I'm planning to use an SAFC2 on my planned Millenia SC'd '86 Sport NA. The intention is to use 550 primaries, 680 secondaries, An FD fuel pump and a rising rate FPR set at +6lb/1lb boost. In researching the SAFC I ran accross the problem of the S4 having a short range TPS. I'd like to have a more accurate fuel correction map on hi throttle based on boost but the NA press. sensor only reads up to atmospheric.

Will the SAFC read after market boost sensors that have a range beyond the 0-5v range? Can I use the TII pressure sensor on the NA harness or will that wig out the NA ecu? I was thinking of using one if it would work.

Another question is whether the SAFC would get confused by the fuel pressure changing according to boost pressure with the rising rate FPR? Will be tuning w/ a wideband also, if it helps answer this question. Will the SAFC constantly correct between LO throttle and HI?

 

https://www.rx7club.com/showthread.php?t=539191..maybe PM this guy?..looks a bit familiar to what you may be doin(?)

 

A turbo boosts kinda when it wants to, so shifting from low to high map is best with boost.
However a supercharger is way more linear with throttle, so the short range TPS should work nicely for you.
You can do the main tuning with the RRFPR, then just tweak it with the S-AFC.
That combination should work great.

 

Sorry, I didn't mention in the orig. post that I intend to use an electrically activated vac valve to control a bypass valve so that I can actually run off-boost when I want and turn it on when I need it. With the SC bypassed it will still probably boost a couple of lbs. maybe 2-3 max. That's one of the reasons also that I want to have the SAFC control lo/hi throttle of a boost sensor instead of the TPS. Will that work this way or will it screw up the AFR correction?

I also was planning to use a manual boost control to fine tune the RRFPR. Bleed off boost pressure going to the FPR to lean out and allow full boost pressure to FPR to enrich, All this done in the cockpit. Any experience with these ? Any suggestions on which MBC would be best suited for this application?

 

your bypass valve idea WONT work .... but the rest seems to be right on good luck

 

The only way I have heard to make a SC selectable is to use a clutch on the drive pulley and a big flapper check valve in the bypass intake pipe.

Most run the SC full time.
Once you drive with a SC, it's REALLY HARD going back to NA.

Getting the S-AFC's THR input from a seperate 2 bar pressure sensor will work.

 

Thanks for the input. Will inform you of the results. Please standby.

 

Has anyone tried to use the TII map sensor on the S4 NA ecu? I'm thinking of using this for my sensor where I might retain the stock sensor for the ecu and run the TII sensor in parallel w/ the signal going into the SAFC for this application.