why the liquid ITB simply won't work
 

After having read through quite a bit of those threads, and gathering some extensive information on the thermal dynamics of the "liquid cooled ITB", I am going to write this post up as something informative.

First, the bypass of coolant to the ITB. The coolant circuit in the throttle body is to speed up the idle stabilization after a cold start. The coolant that runs through the throttle body warms up the quickest because it is recirculated (sorta like the heat riser system on carbed engines or like "carb heat" on airplane engines). Running cool or cold water through there may only fool the ECU into thinking that the engine hasn't warmed up yet and it will continue to keep the idle high and continue to run a richer mixture. Obviously a richer mixture can cause some horsepower loss and even wreak havoc with your idle. If you bypass the coolant flow, the sensor inside does not see the temp of the coolant, and will cause the engine to run richer longer, and your engine will take longer to warm up and stabilize your idle. This is even more so when the weather is colder.

Second, the "liquid cooled ITB" theory. Running a cold liquid through someplace that is meant to receive hot liquid should be a bad idea for several obvious reasons. First, because of the cold liquid, the engine will be even more confused, and this can exacerbate the situation above, as mentioned with bypassing the coolant in the first place.

Also, this is like trying to use a spray bottle full of your own pee to put out a forest fire. The greatest amount of heating and heat transfer occurs in the intake manifold. This is where your intake charge heats up the most. The main reason being the heat via conduction from the head. The little piss stream that flows through the cooling jacket of the ITB has nowhere near the surface area or cooling capacity to even be effective in cooling down the intake charge. In other words, you could run freon or dryice/alcohol mixture through there all you want.... it's not going to do jack. It can, however, screw with your idle and your air/fuel mixture. Think about this from a thermal standpoint. Look at a front mount intercooler for a turbo, and all of the surface area it has with all the tiny foils, etc. That is the kind of surface area you need to cool the intake charge. Again, the ITB simply won't cut it.

The entire purpose of the ITB coolant jacket is to help in colder temperature, is to warm up the ITB just enough to it can get a stable idle after a cold start. After the engine is up to temp, it has no effect on the intake charge temp no matter what you do or don't run through it.

it was still a good thought. it will happen one day

what are you talking about? what will happen one day?

who here has itb's on their car? :|

leave it to s200man and his never ending knowledge of useful junk that nobody else feels like researching. good thread :)

A very imformative post..thanks for the knowledge!!!!!

Better have Gearbox take a look at this, he seems to be the DIY leader of the TB bypass mod.

Its true. I already started to have SERIOUS idle issues. The car would almost choke out and die after a cold start, and sometimes rev for no reason even while driving! The car felt like a mess. Well I reset my fuel trims and the ecu after putting back the coolant hoses. So far the car runs great, even better than before. With the TB mod, I hit the gas and the car wouldn't go. Felt like it was running very rich. Now its a big difference and actually feels faster today at 90F degrees. I think everyone should put the coolant hoses back on the TB. Its a false mod, and I was very wrong to make a big post about it. I had read the adverse effects and posted about them (the sensor problem), but so many people said it was fine so I went ahead and tried. Well its staying stock now and I suggest everyone do the same. Don't forget to do the coolant bleed because I had tons of air bubbles after putting it back to stock. When car is cold, open the radiator cap and run the car til warm. When warm, turn the heater to full blast and watch until no more air bubbles pop. Keep adding coolant to the radiator as it goes down. Revving the engine a bit helps too. Then turn ac to full blast and make sure no air bubbles appear. Turn off car and replace cap. Should be fine now.

ok. so now we know. thanx

Being misinformed on a mod is not your fault. You thought you had something that would work, based on the knowledge you had been presented with you. Can't expect everyone to know everything. :) You weren't wrong in any way.

This thread has gotten out of hand so im going to provide some PROOF


1. Yes Bypassing the throttle body heater will result in a performance increace. There is simply NO need for it in the summer

2. The throttle body heater was designed to do exactly that HEAT THE THROTTLE BODY. In cold places in the winter it snows. snow = condensation.
A sticking throttle body in the winter time with snowy roads could be fatal. Remember people that live in cold areas shoud/do let their car heat up. Your a moron if you hop in your car and drive without letting it heat properly if its 32 degrees or colder, thats bad for your engine.

3. Though it appears that the little motor near the TB circulates fluid, it has NOTHING to do with the heating of the TB. That is for the idle control.

4. The area that houses the coolant is less than 1 cubic inch. (not exact but close). You could run 32 degree water in that area with a large pump and its still wouldnt work. The throttle body is bound to get hot because it sits about 1 foot away from internal combustion temps of 2500 degrees or more.

Now for the pics......................

