boosted 97 zj what do i use for fuel management???

97_gczj · 03-02-2011, 01:58 AM

i am in the middle of doing a turbo build to my 97 grand cherokee with the 4.0 i am putting a t3/t4 at 6 lbs. what do i use for fuel management? i was going to use and obx fmu? but it is used to cut the fuel on the return line to boost fuel pressure on the line in. BUT the zj has only one fuel line no return. and the fuel pressure regulator is part of the pump, so would an fmu still work? or does anyone know what else to use. thanks

KingtheZJ · 03-02-2011, 05:36 AM

you may have better luck with thespeedfreaks.net. most of us here are more geared toward suspension mods, although there are a few engine gurus as well.

mark4370 · 03-02-2011, 06:31 AM

Quote:

Originally Posted by 97_gczj

i am in the middle of doing a turbo build to my 97 grand cherokee with the 4.0 i am putting a t3/t4 at 6 lbs. what do i use for fuel management? i was going to use and obx fmu? but it is used to cut the fuel on the return line to boost fuel pressure on the line in. BUT the zj has only one fuel line no return. and the fuel pressure regulator is part of the pump, so would an fmu still work? or does anyone know what else to use. thanks

Well whenever I had my srt4 you have to get rid of the fuel pressure regulator in the tank. And then use a adjustable regulator and a return line so you can add fuel. Then use the obx to cut the fuel. Do this with your jeep and it should work but keep your I on the air to fuel.

Foundrydude · 03-02-2011, 07:09 AM

The charcoal cannister line could be used as a return line then vent the gas cap. What kind of pump are you using? A custom pump fitted to your sender, a V8 pump, or what?

I don't think most guys boost-reference fuel pressure at 6 lbs so why not just run a fixed regulator set to your desired pressure? The V8 trucks run deadheaded with 20% more displacement.

good luck!

**ratmonkey** · 03-02-2011, 12:21 PM

a stand alone FAST system with proper injector sizing is probably your best at home option. don't forget your datalogging wide band sensor.

jerry rigging a returnless system into a return system in a misguided attempt to boost pressure and over drive your injectors is a bad idea.

failing that, proper sized injectors and a dyno tune.

and fwiw, v8 and i6 and 4cyl jeeps use the exact same pump assembly in 1997, at the same pressures.

you really should have had this all figured out before you even started buying parts.