Thread: Crazy EFI idea?

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Rspears I do plan on controlling spark with the ECU. The new FAST XFI sportsman has that capability. The Sportsman has self learning mode, but it can be tuned with a laptop if needed. The lower priced EZ2.0 ECU only has self learning mode.

The main problems I've come up with are whether the old EGR passage will serve as a vacuum balance and could it actually be used to supply idle air. Those are fundamental problems. Other than that, it's just straight forward machine and fab work. The throttle bodies will need to be angled slightly up to clear the valve covers.

If the idle air idea doesn't work, I could always go with a simple mechanical idle adjustment like a carb, but I would prefer computer controlled idle. The main fab problem is getting the throttle blades fitted well enough to the bores to seal off at idle. I'll have to have a way of synchronizing the throttle bodies, too.

Of course I would do thread to document the process.

Mike

Originally Posted by Hotrod46

....The main problems I've come up with are whether the old EGR passage will serve as a vacuum balance and could it actually be used to supply idle air. Those are fundamental problems. Other than that, it's just straight forward machine and fab work. The throttle bodies will need to be angled slightly up to clear the valve covers.
If the idle air idea doesn't work, I could always go with a simple mechanical idle adjustment like a carb, but I would prefer computer controlled idle. The main fab problem is getting the throttle blades fitted well enough to the bores to seal off at idle. I'll have to have a way of synchronizing the throttle bodies, too.
Of course I would do thread to document the process.
Mike

Mike, just chewing on the EGR passage idea it seems to me that your idea may be a touch of genius! First thought is that it might put more to cylinders closer to the IAC valve, but I don't think it would matter - we're just talking a tiny air bleed so I can't see that the porting really matters. In theory it seems like a good approach to me, but just my opinion.
For the synchronizing of the throttle bodies, I agree that they need to be balanced, but it would seem to me that you would synch full open and closed as precisely as you can, and then you'd have one TPS for ECU/EMS input, is that right? The IAC would kick in to balance idle air, and as you come off idle the A/F map would kick for your transition into fuel control. I haven't looked at the FAST XFI Sportsman, but I'm guessing that you can maybe have individual A/F maps for each cylinder for hole by hole fuel control?