LastBoyScout

Throttle Body (TB) Coolant Bypass Mod

Granted this is a very common mod to do, but there is a small warning to take note of. If you live in an area where the weather tends to get cold, say around 20 - 15 deg F or lower, keep all the original tubing, since you will want this come winter time to keep your TB butterflies from sticking. Short science lesson, heat causes metal to expand, cold causes metal to shrink. Different metals shrink and contract at different temps. The TB coolant lines warm up the TB and make sure that the butterflies dont stick due to size differences.

On to the mod.

Expected Gains: I cant remember where some rich kid paid some people to do the math and then dyno proved it, but the average gain in Horse Power (HP) is around 2 - 3 HP. Sure, some people have claimed around 4 - 5 HP even. The facts are that this mod will cost you around $2 for the hose unless your auto parts store has free scraps.

Benefits: colder air = denser air = HP

I recommend doing this mod if you are installing a Cold Air Intake (CAI) or Short Ram Air Intake (SRI). Might as well since you will have most everything out of the way anyway, right?

You might want to remove any breather lines out of the way and unhook any wiring harnesses that might prove troublesome to reaching the coolant hookups/nozzles. Just remember where everything goes and what goes where. Nothing worse than thinking a mod screwed up your car cause your too bone headed to hook everything back correctly.

Here is what the engine bay will look like on a 2.5 TL (granted this mod I have done on a Maxima, Accord, Geo Metro, Toyota Camry, Legend, and now the TL. it will work similarly on any car. Just follow the coolant flow)

You have 4 access points that you will be dealing with. Coolant Out of main, Coolant in to TB, Coolant out of TB, Coolant Back In to main.


Here are Close Ups of the access points




To bypass the TB coolant you are basically connecting the Coolant Out of main access point and routing your hose straight to the Coolant Back In to Main access point.

Its that easy.

Here is what my bypassed setup looks like (hose highlighted in red to show its path)


If you have any question, feel free to PM me.

Go90go

Good writeup. I was able to do this mod with the original hoses, but it's always nice to use new stuff.

~Cheers~

LastBoyScout

yeah, i used the original hoses on my Legend, but i really didnt like the look of the hoses under the TB. They were kinda dry rot looking.

LastBoyScout

yeah, i used the original hoses on my Legend, but i really didnt like the look of the hoses under the TB. They were kinda dry rot looking.

pretty_ricky302

i need some help

haynTL

where are the 4 access points for the 3.2?

I hate cars

Get an inline shutoff valve if you need to turn the water back on during winter. It's as simple as turning a valve.

The hot water is there to keep ice from forming and sticking the TB, not due to the different expansion rates of the butterfly and TB housing. Every manufacturer uses hot water today. Even my 84 GN had hot water going to the TB.

It typically has to be well below freezing for ice to become a problem. Ice was more of a problem in older carburated cars due to the venturi cooling effect and fuel evaporation.

haynTL

ok i think i did the bypass correct but can someone show me a pic of how it looked finished for the 3.2?

desired_speeds

hit up acura-legend.com, theres a DIY in the DIY section of the forums.

haynTL

thanks man

I hate cars

Seriously it's much easier to just cut one line and insert a valve. 2 minutes and it's done and you can turn it on in the winter if you want.

haynTL

alright i did the mod correctly thanks for the help

Sezniko

iTrader: (3)

here is my set up on an 2006 TL TB coolant

9632tl

Seems like a few of you have done this mod, but no one has said anything about the performance change. Did you notice a difference?

Go90go

Honestly, the difference is negligible. Some cars could get a dyno-proven 6-7 wheel from it, but we wouldn't see anything like that. One upside though, is that it helps stave off heatsoak a little bit, so it you've been driving kinda hard in warm weather, you won't feel the car slowing as much thanks to the throttle body no longer being heated by the coolant.

Two and a half years late, but I Hate Cars is right. If you live in an area where it snows or gets below freezing often an inline valve would be the way to go.

~Cheers~

16MattM16

Can someone tell me where I should put the inline valve for this instead of disconnecting the hoses to bypass. I would like to turn it back on in the winter since it does get cold here

Mr. Showtime

To cap off the throttle body nipple should I be using "rubber vacuum caps" or coolant line caps? Autozone had different size vacuum caps is the purpose of capping just to avoid materials from getting in?