Running without coolant to Throttle body/plenum?

[youdirtyfox]

Yo Guys just been looking at where to hook up coolant lines for my Turbo (B6 & IHI VJ)
and it looks like the heater(matrix) hoses are what most people T into then I noticed they have outlet/inlets
already on them for the TB/plenum feed ( is it TB & plenum? or just TB?) wonder if I can use them for the Turbo...

So I know most of you live in colder climates and all but has anyone/ or does anyone know if
running without these feed lines to TB&P have any adverse affects on running?
If it is just to TB I should be fine removing me thinks.
Thanks
Sam.

[WhiteFinish]

Aren't turbo's cooled by oil?

[youdirtyfox]

Yes they are but some turbo including mine use water as well which helps in the cooling down period.

Turbo that just use oil will have larger oilways inside.

[Nd4SpdSe]

People have talked much about just bypassing that to keep the intake cooler.

Bypassing the coolant lines to the Idle Air Controller means that you'll have rought cold start idles, even in hot weather

Inside the IAC there's thermowax that melts as the coolant get hot, which helps to adjust your idle are your car warms up.

The only way you can successfully not use the IAC is when you're running Megasquirt.

[youdirtyfox]

Ah ok thanks for the info. I will leave that all installed then.

[nolig2278]

But it takes several minutes for the coolant to get warm so how does that help the idle controller. I removed my coolant lines to tb a while ago and I do sometimes have rough starts but I think my bpt has always had rough starts for one reason or another.

Thanks

[MrMazda92]

The only way you can successfully not use the IAC is when you're running Megasquirt.

Please clarify...

I have had mine unplugged for more than a year, without a CEL or rough starts. 2-3 cranks on sub freezing temperature mornings, after not driving it for days.

My MegaSquirt is in a box, on top of my computer tower.

Do you mean to say that it the plug only affects the idle RPM, and the wax itself decides whether or not the coolant feeds through the TB?

I've seen the argument that dry ice, A/C systems, and other methods of "overcooling" intake charges do not function, because the air is moving too quickly through the coated, packed, filled, etc. areas to transfer any thermal energy to or from the cooling medium.

If that is the case, how would the reverse be any different?

I've been curious about this for a while now...

[Josh]

Sam- I Y'd mine in on the TB line off of the hard feed line from the pump. Did not have any issues.

The other thing would be to source a B6T or BPT water pump tube. Either should work just fine. I will look I may have a second one. With the turbo you will probably want to have the IAC for proper warm up.

Whitefinish- Good turbo's or "reliable" turbo's are oil and water cooled With a water cooled you do not have to have a turbo timer for cool down, and they tend to last longer than just an oil cooled.

[Ryan]

Keep in mind its also a safety thing too. The throttle is a (very inefficient) venturi. The pressure drop can cause ice to form around the throttle plate stopping it from closing... which is clearly bad. The hot coolant keeps this from happening.

[Josh]

Aww yes, I never thought about that being an issue in our car but it is very much a reality. One of the bigger issues when I was flying Robinson's. Could be a scary situation.

[Nd4SpdSe]

But it takes several minutes for the coolant to get warm so how does that help the idle controller. I removed my coolant lines to tb a while ago and I do sometimes have rough starts but I think my bpt has always had rough starts for one reason or another.

Exactly. Because there's a wax (thermowax, ohhhhhhh) that the coolant has to melt, which adjusts the idle. Here's a good description

This is a device on the throttle body that is fed by 2 coolant lines. It is a cylinder filled with wax, and when cold, the piston is retracted into the cylinder. An adjusting screw rides on the cylinder, and by way of a pivot, rides on a cam which is connected to the throttle plates. When cold, the setup holds the plates a hair open all the time (as if your foot were on the gas) to keep the cold engine idling a bit higher. As the engine and coolant warm up, the wax melts, the cylinder expands out, and pivot moves off the cam, and the plates close up to normal position (slowly) and normal idle speed.

Please clarify...

I have had mine unplugged for more than a year, without a CEL or rough starts. 2-3 cranks on sub freezing temperature mornings, after not driving it for days.

Do you mean to say that it the plug only affects the idle RPM, and the wax itself decides whether or not the coolant feeds through the TB?

You won't get a CEL. It does only affect your idle rpm. MS is a very smart system and this is what I've read and been told. Being that the OEM system is designed for, knows about, and knows how to control the IAC and relies on that system, it only makes sence that it doesn't work right when it's not there doing what it's suppose to do. MS is smart enough to play with the injection and timing enough to control your idle with the IAC disconnected, so a limit, but depends if you connect only the IAC with the coolant lines disconnected, connect only the coolant lines and not connect the IAC stepper motor, or disconnect everything altogether. Here's some info:
http://www.diyautotune.com/tech_article ... uning.html

I've seen the argument that dry ice, A/C systems, and other methods of "overcooling" intake charges do not function, because the air is moving too quickly through the coated, packed, filled, etc. areas to transfer any thermal energy to or from the cooling medium.

