safcII
 

hi,

has anyone on this forum ever put an safc2 on their car to tune it? i have a 91 miata with a diy turbo kit. i have a apexi safc2 installed on my car. for those who know manual miata tps reads either 5 or zero volts, so its more like a switch, the safc needs to read different voltage per thorttle postion. so first i tried the gm 3bar map sensor (tricking the afc into thinking it was a tps i read about this online and i couldnt get the afc to read with any of the seven gm 3 bar map sensors). so i gave up on the map sensor thing and someone who had a turbo miata with safc told me to get an automatic throttle body, which i had been speculating about since i saw in my book (and on a friends automatic miata) that the automatic tps was a real tps and read different voltage per throttle position. so i got one and put it on my car and when the car is off it changes voltage when i change throttle positions. GREAT!..... BUT! now it says on the afc that its only at 38 percent (read from zero to almost 2 volts, but my book says it reads from 0-4) when fully depressed and when i start the car with my standalone tps (power, ground, signal wire to afc) it wont let you rev the motor over 2500 rpms it and acts like its bouncing the rev limiter? is this an issue with the safc? do i need to go in the afc and select a different sensor type, or is my tps bad? im gonna try my friends later which i know works. thanks if you can help.

~mike

I've never installed one on a miata, however I did install one on my FC rx7 which had a diy turbo +afc on it. The thing is that with the afc, tuning boost in a non oem boosted car based on throttle position is really quite useless as throttle position is a piss poor indicator of engine load ( Notice how when you go up a hill you build boost sometimes? Did the throttle position actually change?...nope). I've never heard of someone using a gm sensor, everyone always recommended the mpx4250, which ( awesomely ) is standard equipment for megasquirts. You can pick one up (here) and the datasheet for it is (here). I'd really REALLY recommend trying this first before you try to tune the car with an auto throttle body.

i really appreciate the help, i think im going to try that since i dont exactly know how to get this throttle body to work the right way. one question though, is that the sensor you used on the rx7, do rx7s have the same type of tps that miata has that does not read in variation? really appreciate the help, im considering just getting megasquirt now instead of waiting till later.

My rx7 was a s5 which did come with the variable tps. And yes, it was that sensor that I used, but I bought it from newark.com instead of diyautotune. I HIGHLY recommend the megasquirt over the safc-2, even for a low end setup. They cost damn near the same amount anyway, and with the Hi-res code and the mspnp maps, setting it up and getting it stock-ish drivable is almost too easy. Oh, and one more thing. Take a quick look at your keyboard. That button just down and to the left of 'a'.... thats the shift key. Please use it.

Good luck with your setup.

hey TS where are you located?

Yeah, i think that is what i'm going to do get Megasquirt. I just have to get my daily driver going, plus i can sell the Safc. Thanks a lot for your help!

TS? Thread Starter? I am in St. Pete Florida.

glad you dumped the safc over all i was disapointed with mine and i wouldn't run it on any vehicle