The "Ultimate" TB Coolant Bypass



Many people have bypassed the coolant passage in the Throttle body to help keep the air charge cooler, thus helping in performance.  The normal way to do this is to unhook both hoses from the Throttle Body and connect them together with a piece of pipe.  While this is effective, it looks, well, rather hokey.  Here is a way to bypass it and make it look good.  This does require a little more work, but is well worth it.

The first step is to remove the Throttle Body from the Plenum.  This will require disconnectiong the TP sensor, IAC motor, any vacuum lines, throttle cable, TV cable and Cruise if equipped, and then the four mounting bolts.  Once off, unscrew the IAC motor and remove all of the IAC/coolant housing bolts and remove the housing.  You will need a new gasket, wich can be purchesed from GM in a kit.  Once removed, you will need to grind off the two nipples flush with the housing.  In the picture you can see after grinding.  The blue is where the nipples used to be.

Once the nipples are cut off, some final fileing may be needed to ensure totall flushness.  Then fill the voids with JB Weld or equivilant.  I used cardboard behind the holes do give the JB Weld support so it wouldn't just run through the holes.  After the first application was allowed to dry, a second application was applied so that there was excess.

After the second application was allowed to cure overnight, the excess was filed down so that it was completely smooth across the surface.  Then it was final sanded, cleaned w/ paint prep (don't use anything real strong) and apply some coats of paint.  I used Black engine enamal to help with the high temps.  Once the paint is dry, it can be reinstalled.  Bolt the housing back up to the Throttle Body using the new gasket.  Screw the IAC motor back into the housing using the new gasket included in the kit.  Then reinstall the Throttle Body to the Plenum and reattach all the vacuum lines, electrical connectors and throttle cables.  I ran a new heater hose from the intake to the heater shutoff valve.  If you go to the parts stores, you can usually find a pre-bent hose that will work. 


Here are some pics of the final product:

Top left:  Front veiw showing the shaved nipple.  From above, this can't even be seen.

Top right:  Here is a side veiw if the other shaved nipple.  Doesn't even look like anything was ever there.

Left:  Here is another shot, no nipples in sight, heater hose goes off, completly away from the TB, you'd never know it was supposed to be there if I didn't tell you.