tuning with an FMU
 

I have a Cartech adjustable FMU...i am just wondering what is involved in tunning with one of these. also will i need any timing changes for a 5-6 PSI setup?

Re:tuning with an FMU
 

Honestly there isn't really any tuneability for an FMU. If it's rich, it's rich, not much you can do about it. And try your timing at stock, if you notice any detonation retard timing a little. At that psi, you probably won't have any problems staying at stock timing, and with the FMU you'll be running plenty rich. :)

Re:tuning with an FMU
 

did u get the adjustable one with the base adjustment too or the one with just the bleeder...either way you can adjust the increase in fuel

Re:tuning with an FMU
 

i have the same FMU and it is shitty, everytime i hit about 2psi i go so damn rich i bog down. i am saving for the "hack" so i can actually enjoy the boost.
good luck

Re:tuning with an FMU
 

well if it goes too rich you need to adjust it

Re:tuning with an FMU
 

I'm considering a Vortech 10:1 FMU.. with stock injectors and stock fuel pump at 7 psi, will I be running too rich as well? Is there anything I can do about that (short of going for engine management..)

Re:tuning with an FMU
 

everyone uses the 12:1 but i heard a 10:1 will be good cuz it wont be so rich, but if you turn up the boost you probably wont have enough fuel to supply so i guess its better to just stick with the 12:1 unless you are going to never raise the boost.........which is BORING!!!

Re:tuning with an FMU
 

I'm starting to consider a Apex'i SAFC now. Particularly one of those Gen 3 ones, just because they seem to be cheaper than an FMU, but more effective..

Re:tuning with an FMU
 

This is interseting. What happens when to fuel flow volume you riase fuel pressure?? it drops like a rock. typically itll drop 10% every 2 psi and by the time you get to 70PSI you have little to no flow left with a stock pump. your gonna need a pump. also id highly suggest getting rid of the fMU and converting to OBD0 honda something or OBD! and getting one of the freeware editors or hondata zdyne etc get the car tunned right pleeeeaassseeee. im tired of reading storys about blown motors. also at 6psi your arent really getting much of a gian anyways. might be worth it to take the turbo off till you can afford engie management to go with it, your engine will thank you.

Re:tuning with an FMU
 

I think im gonna stick with the FMU for now. But if i decide to go the AFC hack route in the future. what will i need. From my understanding i would need obviously the AFC, 450 injectors. (how hard are these to modify to fit to a honda?) and a resistor box?

Iv done a lot of research on this board and could not find much about the resistor box. What is it? where can i get one? and about how much do they cost?

thanks for all your help. sean88accord..i think you need to step down and realize not everyone is a turbo guru. Instead of putting people down, why dont you share your knowledge in a civilized manor?

Re:tuning with an FMU
 

its fairly obvious looking at your car youve got some money invested in it.Why sel the most crucial aspects of its performance and driveabilkity short by Running it in a hacked up ass manner. You could oconvert to a p28 or a p30 ecu run one of the manny boost romds avaiable. run a hondata and get it tunned much mroe accurately then with an FMU a BTM and injectors that are to big.

As for the injector resistor. Are you fimilair with ohms law ? bascially the lower the impednce the higher the current flow

for example

12v x 2 ohms = 6 amps thats 6 amps everytime the injector gets turned on it happens alot ;D

now

12v x 10ohms = 1.2 amps.

It has to do with the amount of drive durrent needed to turn the injector on. Most of the obd1 pcms are unable to run high current. so you have to run a resistor like so

2ohm injector + 10 ohm resistor is 12 ohms.

12v x 12ohms = 1.44 amps.

there are beter ways to run low impednec p/h injectors. I sell hardware for this but its not cheap and with a set of 450cc injectors id highy doubt you would ever need the super stable controll and short PW time to validate its cost on a 10-12 psi car with such a small inector.

but lets explian the advanatges of p/h injectors Vs saturaed or high impedence injectors

there are 2 modes of operation

a saturated injector open on what can best be reffered to a bell curve. current slowly ramps up and open the injector. the minimum amount of time it takes to open and close the injector given the physical limitation of the design are 2.5 msec or so. They also require less current becuase they are high impednce. typically 1.4-1.amps

A peak hold injector is a slightly different animal.

it will rip the injector open with 4 amsp of current ( are box does this in .9 msec) and then it lower the amoutn of current from 6 amsp to .4-.5 amps. whats really important about this is is the amount of time

the minimum PW with a p/h injector is roughly 1.4 msec
the minumum pw with a satruaretd inejctor si 2.5

well when you trying to control a lrage volume injector at low air demands like idle with out the short PW time the peak hold injector can deliver it make the idle typically over rich.

