How To Bypass Coolant Lines to TB
07-16-2003, 01:31 AM
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How To Bypass Coolant Lines to TB
Can you guys help me with this mod. What lines do I pull and what do I use to connect the lines.
2003 Tundra 3.4
2003 Tundra 3.4
07-16-2003, 04:31 PM
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I know that the coolant flows for cold start-up in really cold weather but I live on Guam(hot) and the hot coolant flowing into the throttle body is not good for performance.
I have noticed that after I dive for about 3 hours my truck feels sluggish than when I first started up.
I have noticed that after I dive for about 3 hours my truck feels sluggish than when I first started up.
07-16-2003, 04:38 PM
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That sluggish hot start is probably caused by heat soak. When the engine gets really hot, and is shut off, the engine heat soaks in, and the fuel in the fuel rail boils. It runs rough at first, then it'll smooth out as the fuel cools down. The only thing I could think of is to maybe rig a turbo-timer like device, and make it run your electric fans for awhile after you leave the vehicle.
07-16-2003, 07:53 PM
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96 runner,
Why do not recommend this mod? I've heard from multiple people that you will notice a difference in real HP by doing this mod. It makes total sense to me, and I was actually going to do it tomorrow on my new '97. Do you have any solid reasons why it shouldn't be done? I'm all ears!
Chris
Why do not recommend this mod? I've heard from multiple people that you will notice a difference in real HP by doing this mod. It makes total sense to me, and I was actually going to do it tomorrow on my new '97. Do you have any solid reasons why it shouldn't be done? I'm all ears!
Chris
07-17-2003, 02:49 AM
#6
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In my Toyota EFI & Engine Control Systems book it states:
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Throttle Icing is prevented by use of an engine coolant cavity located adjacent to the throttle valve.
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Incorrect. The coolant would be cold too, wouldnt help a cold start.
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Throttle Icing is prevented by use of an engine coolant cavity located adjacent to the throttle valve.
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I know that the coolant flows for cold start-up in really cold weather....
Last edited by Jay; 07-17-2003 at 02:51 AM.
07-17-2003, 03:39 AM
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So if that's the only reason, then people in hotter climates could leave it off all year, and other that are in colder climates would leave it bypassed during the hotter months, and put it back on in the winter months. Cool! I'm doing it!
Chris
Chris
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07-17-2003, 04:32 AM
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This is a popular mod for newer performance cars. Most cars simply have an attachment on each side of the throttle body. Disconnect both lines and use a piece of pipe to connect them both with hose clamps. I never did it on my Mustang but a buddy did and it didn't effect emissions or his visual inspection either.
07-17-2003, 07:03 AM
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Exactly what Jay said. Heck, I live in PHX, I should do it. But, I often find myself in the mountains, or traveling in colder climates. So for me, its not worth the risk of forgetting about it.
True, it does work. Its an old trick on Honda's too.
When I said risks vs reward, I was taking into account someone forgetting about it during the colder months.
I would like to see some data on how much improvement is realized.
True, it does work. Its an old trick on Honda's too.
When I said risks vs reward, I was taking into account someone forgetting about it during the colder months.
I would like to see some data on how much improvement is realized.
07-17-2003, 08:05 AM
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I'm going to do it, but I'm not going to get a dyno just from that mod. Sorry guys. I wish I had the money to test every mod separately to see the gains, wouldn't you?
Chris
Chris
07-17-2003, 08:52 AM
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There are other methods besides dyno testing.
Click on my sig on "TB Spacer, does it work?" Inside that thread you will find my testing methods.
3 Runs without mod, 30 - 70 MPH, 3rd gear: Take avg (/3)
3 Runs with mod 30 - 70 MPH, 3rd gear: Take avg (/3)
Formula: without mod avg + with mod avg /2 = Delta
I dont care what anyone says this is accurate, especially with cruise control. The ISR mod lost me .2 seconds.
Click on my sig on "TB Spacer, does it work?" Inside that thread you will find my testing methods.
3 Runs without mod, 30 - 70 MPH, 3rd gear: Take avg (/3)
3 Runs with mod 30 - 70 MPH, 3rd gear: Take avg (/3)
Formula: without mod avg + with mod avg /2 = Delta
I dont care what anyone says this is accurate, especially with cruise control. The ISR mod lost me .2 seconds.
07-17-2003, 08:57 AM
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I've considered this mod but for 2 things:
1. The coolant does warm the TB far quicker in the cold than without it. No, it doesn't provide heat at the start, but it does provide heat soon after, assuming the thermostat is installed and working.
2. Imagine during a moderate highway cruise that you realize the throttle is no longer responding, you continue at highway speeds without the cruise control on or your foot on the pedal. Opening the throttle has almost no response. This happened to me once on a 70-degree moist evening. Had to shut down the ignition, pull to the side of the road and saw the TB of the Carburator encased in ICE. Reinstalled the heat riser tube to the air cleaner on my 20R (glad I had it with me), restarted, watched the ice melt and was on my way.
What I would like to have is a manually operated valve on the coolant line going into the TB. I think a heater valve would do, and just run an operating cable with a push knob to the dash. Turn the heat on in the cold or wet, shut it off for hauling a$$.
1. The coolant does warm the TB far quicker in the cold than without it. No, it doesn't provide heat at the start, but it does provide heat soon after, assuming the thermostat is installed and working.
