Throttle body coolant bypass

All the pictures in this thread are from S/C'd trucks and the TB is rotated 180° in that application.

 

Now that makes sense..Thanks!

 

1) 1st Gen Tundra coolant runs right around 180-185° at normal use.

2) Air flow over the MAF is about 5 gallons a second at idle. Much more at higher RPMS.

3) How can a 185° piece of metal (Throttle Body heated by Engine Coolant) heat up 5 gallons of air per second flowing across it and have much negative effect on air temp?

4) Does one think that the Engine Coolant ‘TB heater’ may be to keep the TB metal from freezing as its air is compressed at a high flow rate over itself? Air, when compressed, can be made colder even in warm ambient temps.

5) Conclusion: Keep TB heater running through TB.

 

You ever messed with engines much? colder the air = more the ponies. go read about a turbo on a diesel engine, and read why they added intercoolers instead of straight piped into the intake.

 

I know I’m a little LATE to the party
I live in Northern Maryland were temps range from teens - to - 100’s -so I really like the idea of a ball valve so I’m able to switch back and fourth with this mod

Have either of you successfully installed this ball valve setup ???
If so can I see pics and info / problems or issues
THX- appreciate anything you got

 

You can check my build page for your answer.

I wasn’t discussing Turbos in my post, but an actual Throttle Body on a 1st Gen or Turd Gen for that matter. TOYOTA ran the Coolant Fluid through the Throttle Body for a reason... to keep the TB warm in cold temps.

Back to my point: The amount of air sucking past the TB in warm temps is not going to negatively affect it as the temp will max at 185° (coolant temp max). Highest I’ve seen my intake air temp is around 140°-160° when crawling in traffic. Much less to near ambient temps when at higher speeds.

 

I like the idea and was merely conceptualizing if I were to make use of this modification...They're hard to find, like really hard, but you need micro ball valves...I cannot find tees past 1/4" but 1/8" is considered micro. I think 1/8" would be sufficient for this purpose...I too am in the cold temps and want the ability to change back to winter running mode...I haven't given up on it but have been distracted on other endeavors now...

 

Does seem to make sense to keep it unless there is some sort of real evidence there is more of a benefit in getting rid of it.

Although I am a fan of these sorts of mods....remember doing the carbon filter mod way back when I bought my brand new '07.

 

I think you guys are retarded, but out of curiosity what is the temperature drop? Because even if you have a pretty huge temperature drop, your actual density increase is a couple percent at most.

Ideal gas law can be simplified to V is proportionate to T , so your "horsepower increase" you could approximate as proportionate to your temperature change (or decrease if you're heating it in this case). Increase temperature, increase volume, don't increase air mass, so density goes down. But the "issue" with that is temperature has to be taken in Kelvin/Rankine, which is based on absolute zero.

So with some unit fuckery to keep things simple, if it's ~70F coming into the intake then you'd use ~293K, and then let's pretend the TB heats the air up by 40F, which is ~313K..... Well your volume increase/density decrease is just the ratio, so 313/293 which is ~7% change.

And you may say 7% is a lot, that's like 25hp! Well that's with a 40F increase in temperature! Idk about you guys, but I monitor my intake temperature constantly with the TorquePro app, and for normal cruising I see at most 20F increase in temperature (and with a shitty cone filter, which I'm currently replacing, so not even the stock cold air intake). So for sure this mod does "something", but I would be surprised if there was any significant difference if you actually tested the truck back to back. Course there's the argument for sitting in traffic and wanting all that power and perhaps more heat from less airflow making its wait into the intake, but I'd still be surprised if there's that huge of a temperature change from just the TB.

I think you'd have more luck wrapping the whole intake hose and box in a space blanket and insulation, but curious to see people's results.

 

If you life in a climate that doesn't see freezing temps there is no point in having coolant flowing through your TB.
Heat does not need to be added to your housing to ensure the servo motor on the butterfly does not stick. There is no benefit.
Based on your calculations, you must be aware aluminum is a great material to dissipate heat.
The throttle body is made of aluminum and dissipates the heat from the coolant flowing through it.
This radiant heat is dissipated from the entire housing, both inside and outside the TB valve, therefor increasing intake air temps.
When your Torque Pro app provides IAT, do you actually know where it is sampling the air temp? Pre or post TB?
Assuming the IAT sensor is at the MAF location, it wouldn't actually report the heat added to the system by the TB.
This mod would be no different than a stand-alone trans cooler in the fact that it isolates one system to not increase thermal load on another system.
For the cost of a union and 2 plugs, it is essentially a free mod to reduce heat sources on the intake.
Your suggestion of wrapping the intake hose and box in a space blanket would not be as cost effective as the bypass mod.
But curious to see you prove me wrong.

 

Hadn’t visited this thread in a while.........

y’all guys got too technical and should have just left it up to the bro science lol

 

Did anyone measure before/after air temps? Or is this all theory?

