What to do to a 2056 with 2.0 DJet, Help get this motor worked out. Options

[Teknon]

Ok Motorheads,

Senerio:
New 2056, Slightly more aggressive than stock Isky VP-228 cam, ported 5pt heads with '74 2.0 D-Jetronics. Crane xr700 009 dizzy. Burch exhaust through SSI HX'ers

Question:
What would be some tricks and tips to make this engine more efficient. (IMG:style_emoticons/default/cool_shades.gif)

I thought of having the MPS adjusted for a 2056, read that somewhere. Would like to put an oil cooler in most likely.

What else would be things to concider. The engine is in boxes ready to assemble.

Please chime in

Joe D

[pbanders]

Demick, I read those postings of your tuning efforts on your 2056, you've done some good tuning. I think you'd get it better if you looked at the situation differently. Remember that D-Jet is a speed-density type of FI system. The "density" part is what the MPS is responsible for, that is, measuring the intake air density (i.e. manifold vacuum level). The "speed" part is what the trigger contact points do, which is to determine the engine speed so that the mixture can be corrected for the pumping efficiency curve (the "volumetric efficiency", or VE curve) of the particular engine.

By changing the cam and the displacement of the engine, you've changed the VE curve, and you're trying to use the "density" component, the MPS, to compensate. What you really need to do is to modify the VE circuit in the ECU to accomodate the new cam's effect. This is easier said than done - the ECU does this compensation by "OR'ing" four or five waveform generators together to achieve an overall compensation characteristic. You'd need to experiment with changing the components (resistors and capacitors) to get the desired effect - AND - you'd need to know what the effect of your new cam and displacement were on the stock VE curve to know which waveform generators to modify. The discussion on this circuit is in my ECU page.