2. Imagine during a moderate highway cruise that you realize the throttle is no longer responding, you continue at highway speeds without the cruise control on or your foot on the pedal. Opening the throttle has almost no response. This happened to me once on a 70-degree moist evening. Had to shut down the ignition, pull to the side of the road and saw the TB of the Carburator encased in ICE. Reinstalled the heat riser tube to the air cleaner on my 20R (glad I had it with me), restarted, watched the ice melt and was on my way.
What I would like to have is a manually operated valve on the coolant line going into the TB. I think a heater valve would do, and just run an operating cable with a push knob to the dash. Turn the heat on in the cold or wet, shut it off for hauling a$$.
07-17-2003, 09:14 AM
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Be careful with that mod because it gets much colder in an intake than you might think. The air is moving VERY fast through the intake so even on a moderate day (less than 70F) icing can certainly occur if there is any humidity in the air (humid air draws heat very fast due to the water vapor). The low heat of vaporization of gasoline also helps to cool the intake and these factors combined can cause the problems that PY mentioned. The coolant lines do add some heat to the system but it is really there to maintain a constant temperature in the throttle body (above freezing) which prevents icing in humid climates. So in a constantly hot and dry climate like arizona you are probably safe, but it remains a potentially dangerous mod to do......totally up to you though.
07-17-2003, 11:17 AM
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Interesting stuff, and good ideas! I'm going to explore the valve idea, although I have to admit that I don't have any idea what type of valve would be controllable from inside the vehicle. Any other ideas?
Chris
Chris
07-17-2003, 10:59 PM
#16
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As air passes the throttle plate, its pressure drops. Temperature and Pressure are directly releated. As the volume of air increases, the pressure on the opposite side of the throttle plate can drop to 20in/hg (inches of mercury) or more. The pressure drop at the throttle plate could cause the throttle plate to ice up.
Now, I have no experience with this first hand. Im not sure exactly what would happen, but I cant imagine the tiny bit of performance gain this mod may result would be worth any bit of the reliability that toyota has designed into my rig.
$0.02
Now, I have no experience with this first hand. Im not sure exactly what would happen, but I cant imagine the tiny bit of performance gain this mod may result would be worth any bit of the reliability that toyota has designed into my rig.
$0.02
07-18-2003, 05:53 AM
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Jay is right. When the air passes through the mostly closed throttle plate the pressure drops and so does the temp.
Now where people are going wrong here is when throttle icing is most likely going to occur. It is most likely going to occur in warm or hot climates then cold ones.
Warm air can suspend more moister in the air then cold. It is the moister in the air that is the big problem not so much the ambient temp. The air passing through a mostly closed throttle plate can drop as much as 50* F. You are never going to get throttle icing in the artic as there is almost no moister in the air, but in hot humid climates you might.
Icing is more likely going to occur in carburators and throttle body injection systems then the port type we have. As fuel is vaporized accross the throttle plate you really have a icing problem. It should be less likely in our engines.
Here is what I would do if you want to try it out. Get one of those medical clamps they use to clamp off arteries and veins. Reach in there and clamp off one of the hoses that carries coolant to the throttle body. You only need to do one. Then drive around for a while and see what happens.
You should expect to have the throttle stick open and should drive in a way expecing this to happen just in case.
Let us know how you make out.
Gadget
www.GadgetOnline.com
Now where people are going wrong here is when throttle icing is most likely going to occur. It is most likely going to occur in warm or hot climates then cold ones.
Warm air can suspend more moister in the air then cold. It is the moister in the air that is the big problem not so much the ambient temp. The air passing through a mostly closed throttle plate can drop as much as 50* F. You are never going to get throttle icing in the artic as there is almost no moister in the air, but in hot humid climates you might.
Icing is more likely going to occur in carburators and throttle body injection systems then the port type we have. As fuel is vaporized accross the throttle plate you really have a icing problem. It should be less likely in our engines.
Here is what I would do if you want to try it out. Get one of those medical clamps they use to clamp off arteries and veins. Reach in there and clamp off one of the hoses that carries coolant to the throttle body. You only need to do one. Then drive around for a while and see what happens.
You should expect to have the throttle stick open and should drive in a way expecing this to happen just in case.
Let us know how you make out.
Gadget
www.GadgetOnline.com
07-18-2003, 06:16 AM
#18
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You guys are dead on with the icing ideas. If you're more curious a good source of information about it would be in flying books. Smaller carbed planes get carb icing a lot, no matter the outside air temp.
07-18-2003, 08:48 AM
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Icing on airplane engines is not as bad as in helicopters. In an airplane you still have that big prop turning the engine when you close the throttle, so even if it stalls from icing you rarely know it. You might notice the throttle a tad stiff when you go to advance it and that breaks through the ice and it starts running again. Most pilots don't even know they had an icing problem.
Helicopters are totally different. If the engine stalls from carb ice it immediately stops running and since it automatically disconnects its self from the rotor drive it completely stops running. This is a real serious problem. This is why piston helos will run carb heat much more then airplanes to. It will even be used for hover and take off if there is any visable moister in the air. To bad is zaps so much power.
Like I said before, if any of you are going to try it, always drive like the engine is going to stall at any time.
Gadget
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Helicopters are totally different. If the engine stalls from carb ice it immediately stops running and since it automatically disconnects its self from the rotor drive it completely stops running. This is a real serious problem. This is why piston helos will run carb heat much more then airplanes to. It will even be used for hover and take off if there is any visable moister in the air. To bad is zaps so much power.
Like I said before, if any of you are going to try it, always drive like the engine is going to stall at any time.
Gadget
www.GadgetOnline.com
