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Old 12-17-2009, 09:52 PM
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wncwheeler wncwheeler is offline
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Choke Question

I took the electric choke off my 2 Barrel Motorcraft carb and im in the process of replacing the vacuum hose's on the intake and carb. which lines can I do away with now that I have no choke?

Secondly I know this has been talked about over and over again but if I cap all the ERG lines will I effect the engine in anyway? Are there certain ones I can remove/cap without harm to preformance?

This is a trail only truck so im trying to make the engine as simple as possible.

Thanks Ben
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Old 12-18-2009, 07:39 AM
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brad_fsj10 brad_fsj10 is offline
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Im sure you've thought through the start-up issues you're going to face without a choke so I won't comment on those. As far as "needed" vacuum you'll need to run the distributor vacuum advance (see vacuum diagram).

Vacuum

If you have power assisted brakes as most do, you'll need to keep the mainfold vacuum line to the booster.

As far as the EGR valve, you won't lose any HP in keeping it and you'll probably gain in performance over getting rid of it. The EGR gasses actually cool the chamber gasses, reducing detonation ping. Personally I'd keep it. Route the EGR vacuum line through a temp controlled valve to a ported vacuum source. Again, see diagram above.

That's my 2 cents.
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Old 12-18-2009, 10:48 AM
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710 Burner 710 Burner is offline
 
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I disagree about the EGR. Ditch it. Its probably not working anyway.
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Old 12-18-2009, 02:38 PM
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The EGR valve prevents pinging because the mixture is so lean to begin with, it will ping without being diluted by exhaust gas. You can get the same effect by increasing the main jet size. This will similarly reduce the burn temperature of the mixture, but HC will go up and you'll never pass a tailpipe test.

Another byproduct of high combustion chamber temperatures is higher NOx levels. The EGR promotes a complete burn (lean, low residual HC) with low combustion temps (less pinging, lower NOx) at a cost of some added complexity. I'd keep it.
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Old 12-18-2009, 02:50 PM
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brad_fsj10 brad_fsj10 is offline
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Quote:
Originally Posted by tgreese
You can get the same effect by increasing the main jet size. ...but HC will go up and you'll never pass a tailpipe test..

OTOH.... I'll defer; probably not an issue on a trail-only rig....
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