FMU Ratio...

[dj_hype]

I'm using an FMU because it is cheap and will get my setup running quickly and moderatly safely. Please don't try and change my mind, i'm using an FMU.

With that said, I'm trying to figure what ratio would be best for me. I'm going to be boosting 6-8psi on a T3. I've got a nifty little formula to calculate fuel pressure that will be on the rail related to the amount of boost and fmu ratio. It goes like this, x*y+z=psi with x being the fmu ratio (first part, ie 12 with a 12:1 fmu), y is the amount of boost, and z is the stock fuel rail pressure. so, 10*8+40=120psi which is WAY too high!

my question's are:
1) would running an 8:1 fmu be safe enough
2) what is the maximum rating for the stock rail and injectors
3) love to hear some of yalls fmu settings and results

thanks yall.

[orion::S14]

8:1 should be fine...and at 7psi, it'll add 56psi of fuel pressure...plus the stock base of 43.5...you've maxed it out.

The MOST you want to see at the rail is 100psi - Any more is dangerous IMO.

- Brian

[dj_hype]

so should i maybe go with a 6:1 ratio then? that way i'm not so close to the 100 psi mark at 7psi?

[orion::S14]

That may be too lean...you'll need a wideband to know for sure.

8:1 should be enough fuel...seen that done on a KA-T before, seemed to work well.

6:1 may be enough...try and see...that's the only way.

- Brian