Depends
- Dry ice, and ice, we've done that for cooling at the strip between runs. Remember that metal is a fast material to transfer heat. The concept is explained as simple as for those who "firewalk. Say you got an oven, baking a breat at 350. Everything in that oven is at 350 degrees. You touch the bread, your ok, you touch the metal pan or the grill and you'll burn your finger pretty good. The only way to tell would be to have an IM sitting outside the car, heat it to what it would be on your motor, pass regular air through it and measure the temperature coming out on the other end, that will tell you on how fast it can absorb that temperature difference. Besides, It doesn't cost HP to throw ice on the IM, so why not, what would it hurt really. Would 1lb of ice affect your 1/4 mile, doubt it.

A/C doesn't work because of the laws of thermodynamics. A/C costs HP to use. What it costs in HP you won't make up or gain from because the air is now cooler.

Keep in mind its also a safety thing too. The throttle is a (very inefficient) venturi. The pressure drop can cause ice to form around the throttle plate stopping it from closing... which is clearly bad. The hot coolant keeps this from happening.

Could it also cause the TB to contract (especially with tight tolerances) when very cold, jaming up the TB as well?

[MrMazda92]

I agree wholeheartedly with the point about the throttle plate freezing in place, that's valid and I hadn't thought about it previously!

It's not a huge concern however... Unless you regularly fill your TB with water Even sitting overnight, the potential for condensation buildup on the throttle linkage would be a moot point as well, as the buildup would occur while the throttle was "closed", or as close to it as the stopper allows.

I currently have the coolant lines running through the TB still on my '92(or did, rather, before pulling the IM and TB), but did disconnect the stepper motor. I only ever had problems before disconnecting it(perhaps the motor was bad?), as my idle would start out very high no matter the coolant temp. and only drop after freeway speeds... Driving around town it would not drop below 1,200 or so unless I revved it to 4K+ before slowing to idle again.

That is an informative link, that'll help me to decide my exact course of action after I begin tuning with MS... Maybe I'll figure out what went wrong with my stepper motor to begin with. I always just ran my idle a little high(~900) to make up for accessory draw(stereo, mostly), and my A/C is no longer a factor thankfully.

I was too vague in my dry ice statement, I specifically meant that the same argument people use to say that "using A/C and or dry ice to cool an intake charge(i.e. packing it around the intake plumbing)" will not increase power output because the air is traveling too quickly to cool can also be applied to the "The coolant warms the intake charge on cold start" statements.

I agree thoroughly with what you said about dry ice, and I believe it would most benefit people between runs as you mentioned...

[nolig2278]

Great info,
Quote:
This is a device on the throttle body that is fed by 2 coolant lines. It is a cylinder filled with wax, and when cold, the piston is retracted into the cylinder. An adjusting screw rides on the cylinder, and by way of a pivot, rides on a cam which is connected to the throttle plates. When cold, the setup holds the plates a hair open all the time (as if your foot were on the gas) to keep the cold engine idling a bit higher. As the engine and coolant warm up, the wax melts, the cylinder expands out, and pivot moves off the cam, and the plates close up to normal position (slowly) and normal idle speed.

But my car often stalls when starting up or with in 2 minutes with the coolant disconnected from tb. Since I am in south Florida I don't have to sorry about freezing and I am willing to let the throttle stay open a little extra side the wax isn't melting.

[wytbishop]

People who experience wierd idle problems like the one Blake described are often suffering from low coolant. Because the TB is the highest point in the cooling system if you're low, an air pocket will form there and the thermowax cools enough for the little piston to crack your throttle plate. Rev it up and it circulates the coolant in there, heats the wax and she closes.

I drove with that condition for months before I figured it out.

Disconnecting the coolant lines to the TB is one of those hit and miss things. Some guys it works ok and they swear by it, other guys it's a nightmare.

[Ryan]

I agree wholeheartedly with the point about the throttle plate freezing in place, that's valid and I hadn't thought about it previously!

It's not a huge concern however... Unless you regularly fill your TB with water Even sitting overnight, the potential for condensation buildup on the throttle linkage would be a moot point as well, as the buildup would occur while the throttle was "closed", or as close to it as the stopper allows.

This is wrong. Air always has a moisture content, called humidity. This humidity is what condenses in the pressure drop across the venturi. Has nothing to do with liquid water. Has nothing to do with still condensation overnight.

Because thermodynamics.