Throttle Body Coolant Bypass - Do I revert it to stock for the winter?

[timxpx]

Originally posted by: DEMO24
not even sure why you would bother disconnecting that.

also 11k miles and already replacing the brake pads? damn!

why i did it -- my friend that installed the CAI is pretty knowledgeable... he's installed turbos in 3 of his own cars out of his home garage, one of them included a full engine swap, as well as various other projects. he said the TBB would be paired nicely with the CAI to cut back on heatsoak... and since the CAI kit came with replacement hoses for everything, they had to come off in the first place.

brakes -- there are a little less than 22k miles on the brakes actually -- i put the CAI/TBB with 10k on the car already. 11k is how many miles i've put on since the CAI/TBB

i go through a bit of stop and go traffic around rush hour so i'm guessing my pads would last a little longer if that weren't the case. :frown:

 

[steveox]

It won't freeze. It's not cold enough in NJ. It's next to a thousand degree engine. I say leave it

 

[LTC8K6]

"It won't freeze. It's not cold enough in NJ."

You just keep repeating that when the throttle sticks...

 

[jagec]

Originally posted by: steveox
It won't freeze. It's not cold enough in NJ. It's next to a thousand degree engine. I say leave it

LOL @ thousand degree engine. Aluminum MELTS at 660 C.

Also LOL @ NJ never getting below freezing...I remember driving through there in a terrible blizzard once. There was a good quarter-inch of ice formed on my headlights when I stopped for gas...much more on the rest of the grille.

 

[alkemyst]

Originally posted by: boomerang
Hook it back up.

It could get pretty exciting if your throttle body ices up and the throttle sticks part way open. Coolant is circulated through there for more than warm up.

Now, if you lived in Florida, well I'd say let it be. But NJ, get on it.

QFT...if it freezes where you are at you may find out the hard way why the coolant runs through the TB

 

[steveox]

It's over 1000 degrees inside the engine block - which is metal. Exterior temps are probably around... 150? 200? This is then connected to the metal intake manifold (metal conducts heat, right?) which is then connected to the metal throttle body (still conducting heat?) Ambient under hood temps are always WAY above freezing (once again - 80 degrees at the minimum) so even if the IM was plastic or there were non-heat-transferring gaskets... What happens when you put an ice cube in a sink (room temperature - 68 degrees). It will melt. That engine is warm. Someone PLEASE show me an example where someone did this mod and they were driving down the road at 90 mph and couldn't stop because their TB froze open.

Not gonna freeze. Seriously.. you guys are WILD.

 

[boomerang]

Originally posted by: steveox
It's over 1000 degrees inside the engine block - which is metal. Exterior temps are probably around... 150? 200? This is then connected to the metal intake manifold (metal conducts heat, right?) which is then connected to the metal throttle body (still conducting heat?) Ambient under hood temps are always WAY above freezing (once again - 80 degrees at the minimum) so even if the IM was plastic or there were non-heat-transferring gaskets... What happens when you put an ice cube in a sink (room temperature - 68 degrees). It will melt. That engine is warm. Someone PLEASE show me an example where someone did this mod and they were driving down the road at 90 mph and couldn't stop because their TB froze open.

Not gonna freeze. Seriously.. you guys are WILD.

So when you start your car after sitting idle overnight, it instantly goes from 5 above to 1000 degrees? (Where in the hell did you come up with that number BTW?)

Don't pursue mechanical engineering as a career path. You're not cut out for it.

 

[steveox]

So then how does the coolant warm up the car so quickly? It's not warm when you start it. Your own logic proves your own stupid theory wrong. The coolant will be just as cold! And i'm not saying you're going to start the car and instantly go WOT, nobody does that. Once that thing runs for a minute - underneath the hood is 100 degrees and everything will thaw out.

ALSO, it's drive by wire which means there is an electronic lil guy controlling it. Obviously you're so smart so you know how much force is actually needed to move the TB open and closed... but it doesn't have enough power to pull through a millimeter of ice forming?

And i got the numbers from the egt - because that's what is coming out of the engine block - and generally at idle it's around 900-1100 degrees - at WOT you can easily hit up to 1500

 

[ayabe]

I live in FL so it very rarely gets below 40 degress but we have a few freezes per year. I ran a CAI with the bypass for 6 years on my GSR with no problems FWIW.

