silverintegra83

well here is the problem my vafc reads 2.8 volts on the map sensor b4 i start the car. then idles at 1.1 or so. well this only happens when i am feeding 30-40% more fuel to it so it is running fat or rich as hell however u guys call it . i do this bcuz if you even try to lean it out (go under by 1% under the 0 mark) the map sensor drops to .3 volts and the car shuts off. i am told i should be able to run it 34-38% under the "0" mark. well on the good side of things with it running rich as hell we still tried to dyno it(we were at the dyno shop tuning)it only went up to 5psi cuz it was running so rich. and got 162hp and 130 torque. not bad with no tuning and running very rich. please guys have any suggestions? everyone including the tuner was stumped on this one. we messed with it from 2:00pm to 10:30pm.
jus a quick list of the car

b16a1
t3/t4 turbo
vafc
dsm 450cc
tial 35mm wastegate
no fmu
running a homemade bypass valve
no inline or intank fuel pump( told dont really need it now juz boosting 6psi)

please help guys!


Modified by silverintegra83 at 8:11 PM 8/4/2004

xci_ed6

re initialize(sp?) the vafc. you have to clear it in the vafc - there is a function for this, not just un-plug it. then re-install/set up all the sensors and everything. Sounds like a prob with the vafc, or your sensor.

silverintegra83

we did do that repeatedly. we switch ecu's and we also switch the vafc. so we know that those arent the problems. could the bypass valve effect it? also if running the vafc do i really need the bypass valve?

ITRpwrdEG

That's your problem. The beauty of the VAFC hack is that you don't need bypass valves, a missing link, or any other homemade map sensor device to keep it in check.

Return your Map Sensor setup to stock and reset your VAFC again. Start with the preferred -40% from 2000-8000 rpms. Then, slowly tune from there. Colder plugs and retarding your ignition a little with help keep your car from grenading before you really get it dialed in.

BKR7E plugs are cheap and what most run up to 400hp. (.030 gap)
You will want a 255lph fuel pump. If anything, at least get the 190lph.

Now get in your garage, take off your bogus Bypass Valve nonsense, and let us know the results YO. lol. Good Luck

silverintegra83

ok thats the thing. i don't think i am running the afc "hack". i mean i didn't do anything to the hardware or to the software. so how could i be hacking? i mean i have read all over the internet of this so called hack but still don't know what exactly it does. all i know is with this "hack" you dont need a bypass valve or fmu. thats it. i dont know how to do this hack or what so ever. if ne one wants to explain i truly appreciate it.

silver

Tchleung

Are you sure it's wired properly? They call it a "hack" cause in a sense. you hack into the signals the ECU sees and minupulate them

ITRpwrdEG

This is all you need to consider it the hack.
1. DSM 440 blue top injectors or any other injector 440cc-550cc.
2. resistor box. must have this for ohm resistance
3. VAFC (It has to be set at -40% at least, because this is what tricks the Map signal so much that it doesnt throw any codes up to 8-9psi. The bigger injector you go, likea 550cc, you can maybe lean out to -50% and run 10-11psi without throwing a code, but I don't recommend it.

Let's say you have all of these installed, and you have taken out the Bypass Valve, it still doesn't mean its the hack. What makes it the hack is based on your VAFC settings. Now since you are running 440cc injectors, if you try and run 6psi on only -25% decrease in the map signal, I will more than likely bet you will throw a code when you reach the full 6psi, because you have not tricked the signal by leaning it out enough. Plus, -25% or -30% is just too rich anyways, so why would u run that. You wouldn't. It is pretty close of a tune with -40% give or take, plus you can run maybe 8psi until you see a code, but maybe even 9psi.

So all you have to do is make sure the VAFC is set for a 4cylinder (4in 4out), and that one setting with the (arrow) points to the Northeast. Then, here are some examples of how to lean it out based on yoru injectors and your setup.

2-8,0000 rpms
(-40%) for all rpm ranges

or

2,000 - -40
3,000 - -40
4,000 - -39
5,000 - -39
6,000 - -38
7000 - -37
8,000 - -36

These are just examples, but if you run the second setting, you might only be able to run 7psi, since the map signal got to the point of -36% and didn't lean it out to the -40% like most people run. If you are running safe and have good air/fuel ratios with -36%, then don't put it at -40% just to see another pound of boost. Just play it safe. Have fun, but be safe.

How the VAFC works is that it leans it out so much to make the big injectors act like stock injectors, until you reach open loop and 1/2 throttle or however your VAFC is set up, and then it dumps the fuel for the big injectors.

Tchleung

"So all you have to do is make sure the VAFC is set for a 4cylinder (4in 4out)"

the In/Out has NOTHING to do with cylidners. this MUST be 6 In and 6 Out for a honda serup. The IN/OUT is the input and output sensor type. Honda Map sensor is 6. If you were to use a GM 3 Bar map sensor to stock honda ecu then it'd be 16 In, 6 Out or something I forget the exact setting for GM 3 bar.

