TB Coolant bypass mod

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Sep 1, 2019 | 09:27 AM

#16

ISFpowered

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From: California

Quote:

Originally Posted by threefiveo

I'm not sure about the throttle by wire vehicles, but the other Toyotas I have worked with, the coolant controls the Idle Air Control valve in the throttle body. There is typically a valve in the throttle body that allows air to bypass the throttle plate, and as the coolant heats up as the engine comes to temp, it closes the valve to lower the idle speed. The only thing negative I can think of is maybe the car won't idle down properly once warmed up. The ISF may not even have this.

When I removed the the hoses since I did this when I installed my koyo radiator I looked inside both sides and it’s just free flowing coolant. No valves anywhere.

Sep 1, 2019 | 09:37 AM

#17

ISFpowered

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From: California

Quote:

Originally Posted by SubOrbital

More so than the TB just freezing shut, I imagine there are conditions whereby condensation can form inside the TB and then freeze into ice. Lexus sells these cars all over the world so the TB coolant loop is necessary to prevent that, especially in very cold climates.

Easy way to test improvement from the bypass mod is to log IATs before and after. Given same/similar atmospheric conditions and driving, one should show IATs trending lower.

I guess that’s the idea but the TB freezing I promise will never happen and here’s why. Years ago when I had my Acura TL and this was discussed on acurazine we had someone who lived in Alaska try it and ran it year round on his TL. Not a single time did his TB freeze nor did he ever notice ice form inside his TB. We all kept track of people who did it in extreme cold climates and not a single person reported a frozen TB from this mod. I think the idea is possible that it was designed to prevent a frozen TB but then again it might not. Think about this if you had condensation form inside your TB and froze it who’s to say it’s not in your cylinders, valves, IM, etc and you have ice all inside your motor that little coolant hose isn’t going to change anything. When you start the car in the morning the coolant is cold as well along with everything in the motor it’s not like the coolant stays hot while the cars off to prevent a frozen TB.

Sep 1, 2019 | 09:41 AM

#18

ISFpowered

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From: California

Quote:

Originally Posted by Jwconeil

Nevermind, you put the caps at the beginning of where the old hose was, and also capped the throttle body.

Thanks for sharing. This is now on my mod list, as well as the rear engine breather mod you shared.

Your welcome. To make it look clean I pulled the TB off and pulled the two tube pieces out of the TB and then capped the two coolant passages on the motor with the samco caps. I have seen people use rubber caps and those tend to rip and leak so I found samco made caps specifically for blocking off coolant passages. Plus they have a lifetime warranty.

Sep 1, 2019 | 10:31 AM

#19

WillAP1

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From: FL

Would be interested to hear RR Racing or Figs weigh in on this. Wonder if they have this done on their cars?

Sep 1, 2019 | 04:39 PM

#20

mike33

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From: fl

Quote:

Originally Posted by ISFpowered

Your welcome. Not really sure except for heat soaking your TB. Ran this both on the east coast in negative temps and in the desert where temps are between 100 and 120. No cons only positive are cooler TB temps.

Did you measure the before and after TB temps? Wouldn't the coolant line in the TB act as a temp stabilizer and provide cooling
when the engine is hot, and warming when cold. I would think the engine area near the TB could far exceed 200* during summer driving and the
coolant line may actually help reduce the TB temps.

Sep 2, 2019 | 12:39 AM

#21

KenISF

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Joined: Apr 2019

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From: CA

Quote:

Originally Posted by WillAP1

Would be interested to hear RR Racing or Figs weigh in on this. Wonder if they have this done on their cars?

Yep, would love to hear what they say. I seen this done on multiple cars but no one ever did any test to see any gain.

Sep 2, 2019 | 12:50 AM

#22

Joe Z

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From: Under an IS F since 2008

Quote:

Originally Posted by WillAP1

Would be interested to hear RR Racing or Figs weigh in on this. Wonder if they have this done on their cars?

Maybe @lobuxracer will also provide us the Technical purpose of the function and how we can benefit or not by doing the Throttle Body by-pass mod..

You guys want a quick thrill, unplug the connector on the solenoid for the intake air box / secondary air flap.

Joe Z

Sep 2, 2019 | 08:13 AM

#23

ISFpowered

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From: California

This guy did a before and after with his WS6. His math is off though he said after both 24 mile drives his temperature difference was 16.65 degrees lower after the coolant bypass, however 96.0 minus 73.35 is 22.65 not 16.65.

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Sep 2, 2019 | 11:33 AM

#24

MileHIFcar

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From: Colorado

Interesting video.....Thanks for the upload!

Sep 2, 2019 | 03:22 PM

#25

lobuxracer

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From: Georgia

The throttle body won't ice up in a cold climate ever. The humidity is near zero when it's cold outside. Freezing is more likely in humid environments at low throttle openings because the air is highly endothermic at low throttle openings (gas going from high pressure to low pressure, same concept as most refrigeration).

Does this actually happen? Apparently it is enough of a concern the engineers made sure they spent the money on it. There is nothing a car company does that costs money for no reason at all.

All that said, this has been a common modification over the years without measurable results in any direction other than the obvious loss of full coolant temperature in the throttle body. Supra guys made all kinds of wild claims about it that no one could ever prove.

Sep 3, 2019 | 05:12 AM

#26

Rickna

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From: ConnectiTAX

What size cap did you use?
Thanks

Sep 3, 2019 | 08:54 AM

#27

ISFpowered

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From: California

Quote:

Originally Posted by Rickna

What size cap did you use?
Thanks

That I can not remember BUT if you find out the size of the hose on the throttle body your set. I measured the inside of the hose when I pulled them off and then ordered the caps. If you find the outside diameter of the hose you can go to autozone and measure the inside of a hose with the same outside diameter.