[Shotimes] Re: Heater host Q

[James F. Ryan III]

> It's not necessarily a cold climate thing.


Correct, it is not a cold weather phenom.  My airplane, and all
combustion-engine airplanes, have a 'carb heat control knob'.  Actuating the
knob allows hot air, heated by a shroud around the exhaust manifold, to
enter the induction system and prevent (or melt) ice.

If the outside air temp is between 20F and 70F with visible moisture OR high
humidity, ice may form in the TB.  Also, during low or closed throttle
settings, the TB is particularly susceptible to icing.

The vaporization of fuel, combined with the expansion of air as it passes
the partially open throttle plate, causes a sudden cooling of the mixture.
The temp of the air is it passes thru the TB may drop as much as 60F within
a fraction of a second.  So even if it's 70F outside, the temp after the
throttle plate could be 70-60=10F!!!  Water vapor is squeezed out by this
cooling, and if the temp in the TB reaches 32F or below, the moisture will
be deposited as ice just beyond the throttle plate.

If this happens in you car, no big deal, and the engine may cough, sputter,
stall, and you coast to a stop.  If this happens in an airplane, you could
be in a world of trouble if you're too low or there's not a suitable landing
area nearby.



Jim Ryan
Wayne, NJ
'91 Plus - all white/mocha with fiberglass hood, rod shifter, & rear spoiler

255 Lph fuel pump, SHO Shop can & horn, 80mm MAF, S&B cone filter, SHO Shop
HiFlow Y-pipe & cat-back exhaust, SHO Shop LPM, SHO Shop underdrive pulleys,
SHO Shop HiRevs Jr clutch & steel billet LiteWeight flywheel, reinforced
engine & trans mounts, SHO Shop TQ limiters, SHO NUT aluminum SFBs, FPS '96
SHO front brakes, Carbotech F brake pads, Nook's full-body SFCs, Koni adj
struts, SHO Shop linear springs, 24mm FSB, 26mm RSB, SHO Shop steel f&r
STBs, Bridgestone Potenza RE-730 225/55-16, CATZ MSP fog lights, police
grille

 

 

 


> -----Original Message-----
> From: shotimes-admin@autox.team.net [mailto:shotimes-admin@autox.team.net]
> On Behalf Of Ron Porter
> Sent: Sunday, August 24, 2003 10:56 AM
> To: 'Edward Mazurek'
> Cc: shotimes@autox.team.net
> Subject: RE: [Shotimes] Re: Heater host Q
> 
> Eliminating the TB water will make it much easier to get air out of the
> cooling system, as that TB area is the high point of the cooling system.
> 
> It's not necessarily a cold climate thing. Once the car is hot, the TB
> gets
> enough heat from the engine, anyway.
> 
> Wish I would have saved the article, but the TB water is to cover one or
> two
> very unusual circumstances that can occur just after cold starts (remember
> the water doesn't get hot for a few minutes, anyway). It was something
> like
> having a car in a cool garage, then driving it out into warm, humid air
> (as
> you would have in a southern climate), and there was another situation
> that
> I don't recall.
> 
> Remember that the car makers have to make products that work well in all
> climates and all altitudes. Some of the seemingly weird stuff they
> sometimes
> do is to allow for some unorthodox operating situations somewhere in their
> market area.
> 
> Ron Porter
> 
> -----Original Message-----
> From: shotimes-admin@autox.team.net [mailto:shotimes-admin@autox.team.net]
> On Behalf Of Edward Mazurek
> Sent: Saturday, August 23, 2003 7:24 PM
> To: bobsteig@att.net
> Cc: shotimes@autox.team.net
> Subject: [Shotimes] Re: Heater host Q
> 
> 
> In warmer climates it's probably OK to do this. In colder climates I guess
> the TB could ice up if the conditions were right.
> 
> I'm sure others have more empirical information though.
> 
> Ed
> 
> bobsteig@att.net wrote:
> 
> >Hi,
> >
> >What's the story with this, how can you get away w/o these hoses? Is
> there
> an
> >advantage to bypassing the TB? (by TB I'm guessing you mean throttle
> body)
> >Does it make it easier to drain and replace the coolant? What about
> >overheating the top end? I've seen this mentioned before and got curious.
> >
> >Thanks, BB-NYC '89
> >
> >
> >emazurek@cisco.com>, <shotimes@autox.team.net>
> >Subject: Re: [Shotimes] Heater host Q
> >Date: Sat, 23 Aug 2003 10:54:12 -0500
> >
> >  As far as the TB and IAC hoses just chuck them and put
> >a piece that runs from the coolant pipe back to the block....
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