Still Kinda Confused on This FMU Stuff

Alright I have decided to boost my 95 lewd and I am just going to run 7-8 lbs of boost until I have money to upgrade the internals now I am going the easy route for now and just getting a FMU instead of upgrading the injectors and fuel pump (just for the time being) But if I am getting an FMU what does the the rating of the FMU need to be 12:1 or what?? Really appreciate some help righ here.

THANKS
ROB

I went with a CarTech back when I was using one. The main reason was you can fine tune the "rate of raise", better then you could with the others. However, the opion on them out there varies to some degree. Mine did fine the 2+ years of using it, and it was the old stlye.

Personally, I wish I would have went ahead and got a standalone first. Instead of trying to peice everything togather, in order to control the fuel/ignition systems. There is really no point in trying to upgrade the internals if your going to stay the 200 hp range (D series). Peeps with standalones have gotton well over that with OEM parts and dyno's. Detonation does not care if you are running the latest, greatest this or that, it will destroy it. Controlling the fuel/ignition systems will go along way in saving the engine, rather then using this or that for parts.

a 12:1 is fine, in fact and 8:1 may suite your needs, but flow will ultimately be determined by your pump (don't get an inline) and injectors. The bottom line is that your mileage will drop through the floor because in an attempt to scare away the lean demons you will be running super rich constantly, well, untill you get to the point where the rest of the fuel system can't keep up. an fpr is cheap, and lets be realistic, its not an fmu, its a riser. and cheap has its place, but as I have said to others before, spend the money now or spend more later. IMO you are better off waiting, getting some bigger injectors, a bigger pump (walbro 255s are cheap), and at the minimum, a basemodel Hondata.

to second what is written above though, I went for quite a while on my vortech, not 2yrs, but a while nonethe less with no probs, just don't think its "safe". if that 12:1 fails when you're high in the rpm band, boom. just like that, and no "watching" the guages will help.

the FMU isnt as bad as many people make it out to be but dont plan on making any big hp numbers with it either. As far as that comment about your fuel mileage its only going to cause your injectors to spray more fuel when you are under boost, so when you are just cruising down the road out of boost your fuel mileage will sill be very close to what it was before. The only real downside is that they are not nearly as tuneable as a standalone since they only work on the ammount of air pressure in the intake. I have noticed that on hondas they tend to make the car run quite rich between initial boost and about 4 lbs but that because your stock fuel pressure regulator will support that much of a fuel demand so the stock pressure regualtor along with the fmu causes too much pressure at low boost. As far as a fuel pump I would definately get a better one than the stock since it cannot supply the pressure necessary to feed the engine and running lean is never a good thing.

I got a FMU forsale, used, e-mail me Kyle.McCombs@cox.net I replaced it do to misdiagnoises. will sell cheap cuz i need money

Kyle

Aight, so I'm a little confused on this FPR / FMU stuff. Right now I have a 10:1 JR FPR, but I have an AEM 1:1 that I thought would be a big upgrade for me b.c I was under the understanding the the lower fuel pressure would give me more delivery. Am I correct in this line of thought? Should I perhaps stick with the 10:1? I'm running so uber rich right now that it'd be nice to come back and hit stoich sometime and mebbe not have exhaust fumes that smell like pure petrol :p

the boost dependent fmu changes the fuel pressure depending on its ratio, like in your case you have a 10:1 so for every pound of boost the regulator sees it adds 10 pounds of fuel pressure. as for running rich it isnt bad if its only moderately rich, even with a stock car if you floor it the computer dumps in more fuel causing the guage to read rich, If you are running just on the rich side of stoich then you are probably right where you should be. For a boosted car the ideal air to fuel mixture is actually about 12.5:1 where stoick on your guage is 14.5:1.

right now I'm running uber rich though... like mid to max-out richness on my A/F gauge. Should I worry about that?

right now I'm running uber rich though... like mid to max-out richness on my A/F gauge. Should I worry about that?

Also depends on what the plugs are telling you too, by their color and uniformity. Along with what kind of of shape the O2 is in. Most likely you are running "bit" too rich, and something should be done. The extra fuel will have a tendancy to wash the oil of the cylinder walls, causing scuffing, increased oil usage, ect... Another downside to running rich, it will also cause performance lose too...

The A/F gauge should only be used as a tuning aid, and "never" be relied on by it's self when tuning. Which you probably already know, unless it's a Wide Band ect... The color and unformity of the plugs, will be the final judge. On where the fuel pressure will be set at, otherwise very bad things start too happen, like the above mentioned.

Most peeps will find that #3 cylinder will run a little leaner, then the other three. So thats something to keep in mind when setting it.