I did mine and there is no freezing but then again, we only hit the single digits here from time to time unlike some other colder regions.

I like the minimal power difference but anything on a 302 is an improvement.

 

I have not experienced icing on the throttle body itself per se...

BUt after conferring with a Ford ASE master tech, he specified that it was above all to warm the throttle body as to keep it from
being iced over when in operation.

This is why an operational air by pass valve is so important.

then when the engine warms to normal operating temps, the air by pass shuts down because it assumes the TB assy has been thawed and other engine components warmed.

The tech told me that condensation can be a royal pain expecially when the weather makes temps drop below zero...
Ford engineers kept this in mind as they designed the EFI units.

For us guys here in the warmer states (California) the shutoff valve is a good option.....we all know that colder air contains more oxygen per cubic foot.....than does the hot air.....
this means a bit more peppiness off the line and it may mean a tad better mileage (if you keep your foot off the gas pedal you'll see the improvement anyway.)

I like the off the line power though....I need to get the 5.8 dynoed to see what impact the coatings and portwork have made.

I just finished getting the emissions test done and it passed pretty clean.....a new o2 sensor is also in the works....

but first is the pitman arm removal!!! arg!!!

 

Well, a search for Bernoulli's Principle netted a lot of interesting stuff. Here's one good site that talks about carbs icing:

http://www.abbysenior.com/aviation/newpage21.htm
http://www.montb3ll.net/weber/icing.html

This site goes so far as to say EFI will not ice up:
http://www.katerylien.com/professional/essays/50566.html

What I'm getting out of this is that only in the most severe cold and extremely humid climates *might* our EFI throttle bodies experience icing. Look at the size of carb venturi (note from the sites above that icing occurs because of the temp and pressure drop in the narrow carb venturi) vs the size of our tb's.

I'd be more concerned w/the tb icing while sitting overnight from condensation or humidity. In this case, as you mention, the IAB should compensate, and I'd guess if you let the truck warm up long enough (and had a properly operating t-stat!) the manifold heat would thaw out your troubles. Regardless, the stock setup cannot prevent such icing OVERNIGHT as warm coolant is not flowing during the night.

Plus, look at the altitudes and climates (and speeds) at which airplanes operate vs what our trucks operate at.

 

which is why I mentioned that tech specified icing up due to CONDENSATION......

The truck will run because the air bypass valve will compensate UNTIL the coolant warms up enough to melt anything frozen on the throttle body assembly. This also coincides with the shorter warmup period......

Comparing turbo jets to a truck's throttle body is like comparing apples to pears....even though they use the same principles of physics.....the atomospheric conditions have aparent differences.....

A good example of extreme weather is that of the midwest and
northern states.......not to mention the rockies...

You are getting this info from a Ford master technician....

*shrug*

I do have to say you put up a good debate....

:7

 

I think a valve setup that can be opened in winter, and closed in the other months is the best solution. You need 2 valves, a tee, and some hose.

1)remove the hose into the TB and put a tee in the hose from the radiator.
2)connect the 1 side of the tee to a valve and connect it to the TB.
3)put other valve on the remaining tee connection and connect it to the hose used to bypass the TB.

in winter...open the TB valve and close the bypass valve. After winter...open bypass and close TB!

This would run maybe $10-15 in parts from Home Depot. That solves the fears of icing!!!



:-X12 happy holidays...

Jim

 

Wow, you musta never done too well in those reading comprehension tests in school.

>which is why I mentioned that tech specified icing up due to
>CONDENSATION......

Yes, but as I said above you're gonna have condensation regardless of whether or not you run coolant thru the tb.

Ok, you *could argue* that the warm coolant will melt the frozen condensation sooner. BUT riddle me this: HAS ANYONE ON THIS BOARD EVER NOT BEEN ABLE TO START THEIR EFI FORD AND DRIVE AWAY IMMEDIATELY DUE TO A FROZEN TB BUTTERFLY????????????????????????????????????????? ???????

