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irish13jeff View Drop Down
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Joined: Aug/13/2011
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Post Options Post Options   Thanks (0) Thanks(0)   Quote irish13jeff Quote  Post ReplyReply Direct Link To This Post Posted: Jan/09/2019 at 11:56am
Like these? I’m running EFI and in Florida,think it’s worth running? I’ve only had it for a short time and it ran fine, so not sure if worth the change..
Please don't tell my parents I'm a truck driver..... They think I'm a piano player in a whore house...

http://www.legionofjeepers.com
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DaemonForce View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DaemonForce Quote  Post ReplyReply Direct Link To This Post Posted: Jan/09/2019 at 6:56pm
A TBI system on that manifold really surprises me. This is probably the best setup you could hope to have on a 258.
1971 Javelin SST
American 304 2v | FMX | AM20-3.31

1983 American Limited
Jeep 4(.7)L S-MPFI | 1982 NWC T-5M (4.03/.76) | Dana30IFS/35-2.72
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tomj View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Jan/09/2019 at 10:02pm
i ran a GM TBI system (packaged by Howell) on the 82 or 83 aluminum intake, didn't plumb the water to irt and never wired the electric heater. it ran just great. on a '70 232ci in a 63 wagon. tuned it up with all the Moates stuff.

that's a lovely intake, no problem believeing it's as good or better than the old clifford stuff.

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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FSJunkie View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Jan/10/2019 at 12:16am
I would retain the coolant flow through the manifold and the electric heater in the plenum even with TBI.

The TBI system monitors the oxygen content of the exhaust at the collector, it cannot monitor each cylinder individually. It has no idea which cylinders may be running rich or lean, all it knows is the average for all cylinders. Similarly, the injectors cannot change the fuel mixture for each cylinder individually, only the average.

A cold intake manifold does a poor job of vaporizing fuel, so liquid fuel will tend to puddle in the manifold and run iregularly into cylinders. This will make some cylinders run rich and some run lean even though the TBI system says the average fuel mixture for all cylinders is correct. This is not only bad for engine smoothness and power, but is also bad for engine longevity.

The faster the intake manifold reaches operating themperate and stays there, the more uniform the fuel delivery will be to all six cylinders. The better the engine will run, and for more miles. Warming up the manifold quickly on cold starts will also allow the TBI system to lean the fuel mixture out sooner rather than continue with cold start enrichment fuel mixtures. It's the same as releasing the choke quicker on a carbruetor. Better fuel economy, drivability, power, engine life, and oil life will result.


Inline sixes are long engines and the AMC six is particularly long even for an inline six. Uneven fuel distrinution is the bane of long engines. Much can be gained from preventing it. The Twin-H-Power dual carbruetor Hudson engines did not have any more total carbruetor airflow than the standard single carbruetor H-145 engines. The 20 horsepower advantage of the Twin-H-Power over the standard single carb was more uniform fuel distribution. Nash did the same thing with the LeMans Duel Jetfire.


Edited by FSJunkie - Jan/10/2019 at 12:19am
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1973 Ambassador
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tomj View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Jan/10/2019 at 11:18pm
Originally posted by FSJunkie FSJunkie wrote:

I would retain the coolant flow through the manifold and the electric heater in the plenum even with TBI.


oh absolutely. i wasn't saying that i made the right decision! lol. stable intake temp is nothing but good, and the electric pre-heat would help startup/warmup even here in LA. i was just lazy.

Quote Inline sixes are long engines and the AMC six is particularly long even for an inline six. Uneven fuel distrinution is the bane of long engines. Much can be gained from preventing it. The Twin-H-Power dual carbruetor Hudson engines did not have any more total carbruetor airflow than the standard single carbruetor H-145 engines. The 20 horsepower advantage of the Twin-H-Power over the standard single carb was more uniform fuel distribution. Nash did the same thing with the LeMans Duel Jetfire.

that's pretty interesting, that Hudson info... Hudson's more or less forgotten, they 'went away' at a bad time, and in a bad way...

even distribution is one of the better design features of the 195.6 OHV. it helps that it's a short motor, but the funny anti-reversion wedges are probably there from experience.

i wonder if AMC did anything internally with Hudson's inline engine experience.

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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