I'm in the final stages of getting the 5.8 to go into the truck but there are some details that I'm not sure about and one of them is how the coolant pre-heater hoses get plumbed to the TB. Could someone possibly post clear pics on how the hoses are run to the TB and how they they get plumbed into the cooling system?
I personally prefer to use my TB coolant lines. They help the engine heat up faster in the winter.
Anyway, I don't know what year your truck is, but in my 91, the top hose runs back to a nipple on the radiator neck; and the bottom hose hooks into the thermostat housing.
For the top hose, I originally had a steel line that hooked into the radiator neck, ran across the fan shroud, and then turned into rubber to hook to the TB. However, that line ended up clogging with sludge so I replaced it with a rubber hose.
The throttle body heater serves to prevent icing on cold, damp days. As the air enters the throttle body, it accelerates and drops in temperature. If there is a high amount of moisture in the air, it will begin to form ice on the throttle blades and the throttle shaft. This can cause the throttle to get stuck open (a bad thing). It's the thermostat and cold-start closed loop ECM fuel mapping that helps it warm up quicker
If it was a throttle body injected engine I'd agree with the atomization theory, however on a port-fuel injected engine the injectors are behind the intake valves in the runner, where atomization takes place.
A friend of mine has a 93 w/302 his are like the pictures above, I know because i had to replace both of them the other day when I did a water pump and hoses, mine is a 97 w/351 and one of mine comes off of the radiator. For the life of me I don't remember where the other one is.. I can go out to the garage and look if needed..
Throttle Body heater seems to defeat the purpose of a cold-air intake. What's the deal? Mr. Banks says every 10 degrees of cooler air means 1% power gain. Why heat it up? I figured you'd want to cool the throttle body if that's the case. Is the heated throttle body just for lower emissions upon starting up a cold engine? I dunno...
Thanks for all of the responses guys, especially the pics! The 5.0 that was in the truck had a heater hose tap, the 5.8 used the long rubber/metal line. As soon as it was mentioned, I remembered seeing it on the 5.8 when I was taking it out of the parts truck (the one in the avatar). There's 2 more ports on the TB, on the left (drivers) side that I'm guessing are for vacuum connections?
I believe that the whole idea behind the pre-heater on the TB is to aid the engine getting up to operating temp quicker, reducing emissions. ( cold intake air= richer fuel mixture)
The coolant keeps the throttle blades from icing in winter time. Any time you have a pressure drop like that for prolonged periods of time the temperature drops and any humidity will condense and if cold enough, freeze. This could cause the throttle to stick. I don't think there is enough surface area in the throttle body to significantly heat the air as it passes through.