Throttle body coolant bypass

So I have heard of this mod and since I have spent a lot of time in my engine bay the passed couple weeks I have noticed that the throttle body gets very hot because of the coolant going thru it.

Now before I go bypassing the throttle body, what is the purpose of coolant going to the throttle body anyway? I want to know before I go reversing something that a Toyota engineer deemed necessary.

Also, any of you that have done this mod, have you seen any real world gains from it? Did your intake temps drop if you had the capability to measure it?

lines are very easy to get to if I decide to do it.

 

the coolant running through the TB brings the engine temperature up to normal operating faster during initial start up

 

I see, hmmm, I don’t know how effective that is, makes the bypass more appealing to me since it’s hot here most of the year in Texas and I started letting the truck warm up more on cold starts since supercharging it.

 

I’m in Houston. And the Astros are pissing me off.....

I did the throttle body coolant bypass. I read a lot about it before hand and there were mixed reviews. But here’s the deal, it took 10 minutes and cost $0.00. Did it make a difference? Who knows, not that I can tell. But it didn’t hurt anything, and in theory it helped. I’d def do it again

 

I also did the stock air box mod, the air box charcoal filter delete, and the throttle body metal screen delete. Not sure if air box mod did anything either but it was well worth the $20 it cost just because of the badass sound the engine/intake makes now. I’d do it again. There’s a few post around by @dirtydeeds that list the main things he recommends for performance. He knows his stuff. Try and find them

 

I know the feeling...

 

I’m done. Going to bed lol

 

I have seen dirtydeeds recommend it...........

 

Lol

 

I spoke to him in the phone a few weeks ago and he still recommends it. Basically said you can’t go wrong and it’s free.

 

Looks like I’m doing it tomorrow morning then lol

 

Was told this not recommend if where you live gets real cold

 

Yeah that’s not a problem here, we’re lucky if we actually get a real winter lol

 

Dude! They’re getting handled right now!

 

Same here that's why I did mine as well

 

Search SAMB, you can make your own or someone makes a kit where are you drill a hole in your fender and airbox and add another inlet. The charcoal filter delete is just that little filter inside your air box that’s glued in. I did it but I don’t think it was necessary or did anything. It’s just there to catch gases when your truck is turned off. The metal screen is behind your throttlebody and you can put a different gasket that eliminates it or trim it out. But I don’t think it does anything either. Most people remove it because it makes a whistle when you install a TRD intake.

 

ill explain the easy ones lol, charcoal filter is a thin screen after your air filter, it’s held in there with plastic tabs that you break off to remove it, the throttle body metal screen is right after the throttle body, it’s not restrictive at all but does make a whistle sound when you mod the air box.

 

Has anybody who has done this bothered to check temp of your throttle body before and after at operating temperature?

I would compare the throttle body temp to the temperature of the intake manifold right on top of the motor as well. That supercharger is probably hotter than the throttle body as is, and theres nothing to be done about that.

 

you have two lines of coolant going in and out the throttle body, you can take the line going to the throttle body and connect it to where the line that’s coming from the throttle body connects to, bypassing the throttle body.

 

yeah I wish someone would actually have tested the temps.

What I do have for you is some bro science lol yes the supercharger does get hot but after running it I can still touch the inlet with my bare hands, I can’t However touch the throttle body, especially around where the hoses connect.

 

Good even'n gents!
I've done all these items...save the SABM...I've got the S&B which has a larger inlet. But I digress.

Here's my 2 cents on the TB bypass and screen cut....

The TB bypass is worth it...Especially if you're trying to have 'cold' air come into the intake.
As was mentioned, Toyota's design purpose was apparently to keep the TB warm such that there wouldn't be any chance of the TB sticking in cold temps. That said, after everything's up to temp and the hot-ass coolant in running through the TB, it's blazing hot.
If you're interested in 'cold' air, think about it like this...A hair dryer can take cool air and run it across thinner metal parts much faster than the air coming through our TB's, and how hot does a hair dryer get? So just figure how hot the air is that's normally coming into the intake/engine.

As has been noted, if you're in the far north, I might not do it...or do it for the warmer months, then back to stock during the winter. Takes no time to do the bypass.

