at this point i just need fuel injectors and some kind of engine managment. i was thinking of using rc 550 injectors and a 12:1 vortech fmu temporarily until i can afford an s100 and the dyno time to get it tuned correctly. Now i hear alot of bad things about an fmu but rev hard and drag kits still use them so what are the real downsides to using it? is tuning a problem with an fmu ?detonation? i plan on boosting my car over the winter months(as my car will be parked and cleaned up etc etc for the winter/spring) I am just getting anxious to get my car boosted, i am going to be running an ls at no more than 11psi, is a fmu safe for that amount of boost and obvious question is (which i know )is that should i just be patient and get hondata or go with crome or just get an fmu and be fine with it. i guess i need to know is if i bought an fmu would it be ok temporarily running 11psi daily and is tuning a problem with them? or does it even need to be tuned because i was told that an 12:1 fmu raises fuel pressure 12psi at high?! boost pressure so therefore if it is sending more fuel then i shouldn't need it tuned right or wrong? sorry for the dumb questions but motor swaps etc are easy but this turbo shit is a different world for first time diyer's, and i should do it right the first time or fuck up the first time and learn from experience but 85% of dragva is boosted and the other 15% might be like me or not AND no i didnt search first so if your thinking of posting that just ignore this thread..........................

 

Dude to make it simple.


Wait until you have the cash to get tuned properly so that you don't have to rebuild or buy a new motor a couple of months from now. 11lbs on a FMU is not the smartest thing to do.

 

FMU's are designed for superchargers. You will lean out in the transition from vacuum to boost running an fmu. You'd be better off to use a VAFC and run the hack, just retard your initial timing by about 6 degrees.

 

for the cost of an fmu or vafc you could just chip the ecu and put a safe base map in it. I would recomend that to start then don't drive on it hard until you get it tuned.

 

from what I understand, an FMU maxes out your injectors. They don't spray as clean as they should so it doesn't mix very well. Example, when I first had the blower on my car, (10psi) I had the stock 19# injectors with the FMU, I couldn't get into boost without it laying over, just not enough fuel. So I went to 30# injectors, and no FMU, runs great.

 

with ^, I went thru several d series after running minimal fuel management and didn't care really, but a an ls isnt as cheap so I dont recommend it. Patience pays off.

 

thanks guys, i think i would rather wait and buy hondata then to buy an fmu for cheap then blow my motor then pay a tow truck etc, i guess waiting will pay off, thanks for the good feedback

 

ran 12-14 with one for 2 years and only blew one motor. but in all reality it is best to avoid an fmu when possible. they definitely suck in boost transition and you cant ever really get a clean tune.and depending on the diaphram and boost,hell you can put 150 psi through your injectors easily, now thats a negatory.

 

for a honda it's so cheap and easy to use crome/uber w/ a chipped ecu, it's really pointless to use an fmu. I can't believe people still use them anymore (for hondas).

I don't know if an fmu would even pass smog?

 

do they do road smog tests ?....cause it shouldnt really be running any richer just idling, unless your using an inline fuel pump which most people do with the fmu's since the intank cant handle the pressure demand, but your definitely right, fmu's definitely do not need to be used anymore on hondas.