation.


Secondly,

So far, I have a downpipe, decat, free flow back box, cold air induction kit. Hopefully an intercooler soon.
ECU wise what should I do, considering the following points..

I am in Mauritius where we have no Dynos
The limit of my mods should be the above.

Will I be able to make use of the PowerFC if I have no Dyno facilities available? And can I use something like a GTechPro unit to try anything (I know, it's a bad way to go but have not got much choice.. :-) )

Or can I get a pettit ECU and be pretty safe. And how far can I go mod wise if I change my mind..?


Also off the subject ... With my set up, what BHP should I be expecting??


Thanks again.
Trevor

 

Even though there are no dyno facilities nearby, do you at least have people you can talk to that can tune a Power FC really really good?

Even with no dyno facility you still have hope. You could probably get a wideband O2 and the FC datalogit program. Then you can just load up your maps and do your tuning on the road. Now the only thing holding you back is how well the you can tune the PFC. In otherwords, you should find someone who knows how to tune, or you yourself need to learn how to tune very very well.

 

No we don't have any dyno facilities here in Mauritius. Also, I think the most knowledgable guy here in respect mapping would be the local superchips dealer. I know him well, and he doesn't have a wideband O2 meter.

Soo... I think the route I will take is to buy a Wideband sensor and meter. I have read somewhere that the signal sent is 5Hz and needs something clever to sample the data. Whatever.... Can anyone recommend something sensible for me to start with.


And also, is it something I fit permanently to the car, of have it clamped to my exhaust (inside the tip) during test runs. i ask this because I have read somewhere that the lifetime of the sensors is quite short.

The sensor I have come up with is L1H1 NTK. Am I on the right track?

 

robvas

Re: How to increase fueling? Not with SAFC i think?
Don't put too much faith in to the autometer gauge. It really just tells you your O2 sensor voltage. And they are very easy to get an incorrect reading, by simply having the power wire tapped in to the wrong source.

You'll get different #'s depending on where you get your power source inside your car.

so where should u get your power source from ?

 

you should open your own dyno but if u cant..wheres the nearest one to you?

 

check out the innovate motorsports wideband meter..... http://www.innovatemotorsports.com/lm1.php