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Old 04-05-2013, 06:36 PM
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This is the main reason I have not persued the EFI on the Roots blower. I agree that the fuel demands are much different than the blown sbc equal to some larger cu in motor.

You can see this when you start tuning the blower motor with the O2 sensor and a vac boost gage. At light throttle there probably is not much difference than NA but as soon as you get on the gas harder and not even into boost there is a radical shift in fuel requirement. The transition circuit becomes very important as well as the power circuit. Often idle feeds and high speed feeds need to be adjusted and of course the main jets. Not that EFI can't handle it but the standard maps don't allow for this and I don't think most of the self learn ones do either. Then when you jump the throttle and get boost quickly, the amount of fuel change is huge. It's surprising that the carb can even handle this. In reality the fuel requirement gets covered by being excessively rich. The EFI should be able to adjust for this better and quicker but it takes the laptop to get to the map requirements. Lots of keyboarding.

I'll see most of the suppliers at Back to the 50's this summer and hit them face to face about the blower EFI.

My son says I could save hours of mechanical work by going EFI but then it just becomes hours of keyboarding plus changing injectors and sensors and a half a mile of wire harness.

Don't get me wrong, I'd jump on the EFI if I could be assured that it woulod tune as easily as advertized but so far that has not been the case. I've been around for too long to fall for this advertizing......after all dynosaurs lived for 260 million years and we have only been around for a heartbeat on the time line. haha they must have known something.

I'm going to wait it out. My 2 x 4's run too well now.
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