I just try the VAFC hack on my SI with JR 6lb and it is great. The vacuum to boost tranistion is seemless.

One bad thing is that I loss power and that my car does not rev up as fast as before. When I hit Vtec I don't see the instant jump like before. Another thing is that when I'm in neutral and rev it to 3000 rpm or 4000 it dips down and then up like thr car is rev limiting. When I'm in gear the problem still exist but its not as bad. I don't know if I'm too rich or what. ALso if the problem is the 450 injectors. My A/f ration is pin at rich so that meter is worthless. My check light engine does not come on also.

My current fuel pressure is 30/40. I try lowering it to 22/32 and the problem still exist. Just wondering if anyone saw or had similar problems. My setting on the VAFC -35% at 1000 and the rest is -40%.

Any help would be appreciated.

Thanks

 

You're running a lot of fuel for only 6 psi. Maybe try leaning that motha ***** out to -45% across the board except at 1000 rpm. Keep it -35% there.

 

Why -35% at 1000?? what does that do?

 

Cause its believed that bigger injectors let LESS fuel out when at idle because of the small signal being sent to them, they have a longer time to open up to let fuel out.... so in reality you have to add more fuel at idle then at mid rpms and high...

 

at 6psi we have the high throttle set at anywhere between -30 to -35 to get an a/f ratio ranging from 12.5 to 11.9. it didn't go higher than that. low throttle is -45 all across. this is with setup is with fuel pressure at 44/49, 450cc injectors, gsr fuel pump, safc, 14b on a sohc non-vtec (97 civic dx)

so you might be running a bit lean.. but who knows until you get it on a dyno with a wideband.

 

Why don't u guys run the unit the way it was designed? I do 334hp 258tq 14psi

 

What are you talking about?

 

eh?

 

Do you even have a car? Anyone can post someone elses dyno sheet and claim they have 334hp. Why don't you elighten us on your wonderful setup so we can all ew and aw. Or you could stfu, that would be good too.

To the guy that started this post. Get it on a dyno and see what your numbers look like. You will need to run fairly rich if you aren't doing anything about timing.

 

if you go from -35% to -45% arent you leaning it out? i was having some bogging problems and i actually set mine to -40% at 1000, -38% 2000, -35% 3000, then -33% the rest....runs great! but my fuel is at like 41psi.

 

Yes, which is probably what he needs. This is also on a 1.6 so he will need less fuel than you.
GOKOU, have you pulled the plugs yet? What do they look like?

 

I haven't try running -45% across the board but I try reducing the fuel pressure down to 22/32 and the problem still exist. I think this hack works better on Turbo and higher boost. I didn't think I was going to run into this problem though.

It just seems like my AC is on whenever I hit a certain rev or when I let the gas pedal off at close loop. It sucks and I might just go back to using the FMU setup.

One other thing that suck is that I need to crank my car 2 to 3 times before it can start.


[Modified by GOKOU, 2:35 PM 8/12/2002]

 

Thanks for the settings. I'll try that later. Your fuel pressure is pretty high but then again your boost is at 14. I was thinking about lowering fuel pressure back to 22/32 and run -33% at idle and -45% across the low throttle setting. -40% accross the high throttle.

I still have the JR enrichment relay on. Don't know if I need to get rid of that thing. That may be one of my reason why I'm seeing these problems too.

Yes I need to dyno it with a wideband but the problem I'm seeing now is on partial throttle and not full throttle. In neutral when I rev to 3k it will dip to 2k and then back. When I'm in 2 and 3 gear the car will do that sometimes. It also seems like my AC is on whenever I let go of the gas.

DOn't know if anyone ever have the same problems.


[Modified by GOKOU, 2:40 PM 8/12/2002]

 

I just had them install and ran it around the block so don't know if the plugs can show much. Before this one thing I've been seeing is that my a/f gauge is pin at rich but when I pull the plugs they were white as if I was running lean.

I need to put it on a dyno but this ramping thing sucks. To me it seems like the troubles out weighs the advantages.

THanks

 

Hmm, maybe an injector is sticking open or not closing all the way. Did you have them cleaned/balanced before you put them in? Try listening to them with a stethescope or screwdriver and see if all of them tick.
That is strange about your plugs. I still think you are getting too much fuel somehow. I guess you will know when you dyno it.

 

Now that you mention it I did have the injectors clean and balance. They turn out great. ONe thing I notice is that after the injectors were installed there was a loud ticking sound. I figure the loud ticking sound was normal.

I use the stock injector 0 rings with the DSM 450 injectors. Not sure if this was the correct way. I can't believe I'm the only one who have this problem when going to the hack. I think the hack was not meant for SC.

 

dutchie here's my setup: 94 acura integra rs
drag kit
ross 8.5 pistons
eagle rods
ferrea 1mm oversized stainless valves
race engineering block guard
skunk manifold
RC 64mm overbored throttle body
type r oil pump
ur single race pulley
-8 fuel feed
-6 return
aem fuel rail
twin walboro fuel pumps
aeromotive regulator
aeromotive fuel filter
apexi s-afc
apexi s-itc (ignition timing control)
profec b
auto meter fuel pressure,oil pressure,exhaust temp,air/fuel,boost gauges
would you like some more theres quite a bit more mods.

let me know if this shuts u up?

