It really sux! Our cars are designed around a throttle possition sensor which opens to the max at a partial throttle. This causes the SAFC to see full throttle at only about 1/3 throttle by my foot. Of corse this will cause problems with tuning the safc around partial/mid throttle.

What if we grab say a simply tps out of any kind of car from a junk yard (or buy a cheap tps) and rig it onto the throttlebody. Then use the ECU's stock 5v power signal, ground, +12v to wire the new TPS, then take the sensor lead from the TPS (1v to 5v variable) and wire it directly to the Apexi SAFC. This would ideally make tuning much easier and efficient.

 

Yup- Or you can get a TPS from an S5!

It has 2 plungers- a full range and a narrow range- the S4 just has the narrow range.

You will have to cut the plug off, and use the s4 plug, wired into the narrow range plunger (just like the stock TPS on S4's)

The full range is used for the OMP on S5's.
Just take the signal from that (which the s4 ECU doesn't need)and send it to the S-AFC.

I don't know if the TPS will bolt dierctly on, but it'll be closer than any other car's setup I'm sure.

 

Finding an S5 in a junk yard is like finding your dick after you swim in the ocean.

 

So true. I have seen one and went back 4 days later to get something and half of the car was gone.

 

THe throttle linkages on an S5 TB are diffrent then on an S4, you will need to swap out the whole linkage (or TB) inorder to make the TPS work correctly...

Here's an even easier method.. If you search the fourms, I'm sure you can find alot of information I posted up some time ago about using the boost sensor output rather then the TPS output for your s-afc.. using this method you will get boost dependant fueling (more or less).. THe only change I would make from my original method, is to tie into the boost sensor line before the FCD (I tied into it at the ecu, which is after the fcd).. this will give you a bit more resolution to play around with (Other wise you'll read 100% boost/throttle at aprox 6 psi)..

 

I don't know why you'd bother hooking your S-AFC to the TPS in the first place. Manifold pressure is a much more accurate measure of engine load than throttle position.