THROTTLE BODY COOLANT BYPASS
MANUFACTURERS RUN COOLANT THROUGH THE THROTTLE BODY TO HEAT IT UP. THIS HAS SOME DESIRABLE RESULTS, THE FIRST BEING THAT THE THROTTLE BODY WON’T FREEZE AND STICK WHEN DRIVING IN FREEZING COLD WEATHER AND TO HEAT UP THE AIR TO IMPROVE FUEL ECONOMY.
THE ACTUAL RESULTS ARE THAT THE HOT AIR GOING INTO THE ENGINE IS LESS DENSE AND WILL REDUCE POTENTIAL POWER OUTPUT. HOT COOLANT GOING THROUGH THE THROTTLE BODY ALSO ADDS TO HEAT SOAK OF THE INTAKE COMPONENTS AND THIS THE INTAKE AIR TEMPERATURES FURTHER REDUCING POTENTIAL POWER OUTPUT.
AS TO THE FREEZING THROTTLE BODY POINT, THE CAR WILL BE COLD WHILE SITTING FOR LONG PERIODS AND THIS INCLUDES THE COOLANT, SO THERE WILL ALWAYS BE AN ISSUE WHEN TRYING TO START THE CAR IN VERY COLD CLIMATES. WHEN THE CAR IS WARMED UP, THE UNDER-HOOD TEMPERATURES WILL HELP KEEP THE INTAKE FROM FREEZING AND STICKING.
TEST DATA FROM A 2014 3.8 V6 SHOWS THAT INTAKE TEMPERATURES INCREASE BY 30% AT LIGHT THROTTLE AND 16% AT WIDE OPEN THROTTLE. THIS IS FAIRLY SIGNIFICANT WHEN IT COMES TO POTENTIAL POWER OUTPUT.
SOME PEOPLE HAVE REPORTED THAT THE REV HANG ISSUE COMMON WITH FACTORY TUNED CARS GETS SLIGHTLY WORSE AFTER THE BYPASS. ONCE TUNED, THIS ISSUE SHOULD GO AWAY.
|1. Let the car fully cool down to prevent injury
2. Remove the intake tubing from the throttle body.
3. For more room, you can also remove the factory air box (if still equipped), but it is not necessary. You can also unplug the throttle body wiring harness to keep it out of the way and prevent damage.
4. Locate the rubber hoses attached to the bottom of the throttle body. (BK2 shown, BK1 will be similar)
|5. To prevent coolant getting on the exhaust manifold or other components, place paper towels under the lines and cover any components in the area.|
|6. Using pliers, slide the upper clamp down to the middle of the hose
7. Gently slide the hose off of the nipple on the throttle body. If you have trouble, you can use pliers to gently rotate the hose in place to loosen it up. Be gentle.
|8. Using pliers, slide the bottom clamp to the middle of the hose
9. Gently slide the hose off of the nipple on the coolant supply line.
10. Repeat process for the second hose.
11. Both hoses must come off. Note that the lines may still contain coolant, be care to avoid any spillage.
|12. Once both hoses have been removed, make sure to clean up an excess coolant that may have spilled.
13. Gently slide one end of the supplied bypass hose on to the coolant supply hard line. Be sure it’s on at least 2 inches.
14. Tighten the supplied worm clamp. Do not over tighten, it just needs to be snug.
15. Attach the other end of the supplied bypass hose to the coolant return hard line.
16. Tighten the clamp.
|17. Reinstall the intake components and plugin the throttle body harness if you unplugged it.
18. Start the car and let it idle for a minute.
19. Monitor the bypass and check for any coolant leaks.
20. If you have any leaks, check that the hoses are on the hard line far enough and that the clamps are tight enough.
21. If there are no leaks, drive the car around until it reached full operating temperature.
22. With the car fully warmed up and idling, inspect the bypass once more and check for leaks.