 

damn... making all that power w/o a standalone? not saying it can't be done but i would be scared personally... then again i'm a sissy since if i blew up this motor i'd be kinda stuck for a while

 

DRAGLS,

If that's your setup, could you give some insight how you're running 14 psi on the hack? Are you running a different MAP sensor?

 

No tell me more. What injectors? What FMU rate? What are your fuel settings on the AFC? Oh and where did your copy and paste that from?

GOKOU: Ya you use the stock rings with the injectors. Tell me more about the enrichment relay on the JRSC. Is it easy to take out? If it is try that and see if it helps.

DC2: He's not running the hack. Apparently he thinks it isn't the proper way to use the AFC .

 

Dutchie,

He doesn't seem quite clear what he's trying to point out. If he says he using the AFC without the hack, along with the antique ITC (which isn't a S-ITC, just an ITC) what the hell is he doing for the whatever ECU he runs to read boost?

Twin Walbro pumps? I smelled that from a Supra forum.


[Modified by DC2, 1:44 AM 8/13/2002]

 

Ya, this guys an assclown. If he is for real, his setup doesn't read boost and will probably blow up in a couple months. He would be running 440cc injectors with a 4:1 FMU or something. I don't know, I don't think he does either.

 

The JR enrichment relay is use to trick the the computer into thinking the air is at a very low temperature when on boost, which opens the injectors more to deliver more fuel. This could be why I'm running rich. It is hook up to the IAT sensor which is on the intake in my case.

I might just revert back to the FMU setup. This could be why most SC don't run the hack.

 

OK, lets recap:

I'm sure you're hooked up right but just to be safe, lets review what is needed to do the AFC hack on a JRSC:

You yanked the stock injectors in favor of the DSM 450's and either put resistors inline with them or ran a resistor box. You set your vac and static fuel pressure to stock, you installed the VAFC per the instructions without swapping MAP for TPS or anything, and most importantly on a JRSC you took the MAP off the TB and ran a hose for it's signal to a port on the JR manifold and plugged up the hold left on the TB.

So lets assume you've done all this, lets address some of the problems:

Long crank time: Have you done the ENDYN FPR drilling mod to get your fuel pressures down to reasonable levels? If so, that is the cause. Drilling the FPR lets the pressure bleed down almost immediatly after the pump stops. If you change your starting habits to turn the key on and let the pump prime for a second and then turn it to start the problem should be bypassed. Just don't wait for the pump to stop priming, just a little delay in-between on and start.

Dragging when gas is let off: This is the one drawback of the hack IMO. The transition from 0 gas to very little gas is not smooth. I don't know that we've ever figured out why it does this but in a week or so you'll learn to drive around this little flaw.

Surging RPM under no load: We've PM'ed about this. If you rev to say 4k in neutral the ECU is adjusting the STFT (short term fuel trim) to try and find stoich (14.7:1). The problem is that since the injectors are so big (another theory is that they are slower to open and close), even though we're trimming out pulsewidth by introducing phantom vacuum with the VAFC, the pulsewidth differences are not granular enough to keep a steady RPM, so the ECU see's a slightly rich mixture at say a .5ms pulsewidth @ 4k RPM so the next smaller pulsewidth it knows about is .4ms which is too little to support 4k so it drops to 3k RPM's. While this is annoying while revving to a constant RPM in neutral in the driveway it should not be noticable while driving due to the load.


I'd leave the JR relay in for a bit longer and look at your A/F readings under part throttle and WFO. Try the "calibrating a modified fuel system" highway method to find where the narrrow trim should be at and set your throttle points to 25%/75% and leave the wide throttle at -40 and let the VAFC interpolate when inbwtween 25 and 75% throttle. If WOT runs are rich then take more out of the wide but leave the narrow alone. Try setting the VTEC engagement at stock with 0% correction for a while.

Why is your A/F gauge screwy?

 

First of all I would like to say thanks for taking the time to write all of this down. I guess we are the only two with SC using the hack method. Good thing I have you to help me.

Yes I replace the stock injectors with the DSM 450 with resistor inline. I ended up with the huge resistor type because I didn't know there were smaller the inline resistor type. The VAFC is hook up per the instruction. I had that thing for over a year now. The map is now seeing boost and the hole on the TB plugged. I did notice a louder ticking noise from the engine (maybe injectors).

I use the AEM FPR and didn't have to drill any holes. Starting still sucks. I'll try your method. I've been experiencing a lot of dragging when the gas is let off. This bothers me more then transition from 0 gas to little gas.

Surging RPM under no load, this I've experience. The part that annoys me is that this is also happening under load especially in 2nd and 3rd gear where I'm usually in. It happens sometimes around and at 2k-4k. I would be at a constant rpm and then a sudden rpm surge and jerk. I don't know if this was cause by letting go of the gas (doubt it).

I'll use your "calibrating a modified fuel system" to see if I can find better setting for the narrow trim. I'll also change my throttle points and see what happens. I think my A/f gauge is mess up. It's pin at RICH. The only time it seems to be working is in the morning when the engine is cold. DUring that time it bounces back and forth between lean and rich but after 5 minutes of driving the light slowly goes toward rich and stays there. Is there any or way to read A/F? WIll reading 02 voltage help?

Thanks again.