Okay. Rebuild is done. Everything's running good, but now I think I want to start tuning the fuel system somewhat. What exactly do I need? I'm going to make one of Corbin's A/F gauges, but I think I will also need some type of FPR to adjust the pressure. Is that all I need for basic tuning? Would it be better to just get the S-AFC? What about the AFX ECU? All of these modify the A/F, but if I plan on going with that ECu in the future, isn't the S-AFC kind of redundant since the ECU leans things out anyway? Please educate me.
#57010, "RE: NA fuel tuning questions" In response to Reply # 1
I don't see why you wouldn't be able to, you would still just be modifying the o2 readings. Might even be able to get more drastic results because of the AFX ECU's timing advance. But I couldn't tell ya for sure.
--Alpine 7893 Head Unit --2 Alpine MRD-M500s --2 Alpine Type R 12s --2 Pair Type R Coaxials ^^^Mobile Earthquake^^^
#57011, "RE: NA fuel tuning questions" In response to Reply # 0
>What about the AFX >ECU? All of these modify the A/F, but if I plan on going with >that ECu in the future, isn't the S-AFC kind of redundant >since the ECU leans things out anyway? Please educate me. > >
you're probably gonna wanna stay away from the AFX ECU because since it does advance timing and all types of good stuff, it isn't exactly ideal for boost. advanced timing makes the cylinders more likely to detonate so you have to be real careful with that.
#57058, "RE: NA fuel tuning questions" In response to Reply # 3
Since he just did a higher compression rebuild, lets tune that before we worry about boost.
The adjustable FPR with new lines/filter, will allow you to set idle fuel pressure. If you have a ported/polished head the vacuum reading may not allow for much variation in FPR, ask Thura (Avenger). I still say to have some adjustability of your exact set up keep the S-AFC. I would be toast without it. My car would not idle. The AFX ECU is much more acceptable of mods, so you start off from a better place, but I like being able to fine tune to each individual car.
as for tuning, an Air-fuel gauge and EGT are great gauges, poplus a datalogger would be a help.
15.9 @ 86.7mph
Smooth idle? We don't need no stinking smooth idle.
#57066, "RE: NA fuel tuning questions" In response to Reply # 4 Aug-12-03 04:52 PM by Avenger
Actually my idle FP woes came with the cams. Too much overlap lead to very little vacuum at idle ... actually just about the same amount of vacuum that I get at WOT. Well this leads to my idle FP being the same as my WOT FP because FP is set from vacuum. So I have to set the FP to what I really want at WOT and then use the AFC to lean it out at idle so I'm not drowning the car with fuel. Michael has the same problem as mine too ... he just doesn't know it yet.
To address your questions, you don't need an adjustable FP Regulator yet. If you did you would have to run a return line since it looks like your car is either 97 or 98 Talon so it uses the "returnless" fuel system. Also either a different fuel rail or modfiy your current one to get a return line off your existing rail.
I would get an S-AFC first but at the same time get a digital A/F gauge. This will allow you to fine tune your fuel curve according to your o2 voltage. Just remember it's not completely accurate but it's a good general tool for tuning.
The AFX ECU is a great mod. You can't tune the ECU itself (nothing actually program the ECU itself) but it comes with a much more aggressive fuel map and ignition timing. Very nice for N/A. If you boost on it be on top of your game in terms of tuning. The aggressive nature leads to predetonation if you don't realize it's not acting like a stock ECU.
The AFC and the ECU are not redundant. Remember that the AFX ECU just comes with a more aggressive cureve. You wouldn't be able to fine tune any more with that. Add the AFC and you can do a little more. If you're running the AFX ECU and stock cams you shouldn't have any problems with not having enough fuel. The stock fuel injectors are plenty unless you are throwing on bigger injectors so you have to lean out the fuel curve on the AFC some more thus getting a few more degrees of timing advance. If you plan on staying NA get cams and cam gears. They yield very impressive results and with the setup that you look to be having sounds like a good NA beast.
#57135, "RE: NA fuel tuning questions" In response to Reply # 5
>Actually my idle FP woes came with the cams. Too much >overlap lead to very little vacuum at idle ... actually just >about the same amount of vacuum that I get at WOT. Well this >leads to my idle FP being the same as my WOT FP because FP is >set from vacuum. So I have to set the FP to what I really >want at WOT and then use the AFC to lean it out at idle so I'm >not drowning the car with fuel. Michael has the same problem >as mine too ... he just doesn't know it yet.
Out of site out of mind, brother.
Yeah I know the car has vacuum issues... as well as several other, all of which need to be fixed by winter, or emissions testing will be interesting. I'll address any FPR issues once I have one... of course that may be once I have another toy on the car to screw things up even further...
>To address your questions, you don't need an adjustable FP >Regulator yet. If you did you would have to run a return line >since it looks like your car is either 97 or 98 Talon so it >uses the "returnless" fuel system. Also either a different >fuel rail or modfiy your current one to get a return line off >your existing rail. > >I would get an S-AFC first but at the same time get a digital >A/F gauge. This will allow you to fine tune your fuel curve >according to your o2 voltage. Just remember it's not >completely accurate but it's a good general tool for tuning. > >The AFX ECU is a great mod. You can't tune the ECU itself >(nothing actually program the ECU itself) but it comes with a >much more aggressive fuel map and ignition timing. Very nice >for N/A. If you boost on it be on top of your game in terms >of tuning. The aggressive nature leads to predetonation if >you don't realize it's not acting like a stock ECU. > >The AFC and the ECU are not redundant. Remember that the AFX >ECU just comes with a more aggressive cureve. You wouldn't be >able to fine tune any more with that. Add the AFC and you can >do a little more. If you're running the AFX ECU and stock >cams you shouldn't have any problems with not having enough >fuel. The stock fuel injectors are plenty unless you are >throwing on bigger injectors so you have to lean out the fuel >curve on the AFC some more thus getting a few more degrees of >timing advance. If you plan on staying NA get cams and cam >gears. They yield very impressive results and with the setup >that you look to be having sounds like a good NA beast.
No need to comment on the above, all very well said.
Thura... love the new garage ornament sig!
15.9 @ 86.7mph
Smooth idle? We don't need no stinking smooth idle.
#57164, "RE: NA fuel tuning questions" In response to Reply # 6
Thanks guys!
I'm not planning on any boost for many years at this point. I think I will see if the wife will let me get that ECU and some head work. Like I said, I plan on making one of Corbin's A/F gauges here in the near future. So I think I'm trying to decide whether 'tis better to go A/F + EGT + ECU or A/F + EGT + AFC. I still need the most power ("bang" is not a good idea here ) for my buck.
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) for my buck.