ModAddict

Is the Static pressure checked by removing the vacuum line from the FMU? If so, my static pressure is 65psi, and at 18inHg it drops to 38psi. If I take it to 1psi boost, and the FP goes to 75psi, does that mean the FMU is at 10:1 rising rate? 75psi @ 1psi boost - 65psi static = 10psi FP:1psi boost. If that's the case, at 6psi boost, i'd be at 125psi FP,...? I have to go for a ride to see where it's at at 1psi, 2psi, ect....

edit: Just went for a ride and that's about where I'm at; 1psi boost = 75psi fuel, 2.5psi boost = 90psi fuel, 3psi boost = 95psi fuel, 3.5psi boost = 100psi fuel. My fuel gauge only goes to 100 but the needle pegs out past 100, maybe 110.

ModAddict

Ok, back to the intercooler,...we could also add this to the heat exchanger, http://www.designengineering.com/cry...r_sprayer.html and this http://www.designengineering.com/cry...ir_intake.html to go between the intercooler and the intake manifold, for those special ocasions.

Pull_T

Yes...looks like you have a 10:1 rising rate, I don;t see why you need to be at that high a rate though. esp when you guys are seeing 10s and 9s in you A/F. There is some power to be had right there just by unflooding the motor and keeping the AF at a still safe 11.0-11.5 ratio.

On edit - I must applaud what you and Scalbert are doing here even if the aftercooler pans out as unfeasible. Awesome to see knowledgable guys going above and beyond the kits on their own. Hell, in my realm (Mustangs), most everything is already "figured out" and theres ample parts to do damn near anything you want.

scalbert

Dropping the static pressure also decreases the rate to an extent. But only so much; after that a spring adjustment is needed

From what I have found the stock injectors are about 31 Lb/Hr units.

scalbert

I agree and has led me to look at running larger injectors on a lower pressure. Maybe 36 Lb unit; the J32A2 runs about 40lbs w/ 20 inches vacuum and we could drop this to about 32 lbs with the larger squirters. This may take the under boost fuel pressure to about 80 - 85 PSI.

Unfortunately this requires the upper intake manifold to be removed to get to the injectors.

But in the end I would like to control the pulse width...

scalbert

It is supposed to be a 12:1 unit but at this stage who knows.

Once again, I agree, I don't see a need for this high of a ratio. I know the J32A2 runs 10.5:1 CR which is not boost friendly but so aren't others. My guess is that since Comptech is in California they tuned for the available 91 octane.

I do feel that with 93 grade and backing off on the fuel may yield a few more ponies, exactly in the 11.05 or so ratio. But only time will tell after we get more dyno's and A/F ratios logged.

scalbert

Yes, normally the pressure is measured without vacuum as it can vary depending on load. But your numbers match up exactly with what Comptech stated they should be and mine are now showing.

ModAddict

My a/f ratios are still hitting 9's! I'm going to try the smaller calibration disc, or at least talk to Comptech about it.

I'm going to see about buying the elbow that bolts to the intake manifold and try cutting and spinning the elbow. If that works, I'm going for the silicone connectors, and then see what lenghth IC to get. I can do this with no fabrication and off the shelf parts!

Red Rider

You guys are amazing, keep up the R/D