 

[alkemyst]

Originally posted by: boomerang

Originally posted by: steveox
It's over 1000 degrees inside the engine block - which is metal. Exterior temps are probably around... 150? 200? This is then connected to the metal intake manifold (metal conducts heat, right?) which is then connected to the metal throttle body (still conducting heat?) Ambient under hood temps are always WAY above freezing (once again - 80 degrees at the minimum) so even if the IM was plastic or there were non-heat-transferring gaskets... What happens when you put an ice cube in a sink (room temperature - 68 degrees). It will melt. That engine is warm. Someone PLEASE show me an example where someone did this mod and they were driving down the road at 90 mph and couldn't stop because their TB froze open.

Not gonna freeze. Seriously.. you guys are WILD.

So when you start your car after sitting idle overnight, it instantly goes from 5 above to 1000 degrees? (Where in the hell did you come up with that number BTW?)

Don't pursue mechanical engineering as a career path. You're not cut out for it.

Nominated for idiot of the year posting. Fails for realizing many intake manifolds are no longer metal as well.

 

[steveox]

Fails to realize that OPs intake manifold is metal. Also fails because I took into account plastic manifolds in my logic. Next?

 

[LTC8K6]

It doesn't need to be freezing outside for the air passing through the TB to create ice in the TB.

So the fact that "it doesn't get cold enough" is meaningless. It gets cold enough on the back side of the throttle plate.

The TB is heated for a good reason.

However, as I said before, it's not my car and anyone is certainly free to believe what they want and do what they want with their car.

Unlikely doesn't mean never.

 

[steveox]

Originally posted by: LTC8K6
It doesn't need to be freezing outside for the air passing through the TB to create ice in the TB.

So the fact that "it doesn't get cold enough" is meaningless. It gets cold enough on the back side of the throttle plate.

The TB is heated for a good reason.
[...]
Unlikely doesn't mean never.

I'm not saying that it doesn't need any heat, I'm saying the ambient temperature created by the engine is warm enough to prevent the TB from freezing.

You are right about saying never, so maybe I wouldn't say never but I would say it has less than .00001% chance of happening.

Once again, I base this on previous experience, and user feedback. As stated before I have not read/heard/seen/watched a single case of the TB freezing open while driving. Show me where it happened and I will stop talking. (Generic statement, not to the individual quoted above)

 

[LTC8K6]

The temp of the engine block has nothing to do with it, though.

All of this has already been explained in the thread.

You need to worry about humidity more than temperature, anyway. It's cool, humid air that causes the trouble. It's not freezing cold air, because freezing cold air can't hold the moisture that would form the ice.

When air pressure drops, the air cools, and it can't hold the moisture anymore. So you get condensation along with cooling in the TB.

Except you don't, because the mfg knows all this already and heated the TB.

I see no point in going over it all again.

 

[alkemyst]

Originally posted by: steveox
Fails to realize that OPs intake manifold is metal. Also fails because I took into account plastic manifolds in my logic. Next?

you failed son, do not pass go, do not collect any IQ.

You answered in general, so I replied in kind.

What is your logic in why the coolant passes through the TB?

On start up both the engine and TB will be cold as well as the coolant.

Please explain...

 

[steveox]

Warmer air = less gas = inflated MPG because that's all auto makers care about

the reasons for mentioning the engine block temp were simply to state that as a whole - underneath the hood is going to warm up (nobody is going to argue that)

as the ambient temp under the hood is warmed - so are the items inside of it - the throttle body - thus being sufficiently warm enough to not freeze while under WOT.

the only reasons i'm continuing on with this is: a) still not a single example of it freezing b) someone above was all hard-ass blah blah when you kill a family because your TB is stuck open

also: what about the oil vapors that are present inside the throttle body? those aren't going to freeze

 

[LTC8K6]

Once you start moving, the under hood temp will equal the outside temp, so you can quit talking about how hot things under the hood get as related to TB icing.

Who drives at WOT anyway?

The venturi effect would be most pronounced at part throttle.

I don't have any oil deposits in the TB on any of my cars, so I guess the oil vapors are minimal.

The heated throttle body will not warm the intake enough to make a fuel economy difference, although I suppose on a cold day every little bit helps.

You can, of course, "what if" all day long.

You ask for examples of TB icing, but hardly anyone disconnects the hoses or installs an insulator pad, so why should we expect to hear much about TB icing?

TB icing was bad enough on some cars that recalls were issued to retrofit heated TB's on them.

This is all well known.

