Stealth TB bypass
06-20-2006, 05:16 PM
#1
TECH Apprentice
Thread Starter
Stealth TB bypass Got off work Monday morning (work graveyard, Tu/Wed off 
) and decided to do some free mods on my newly acquired 98 Z28. Did the FRA 1st, then chopped the EGR tube, followed by porting the TB, throttle bump stop, and finally, the TB bypass.
I'd done some research on the TB bypass, found there were 3 variations on it. Install a 5/16 hose from the barb on intake manifold to barb on radiator, or install a tube between 2 hoses that normally hook to TB, or cap off barbs at manifold & radiator.
Problem w/methods 1&2 was that some people found that if hose drooped or tube wasn't routed just right, contact with accessory drive belt/pulleys was possible. Problem w/method 3 was getting caps that would work, plus needed hose clamps.
I decided to add method #4. I looked through my machine screw collection to see if one would screw into either the large or small barb on the TB. Found one that screwed in nicely on the outer lip of the small barb till it hit the tube section itself. So I unscrewed it, put a dab of RTV on it, screwed it in tight. Then I cut off head, leaving 1/8" sticking out in case I ever wanted to remove it. This plug would stop coolant flow thru TB, prevent heat transfer to TB. Original hoses hook up like stock. No danger of my TB freezing out here in the high desert of West Texas, so no downside to it, worthyness of mod aside.
By the time I was done it was late, I hadn't slept for a long time, & I was tired from working mucho hrs straight at work & on the car, so I didn't want to risk a test drive. Just downed some Bud Lights, and had some serious sleep till 9 this morning.
Took the car for a test drive & to pick up some lunch. Didn't feel any difference at all. But then again it's sucking in 100* air. Time to relax till I go over to my GF's tonite to give her a poke.
.
) and decided to do some free mods on my newly acquired 98 Z28. Did the FRA 1st, then chopped the EGR tube, followed by porting the TB, throttle bump stop, and finally, the TB bypass. I'd done some research on the TB bypass, found there were 3 variations on it. Install a 5/16 hose from the barb on intake manifold to barb on radiator, or install a tube between 2 hoses that normally hook to TB, or cap off barbs at manifold & radiator.
Problem w/methods 1&2 was that some people found that if hose drooped or tube wasn't routed just right, contact with accessory drive belt/pulleys was possible. Problem w/method 3 was getting caps that would work, plus needed hose clamps.
I decided to add method #4. I looked through my machine screw collection to see if one would screw into either the large or small barb on the TB. Found one that screwed in nicely on the outer lip of the small barb till it hit the tube section itself. So I unscrewed it, put a dab of RTV on it, screwed it in tight. Then I cut off head, leaving 1/8" sticking out in case I ever wanted to remove it. This plug would stop coolant flow thru TB, prevent heat transfer to TB. Original hoses hook up like stock. No danger of my TB freezing out here in the high desert of West Texas, so no downside to it, worthyness of mod aside.
By the time I was done it was late, I hadn't slept for a long time, & I was tired from working mucho hrs straight at work & on the car, so I didn't want to risk a test drive. Just downed some Bud Lights, and had some serious sleep till 9 this morning.
Took the car for a test drive & to pick up some lunch. Didn't feel any difference at all. But then again it's sucking in 100* air. Time to relax till I go over to my GF's tonite to give her a poke.
.
07-12-2006, 11:29 PM
#5
That's normally called the "steam vent" or the "bleeder vent". You can't just plug it. If it's sole purpose was heating the throttle body (which it's not) why the hell would it be pulling coolant from 4 different spots on the heads?
I would yank those coolant tubes out of the throttle body, then run a hose from the line between the heads to the radiator.
I would yank those coolant tubes out of the throttle body, then run a hose from the line between the heads to the radiator.
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07-13-2006, 07:43 AM
#8
Staging Lane
Join Date: May 2006
Location: LaPorte, Texas
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I found the best part about doing the TB by-pass is that it only takes a second to get the TB off and you don't have to worry about coolent getting on your belts. As far as picking up hp......not sure it matters after the motor has been running 10minutes due to heat soak. Also, I would NOT plug the hose line from the radiator to the coolent nipple past the TB. I had mine pop off when I did a bad first install of the TB bypass mod. So I know it builds up pressure in that area. So I think flow is needed in that area. Just trying to help. Good job in thinking outside the box. Stealth mods are always cool! 
