S-AFC question w/ JRSC
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Honda-Tech Member
Joined: Jun 2004
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From: Dont Steal My Car, Ct, USA
all right, i was thinking, when u turbo a honda the Map sensor detects boost, when the motor is NA then it detects little or no vacuum at WOT, my question is when u are running a JRSC and the map is on the TB, then at WOT it will be detecting alot of vacuum because its getting sucked through, or am i wrong and its the same theory as being NA?
What has to be done to compensate for this, changing the map to the manifold or different afc settings or what?
What has to be done to compensate for this, changing the map to the manifold or different afc settings or what?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93supercoupe »</TD></TR><TR><TD CLASS="quote"> its the same theory as being NA?
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its the same as NA. Depending on what you are trying to do with the S-AFC would dictate where the MAP sensor needs to read pressure from. If you are running FMU with stock inj. I'd say leave the MAP sensor on the TB. If you are running the "HACK", than I believe you'd relocate the MAP sensor to the intake manifold to read boost. I'd check on this since I've never installed the "HACK" or have any personal experience with that setup.
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its the same as NA. Depending on what you are trying to do with the S-AFC would dictate where the MAP sensor needs to read pressure from. If you are running FMU with stock inj. I'd say leave the MAP sensor on the TB. If you are running the "HACK", than I believe you'd relocate the MAP sensor to the intake manifold to read boost. I'd check on this since I've never installed the "HACK" or have any personal experience with that setup.
Well, the SAFC is different in your setup for two reasons:
1) Like you said, the MAP sensor is not sensing boost. You don't have to worry about oversignaling, and you can still use the "hack" to run larger injectors. The difference in this case is you want to run the absolute smallest injectors you can get that will supply enough fuel, to avoid ignition advance as much as possible.
2) Unlike a turbo, the supercharger's boost output is basically RPM-dependant. The SAFC is also RPM-dependant, so it should be possible to tune a proper AFR in all throttle/rpm situations.
I would think, that since the boost ouput is a function of RPM with a supercharger, you should be able to use nothing more than the SAFC and a BTM to get fuel and ignition timing spot on. This still isn't as good as a standalone system, because fine-tuning is impossible, but it should be safe enough.
1) Like you said, the MAP sensor is not sensing boost. You don't have to worry about oversignaling, and you can still use the "hack" to run larger injectors. The difference in this case is you want to run the absolute smallest injectors you can get that will supply enough fuel, to avoid ignition advance as much as possible.
2) Unlike a turbo, the supercharger's boost output is basically RPM-dependant. The SAFC is also RPM-dependant, so it should be possible to tune a proper AFR in all throttle/rpm situations.
I would think, that since the boost ouput is a function of RPM with a supercharger, you should be able to use nothing more than the SAFC and a BTM to get fuel and ignition timing spot on. This still isn't as good as a standalone system, because fine-tuning is impossible, but it should be safe enough.
Thread Starter
Honda-Tech Member
Joined: Jun 2004
Posts: 2,852
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From: Dont Steal My Car, Ct, USA
I would think, that since the boost ouput is a function of RPM with a supercharger, you should be able to use nothing more than the SAFC and a BTM to get fuel and ignition timing spot on. This still isn't as good as a standalone system, because fine-tuning is impossible, but it should be safe enough.[/QUOTE]
Thats exactly what ive been trying to ask people, but all they say on this site is "You need hondata or uberdata", which is BS.
I dont understand what u meant by runing the smallest injectors possible, i dont see the advantage of this.Can u explain?
Thats exactly what ive been trying to ask people, but all they say on this site is "You need hondata or uberdata", which is BS.
I dont understand what u meant by runing the smallest injectors possible, i dont see the advantage of this.Can u explain?
well you don't NEED Hondata or UD, just that they could do a better job compared to FMU+S-AFC+BTM... I ran a modest 6psi JRSC FMU for a few years and it ran great with a nearly perfect A/F putting out 209 whp.
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