Apexi S-AFC and the RS DOHC

[mazda20]

Okay I have done some research and I am realizing that the throttle on these are either 0% or 100% in which case the S-AFC will not read it properly on the HW MAF Sensor. Correct?<P>Does it matter then if I change Lo Throttle Settings or Hight Throttle Settings?<P>Everytime I push on the gas the engine shuts down, is this Fuel Cut? How do I fix that?

[maldo]

I had that problem with my initial tuning. It has to do with your throttle voltage, make sure the arrow is pointing upwards. This should correct it, otherwise play with the sensor types a bit more.

[mazda20]

Okay that makes sense, but I read somewhere that if you have an On/Off type throttle which I think I do then I should set it to *** asterisk settings.

[mazda20]

Moving on up!!

[jonathanj]

i installed the afc in my car and did not have any problems at all. But maldo is right. After you get that there is a pretty simple way to tune your car. Get a EGT gauge (exaust gas temp) after it is installed you can tune the AFC with it. I use a Greddy EGT it works awsome. Now the richer a car runs the cooler an EGT reading is. The leaner the hotter. You want to try and keep your car right around 800- 850 degrees at full throttle in third gear. So if your in thrid gear under full boost and yoour EGT is reading 900 get off the gas or eventually you will have no motor. At 900 degrees in any car is when detonation starts. good luck if you have any questions e mail me. peace jon

[cjthor]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by jademx3turbo:<BR><STRONG>i installed the afc in my car and did not have any problems at all. But maldo is right. After you get that there is a pretty simple way to tune your car. Get a EGT gauge (exaust gas temp) after it is installed you can tune the AFC with it. I use a Greddy EGT it works awsome. Now the richer a car runs the cooler an EGT reading is. The leaner the hotter. You want to try and keep your car right around 800- 850 degrees at full throttle in third gear. So if your in thrid gear under full boost and yoour EGT is reading 900 get off the gas or eventually you will have no motor. At 900 degrees in any car is when detonation starts. good luck if you have any questions e mail me. peace jon</STRONG><HR></BLOCKQUOTE><BR>What year is your car? And what turbo swap did you do? If you had anything but a dohc to start off with allllll your settings are different.

[OsoSlo z28]

as far as the temp goes, it depends on where you are taking the readings. if you are taking them on one cyl or between two specific cyls, then yes, stay under 900. but if you are taking temps after the turbo(exhaust pipe) then you could see readings of around 1100 or so and still be ok.

[mazda20]

I think I might have found the problem for the most part (although I the EGT recommendation is something I will get) It seems that maybe my MAF Sensor is in the wrong place. I currently have it right before the turbo...therefore it is reading all the air going into the turbo, not necessarily all the air into the intake (hence the BOV). <P>Should I move the MAF beyond the BOV closer to the intake so it reads what is going into the intake?

[cjthor]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Kick @#$ Mazda:<BR><STRONG>I think I might have found the problem for the most part (although I the EGT recommendation is something I will get) It seems that maybe my MAF Sensor is in the wrong place. I currently have it right before the turbo...therefore it is reading all the air going into the turbo, not necessarily all the air into the intake (hence the BOV). <BR> You have the maf in the correct place.<P>Should I move the MAF beyond the BOV closer to the intake so it reads what is going into the intake?</STRONG><HR></BLOCKQUOTE>

[mazda20]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by cjthor:<BR>[QB][/QB]<HR></BLOCKQUOTE><P>I guess this means that you want to know as well, I did notice that the 323 Turbo setups from the factory have it setup with the MAF before the turbo, at least the pics that I have been able to find.<P>If anyone knows the answer to this please help us out.

[jonathanj]

To answer a few questions. I have a 94 dohc 1.6 . I custom made a turbo kit for the car. It is a t3 pushing 5psi on factory fuel system (pump and injectors). As for my egt i put it on the last cylinder to receive fuel, because if any cylinder will detonate it will be this one. Your mass air is in the right spot as well. Check this out guys i replaced my mass air meter with one from a toyota supra. It flows a lot better and is capable of receiving a higher reading than are factory peice. It plugged right in but i had to change my piping diameter. Another one that is easier to get a hold is from a toyota solara. And the HKS ssbov doesnt leak air under boost and stays closed at idle. This means that you will not get a false reading at the mass and run rich or stall. sorry it is so long but it is good info. if i left anything out let me know. peace jon

[maldo]

The FC3S MAF works well too, but again you would need a larger pipe for it to bolt up. All 323GTX motors have the MAF in from of the turbo. Reason is, the air is sucked through the MAF by the turbo, into the intake. Any air that is bypassed by the BOV is recirculated behind the MAF so it doesn't receive a false reading, if the air isn't recirculated the motor will run rich. I imagine the reason for the MAF being where it is is mainly because of packaging, no room above the valve cover. The velocity of the air after the turbo is much greater and more compressed than before the turbo. A lot of it has to do with the metering device,

[mazda20]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by maldo:<BR><STRONG>the air is sucked through the MAF by the turbo, into the intake. Any air that is bypassed by the BOV is recirculated behind the MAF so it doesn't receive a false reading, if the air isn't recirculated the motor will run rich. I imagine the reason for the MAF being where it is is mainly because of packaging, no room above the valve cover. The velocity of the air after the turbo is much greater and more compressed than before the turbo. A lot of it has to do with the metering device,</STRONG><HR></BLOCKQUOTE><P><BR>Youre the man, so I could reciculate the air that would definetly work, When you said something about the metering device what did you mean by that?<P>Do you think it would be better to mov my MAF closer to my intake and move my BOV down some or should I just recirculate the air and leave my MAF Sensor where it is?<P><BR>Also as far as a larger MAF Sensor I thought they were all the same in regards to reading the air flowing through, I mean dont they all read like 0 to 5 volts to the ecu?<p>[ June 13, 2002: Message edited by: Kick @#$ Mazda ]

[mazda20]

bump

[maldo]

The air that is beign recirculated has to reenter the intake tract after the MAF. When I was referring to the "metering device", what I meant was it depends on what you are using - hotwire or flapper design.<P>Personally, I would leave the MAF at the end of the J-pipe, recirculating your air back into the j-pipe just behind the MAF. I believe one of the Probers tried it the other way once upon a time, not sure of the results.<P>In order to work with our ecu, the MAF sensor must read the correct voltage, 0-5 volts. It must also operate in the correct direction, that being 0-5 or 5-0 on startup. This depends on the ecu, voltage can be found in the shop manual. The problem with the stock (flapper) style MAF is that it is the biggest restriction in the entire system. The stock MX-3 unit flows roughly 145cc, the manifold is capable of 165+cc of flow. To improve this, the 86-88 MAF from the RX-7 (non-turbo) will work - flow for that MAF is around 200cc.