Throttle Body Coolant Bypass
 

cut and paste from my thread in the accord forum. this mod should work w/ pretty much any honda motor. and still hasn't caused me any problems. Those who live in colder climates may want to use caution doing this mod, or put it back to the stock configuration when the colder months come around. The pictures are from a 98 Accord but the coolant lines are very similar to other honda motors.


okay...this is pretty much a FREE mod. i know all you peeps out there like that...free engine upgrade....well this is pretty much an easy diy that adds about 2-5hp (i saw the dyno somewhere, but i forgot where).


There is a color code in the letters...red means you just totally disconnect those, blue you connect together somehow, and white is just a guide so you know where you are in the engine bay. Oh yeah, do this mod when your car has been sitting for a while, that way you don't spill hot coolant on yourself. You'll need needlenose pliers to remove the clamps and to pull some of the hoses off, and some coolant in case you spill too much.
https://www.superhonda.com/photopost...5throttle1.jpg
I took the intake piping off so it would be easier to work with. Disconnect points A and B. The hose that came from A will connect to point C, and the hose that came from B, you just put aside. some hoses are easier to connect that others, so switch them around as you like just as long as you get point C to connect with point D.

https://www.superhonda.com/photopost...5throttle2.jpg
Does the metal pipe at E look familiar? there's a coolant line that runs through there so i just moved it under the intake pipe. F is the main coolant line that runs back to the radiator. D is located just above F, near the block. The next picture illustrates that the best:

https://www.superhonda.com/photopost...5throttle3.jpg
Once you get C to connect D using any combination of hoses, then you're pretty much finished. This is what the final layout should look like:

https://www.superhonda.com/photopost...5throttle4.jpg

for your reference, the stock flow goes from A to B to E to D. Points A and B are input and output from the throttle body. we simply bypass those by adding the point C and connecting it to E. I have no clue how this mod adds power, but i know it does. I felt a slight gain after doing this, plus my gas mileage is slightly better. my engine temp gauge sits between 1/8-1/4 depending if it's cold or hot outside. normally it would of been at 1/4-1/2. so my guess is that the engine runs slightly cooler, thus adding more power. hell it works

*Disclaimer*
This is only an article on what I've experienced. You may choose to do this modification of your own free will. I and SHO will not be held responsible for any mistakes you may make.


Write Up Thanks to "UltraMagnetical" from superhonda! Thank you!
http://www.superhonda.com/forum/f93/...on-diy-126421/

I don't think this is recommended in cold climates. This disables the FITV which makes the engine fast idle while it is warming up so that it will warm quicker.

The only reason this mod is done is to keep the throttlebody's temp lower (so it does not heat up the air intake charge) and colder intake air is denser and more power is gained. For people in colder climates you would just undo the mod for winter, and redo in the spring.

I wouldn't re-plumb everything unless one of the parts has a leak, or you're setting the car up strictly for racing. If you just want to try to add a little (imperceptible, I would think) power to your daily driver, simply put a clamp or valve on one of the hoses to stop the coolant flow. Then it's very easy to reverse the mod if you need to.

Exactly what I was thinking.