>The truck will run because the air bypass valve will
>compensate UNTIL the coolant warms up enough to melt
>anything frozen on the throttle body assembly. This also
>coincides with the shorter warmup period......

Truck won't run much above idle on just the IAB, see my question above.

>Comparing turbo jets to a truck's throttle body is like
>comparing apples to pears....even though they use the same
>principles of physics.....the atomospheric conditions have
>aparent differences.....

Here we can return the reading comprehension part, obviously you did not read the links. We're not talking about "turbo jets," we're talking about prop planes.

>A good example of extreme weather is that of the midwest and
>northern states.......not to mention the rockies...

Midwest and northern agreed. I live in the Rockies, altho sorry I couldn't stomach Aspen for more than a few minutes.

>You are getting this info from a Ford master technician....

Oh please! As if that matters. Did he actually design the motor? Was he one of the EFI *engineers?* I've seen plenty of questionable info from Ford "master techs." Sure, he turns wrenches all day (NOT a bad thing) but he has no true idea what the original intent was of the Ford DESIGNERS.

>*shrug*

Ditto.

 

[updated:LAST EDITED ON 13-Dec-02 AT 03:32 AM (EST)]re:Wow, you musta never done too well in those reading comprehension tests in school.
-------------------------------
First of all I see no need to start insulting people.....

I merely see both of us trying to prove a point

I am clearly seeing your point of view as a valid one....

I am merely quoting a master tech that has been working the industry for over 20 years.

As for my studies, I currently have a 3.8 with calculus, chemistry and physics as a work load......so my comprehension is fine, thankyou.

As far as the debate goes I will have to talk to my mechanical engineering instructor....ha may have better insight as to why the Ford engineers did what they did.

I will get back to you with a more detailed answer.

Stay tuned.

 

re: altho sorry I couldn't stomach Aspen for more than a few minutes.
--------------------
I merely travel to this area to visit my sis and bro in law and do some skiing and snowboarding.

The summer months yield some good trout fishing....and horseback riding....

I do have to admit Aspen is more of a look at what I have society.....the ranch is actually 11 miles outside of ASpen....
we only go to town to have a nice dinner from time to time.

So you see, we can actually agree on some things *g*

 

>Well, a search for Bernoulli's Principle netted a lot of
>interesting stuff. Here's one good site that talks about
>carbs icing:

Honney you forgot the one critical thing for carb icing; You need to have the introduction of the the fuel in a mist which super cools the air in the venturi which causes the humid air to freeze. For carb icing to occur the dew point and the temp have to be within a few degrees of each other without all these factors coming together at the right time you can not get carb icing.

>Plus, look at the altitudes and climates (and speeds) at
>which airplanes operate vs what our trucks operate at.

An airplane is more likely to get carb icing on the runway taxiing than flying at attitude. The type of icing that a plane will get at attitude is not what is called carb icing, it is icing that will occur from ice in the air and is called rime ice or sheet ice and is totally different than card icing. A airplane in Florida taxiing in 60 degree weather has more to fear from carb ice than a plane up in Aspen in below freezing weather. This is all to do with the dew point and temp ratio. But what is more important is you will not get icing of the TB just from the venturi effect in the Benoulli's Principle you have to add fuel to the equation and with the fuel being added way down stream near the valves you cannot get icing from this. The only way to get the ice would be as you said from condensation build-up over night in freezing weather.

As a pilot I have a lot of knowledge on this subject. We are taught what causes carb icing and how to cure carb icing. Pilots are very concerned with this issue because it can put you in a dangerous situation very quickly. I hope this clears up any mis-conceptions about carb icing. As for the the mod talked about here I did this to my truck over a year ago with no problems and I have nothing but good things to say about this mod. Good luck to all, who try this mod,

Rick
86 302 EFI, bored 60 over, AOD,
Headman Headers, Flowmaster 40 series,
2 inch dual exhaust, MSD ignition

 

>Honney you forgot the one critical thing for carb icing; You
>need to have the introduction of the the fuel in a mist
>which super cools the air in the venturi which causes the
>humid air to freeze.