ITRpwrdEG

He's right. It's actually the map signal In and Out. I thought something had to do with a cylinder setting, but there can't be, cause Apexi's unit can't tell how many cylinders you have. That would be like it knowing how much horsepower you have and guessing that it has to be an 8cylinder with that much horsepower. Just do some searches as well. Find out what negative percentages work the best with the VAFC hack. But from my research, -40% is a good base set for all rpm ranges. And this is all with stock fuel pressure. Around 42psi I would imagine.

Tchleung

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ITRpwrdEG &raquo;</TD></TR><TR><TD CLASS="quote">He's right. It's actually the map signal In and Out. I thought something had to do with a cylinder setting, but there can't be, cause Apexi's unit can't tell how many cylinders you have. That would be like it knowing how much horsepower you have and guessing that it has to be an 8cylinder with that much horsepower. Just do some searches as well. Find out what negative percentages work the best with the VAFC hack. But from my research, -40% is a good base set for all rpm ranges. And this is all with stock fuel pressure. Around 42psi I would imagine. </TD></TR></TABLE>

Correct. when you are setting the VAFC up. you msut set the numebr of cylinders, and what throttle type. the throttle sensor type is the northeast arrow you were talking about and at that same screen you pick how many cylinders :D BTW. what motor were you running -40% on? I've tried -40% on my b16 with 450 CC's and it didn't run all that great

ITRpwrdEG

A year ago I bought a 00SI that was built. had a greddy turbo kit on it. He was running the hack and he had -40% I'm pretty sure. It was right around there and it ran ok. It ran a little rich though. Sometimes it threw a code, but that motor turned out to be junk, so it was blowing so much smoke and running rich and god knows what it was doing. But on a clean motor, I bet -40% would have been a good ballpark figure. I got that number from various VAFC Hack threads. People seem to at least run -40% up to 4,000, then sometimes they keep that all the way to redline, or they go -39% to -35% range. Everyone claims this and that. It's hard to pinpoint it, since its kind of a bandaid setup. Hondata would be more efficient and low budget. Uberdata would be even more budget and be a little safer than the hackt. The VAFC hack is just fun for the beginner, cause you can play wtih settings, but PLAY WITH CAUTION.

silverintegra83

hey guys. thank you so much for explaining everything to me. we found out the problem. i bought the vafc used and the guy i bought it from jumped some wired inside the heat shrink hence we couldnt see it. so we thought there might be a wire inside the heat shrink that was cut or something and thats how we found out. we unjumped it and it works fine. dyno was 204hp and 148 torque at the wheels on 9psi. is that good? well thanx again guys!!

silver

ITRpwrdEG

I am glad that you found the majority of the problems. You should still not be using the bypass valve. This will alter the map signals that the VAFC normally needs to see when taking a negative value out of the voltage signal.

204whp is definetely an increase, but i still think something is wrong. You said you had 165whp or so at 5psi, and now when you turned it up to 9psi you have 204whp. That seems about right, so what makes you think it's 100% fixed? Of course when you turn up boost the horsepowers gonna be better than what you originally had. On average, most kits do 16-19whp per pound of boost. So that means, when you were at 165, you should at least be at 230 or so with 9psi. But from the beginning, you should have been way above 165 at 5psi.

On 5psi, the way your car originally should have run, you should see 185-205whp. So if you were to turn it up to 9psi, I would think you would see 240 easily. B16's are high reving and if your t3/t4 is a decent size turbo, it should not be dying off at the high RPMs.

PLEASE disconnect that bypass valve. You may have already and just forgot to post that you did, but if you didn't, thats probably were 20-30whp went. And if you already did, then you have a tuning issue.

Good Luck

silverintegra83

k so i didn't unhook the bypass valve. but the thing is i do not know a lot about my turbo setup yet. my car was dyno tuned at 9psi with the bypass valve(so my engine doesnt give out). if i take the bypass valve out will that effect the tuning that was done? and will i still be safe boosting at 9psi without the bypass valve? bcuz right now it is tuned to be safe with 9psi with the bypass valve. i totally understand what ur saying but i juz want to be safe.
tia
silver

ITRpwrdEG

I see what you are saying. What you could do is leave the settings you orginally started with on your VAFC at 5psi, then unhook the bypass valve, and see how it runs without it. Be sure to remember your VAFC settings now, so you can always throw the bypass valve back in and return it to the way it was.

Do not touch your RPM intervals on the VAFC. Just put it back to the way you had it when you were running 5psi. But disconnect the Bypass. I would recommend around -40% from 2000 - 8000 rpms. I hope you have good plugs though, just to be safe. If you can already tell it runs awsome with only 5psi with those settings, then you know your setup now is nothing compared to the low boost you have now. Imagine how 9psi would feel if the bypass valve was really holding back your true horsepower. Do it slow. Listen for any signs of detonation. You should be ok. Just don't think you have to impress some car while tuning with the VAFC. Get it dialed in and watch it for a day or so.

REMEMBER YOUR SETTINGS RIGHT NOW. You can always put it back to the way it was.

Good Luck Mang