Also, re the screen;
I would not recommend just breaking the screen. The outer part serves as a bit of a gasket. It's all metal, with a rubber coating on the ring. The metal is tough and is best cut with some snips.
I took mine out, cut the metal screen out, then dremeled the remnants, so that the inner circle was smooth.
**Leave the little tab that's on the outer edge. It aligns back onto the intake.




If you really want to get nutty and while you have everything nearly apart...
Take the TB off and port/polish the inner parts, knocking down the high parts.

I did this last year. I didn't take pics of the final product, but it was shiny! I used various grinding then polishing wheels on the Dremel.
This is a pic of the before from the back side. The front side looked the same, in terms of the inner surface, the raised lip and the blade axel.
The inner lip had a rise of about 1/32. I took it down until is was smooth with the outer edge part and my fingernail wouldn't catch when sliding over it.


This is the front after thinning, just before polishing (arrows noting the edges that were thinned, rounded)

 

I haven’t done the bypass yet so that’s stock (albeit when I installed the supercharger I had to rotate the throttle body 180 degrees so it’s bottoms up compared to a n/a truck) but I’ll try my best to draw it out here, red is where the line would run, blue is just the caping of the throttle body.

 

A few people have done it with no repercussions from what I’ve read, also dirtydeeds says it’s a good free mod. I can’t however find actual temps on before and/or after

 

I remember when I did it...
After running for several minutes or a short drive the TB would be hot enough you couldn't keep your hand on it. After doing the bypass, I could do the same short drive then touch it no problem.

Do you have a laser thermometer? You could let it run for say 10-15 mins or go for a short drive, then check the TB temp.
I can do the same, then compare the differences?
PM me if you want.

 

Im pretty sure I’m doing the bypass tomorrow lol just makes sense, plus boost weather is coming lol

 

I doubt it. The thermostat is more for the inner engine coolant.

The coolant really only runs through a small portion of the TB...which is the main housing (which holds the actuator for the blade axel) which I assume is what Toyota intended to stay warm, since it's electric and not cable driven.

 

Indeed. My ass-dyno always seems to feel the 5 hp gain in the winter. Lol.

 

Interesting way to look at it @GAknight

It's been decades since I have used a hair dryer but I recall seeing the nichrome wire coils turn bright orange as a kid. I don't have a hair dryer to test with my laser, but after looking it up a metal turning that color should appear above 800f. Nichrome can hit 1000f easily before melting point is reached.

The coolant passing through the throttle body is in the ballpark of 300f and constantly passing through it. I think I'm going to dig around my garage to look for my temp laser, this is getting interesting.

 

Yep...
All great points there sir!
Certainly the metal coils in the hair dryer are going to be hotter, but the air moving through the TB is not moving as fast.

Truth told, I've gotten a bit nutty with this whole thing this past year.
I started out looking at an aftermarket intake, but they really don't make sense unless you're running a SC, which of course those kits come with a new intake anyway.
After some research and talking w/ a buddy; I learned the 5.7 hemi's have some nice mods available for larger TBs and intakes.
This led me to looking/finding a larger TB. Problem is getting a matching intake...I can't seem to find an aftermarket one.

That led to my latest adventures of buying another intake. Aside from possibly mod'ing the TB connection, I'm interested in the outlets and their matching to the heads. Having just finished a move to a new home a couple months ago, I've yet to dive into this project.

I will say...the inner parts of the intake on the TB side are NOT nice and smooth and even have some plastic molding protruding out, so there's definitely some air disruption going on there. My plan is to take the new one apart (they're in two parts; upper and lower) and then smooth out the inside.
I'll also add some type of heat shielding, (DEI, etc.) on the underside or perhaps the whole thing.

I've also been working on a k-type thermocouple set to measure the air temps in the filter box, intake tube (which I might can read from the MAF with Techstream), and the intake (just after the TB and in the inlets to the head).

All this may be for nothing...but it's cheaper than a SC. Short of pulling the engine and porting/ polishing the heads, if I can get more air 'available' to the heads, there may be a few hps free for the finding....

 

I ran my first quick errand this morning, got back home, opened the hood, throttle body was already hot, supercharger not so much, so I decided then and there to do it, I just let her cool down a bit first. Thanks for the feedback fellas. This forum is the sh#t lol