MILD THUNDER

iTrader: (3)

Yep. And many decades ago, when carb's came from the factory on GM's, they had heating elements under the carbs. Also, had hot air tubes from the exhaust manifolds feeding warm air to the carburetor when the engine was cold. They did this, because even a 455 station wagon engine with a cam so mild the thing could idle at 400rpm, wouldn't stall when cold. Wouldn't have went over well when grandpa goes and buys a brand spankin new 1975 Fleetwood, and engine is stalling out as soon as he pulled off the showroom floor.

Now lets stuff a 7000RPM cam into a motor with a race carb, big high rise intake manifold, no water thermostats, a super efficient intercooler getting 50* lake water pumped thru it, and complain it doesn't want to idle in gear.

I see absolutely no good reason to run water thru the chiller at idle on a blow thru carb setup. If someone knows why he should keep water flowing thru it at idle, I'd like to know why. This procharger stuff is new to me.

mike tkach

iTrader: (3)

can you tell its wintertime?

Young Performance

Joe, you already know my answer. I wouldn't do it.
Eddie

MILD THUNDER

iTrader: (3)

Thank you!!!!!!!!!

compedgemarine

I cant tell you wether it is right or wrong but I work on an Eliminator that has a blowthrough procharged 509 in it and he runs water thru the intercooler at all times and it idles perfect even when cold. the carb is from C&S and was built specific to it and I spent alot of time fine tuning it but now it runs as nice as an EFI. I did not do the original setup and I dont know who decided to run water to the cooler at all times, I just work on what they have as the original builder as long since moved away.

tunertech

FWIW
The heat exchanger in the exhaust path was to draw warm air through the choke spring body, in return warmed the bi-metallic spring reducing active choke. The amount of heated air actually reaching the engine via the carburetor has no affect on idle characteristics.

TB's - Coolant is circulated to eliminate any possibility of ice accumulation in the venturi is the primary purpose, secondary results in clean flow for idle specifically important in fly-by-wire throttle systems.

tunertech

oh yeah for the boat

forced fed separate p/u separate dump, no water at idle

MILD THUNDER

iTrader: (3)

I wasn't talking about the hot air for the choke. I was talking about the heat risers they used to put in the exhaust manifold. It was plumbed directly into the air cleaner assembly, and fed warm air back into the carburetor. Some actually had ''heat riser'' valves, that went between the exhaust manifold outlet, and the exhaust pipe. When the engine was cold, the valve would shut, forcing warm air from the exhaust into the air cleaner. Once the engine warmed up, valve opened, things went back to normal. The valves became problematic themselves, and most got welded open, or removed. They then went with just a tube that collected heat from the manifold, with a thermostatic flapper on the air cleaner. When the engine was cold, flapper door shut, focusing on sucking heat from the hot air tube, which mounted to the manifold.

High power airflow wasn't a concern. Because with the old quadrajets, when the choke was engaged(cold Engine), the secondaries would not open.

FIXX

iTrader: (2)

amd also failed to mention the ports in the center of the cylinder head that went under the intake to warm up the carberator and the fuel going into the engine..he dont have that option with a single plane manifold...

Villian III

Adjust the idle mixture screw to make it idle better when cold, or change the air bleed jets on the idle circuit. in that order. A smaller idle bleed jet will richen it up a little, but be careful with this mod as it will affect the transition from idle to mid RPM AFR's, and could cause it to stumble a little.