There is been a lot af talking about the S-AFC lately so I got interested in this cool device and did some searching on the Web. I found out that I don't really need one because I have an allmost stock NA, but it would be nice to have one. My car is running rather rich so I could improve gasmilage with such a device, and the blue screen looks really impressive in the car.

I also need some way to open my sixth ports because I don't have cats anymore (my car is s4), I've got a straight pipe from the (stock) header to the Y-pipe. So I was thinking about a RPM-switch and a 12V compressor (like for an aftermarket horn if I can find one that makes enough pressure, or I might use the airpump and an airswitch) to operate the ports. ( the ports are wired open now, but this doesn't really help in improving gasmilage at all)

When I was checking the parts-trader website I did not find many S-AFC but a lot of V-AFC's. These are especcialy for honda vtec engines. It has an extra feature for engaging and disengaging the vtec system (at different RPM's, so 4000rpm for engaging (when revving up) and disengaging at 3500rpm (when revving down) belongs to the possibilities). If its possible to modify the wire harness of such a V-AFC, put it in a N/A FC, and get the vtec signal to a relais that switch on and off a compressor (or a switch that opens a hose coming from the airpump) to open the ports we would also be able to program the ports from inside the car.

Is this done before? Would it work? Would it be worth it?

Marco.

ps. I live in europe ( gas is $4 a gallon) so gasmilage is an important isue for me, and I usually get about 180-200 miles a tank (I do have a very heavy right foot) so gasmilage ( and maybe the right foot ) really has to improve.

 

Sounds like a sound idea. But unless you are going to use a different opening and closing RPM you might as well use the signal from the ECU. I'm not sure if a series 4 even uses the ECU to control the ports but I would guess they do.

But if you use the vtec version you could put one of those vtec sticker on your car. And that alone is worth well over double what the fuel controller is worth.

 

One major problem with the V-AFC - it will ONLY work with Honda MAP sensors. It doesn't let you select other airflow meters, which would be necessary to make it work on an RX-7. I've researched this myself, since that would be a killer way to switch the 6 ports.

So, you're stuck with the Super-AFC .

 

Hmm, to bad. Actually it sucks, because I think there is a fair chance that the S-AFC and V-AFC only differ in software. Well... I think I'll just go for the rpm-activated switch then. The S-AFC will have to wait for some time, it's to expensive just to be used for it's looks.

Marco.

 

Marco:

The V-AFC isn't the only fuel/VTEC controller out there! Here is another very popular unit from Field. It actually has adjustable dip switches on the back of the unit, allowing you to set the unit for various cars.




I toyed with the idea of using the VTEC controller portion to control the VDI [series 5 car] - using the theory you discussed. I actually have one of these Field units sitting on my shelf. Looks like my 7 will be sold before I get a chance to complete the project.


More on using a Field AFC unit in an RX-7: