Re: [Amc-list] TBI fuel injection tuning...

[Frank Swygert <farna@xxxxxxx>]

I tend to agree with you on your thoughts about carbs, but still dislike them compared to any type of EFI. You drive in mostly nice weather, with only some somewhat radical altitude changes on occasion. The altitude changes throw a monkey wrench in the carb works, but not enough to be a problem. Throw altitude AND weather at a carb (especially weather) and it gets funky. So you really need to tune for your location, and change tune with big climate/weather changes (seasons, where we have them). EFI does all that for you, eliminating a lot of maintenance that should be done (but often isn't). If you're going to be playing with an engine and trying different things, you either have to invest big bucks in an adjustable EFI system, or use a carb. Once you have everything worked out, then EFI can be added in a relatively affordable fashion (could be done for under $500 with mostly salvaged parts... ).

I don't think you'll improve on gas mileage with the 196 and TBI much at all, if any, 1-2 mpg tops. Power would be about the same -- maybe 3-5 hp. Those are typical gains from the carb engines when the OEMs were converting. Fuel delivery is more precise, so emissions are better -- that's the main reason for the wholesale switch to EFI. TBI was just a nice and easy stop-gap until port injection could be studied and spun up. 

You don't have really cold weather to deal with, so that's not an issue, but drivability should improve dramatically, especially if you add a Pertronix and hotter coil to the EFI (you really need hot electronic ignition with EFI for max benefit). Almost instant starts and being able to drive off right away on a cold day with little warm-up time is easy for EFI, a carb stumbles and spits and sputters until the engine is good warm. I don't go out and crank the Rambler even on a cold day -- it was in the mid 20s this morning! I don't floor it right away, of course, but I can start it, idle for 10-15 seconds, then casually mossie down the road while it's warming up. That's even better for the engine than letting it sit there for 3-5 minutes idling! 

-----------------
Date: Thu, 20 Nov 2008 14:00:32 -0800
From: Tom Jennings <tomj@xxxxxxx>

I don't hate carbs. I've come to realize carbs are totally fine when you 
only ask them to do simple tasks, like on the 195.6. No fancy 
multi-staging, no progressive linkages, no smog compensation, maybe an 
automatic choke. And you stay on top of it. Then they're fine.

ALl the carbs I had trouble with, ever, were the later jobs with all the 
finicky smog stuff or performance carbs that need tons of tweaking. (Not 
because they are not good; but because you are trying to make them work 
over a much wider range of values.)

I don't even think the Howell kit will get me better mileage than a 
well-tweaked 1 bbl Carter YF. But it'll be more like a perfectly tweaked 
Performer carb that I never have to change power valves on, turn screws 
on, and it will work at altitude too.

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)


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