1loynesy1

i have tried searching on web and on this site for the infomation im in need of and havnt had much luck and have been looking 4 a wile,i have a 1.5ils vtec, i am going to fit a turbo on with a wastegate holding pressure at bout 6 or 7 psi as i have been told that the standard engine can handle with these pressures?? i found on a thread from this site that a vorech fuel management unit is ok and safe for bout 7psi, i have a low budget but if it needs 2 be higher 2 make it a safer system then so be it. also if a fmu is the answer how am i sure of wot ratio to go for 12:1 , 10:1, 8:1, 7:1?? havnt a clue, as u can guess im new to this, but am trying to get more knowlegde, hopefully from you guys.

busa4

an fmu is not the way to go. it adds fuel exponentially which is not a tune. the engine will be very rich across all boost rpm range. this takes away power, fuel economy, causes cylinder wash down, increases rail pressure to dangerous levels and strains the injectors and fuel pump.

since your running low boost i suggest using the stock fuel system and purchase an extra injector controller. the extra injector controller will add fuel under boost only. they can be on the cheap with two large injectors mounted on the boost pipe just before the throttle body or they a system can be made to mount an injector in each intake runner just like the stock system(recommended).

another alternative is a chipped and tuned ecu with larger injectors.

1loynesy1

ok thanks, ive looked into it and have found a injector controller from greedy the relic or sumfin, i aint no wireing expert so hope i can work it out lol, but with the extra fuel and air goin in, is this goin to have a drematic affect on bottom end even though im running low boost? cause im goin to use the car for every day use and cud do without the thought of detonation or melting a piston at the back of my mind. thanks

busa4

injector controller require very little electrical work. power and ground to the controller. a boost line to the controller and injector pigtails. the best for you will be once pretuned for your application and the only one that does this is in the link below.

RSR Additional Injector Controller

SlowSL

I've never heard of fitting other injectors into the intake, that just seems strange to me. What you would need I would guess are larger fuel injectors to supply enough fuel to meet the demands of the extra airflow. In order to control the injectors you need to trick the ECU into thinking there is less airflow than really is. To do this you need is a good AFR controller, I'm sure you can find a cheap bare minimum controller. You set your mainscale to your injector size, then you can fine tune a wide range of paramaters to get your AFR right all around. You need a wideband 02 sensor installed to keep tabs on AFR, and you need a datalogger to keep track of knock. That's how most cars tune AFR/timing/boost, you just keep upping everything untill you begin to get some knock, then you back it down a bit. If you've heard 6-7 psi is all the block can take, I wouldn't push it. I'm sure you could get detailed info from one of the Honda tuning forums.

busa4

the extra injectors supply the extra fuel for the extra air be entered into the engine. this setup allows you to keep your stock fuel system and doesnt require stock ecm chipping/tuning. the best way to build it is by putting one injector on each cylinder that way each cylinder gets the correct amount of fuel. each cylinder will have two fuel injectors. the primary injectors are the stock injectors and the secondary injectors only work when engine is boosted. very reliable setup.

SlowSL

Seems like that would cost a good bit of money to fab up a the fuel rail & plenum to fit two inj. per cyl. On top of that, what would be used to control the injectors? If only an on/off type of switch, there is no way in hell you will have a good AFR. You would need a way to control them throughout the rpm range. I know an AFR of 11.7 compared to 10.8 for me is night and day. Wouldn't a simple piggyback & larger injectors be easier?

SlowSL

Generally 11.0-11.7 is considered safe. You can lean out a bit more on race gas w/out much worry, I see 12.2 or so on race gas. My car rapidly loses power under 11.5:1, and begins to throw out rich black smoke around 10.8:1 or more.

busa4

cost less than a custom tune. fuel rail is cheap. all you have to do to the intake manifold is drill holes for screw in injector bungs or weld in injector bungs. the injector controller is a control unit that reads boost and adjust injector pulse width based on how much boost.
the on/off type switches were used in the 90's when electronics were not available.

larger injectors or a piggy back still require expensive tuning. most tuners charge 500.00 or more for a tune. if larger injectors are installed then the only choice is a custom ecm tune as theres no other way for the ecm to know there are larger injectors installed.