1jz fuel cut defender

[pete05]

ahh well i got one on the way now, is it worth putting a safc on a 1j?

[Officer Doofy]

Sure if you want to extract every bit of power out of it and know that its safe
You dont have to but it is piece of mind

A safc should raise the boost cut so you might not need the fcd too

[pete05]

safc trims fuel mix doesnt it?

[Xistant]

safc trims fuel mix doesnt it?

i suggest you read up on google what a SAFC does

saves getting neg'd for such a silly question

[Officer Doofy]

yeah its a air fuel controller
so as it trims fuel it can raise the fuel cut
I have a good write up on the jaycar version that i can email too you if you want
Or you could just go down to jaycar and buy their kit book with lots of goodies in it

[pete05]

yeah throw me an email on it if thats ok, just thinking i might be able to clean up the fuel econony a little bit

[Officer Doofy]

My bad pete i got confused
safc is a afm controller
Hit me up with your email via pm and i'll forward the jaycar one on to you to have a read

[pete05]

pm sent on email

[The Witzl]

Doofy,

you are referring to the Jaycar digital duel adjuster arent you?
I am referring to the NEW kit - which is a $20 fuel cut defender, KC5439

http://www.jaycar.com.au/productView.asp?ID=KC5439

[Officer Doofy]

Yeah Karl thats the one
Pete already has a fcd on the way
He is now looking at fuel adjusters

The new jaycar fcd looks the goods though
Even though the clamp voltage is not adjustable 3.9 volts will be fine for the 1j
Im sure you will start to sell heaps of these!

[chris davey]

don't get a safc yet. Get the FCD installed. Clamp at 3.8v. Go to dyno and check AFR's. If too rich clamp it a tiny bit lower like 3.75.

Think of it this way. Your ecu knows how much vacuum or boost the engine has by getting its signals from the map sensor. The map sensor reads from 0-5v. 5v being the highest amount of boost it can read to. (search this if you want more info)

So when you install a FCD you are effectively clamping the voltage that the ecu sees and therefore tricking it into thinking you are running less boost. What this will do is decrease the amount of fuel injected and also run more timing. If it ran too much timing, the knock sensors would detect it and retard timing to keep your engine alive.

So adjust FCD and aim for 12.0:1 AFR's. If you can get that then IMO you do not need a SAFC or Jaycar DFA.

[Wildsupra]

With a GREDDY FCD and stock computer with a few mods i managed to pull 297hp on 13.5psi, the reason for the FCD was due to the odd boost spike here and there and extra cold weather would cause it to hit fuel cut as well. At 13.5 psi the ratios where around 12:1 and at 15.5psi when i later dynoed it, it was 12.8:1

So 1psi over fuel cut was no real drama although it is getting a bit close to "un safe" ratios you might say.

[pete05]

Thanks for all he replies guys i have my hks fcd on the way so i will have a play with it when it comes in

[Ribfeast]

HKS FCD on setting 8 (around 4 volts) got me around 330hp atw @ 18psi. You could lean it out slightly more if you are running lower boost (eg 13-14psi), so maybe put it to around 3.7-3.9V. Not sure what setting number this is on the FCD though.

So basically the HKS FCD acts as a blanket SAFC/fuel computer, no individual adjustability for various rev points. Does the job nicely though

[Danners]

I have a genuine HKS FCD for sale if interested. It is the standard type