 

Does anybody know the size of the ID of the tube? I’m planning to get 2x 3-way ball valves (one for before TB and one for after) and an extra piece of tube for bypass during winter. Thanks.

 

If you have a set of drills, use the chucking end as a gauge to measure your tubing.

 

5/16" IIRC

Edit: I actually think they're 1/4" and that's where I ran I to problems as the ball valves become micro ball valves...

 

Lets hope its 5/16 because I have those valves. If it does work I’ll take some pictures and post. I’ll try to get it done tonight.

 

What size drill bit do I need to perform this mod?

 

None?!

 

Damn, I just tripped over this thread right here..... I may just jump on this mod.... does freezing temperature include that morning frost that builds up on roof tops, and sometimes your windshield and roof?? Or a couple inches of powder on the ground, and I don't mean the nose candy type.... Bay area Nor Kal type weather.. I'm just curious, now...

 

This aged horribly....
Did you have any issues with the Tundra in the Texas freeze of 2021?

 

Just spending a rainy day watching football and reading the Tundra forum. Stumbled on this one and seems fairly simple and logical. Has anyone actually seen noticeable gains? Seems many people have very deep opinions on if this mod actually proves gains but not many people posting real experiences.

 

Honestly I have seen 0 gains with my real world ass dyno or mpg. I swapped back to heating due to temps getting cold.

 

Real experiences? No ill side effects and this will be my second Northeast PA winter with this bypass done. Gains? Probably, but nothing to break your neck. How much horsepower do I think it gained? No clue but we can guess a number lol; 1hp, 10hp, .1hp.
Honestly, thinking logically, cooler air = denser air = more power at the end of the day. What the engine does with that is it's business, I didn't tune it, I just delivered the goods (cooler air).

 

You run yours bypassed throughout the winter? I read something before about possible moisture build up in the throttle body by not having it warmed up.

Moving down to FL at the end of the month and I’ll be swapping mine back. Even though I didn’t feel a difference cooler always is better.

 

No problems here. My 2011 ram hemi had a fly by wire throttle body with no coolant plumbed through it from factory, no issues. If there's moisture build up I'd speculate another issue is happening. Can't say it's to keep the throttle from freezing either since the butterfly opens at idle (there's no IAC valve). I'm not an engineer or factory trained tech but my guess is to heat the incoming air as the engine is warming up to increase combustion temps to heat up the after treatment system up faster to get the system running efficiently as fast as possible... Catalytic converters lol, sorry I work on diesels as a truck mechanic.

 

I’ll swap mine back sometime before my drive down south. Not trying to get under my hood in this 10 degree weather. Soon I’ll never have to worry about freezing temps again.

 

where did you get the rubber caps to cap off the coolant pipes?

 

Cool thread. I've often wondered about this very old school system on the Tundra.

Back in the day there was all sorts of thermostatically controlled devices not to mention carburetors sitting on hot cast iron intakes with a little spacer...

However at wot the carburetor system actually cools the incoming charge substantially through several thermodynamic mechanisms. JT effect and heat transfer from phase change in gasoline.

on this system with port fuel injection, the MAF measures the mass of air incoming and also the intake air temp. Combined with throttle position, cam position, crank position, and rpm, the ECU calculates the timing, phasor position, injector pulse width, and in general transmission shifting strategy.

So counterintuitively they routed engine coolant to the throttle body.

At wot throttle this system may not be adding as much heat as you'd think.

The throttle blade is basically parallel with throttle body. Air flowing over this is removing heat from the blade (at least until the two are the same temperature). There isn't much surface area for convection. Many other throttle body systems don't have this feature of a coolant passage. The throttle body temp rises and falls with engine temp.

So accounting for the heat transfer, there is heat transfer from the aluminum housing to the atmosphere. And then there is heat transfer to the internal air flow going through the aluminum housing/casing.

Looking at the inlet and outlet of the coolant flow it appears to be a very small area that gets the coolant flow.

So it doesn't look to me like there would be a huge convective heat transfer into the air flow.

It must be for something else...

Looking at other throttle bodies they don't have an electrical heater nor do they have engine coolant passages. But they do seem to have the throttle body machined differently and also positioned differently. Most non toyota throttle bodies seem to be thicker in many areas.

The Tundra and other toyota throttle bodies look to have a very small air gap when closed. No matter if the blade is brass or aluminum.

And the coolant passages seem to land right at where the air gap is positioned.

I'm thinking this is to maintain some dimensional integrity of the housing. For part load conditions under closed loop, this will ensure the throttle body will have a steady "orifice size" which then allows for less variation in air flow.

With engine at cold conditions or at wot the engine control regime is open loop and running off feed forward program based on maf flow and tps.

 

Any auto parts store should have them.

 

What size are those hoses? Are they 3/8” or 7/16”