Throttle body heater delete (Page 3/5)
Patrick SEP 02, 06:32 PM

quote
Originally posted by Yellow-88:

Yeah, chill your bear on the Rochester...



...

I suspect you meant beer. It would be rather difficult to convince a bear to climb into the engine bay!

The frost on the carbs was usually a short term phenomena (on my SBC and BBC engines), as eventually the exhaust crossover incorporated into the intake manifold (for this very purpose) would heat up the carburetor enough to eliminate the frost.


quote
Originally posted by Yellow-88:

...and roast a weenie the manifold. Yeah.
I wonder if anybody ever did it?



Wrapping meat in aluminum foil and cooking it on the engine during a long drive is not an unheard of practice!

How to Cook Food on Your Car's Engine

[This message has been edited by Patrick (edited 09-02-2024).]

Vintage-Nut SEP 02, 10:24 PM
To me, the throttle body 'heater' is actually a coolant supply and return loop which can help in cold conditions as everyone mentioned.

But nobody mentioned about circulating coolant in the throttle body and perhaps prevents overheating too?

And warming the intake air, I believe this is part of "maintaining optimal operating temperatures" and "reducing emissions by ensuring complete combustion of the fuel-air mixture" in the early era of multi-point injection.

And yes, I agree that these coolant lines are a pain to work around the distributor!

My two cents....

------------------
Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles

css9450 SEP 03, 09:46 AM

quote
Originally posted by Dennis LaGrua:

Never believed that the throttle body heater lines did much good. Few if any vehicles use such a scheme,




quote
Originally posted by 82-T/A [At Work]:

Are there similar cars from that era that use coolant lines on the throttle body or intake?



Lots of cars used throttle body coolant lines; the 2.8 and 3.1 MPFI engines and 3100 and 3400 SFI engines all do but so do V8s at least as far back as the tuned port era. The LT1 engines have them and I think the LS engines do but I am not certain. Other manufacturers use them also.

Some people delete them for the 0.0002 HP that might be gained by having a cooler and denser stream of incoming air.

I tend to think the system on the Fiero is noticeably complicated because of the need to route the coolant to the "rear" of the engine, because that is where the throttle body is.
82-T/A [At Work] SEP 03, 10:44 AM

quote
Originally posted by css9450:
Lots of cars used throttle body coolant lines; the 2.8 and 3.1 MPFI engines and 3100 and 3400 SFI engines all do but so do V8s at least as far back as the tuned port era. The LT1 engines have them and I think the LS engines do but I am not certain. Other manufacturers use them also.

Some people delete them for the 0.0002 HP that might be gained by having a cooler and denser stream of incoming air.

I tend to think the system on the Fiero is noticeably complicated because of the need to route the coolant to the "rear" of the engine, because that is where the throttle body is.



After posting this, it occurred to me that the Iron Duke has this as well. Coolant passes through the intake manifold as well, simply for the purpose of warming up the air and preventing that as well. I plan to leave it on mine, simply because... why not?

But I wanted to comment on your "noticeably complicated" part. The one positive to this, is that with all of these extra tubes and hoses... going back and forth, etc... for the heater core, intake heating, and the threshold coolant lines... that's a LOT of extra coolant. A properly running Fiero (that hasn't been modified or messed with), should really never overheat. I remember my 87 Fiero in its prime. Almost totally stock... just hogged out exhaust manifolds and 1.52:1 roller rockers... and in ~80 degree Florida weather, I'd have it idling in the shade, and with the 180 degree thermostat (I know, changing that out to 195), it would sit at the 1/4 mark, and the fan would never come on. It would just sit there, nice and cool...

I should know this, but I wonder how the coolant capacity of the Fiero compares to say, a Chevy Corsica from the same year with the same engine?
1985 Fiero GT SEP 03, 11:23 AM

quote
Originally posted by 82-T/A [At Work]:


I should know this, but I wonder how the coolant capacity of the Fiero compares to say, a Chevy Corsica from the same year with the same engine?



Chevy Citation 2.8 is 10.6-12.2 quarts depending on AC, Fiero is somewhere around 14/15 if I remember correctly, so a few quarts-a gallon more.
82-T/A [At Work] SEP 03, 01:35 PM

quote
Originally posted by 1985 Fiero GT:

Chevy Citation 2.8 is 10.6-12.2 quarts depending on AC, Fiero is somewhere around 14/15 if I remember correctly, so a few quarts-a gallon more.




Aside from my wallet, and new sources of potential leaks... I think this is a huge positive.
Vintage-Nut SEP 03, 01:48 PM
The cooling system fluid capacity of the Fiero 2.8L engine is 13.8 quarts
The coolant recovery tank volume at the FULL line is 3.5 quarts

[This message has been edited by Vintage-Nut (edited 09-03-2024).]

Patrick SEP 03, 04:34 PM

quote
Originally posted by 82-T/A [At Work]:

After posting this, it occurred to me that the Iron Duke has this as well. Coolant passes through the intake manifold as well, simply for the purpose of warming up the air and preventing that as well. I plan to leave it on mine, simply because... why not?



IMO, we're talking apples and oranges here. The 2.5 has TBI, whereas the 2.8 does not. With the injector located in the TB of the 2.5, atomization of fuel is taking place within this TB... and therefore freezing up of the 2.5's TB is a very real concern if warming measures are not taken.
82-T/A [At Work] SEP 03, 09:50 PM

quote
Originally posted by Patrick:

IMO, we're talking apples and oranges here. The 2.5 has TBI, whereas the 2.8 does not. With the injector located in the TB of the 2.5, atomization of fuel is taking place within this TB... and therefore freezing up of the 2.5's TB is a very real concern if warming measures are not taken.




I assume the freezing up doesn't come from the fuel (as it doesn't freeze at normal freezing temperatures) and more to do with the water vapor possibly freezing as a result of the venturi-effect (insert correct science here)?
Patrick SEP 03, 10:14 PM

quote
Originally posted by 82-T/A [At Work]:

I assume the freezing up doesn't come from the fuel (as it doesn't freeze at normal freezing temperatures) and more to do with the water vapor possibly freezing as a result of the venturi-effect (insert correct science here)?



Don't be so quick to dismiss the effects of fuel atomization on carburetor (and/or TBI) icing.


quote
Originally posted Here:

Carb ice forms because the pressure drop in the venturi causes the air to "cool," and draw heat away from the surrounding metal of the carburetor venturi. Ice then can begin collecting on the cooled carburetor throat. This is the same principle that makes your refrigerator or air conditioner work.

Meanwhile, fuel being drawn through the fuel discharge nozzle into the airflow atomizes into very fine droplets that evaporate easily. When the fuel changes from a finely atomized liquid to a vapor it, too, cools—stripping more heat from the surrounding metal.

The result is that the carburetor's internal temperature may drop below freezing, even on a warm day. If the ambient air contains sufficient moisture (which can be the case even in seemingly dry air), frost (carburetor ice) can form on the inside of the carburetor.


[This message has been edited by Patrick (edited 09-03-2024).]