genyosai

Anyone know why Hondata recommends a 1:1 fuel rise when using their system? I have the Hondata Stage2B running 10psi with 440cc injectors:



I want to "up" the boost, but my injectors are a at about 86% duty-cycle at 8300rpm. I have new 720cc injectors to install, but we have no Hondata tuner in town. I have to drive about 300 miles to the nearest tuner.... something I have no time to do for a while.

Anyway, I was thinking I could put my Vortech FMU back on with a low 4:1 spring kit. This way I could push more fuel, making it rich, and then go to our local dyno to lean it out by adding boost. HOWEVER... I just realized that increasing the boost MAY increase my injector duty-cycle IF the duty-cycle is controlled by MAP readings.

Anyone have any thoughts on this idea??

Thanks,

Firedrake

Upping the fuel pressure will decrease duty cycle, because it'll essentially make your current 440's act like bigger injectors.....that 440 cc flow is rated at a certain fuel pressure, and lowering the pressure will up the duty cycle, upping the pressure will lower the duty cycle......
I had to run 54 psi fuel pressure just to keep my 450's under 100% duty cycle on my prelude....
However, I wouldn't suggest putting the FMU back in......at 10 lbs and a 4:1 FMU, you'll be WAY too rich (looking at your current a/f's).....upping the boost will just make it that much worse.....
If you could just turn up the fuel pressure about 5-10 psi or so (via an aftermarket or modified FPR) that would do the trick and you'd be fine to run another couple lbs of boost.......
Brian

20lb.teg

Well, how much did you put into your setup (turbo motor and all)? How much do you care for it? My suggestion, DON'T UP THE BOOST! just wait until you can drive there and do it that way. That way it's safe, you know you'll be alright for now and 10 psi... at almost 290 hp... You aren't hurting for power leave it alone until you can get it done right. I'll put it even simpler:
1.) Wait for the trip to do the tuning the proper way, or
2.) Blow it up and have to wait until you can save enough money for either a new motor or rebuild...
I would just wait dude, the motor is not worth your extra kicks and giggles...

anyway my 2 cents.

Later,

Sean C.

genyosai

Thanks for the great feedback here, guys. I thought that the MAP reading more boost would make the ECU increase duty-cycle. So how does raising the fuel pressure decrease duty-cycle? I mean... how does the ECU know the fuel pressure is raised in order to lower the duty cycle... there are no fuel pressure sensors.

I have a substantial amount of money into the whole car, blowing it is not an option simply because of the inconvenience of downtime. You can see pics and mods-list here:

http://home.sc.rr.com/ntgr/images/civic/

The block was built by Import Builders. The turbo is a T3/T4B, but I have a T3/T4E that I need to put back on. As for turning up the base fuel pressure, I'm already at 60psi which is what Hondata recommends. Wouldn't 70psi be high for base pressure?