1.8T_EG

... the concensus on h-t is that when running the hack with 450s, the max boost you can run is 11-13 psi... right?

... with 550s, the max boost you can run is about 17-19 psi... (somewhat theoretical, anyone running this setup who can speak on it?)... (see https://honda-tech.com/zerothread?id=275379)

... so what are the largest injectors that can be used with the hack?... and what is the respective highest boost you can run?... (anyone with experience?)

... below are some percentage reductions to the map sensor output according to different sized injectors (using the equation : (1 - 240/550) x 12.5 /14.7 )... notice the bottom two which cannot be used with the vafc... this leads me to my last question... is it possible to run a custom circuit and a vafc at the same time in order to used injectors larger than 550?

310 -19.2012%
390 -32.7054%
450 -39.6825%
550 -47.9283%
680 -55.0220% (cannot use with vafc - limited by -50% cut)
720 -56.6893% (cannot use with vafc - limited by -50% cut)


((just some random thoughts that popped in my head on the drive to work))

DSF

The pressure limitations are not a function of the injectors, but rather of the stock MAP sensor's physical limitations. It is possible to wire up a 2/3bar MAP, but the signal the ecu will be receiving will end up being very compressed causing possible ignition issues as well as unknown drivability problems. But no one knows for sure. Besides, anything more than 12psi should really use a standalone if a reliability is anything of an issue.

VaporTrail

exactly. One could have all the fuel in the world, and without proper ignition control (and guess what kids, a BTM isnt it!), the motor's going to blow. Fuel is only half of the equation...

filetofit

Now thats a good question, give it a try.

Actually you could just use a $2 potentiometer from Radioshack in conjunction with a VAFC to bring your max fuel cut to as high a percentage as you want. All you gotta do is get a 10K pot and wire it on the output of the VAFC and to ground then connect the wiper to your ECU input. THe ECU input resistance is about 100K so you won't have any problem with current draw away from the voltage divider.

But I don't know what the limit is as far as driveability goes to compacting the stock maps.


[Modified by filetofit, 6:57 PM 10/22/2002]

RudeLude

so has anyone used bigger than 450's without any uprobs?

kpt4321

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DSF &raquo;</TD></TR><TR><TD CLASS="quote">The pressure limitations are not a function of the injectors, but rather of the stock MAP sensor's physical limitations. It is possible to wire up a 2/3bar MAP, but the signal the ecu will be receiving will end up being very compressed causing possible ignition issues as well as unknown drivability problems. But no one knows for sure. Besides, anything more than 12psi should really use a standalone if a reliability is anything of an issue.</TD></TR></TABLE>


You're right that there are physical limitations, but that's not the only problem. There are also electronic limitations, and if you ignore them, you will get crazy CE light action.

We tried to run a 3-BAR MAP in my friend's Integra, and it wouldn't idle. I think we will try it again sometime with some new tricks, but it was useless.

RudeLude

[QUOTE=filetofit]Now thats a good question, give it a try.

Actually you could just use a $2 potentiometer from Radioshack in conjunction with a VAFC to bring your max fuel cut to as high a percentage as you want. All you gotta do is get a 10K pot and wire it on the output of the VAFC and to ground then connect the wiper to your ECU input. THe ECU input resistance is about 100K so you won't have any problem with current draw away from the voltage divider.

But I don't know what the limit is as far as driveability goes to compacting the stock maps.


tell me more about this setup. Has anyone tried this yet? if so what were the results? if this is true, would that mean that i could use the vafc to control like 72lbs injectors?

RudeLude

????

slywfbpsi

you could use the cybernation black box, and run it with the safc or vafc. They have run as big as 850cc with that setup, without changing the map sensor. The black box doesn't let the map sensor see boost until 60 psi.

RudeLude

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slywfbpsi &raquo;</TD></TR><TR><TD CLASS="quote">you could use the cybernation black box, and run it with the safc or vafc. They have run as big as 850cc with that setup, without changing the map sensor. The black box doesn't let the map sensor see boost until 60 psi.</TD></TR></TABLE>

where would i find one of the balck boxes? and how much?

20gcivic

I am using a 10k pot from radio shack and I thought I was doing something new. I have been running the set up for 6 months now. The funny thing is I am not running an afc at all. All I have is a two dollar pot intercepting the map sensor wire to the ecu. I installed dsm 450's and a resistor box and started the car. I then tuned it with my a/f gauge. I have a 99 civic dx with a homemade turbo kit. I was running 18-20 psi daily for 4 months before I melted a piston. This was on a bone stock motor with only the turbo kit and a 3000gt fuel pump on 100 octane fuel and a radio shack pot for fuel controll. I ran a 1/4 mile pass of 14.0 at 102 with no dyno time or fine tuning, full interior, stock 14 inch steelies with stock 175 tires. No traction. Again I run 18psi of boost with no map cel. I now have another stock motor in there and am running 14psi daily to keep it safe for a while. I definately think that 550's or 660's are feasible if you were to use the pot with an safc. I am actually going to be trying some 550s with an afc soon in my set up. Ill keep you posted.

slywfbpsi

http://64.207.145.150/cybernat...id=29

TurboJesse

technically you could get any size injectors to idle/run with an AFC, the amount of time spent on the dyno tuning it though would easy pay for a standalone, not to mention lack of control over ignition timing..

kpt4321

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mpir3 &raquo;</TD></TR><TR><TD CLASS="quote">technically you could get any size injectors to idle/run with an AFC</TD></TR></TABLE>


Not with just an AFC. It does not have the reduction necessary to run injectors bigger than 550 cc/min.

kpt4321

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 20gcivic &raquo;</TD></TR><TR><TD CLASS="quote">I am using a 10k pot from radio shack and I thought I was doing something new. I have been running the set up for 6 months now. The funny thing is I am not running an afc at all. All I have is a two dollar pot intercepting the map sensor wire to the ecu.</TD></TR></TABLE>


This is the exact same thing as using a SAFC with all the maps at -35% or -40%, or whatever, a pot just gives you the same correction across the board, all the time.

The thing about the SAFC is that it allows you to tune at each rpm interval.

TurboJesse

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kpt4321 &raquo;</TD></TR><TR><TD CLASS="quote">


Not with just an AFC. It does not have the reduction necessary to run injectors bigger than 550 cc/min.

</TD></TR></TABLE>

i understand that, i should have said using an FPR or FMU technically you can run anysize injectors...you would be stupid if you went through the process though.

silverbulletgsr

I just installed a custom turbo kit with 450cc dsm ijectors and a vafc, t3t4 turbo, fmic,resistor box, fpr. For some reason my car hits fuel cut anywhere from 5800 to 7200. I have tried turning the fuel pressure up and taking it out of the low end with the vafc. I have tried putting the fuel at 0 across the board at WOT. I still can't get it to do right. Anybody have any suggestions?