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Thread: HOW TO: B14 Throttle Body Heater Bypass

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2008-09-07 01:31:16
HOW TO: B14 Throttle Body Heater Bypass
HOW TO: B14 Throttle Body Heater Bypass

Our cars have Coolant running through the Throttle Body, thus heating up the Throttle Body. When installing a Cold Air Intake (CAI), you are bringing cold air into the engine, thus giving the car more power.

With the throttle body being heated, that cold air can warm up, thus not getting the best results possible out of a CAI. Bypassing the coolant passage way can help the air keep colder.

CarBibles.com mentions this as an important mod to consider when you install a Cold Air Intake. Source
Throttle body heater bypass

Cold air induction kits work pretty well but you need to do your homework first. A lot of cars have throttle body heaters, whereby coolant from the engine is circulated around the throttle body casing. The idea is to warm up the throttle body to prevent icing in cold weather. The problem is that these systems are hard-wired and don't take account of external air temperature, so even in the heat of summer, hot coolant is routed around the throttle body. This is a problem for CAI kits because you've gone to all the trouble of putting a nice kit in to suck cooler air into the engine, but at the final hurdle it runs through a 75°C throttle body which heats it up again, negating the whole point of the CAI kit in the first place. The solution to this is a throttle body heater bypass, which essentially involves pulling the coolant hoses off either side of the throttle body and patching them together with a length of copper pipe and two hose clamps. When you do this, the throttle body stays at ambient temperature and the CAI kit gets a chance to do its job. The only downside to this is if you live in a cold, humid climate, you might suffer from icing in the winter. But hey - if you do, reconnect the coolant hoses for the winter...

The coolant was designed to run through the throttle body for a reason, to keep the butterfly from freezing shut or open. If you live in a cold area, I would avoid doing this. I personally will go back to stock in the winter.[/I]

I will honestly say it is not too great of an idea to go this route with a Daily Driver car. A better choice is to go with the ThermoBlok Spacer Kit. They have a Intake Manifold/TB spacer. This will give you bigger power gains and a piece of mind

This is a fairly simple mod that shouldn't take longer then an hour to install

Items Needed
  • Pliers
  • 1 1/4" Hose Coupler (3/8" might work better)
  • 2 Hose Clamps (You might get away with stock ones with 3/8" Coupler)
  • 2 Rubber Caps to block off old pipe.
  • Screw Driver

  1. Take out the Intake to free up some space, disconnect the TPS and other Sensor

  2. Locate the the two hoses that send the coolant to the Throttle Body

  3. Disconnect the two coolant hoses

  4. Then cap off the two coolant lines

  5. Put in the coupler into the one end of the hose and tighten the clamp

  6. Plug the other end of the couple into the other hose and tighten the clamp

  7. Finished Product

Now I noticed that my water temperature was higher then normal. So that means that the intake does actually cool the water pretty well. I think Redline Water Wetter might do the trick at keeping the water temperatures down though.

Onto some numbers, now these are not 100% accurate and are not dyno proven. These numbers are from ScanGauge II, and are BHP numbers.

Base Number: 159 BHP (15% Drivetrain Loss 138 WHP) with 82*F Intake Air Temperature
After Number 164 BHP (15% Drivetrain Loss 142 WHP)with 83*F Intake Air Temperature

IF you have any suggestions let me know!
2008-09-07 04:27:37
Drive train?
2008-09-07 04:40:26
Haha I can't spell
2008-09-07 13:33:00
damn didnt think it would give you that much extra power.

think i read somewhere like 1 degree drop in intake temp is worth like 5 of 10 hp
2008-09-07 13:38:52
Originally Posted by L4t3ncy
damn didnt think it would give you that much extra power.

think i read somewhere like 1 degree drop in intake temp is worth like 5 of 10 hp

Really? I doubt it's that drastic, but I've noticed with a CAI I can finally get some descent butt dyno results. The WAI would only feel good in the winter.
2008-09-08 02:52:11
So I drove home, car had a chance to warm up to 180*F Coolant temps. I got home, opened the hood and the Throttle Body was just a little warm, Intake Manifold was just a little hot. Touched the VC and was impressed on how cool the TB stayed!
2008-09-08 07:20:56
lol, thats so comen sence, i dont know why i never thought about that.. lol
2008-09-10 22:52:19
sooooo... never tought bout this before... nice mod VADIM... any butt dyno results so far?... try it with the Beltronics FX2!!!
2008-09-11 01:48:06
Originally Posted by Fernando
sooooo... never tought bout this before... nice mod VADIM... any butt dyno results so far?... try it with the Beltronics FX2!!!

But dyno is not bad because the air keeps colder

Yeah i'm still trying to configure that, it is showing my car as having 120 whp. When I dyned 125 with much less mods ;-)
2008-09-12 00:58:35
So far it seems like the coolant temperatures are about 10*F higher. This should be ok in the winter, help the car warm up quicker, but in the summer might be a little problematic hehe.
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