Just a bit of info.

Re:tuning with an FMU
 

Sean, as accurate as what you say may be, its over the heads and overkill for many of the questions and people here.

Accord dude:
the "AFC Hack" has become more than just using an AFC. What happens with the motor when you use the AFC hack is that the MAP signal gets scaled to a lower figure. You do not get a check engine light running 8psi (for instance) because the ECU sees 8psi scaled (usually about -40%) with an AFC, which is no longer a boost signal. It no longer sees boost, so it just happily fires an injector, which happens to be a nice big 450cc injector. The car gets approximately 450/240 times as much fuel, and runs quite happily in boost.

Point being: you can scale the MAP signal with about $10 of parts from radio shack and have the car run just fine. There is a turbo 97 H22A prelude running 10psi with a t3/04e and 550cc injectors running well on nothing more than a MAPhack of sorts.

Re:tuning with an FMU
 

blundar: wow, that answered so many of my questions. A DIY of that Radio Shack project you described would be fantastic. Anyone?

Re:tuning with an FMU
 

thanks a lot sean88accord...a little over my head. but thank you for the explaination. Thank you as well blunder..for putting it in more lamens terms.

jsut let me get it straigt...are you saying i can use the AFC hack/450s without a resitor box using radio shack componants? or are you saying i frankly dont need an AFC at all?

Re:tuning with an FMU
 

yes/no

You do not need an AFC box. you can use a voltage divider circuit (hint: read some of the threads above carolina hondas ... Joseph's post) which can be made from about $10 in radio shack parts.

You do not NEED a "resistor box" with 450cc injectors, but you NEED something. You can substitute 4 resistors from radio shack, but I forget the resistance you need. If you do not use something, you will cook your ECU. Someone else can probably answer this for you. I want to say 1 watt 10 ohm but I'm not sure.

Using resistors is ghetto, mind you, but honda did it from the factory on many of their cars, and it works. If you are curious why it is ghetto, you can ask Sean - he explained it very well to me.

Re:tuning with an FMU
 

Here's the schematics of the MapHack that Joseph Davis created. XDEep used this for a while, said it worked great!

Just sort of makes it hard to tell where to tune your maps.. (because of the scaling)

http://www.carolinahondas.com/forums...ht=trailerpark

Re:tuning with an FMU
 

actually you dont need a resistor box at all to run the 450's. Our accords already have a resistor box built in and run low inpedence injectors. Trust me. Your car is either a 93 or 92. On my 93 I ran the afc hack with 450s and had no problems. If you want you can look at the box yourself, its the silver box on the right side of your engine bay (its about 1 by 2 inches) below the strut tower.

Re:tuning with an FMU
 

Well.. just lowering voltage won't help.
I tried this myself with 345cc injectors.
What was wrong?
Well.. I did study it somewhat... and here are the issues:
When decelarating MAp signal wouldnt be decreased enough, so even touching gas pedal would cause backfire. Ad decelaration MAP reads arround 0.3-0.4V.
THis is a problem, cause at idle it reads arround 0.9V - if you lower it too much, you'll get erratic and jerky idle. Lowest you can go with 345cc is near 0.65V, not lower.
Next... at very light gas (like 5-10% throttle), and arround 3-4krpm - when you just try to keep the speed in 1st/2nd gear you'll notice sputtering.
This is due to pretty high vacuum at that throttle position and revs which causes MAP signal to go down quite a lot.
Decreasing it more (due just to reducing voltage) makes ECU think something crazy, thus cutting of fuel (too much vacum) and making it sputter.
At 1/3 and more throttle it worked nicely tho... but that sputtering at very low throttle and backfiring makes that unusable (well, at least for me).
This is why you need more complex electronics to controll it.