OK correct me if I'm wrong, The purpose of a fuel cut defenser is to Trick the ECU Into thinking your boosting less then you really are to prevent the rear rotor fuel cut (which is bad for engines). From what I've been reading the ECU cuts fuel at around 8 psi, and something like 3.5v at the boost sensor. The FCD acts like a filter between the boost sensor and the ECU , removing any voltage above the 3.5v....This is where I get confused. once the maximum allowable boost is reached and the FCD levels off to around 3.5 volts. The ECU is only seeing 8 psi of boost, and as the boost continues to rise the ECU starts undercompensating for the higher boost levels, eventually leading to another lean condition....with out compensating with some sort of stand alone fuel controller, it just doesn't make any sense to me. It's like blindfolding yourself and trying to pase someone on the freeway. even if it prevents the complete fuel cut off causing an extrem lean condition, it seams like it would put extra wear and tear on your engine running at a slightly lean condition.

 

yup, youre exactly right. at over ~ 10 psi, an FCD is an accident waiting to happen unless you have some type of fuel compensation. The idea is to run an FCD and an SAFC or something similar, to allow for more fuel at higher boost levels.

pat

 

for the price of an fcd almost you can get an rtek chip that acts as an fcd but also retards timing up to 14 or 15psi. it also turns 2nd fuel injector cut on to 3500 rpm instead of 3800. This along side an safc is a very safe way to boost past 10psi.

 

When using an FCD with an SAFC tied to boost instead of throttle, you also need to tap the SAFC input wire to the boost sensor wire BEFORE the signal gets to the FCD.. or the SAFC will never see higher than the cut off of the FCD....

 

http://fc3spro.com/TECH/FAQ/fuelcut.html


-Ted

 

N00b question and it wasn't in the FAQ, whats a SAFC?

 

Not too detailed, but it might help...
http://fc3spro.com/TECH/MODS/EL/FUELCON/APEXI/afc.htm


-Ted

 

a safc is an add on device that 'tricks' the stock computer into adding more or less fuel.

kinda like a programmable computer, except it goes through the stock ECU.

pat

 

Oh ok, I couldn't figure out what it was. Thanks a lot.