While googling around for it's purpose I found a few sites that said it reduces emissions at cold start while the engine is warming up. However the majority of sites say to stop the TB from freezing up in the winter. Apparently while the engine is running even. Here's one quote

Humm I would have thought the heat transferring up the aluminum intake from the cylinder head would more than keep the TB from freezing up.

So what do other guys in cold weather do? Here in KC we see cold below freezing temps in the winter. I think the coldest I've ever seen was -20F but 0F to single digits is more common winter temp here.

There's probably very minimal HP to be gained by removing them but worth checking into. I noticed the coolant hose actually loops after the TB and goes through part of the intake just behind the TB as well.

 

I bypass mine due to the coolant temps running through the intake manifold. I also don't drive the car much once the temps drop too low. I use to switch them back to stock for winter when it was my driver.

 

I removed my fast idle thermo valve and joined the coolant lines.Blocked the throttle body off with a plate.Only because i was cleaning it and broke the plastic plunger inside and could no find a cheap enough replacement.
I also have that same problem with cold weather and my car stalling every now and then as i'm warming it up.Now i now why.

 

Hmm interesting read... Something to keep in mind!

 

It was mainly implemented for cold weather starts to heat the intake charge. All it does on performance applications is raise IATs for no good reason.

Ditch them

 

Interesting info. This is my daily so sounds like I'll just leave it there. Frozen up in the winter doesn't sound like any fun lol.

 

Ya if you live in cold climate leave it on.Remove it if you live in places like California.
It did not effect my performance.
I removed mine because my FITV malfunctioned causing my idle to fluctuate when cold.Tried cleaning it and that's when it broke so i just left it off.Its not worth replacing.
No idle fluctuation now just stall problem as its warming up when cold outside but it starts back up right away.

 

I'm in cali and loop or block all my coolant lines. Besides the heater and radiator.

 

Yeah freezing cold here in winter so I'll leave it.

 

I always wondered about this. Prior to my Civic I owned 3 Saturns, which have a similar intake manifold and TB placement to ours, however they do not have any coolant lines going through the TB. All through college in Utica, NY I never had any problems with the TB sticking, and I would frequently have to drive to class at 7am with temps below -10F.

I wonder if Civics transfer less heat into the TB? Or perhaps the main reason for including the coolant lines was emissions and not preventing a freeze up.

 

And what about the water in the IACV??

 

That is very odd. Probably to stop it freezing up too?

 

don't know too, Have you removed this water hoses?

 

I bypass the tb and the iacv here in texas. It get below freezing in the winter and I don't have any trouble.

 

I bypassed mine because looking at the skunk2 throttle body's the black series tb has the coolant passage deleted to keep the tb cool in racing conditions. The cheaper alpha series skunk2 tb has it. So i just got the cheaper skunk2 alpha 70mm tb and just bypassed the coolant passage. I dont think theres much major difrences between them.

 

Removing the lines from the tb is no big deal in cokd weather.

You need to remember that as the motor temp goes up every part of the motor heats up. So you'll already have heat in the intake manifold and tb and iacv... and even in cold weather the temp of the air in the engine bay gets pretty high as well.... so unless you have a real cold air intake setup on your turbo, iyou'll be ingesting air that's over the freezing point. While the intercooler will get those temps back down pretty lol you need to remember that the interintercooler piping (cold side) will absorb ambient heat from the engine bay and transfer it to the charge air.

 

I was wrong with my problem.
The stalling issues i had was a clip on distributor rotor that was loose.I put back on the old screw on type rotor and i have no issues.Don't buy the clip on type by the way.
I live in Spokane Wa were its cold right now and my car has been running excellent without the FITV.

 

Where is this clip?

 

If the car is stock why worry about it? If the car is modded as most are in here, why worry about it. I doubt your driving a heavly modded car in that cold of weather, lols. In cali I took all that off. No need for high iat casue of engine coolant heating the tb.