Did a search but didn't find much info..

I've got some DSM 2nd gen injectors that I'd like to put in..
I'm going to be controlling them w/ a vafc and the fmu that came w/ my drag kit.

What diaphram ratio should I use..right now it's the stock 12:1 that comes w/ my kit..

The car has a 9:1 compression KG built B16 benson sleeves w/ arias pisons..

Going to order a Hondata but for now this will have to do..

So what would be a good static fuel pressure to begin w/ and what size diaphram for the fmu...

What kind of boost levels can I expect to achieve running this set up provided it's tuned well..


[Modified by BlwnBlue, 11:14 AM 4/30/2002]

 

Man oh man, you can do alot of tunign with that setup. This is what I personally would do.

If the DSm's are 450cc than I'd runa 6:1 disc and have the vafc at -35% across the band. Id use 5 psi less than stock pressures with no vacuum and I'd tune from there.

I would stay at about 10psi until you can get a wideband o2 or hit the dyno.

Randy

 

Not to start anything..., but why not save the headache and wait to install the 450's when you get the hondata.

...or you could run the ever so popular "AFC hack"

 

With the 450cc injectors there is no need to run a FMU at all - with the stock FPR and fuel pump they will flow enough fuel to run you up to around 8-9 psi of boost with a HUGE margin for error. I was running 9.5:1 AF ratio at 8 psi boost with that setup until I leaned it out with the VAFC.

 

You shouldn't need any type of FMU if you're talking about using the VAFC hack.

Ditch the FMU, set fuel pressure at stock, install 450's, allow ECU to see boost IE: no check valves, set narrow throttle on VAFC for -30% across the board and -40% across the board on wide throttle, fine tune from there.

 

Well from a cost standpoint I can't afford it right now..I've already got this other stuff..so I figure why not use it..

I'm running 8 psi now..so to change injectors to run the same amt of boost is not really what I was wanting to hear..I was personally thinking about running 13 to 14 psi out of the set up..is that possible..

 

If your interested in the "AFC Hack", check the link in the bottom of this thread...
https://honda-tech.com/zerothread?id=166394

I'm running 8.5psi on this mod I know others are running higher.

 

that is awesome info,
but I'm looking to run like 13-14 psi ...if I keep the FMU and just lower the ratio of diaphram I use, wouldn't that work better in my situation..instead of just running the same boost as I am now...to me it doesn't seem any better than what i've got going now..and to me it doesn't contitute and "upgrade" ...450's aren't even stressing over the 8.5 psi you're running considering that the stock injectors would work just fine(as I am using now)...I wanting to upgrade the injectors to get more fuel to up the boost..

All of that info is VERY helpful and I appreciate the help but I'm looking to get more power using this setup..My goal is to get about 325-350 using this setup...I'm more worried about getting more power whereas the solutions you've provided you've made my goal getting rid of the fmu..

 

I think the point is nobody in here trusts an FMU at 8 psi, and we certainly wouldn't encourage someone to run an FMU at 13-14 psi. With a 1:1 FPR and a good fuel pump I would trust 450s to maybe 11-12 psi, any higher and I think you should be running larger injectors. FMUs are just generally unpredictable and unreliable. That's the only reason you're getting these answers out of us.

Aside from that, you should be able to hit 325-350 at 10-12 psi with a well-matched turbo and good tuning, but again - good tuning and FMU don't generally show up in the same sentence.


[Modified by dbman96, 11:47 AM 4/30/2002]


[Modified by dbman96, 11:48 AM 4/30/2002]

 

I am very interested in this.....I plan on using on my project ZC turbo....Know any good links explaining how to hook up DSM injectors?? Thanks....

EDIT: Will this work with just an AFC also?? I dont see why not...


[Modified by TrayDay2K1, 8:25 PM 4/30/2002]

 

I can see that...so everyone in here that runs more than 8-10 psi has a standalone..I no I'm not the only poor one that can't afford a stand alone right now..

 

no, but most of us poor people just accept the fact that until we can afford a standalone we're smarter not to risk blowing up our engines and thus making ourselves poorer.

 

I C...so there is a reason I am broke...

But really...I don't think that is the only way...

I was also noticing that with the vafc hack most people are only running 91 octane..would higher octane help run higher boost ..or is it the actual act of the computer reading boost that limits the amt of boost one can run?

