ROSHX7

Just wondering, but there are a lot of Fuel Cut Defencers out there. Racing Beat got one, JET does and also HKS I think. But is one better then the OTHER or do they all do the same thing and are all equally effective and reliable? If money wasn't an ISSUE, which FCD would you guys MOST RECOMMEND?

Erik

i'm not sure if one is better over the other...but i think the racing beat might be easier to install. doesn't that just plug into the boost sensor on the strut tower? i think the HKS one is not specified for the FC so you would have to splice into the ECU or something to hook it up. but thats just from what i've heard

13BAce

I've heard that the HKS FCD lets the ECU see the correct amount of boost until fuel cut is seen, but the RB FCD changes the amount of boost seen constantly.

ROSHX7

I'm concerned cause I got the Racing beat one right now. So your saying that the RB one, doesn't even let the ECU know your running 5psi to 8.5psi? Cause all the FCD do is tell the ECU once your over 8.5psi, that its STILL 8.5psi right? So is the RB a more dangerous FCD to have?

Chris Ng

Your bosot sensor will read well past 8 psi.. voltage will go from 0 to 5 volts.. the ECU cuts fuel at 3.8 volts (aprox) which translates to aprox 8 .5 psi (or there abouts)..

The HKS unit gets around this by lowering the voltage seen by the ECU throughout the entire range of the pressure sensor signal..

The RB unit is a clamp style FCD .. it lets the ECU see the correct voltage right until it hits 3.5 volts .. at that point it clamps the voltage.. the ECU will never see beyond 3.5V

If you really wanted to, you could calibrate the RB unit by taking the cover off and finding a poteniometer in it that you can adjust a tiny bit.. that way you can increase the clamp voltage from 3.5 to about 3.7V .. this allows the ECU to read correct just up to the point of fuel cut..

13BAce

I had always thought that the RB FCD was the one that lowered the voltage the whole time.

13BAce

The ECU doesn't rely solely on the pressure sensor. The air flow meter is more important. My brother's car came with the RB FCD and the RB turbo back exhaust with a cat replacing the presilencer, and it runs ok.

Chris Ng

13bAce: I've compared the output of the RB signal from the stock signal using a voltage meter and a handpump and found that the RB FCD was of the voltage clamp variety.. mind you, I couldn't tell you if they changed things around over the years of selling these things..

13BAce

Ok, thanks Chirs. I'll try it. I once had a shop tell me the information I had. They may have just been trying to sell me on the HKS FCD.