... vafc hack with 550's
09-10-2002, 06:19 AM
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Re: ... vafc hack with 550's (1.8T_EG)
... does anyone have the flow ratings for stock second gen rx7 injectors?... i was told that they are 550 but i am not sure... also will this work with the vafc... thanks...
09-10-2002, 08:47 AM
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Re: ... vafc hack with 550's (GraphiteAccord)
You can use 550's but it will run very rich. You'll also need an adjustable FPR to lean it out, but I'm sure it will still run very rich.
09-10-2002, 10:42 AM
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Re: ... vafc hack with 550's (1.8T_EG)
The consensus on this board seems to be a -35% cut in MAP sensor output voltage with the VAFC hack and 450cc injectors. That still leaves you with substantial room to compensate for 550cc injectors since the VAFC goes to -50%.
I' say try
(1 - 240/550) x 12.5 /14.7 = -48%
and a little less of a cut at idle (-40 to -45%)
I' say try
(1 - 240/550) x 12.5 /14.7 = -48%
and a little less of a cut at idle (-40 to -45%)
09-10-2002, 10:56 AM
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Re: ... vafc hack with 550's (filetofit)
... that is exactly what i was thinking... now, with a higher correction factor, does that allow me to run higher boost?... say in the 12-14 psi range?... also, how much will the larger injectors be a concern since they will take longer to open?... thanks...
09-10-2002, 01:52 PM
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Re: ... vafc hack with 550's (1.8T_EG)
Yes with larger injectors you should be able to run more boost.
(3.0 volts x 0.52)/15 psi = 0.104 volts per psi
2 volts / 0.104 volts per psi = 19 psi boost,
One of the downfalls of the hack though is it leaves the issue of boost timing retard unaddressed. Since you'll be using stock timing, at high boost you'll be running a lot of advance. You need some way of dialing out the advance.
You'll need to use a smaller cut in MAP voltage at idle to compensate for the larger injectors opening time. Hondata recommends adding back 30% pulsewidth at idle after applying the injector multiplier. Hard to say what that corresponds to in terms of MAP voltage cut.
http://www.hondata.com/techinjectorsizing.html
(3.0 volts x 0.52)/15 psi = 0.104 volts per psi
2 volts / 0.104 volts per psi = 19 psi boost,
One of the downfalls of the hack though is it leaves the issue of boost timing retard unaddressed. Since you'll be using stock timing, at high boost you'll be running a lot of advance. You need some way of dialing out the advance.
You'll need to use a smaller cut in MAP voltage at idle to compensate for the larger injectors opening time. Hondata recommends adding back 30% pulsewidth at idle after applying the injector multiplier. Hard to say what that corresponds to in terms of MAP voltage cut.
http://www.hondata.com/techinjectorsizing.html
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09-10-2002, 02:45 PM
#8
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Re: ... vafc hack with 550's (filetofit)
Yes with larger injectors you should be able to run more boost.
(3.0 volts x 0.52)/15 psi = 0.104 volts per psi
2 volts / 0.104 volts per psi = 19 psi boost,
One of the downfalls of the hack though is it leaves the issue of boost timing retard unaddressed. Since you'll be using stock timing, at high boost you'll be running a lot of advance. You need some way of dialing out the advance.
You'll need to use a smaller cut in MAP voltage at idle to compensate for the larger injectors opening time. Hondata recommends adding back 30% pulsewidth at idle after applying the injector multiplier. Hard to say what that corresponds to in terms of MAP voltage cut.
(3.0 volts x 0.52)/15 psi = 0.104 volts per psi
2 volts / 0.104 volts per psi = 19 psi boost,
One of the downfalls of the hack though is it leaves the issue of boost timing retard unaddressed. Since you'll be using stock timing, at high boost you'll be running a lot of advance. You need some way of dialing out the advance.
You'll need to use a smaller cut in MAP voltage at idle to compensate for the larger injectors opening time. Hondata recommends adding back 30% pulsewidth at idle after applying the injector multiplier. Hard to say what that corresponds to in terms of MAP voltage cut.
Full timing at high boost baby.I was playing around with my car..i turned up the fuel pressure, and down the afc to -45%. The car ran awesome in boost..but idling and normal driving was pretty ruff. It did work though. I lowed the fuel pressure back down and have my afc at -40% and it works much better. My idle is set at -30%.
liam
09-10-2002, 02:59 PM
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Re: ... vafc hack with 550's (liam821)
well i have been running the hack since may when i put my turbo in and it seems to work ok but it isnt good past 7-8 psi on my car. granted im runnig a b16 so it will require more fuel but i am using an fmu with an 8:1 in it. i have my lowest setting at -35% and my max is -32%. i tried to run 10 psi but it leaned out and started poping. i do have an msd 6btm set at .5 degrees retarded so i dont think it was the timing but i do know that it leaned out so im going to fix that by running my check valves and set the fuel at -25% or somewere in that range. the hack is an awsome idea in it works great i have used it all summer with little problem and all my friends are shocked at how it works ...i love when someone with a 92 and up civic or 94 and up integra asks me if they can run it to and i tell em no ... then i tell them to get the resistor pack nd they say o hell no..at least us old school guys have something that the newer cars dont have without alot of work. 
09-16-2002, 12:22 PM
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Re: ... vafc hack with 550's (turboedef9)
The idea of the AFC hack is that you don't need an FMU. If I understand you you are using big injectors, an AFC and an 8:1 FMU. So first you'd need a massive fuel pump for that....high pressure and high volume. If you have a good pump, and you're using it like you say, you are probably running WAY rich. I don't know the full details of your setup but it sounds like you'd be running rich rather than lean.
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