Heres how it appears with the Idle control valve and the coolant entry and exit lines.http://memimage.cardomain.net/member...323_8_full.jpg

Here the same view with the cover peice removed.
http://memimage.cardomain.net/member...323_9_full.jpg

Notice
1. Gasket seperating the coolant entry, the idle air intake and the port that send this air into the intake manifold.
2. How small the coolant pocket is.
3. The intake port is black from the being so close to the area of combustion.
In this pic you can see the intake port (where the light is shining through)
http://memimage.cardomain.net/member...23_10_full.jpg


Now theres some proof, this site needs more of it every thing is always speculation.

:)

:giggle:

PS the idle control sensor ONLY controls idle. It is commanded by the ECU from inputs from the Coolant Temperature Sensor, as well as the primary 02 sensor.

Here. this is from a Master ASE tech who has worked on more 7thgens than any of us can count.

No it will not result in any performance gains.

The only reason I thought it was working was the whole tb staying cooler. Heat transfers from the coolant to metal very quickly. But I guess if air moves fast enough, 1-3 inches of hot metal isn't gonna do much to heat that air.

Dizzle, you say there is no need for the iac in the summer? Then why was my car to the point of being unsafe to drive?

Nothing like a healthy debate...
I am learning a lot here...not much to add other than what s200man is saying makes a lot of sense, and the fact that gear had problems just validates it!!

Rebuttle Dizzle...Dynos to validate your point!!

Good info at the right time since im doing ITB's on my K swap. :sweet:

Just for an update, I reset the ecu and replaced the coolant hoses to the throttle body first. So far 3 days and no more idle problems.

Maybe your not the most mechanical inclined individual, but you can CLEARLY see in the pics that the Coolant passage in the TB has NOTHING i repeat NOTHING to do with the Idle air control valve. SO the fact that Gearbox says this is effecting his idle just proves he HAS NO IDEA what he is talking about.

Ya you're right I know nothing about cars. Whatever. I'm just happy that when I put the coolant hoses back, my idle got fixed.

And I guess s2kman doesn't know anything about cars either. :_please:

NO READ AGAIN. No need for the TB heater in the summer. Tough s2000man doenst believe so I know that it keeps my throttle body colder than it would be if 220 degree coolant was running through it, which equals a perfomance increase. Its a proven fact that colder air is more dense which equals more power.


READ ON
MAZDA 6
MORE PROOF

This guy claims 10 hp and .2 gained at the tracked with this mod.
http://www.ultimateresourceguides.co...-freemods.html

Yet another.
http://www.dragsource.com/tbcoolantbypass.html
http://www.bmrfabrication.com/tb-dyno.htm
And a dyno from a ws6 (i know its not a civic) dam good gain if you ask me.

lol... :hithead:

Everyone.

hm, perhaps I'm getting mixed up.

afaik, ITB = individual throttle bodies.

I'll agree with this. I did the coolant bypass and my no longer bogs in very hot temperatures... and I don't have any idle problems ...

Some master mechanic you know. If there was h20 flowing through the Idle Air Control Valve, the car would NOT idle. If that was the case the WHOLE intake manifold would be completly wet inside.

Air comes into this port, which then it goes to the AIC valve which determines HOW MUCH air will go into the intake manifold to keep the car at a steady idle.http://memimage.cardomain.net/member...23_11_full.jpg

After it passes the IAC valve that air is sent to the intake manifold via this port. http://memimage.cardomain.net/member...23_12_full.jpg


How the IAC works. There is a small rotor inside this unit. The rotor constantly spins. If the engine is cold its going to spin fast, resulting in a idle of about 1500-1900rpm. When the car is FULLY warmed up the speed of the rotor slows down, to give you a stable idle of 720 +- 50 rpm, again this is based off the coolant temperature sensor as well as the heated 02 sensor.

Pic of the IAC
http://memimage.cardomain.net/member...23_13_full.jpg
Again notice the seperation of the cooland entry vs the IAC ports.

Ditto, but according to S2000man, he's probably going to tell me it's all in my head. ;)

My car actually felt more responsive after putting back the coolant hoses (prolly cause I wasn't running as rich as before). So smart guy, why did honda put coolant running to the tb if it doesn't affect the idle? And why did my car go back to working normally after I put the hoses back on?

If you say its only for heating the tb, so the valve doesn't freeze open in the winter, I can tell you that never happened in my old car, which didn't have the heater at all. On our new cars, the tb heater also heats AIR coming through those ports to determine how the car idles. when the coolant warms up, it also warms the air going through the ports, which tells the ecu that the car is getting closer to operating temp.

Ahh.... so that DID fix your problem? After our PM's, I find it interesting that the ECU can get so far out of whack without throwing a code to give all those problems. Although I thought you had already reset it before.

Ya learn something new every day. It really drives home just how complicated these cars really are.

ya well putting the coolant hoses back actually solved the problem, since I had tried the ecu reset and it didn't help before. Thanks again for all your advice tho.