 

according to popular info, the stock map is only good for around 10psi. Thats the most limiting factor i think.

 

well my 450 come in tommorow and i will be doing the v-afc hack i have the tuning discs for my fmu (440 cc and higher) i an running both my fum and my stock regulator and the fum since the fmu is boost dependant the injectors would run at a flat 40 psi if it isnt hooked up. i dont see the problem with running both sice 1 way or another you get the fuel you need and i would think that by having both would give you a safety net also. 1 last thing if you go on vortech's site it states you must run a your vaccum dependant regluator wether it be stock or after market since the fmu is boost dependant and does not adjust it self on vaccum. the super fmu..not the one that comes with the drag kit handles everything but it is also more expensive and looks kind of like the regular fmu but the bottom part is different (has more hookups on it) and is silver colored but im going to give running both a shot first to see what happens but remember it is alot safer the run a little rich than lean at all i'll keep you posted.

 

As soon as I get a connector harness (know where I can get one?), I'll wire in my GM 2bar map sensor and see how that goes As it is, I get a map code when I boost in 5th gear and I see just under 9psi. How much boost do you think a stock block SOHC @8.7:1 can run? Guess I'll find out

 

Not a good idea with a stock ECU, you would run lean. The GM 3bar map has a greater range, meaning it crams more pressure reading into the same voltage scale as the stock map. Lets just say for example (these numbers are not acurate) they work on a 5v scale. When the stock map reaches its maximum level at 10psi, it will be putting out 5v. Now lets say at 10psi on the GM map, it will only be putting out 2-3v. The computer essentially sees less boost then there really is, which is not a good thing.
Now if you have a standalone, you can let the computer know the right scale.

 

I run 12psi on my AFC mod actually. RC 440's on a D16 w/ GReddy turbo..

 

So, I'll just adjust my VAFC to compensate. Isn't that what we're doing already by altering the map signal the ecu sees. I'm just giving myself some extra room to up my boost without having to up my fuel pressures (or conversely use less negative trim on the AFC which will throw a map CEL). All the ecu does is coralate injector pulse width with a given map voltage. By adding boost, we are already screwing up the voltage/manifold pressure relationship.

FYI: I'll be using a 2bar, not a 3bar sensor, so voltage shift should be minimal.


Added: Hmm, I wonder if you could run boost using just a 3bar map and no AFC? What pressure would be equivalent to @3V on a 3bar unit? Obviously the AFC is handy for tuning, I'm just curious if it would work


[Modified by DSF, 11:47 AM 5/1/2002]

 

Well I've been reading a little on this hack thing...Are 450 the perfect size for this setup..or could it possiby be done w/ 550cc injectors...and then more boost? also lowering fuel pressue..would the computer be able to compensate for the larger injectors given the current settings of -40%?

 

I believe MDA on this board (and on Hostboard) is/was running 550's with this hack. Still, I'd probably limit boost to around 12psi. Yes, you may be able to amply fuel 14psi, but there is more to it than just fuel for that boost on stock internals. The hack works, but it's definitetly not the sexiest way to get things done. That's why I use the "hack" on my beater turbo CRX and Hondata in my "more expensive" boosted Civic

 

I'm not on stock internals..I read all 5 pages of that **** and am REALLY confused..
Just to see if I got it right...There are 2 ways of doing it..way # 1 hooking up normal and use it as normal..w/ the -40% settings allowing the computer to see boost!
#2 trade the tps sensor wire for the map sensor wire when installing the VAFC and still use the -40% settings ...still allowing the computer to see boost? Am I right or way off..

 

Opps, my bad


Yeah, there are different ways that people are running this mod. Personally, I'm running the map sensor signal to the map input for the VAFC like it says in the instructions (with no missing link, check valves, etc.). However, I am also running the map sensor signal into the tps input for the VAFC. This way my hi/lo VAFC maps become vacuum/boost maps. I set my low throttle point for 50% (% where my map voltage is at atmoshphere) and my high throttle point at 95% (% where my map voltage is before I reach full boost). IMHO, I think it's more usefull this way as opposed to throttle fueling, but that's just me.

In a day or two, I'll have my geoshitties website up with picture and schtuff