i am confused
have been reading posts coming only from hahn users in relation to 30lb. injectors
the questions seem to be about static fuel pressure
...i was under the impression that the stock ecu could control these without any help-
i have a star kit and have just bought these injectors and an 8:1 disc for my fmu
the question is- do i need an afc in order to be able to idle properly and not bog down or send out clouds of black smoke when i accellerate ?

many thanks

jean-pierre

you need a means to lower the idle and static fuel pressure. the stadard fmu doesnt allow any adjustment other than what disc you use.

you need a different fmu thats allows you to make that fp adjustment. a SFMU does allow you to do just that.

Acctually Deano D has been running 10psi on the star kit with the 310's and an 8:1 disc here are some of his comments:
Star Stage 1 with a Starion front mount and 2 inch
Intercooler piping.

I have a testpipe(testpipe.com) and 2.5 inch mandrel flow through
exhaust.

Time with kit: 8 months and 7000 miles
EGT: 1600 at 10 psi top of third gear
I do not have my corbin digital A/F hooked up yet. There are others with
the exact same setup as mine and they get 1.02(rich) readings. I would
not recommend leaning it out any more to achieve a .92-.95 reading. This
will cause your egt to climb much higher than 1600 degrees. With high
fuel pressures it seems to be a curse to have high O2 readings. The
plugs
do not look too bad and it works fine so far.

Future fuel system: 48lb injectors (504cc)/S-AFC/3:1 fmu disc/ring

i guess i'll just give it a shot with the 8:1 disc and the injectors
couldn't hurt right
worst case scenario, i take them out and save up cash for an sfmu right


jean-pierre

Please let me know the results. I'm in the EXACT same boat. I have teh SAFC and 30 lb injectors. I'm waiting to see if I will need the SMFU of not to get me by.

When starting the car, it idles a bit rich. No big deal. When water temp rises to approx 180 degrees, the ecu can use short/long term fuel trims so you to drive with these injectors. It usually takes 2 minutes in the summer mornings(during the rest of the day probably 30 seconds). Basically when my water temp gage reads 1/4 above the full cold line.

Winter time it takes a bit longer. Car has to warm up anyway to drive with heat.....so no big deal either.

If you have to just start it and drive, you can step on the gas pedal and allow the car to die from over fuel, restart quickly and then you are off. For some reason it pulls fuel then and allows you to drive off. It kind of runs crappy for 30 seconds until water temp reaches 180 degrees.

If anyone has anything in writing that says something other than 180 degrees, just post to this. I got the info from the 4g63 guys and I think it is the same temp on our cars.

Hot ass summer days, I have to drop to 9 psi for hard 3rd/4th gear pulls at max rpm. When I run a good mix of C16 race gas I run 10.5 psi without any problems. It stays approx 1600 degrees in 100 degree heat. I have tried boosting 12 psi, but the ecu pulls too much timing, because I have reached fuel pressure limits on my pump/injectors. The car was not faster at the track and actually ran a bit slower.

I have found my best race gas/boost setting to give me the most power in summer. 10.5 psi with 1 gallon of C16 per 5 gallons of 93 pump gas.
The car runs great(idle also), my egt stays slightly below 1600. This is also when I run my best times at the track. When my egt climbs to approx 1650, the car does not pull as hard even at 12 psi. I also did this on high amounts of C16 race gas so I could run leaner. When the fall comes and the temps drop, I may be able to get away with 12 psi and keep the egt down to below 1600.

What kind of fuel set-up are you running? Just the Vortech FMU and a disk or do you use a S-Afc too? Do you have the S-FMU instead?

Vortech FMU......not the super, just the regular standard

8:1 FMU Disc/Ring This probably gives me approx. 7 psi more pressure for every psi of boost. Rough guess!

Accel 30LB injectors(high imped/bosch type/saturated).....cannot vouch for any other types/brands

Fuel pump rewire from battery


Good luck.