spork Posted February 28, 2005 Share Posted February 28, 2005 First off, I have an 83 nissan 280zxt. I'm using the em4-6f system. I have rpm fuel values set at 82 after 4500rpm, yet the car still goes rich higher up in the rpm and it's not boost related. It will go rich slowly, but seems more like its a product of time rather than anything else. The longer I'm in a gear, ther richer it will end up before I shift. I'm using the innovate WB meter to verify this while tuning. Boost is a constant 18psi, but as the rpms climb the car goes rich. Could this have something to do with the motors lack of airflow? Maybe a need for portwork, upgraded cam, etc? The basics of my motor are as follows: 2.8l inline 6. Custom intake manifold (J. Thagard's) and turbo header, masterpower T-70 turbo, forged internals, stock cam, light headwork, 1mm oversized exhaust valves, and then all the little things to go with that stuff. All I can figure is that the car can't flow the air needed for the fuel being put into the motor at the upper rpm range. I even tried a new wb sensor just incase mine was messed up somehow. Any help is appreciated on this. James Roraback Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted February 28, 2005 Share Posted February 28, 2005 I had to do some funky programming of my fuel curve after 4500 rpm's too. I believe I actually had to ramp down the fuel values slightly to get the a/f correct. Mine was not boost related either. Anyway, you should be able to tune it by slightly lowering the fuel values where it is too rich. Quote Link to comment Share on other sites More sharing options...
spork Posted February 28, 2005 Author Share Posted February 28, 2005 so, you're saying you lowered the rpm fuel values to compensate? Quote Link to comment Share on other sites More sharing options...
Drax240z Posted February 28, 2005 Share Posted February 28, 2005 rpm fuel values are going to mimic your torque curve. With any restriction in your exhast/intake system your torque curve is going to fall off at higher rpms, so your fueling should as well. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted February 28, 2005 Share Posted February 28, 2005 What Drax said Quote Link to comment Share on other sites More sharing options...
spork Posted February 28, 2005 Author Share Posted February 28, 2005 rpm fuel[/b'] values are going to mimic your torque curve. With any restriction in your exhast/intake system your torque curve is going to fall off at higher rpms, so your fueling should as well. I guess I'll just have to try it and see, but I'm going from 12:1 fuel at 42-4500 to 10.14:1 at 6200. that seems huge... Quote Link to comment Share on other sites More sharing options...
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