Here is one example: Yes I know this particular one mentions sub zero temps, but it is well known that such icing does not require such low temps, but rather cool temps and high humidity. I believe this one occured in the lower temps because the cars already had some anti-icing, but it was just not good enough when temps got really low.

NHTSA Campaign ID Number: 79V206000
Recall Date: 09/14/1979
Component: 1976 SAAB 99 VEHICLE SPEED CONTROL
Potential Units Affected: 61739
1976 SAAB 99 VEHICLE SPEED CONTROL
Recall Date: 09/14/1979

Summary:
UNDER CERTAIN CONDITIONS SUCH AS AMBIENT HUMIDITY AND VEHICLE PRE-CONDITIONING BY REPEATED COLD START, AND SHORT TRIP DRIVING CYCLES IN COMBINATION WITH SUB-ZERO TEMPERATURES, THERE EXISTS THE POSSIBILITY FOR ICE TO FORM IN THE THROTTLE HOUSING AND TEMPORARILY IMPEDE FULL CLOSURE OF THE THROTTLE PLATE WHEN THE ACCELERATOR IS RELEASED. THIS ICE BUILD-UP IN THE THROTTLE HOUSING MAY CAUSE HESITATION IN VEHICLE DECELERATION AND INCREASED STOPPING DISTANCES.

Consequence:


Remedy:
THE DEALER WILL MODIFY THE ENGINE INTAKE SYSTEM TO FURTHER IMPROVE PREHEATING OF INCOMING AIR IN COLD WEATHER. THIS WILL BE DONE FREE OF CHARGE.

Potential Units Affected: 61739

Notes: SAAB 99

 

[steveox]

There are a very large # of people who HAVE done this mod though. If you search google, you will see a thousand threads just like this one of people going back and forth whether or not it's bad for the car. Nobody really knows. That's basically what I'm getting at. You gave evidence of a 30 year old car that is a completely different animal. Things are infinitely different since then. Electronic throttle bodies? Fuel Injection?

I'm glad you gave the example - I think it's awesome because this is finally getting into more than just a you're right - i'm wrong thing, but I don't see where anyone who has done this mod has had issues. That's all I'm saying.

 

[LTC8K6]

The example I gave is an early fuel injected car. That's precisely why I gave it.

According to you, the TB is hot anyway, so why would they have TB icing even if they disconnected the hoses?

Apparently the mfgs go to the trouble of heating the TB for no apparent reason, since it gets hot anyway all on it's own.

It turns out that on some cars, the TB coolant flow is controlled and it only comes on if the engine computer thinks it's cold enough, so the stupid TB heat isn't on most of the time anyway, so some people are disconnecting....nothing.

There is also the location of many TB's, such as on the LS6, which are nowhere near close enough to get much heat from the engine block.

That is my last comment on what I think is the poor practice of disconnecting or getting around TB heat.

 

[jagec]

Originally posted by: steveox
It's over 1000 degrees inside the engine block - which is metal. Exterior temps are probably around... 150? 200? This is then connected to the metal intake manifold (metal conducts heat, right?) which is then connected to the metal throttle body (still conducting heat?) Ambient under hood temps are always WAY above freezing (once again - 80 degrees at the minimum) so even if the IM was plastic or there were non-heat-transferring gaskets... What happens when you put an ice cube in a sink (room temperature - 68 degrees). It will melt. That engine is warm. Someone PLEASE show me an example where someone did this mod and they were driving down the road at 90 mph and couldn't stop because their TB froze open.

Not gonna freeze. Seriously.. you guys are WILD.

Aluminum is a great conductor. Steel is actually quite poor. Stainless steel is lousy. The block itself will be at a fairly even ~90-something C. On cold days, the under-hood temperatures will be significantly lower than that, given the constant swirling of cold exterior air into the bay and around the block. The hot gases inside the block have a very low heat capacity, very small residence time, and poor heat transfer coefficients between them and the metal which surrounds them. Conduction depends on temperature differential, material properties, and area...generally the TB-engine block connection isn't very high-area at all, AND it's internally cooled by the air rushing in and the venturi effect. Carb icing was a serious problem back in the day...while carbs were also evaporatively cooled by gasoline, it's still quite possible for these things to ice up just based on below-freezing ambient temps and the venturi effect.

 

[alkemyst]

ftw...in sub zero temps with a coolant bypass I am betting MANY TB's (since some are mounted differently) are not hot to touch.

Still even if it doesn't happen regularly do you want to give up 1-2HP over a possible self-assplosion?!?