No, I didn't forget that but my brief research indicated that the air alone was enough because it is a moving fluid as applied to Bernoulli's Principle. OTOH other sites do say (now that I look closer), "Vaporization of fuel and expansion of the air in the carburetor causes sudden cooling of the air/fuel mixture."

>The only way to get the ice would be as you said from condensation >build-up over night in freezing weather.

That's what I'm thinking, in which case the warm coolant won't help you until the truck's warmed up, and the coolant thru the tb will not *prevent* this overnight.

>As a pilot I have a lot of knowledge on this subject.

I don't doubt that and will defer to you on such matters.

>I hope this clears up any mis-conceptions about carb icing.

Not really but thanx for trying.

>As for the the mod talked about here I did this to my truck over a
>year ago with no problems and I have nothing but good things
>to say about this mod.

I'd like to state I believe the power gains from this "mod" are negligible. I did it ONLY to clean up the engine compartment and create one LESS failure point for the cooling system while on the trail. I'm a firm believer in the K.I.S.S theory and running superfluous coolant lines all over the engine bay does not fit with that.

 

>I am merely quoting a master tech that has been working the
>industry for over 20 years.

I am NOT saying the tb will not ice up, and if I experience this I'll be the first to admit it. I'm just *questioning* whether or not the coolant lines are necessary in a real-world environment. At the present time I'm very skeptical.

Examples abound of every auto manufacturer designing questionable things. Just a few of Ford's: distributor mounted TFI modules, rusting tailgates, cracking rain gutters, auto hubs, push button transfer cases, and Twin Traction Beam.

I'm just wondering if the tb coolant fits in the above list.

 

I just read something that made sense.....

re:"Vaporization of fuel and expansion of the air in the carburetor causes sudden cooling of the air/fuel mixture."

Think about this......if the expanding air causes it to cool (principles of air conditioning) then what will heating the air up to 200 degrees F do? compressing air heats it up.....

so if you heat the air, the molecules will go up in psi.....

Now I am thinking more of keeping each runner in the manifold semi force filled with air.....keeping runner velocity up.....

this is a good discussion!!

:-)

still haven't had the call to my instructor returned....

 

Anyone have some photos of the bypass? I would like to see what it looks like when finished. Maybe a how to and parts listed so it would be easy for the rest of us to do it with the Valve so you can switch it on and off.

 

btw the efi 460 throttle body has no coolant lines but is nearly the same as the small block tb

 

Was reading this post out of interest on the egr blockoff and then got caught up in all the debate. About 8 years ago I had a 1989 Bronco 2, I know this is big bronc forum but my problem relates to your issues. I had a short drive to work and live in the midwest, in summer we will see over 100 degrees f. with humidity sittin around 90%. In the winter with wind chill it will get down to 50 to 60 below on very cold windy nights. Well my tb froze up. I would let it warm up long enough to clear the windshield and go to work, rarely did the motor warm up to normal on the guage on these short cold drives. I was driving to work went to downshift and the rpm increased, tapped the pedal and it moved as normal but did not affect rpm, so I put it back in a high gear to slow the engine down and shut it off. Had it towed to dealer, they found no problem,(it had warmed up in their shop), the next morning same thing happened. Third day I let it fully warm up before going to work and blocked the radiator with cardboard. NO problem that day. Called the dealer and told them, they said bring it in and they would leave it set outside and check it in the morning. That afternoon they called and said the tb was icing up, while it was this cold out just let it warm up longer. So yes they can freeze but it takes a temp extreme to do it. I know this was long but I hope it helps clear up some of the confusion.
T. Roberts
UFD Local 1147