Cool throttle body trick

Spook50

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Since my engine is sans EGR, I decided to bypass the coolant passage on the throttle body to see if getting cooler air into my engine would make a difference. Oh yeah, it does. A big difference. My truck feels like a rocket on the freeway now. Just another reason to desmog, guys :D

But, I wouldn't do this if your EGR system is still installed and working. From my understanding, that coolant passage helps cool the hot exhaust gas entering your intake manifold.
 
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Doc

 
 
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I think you will also find that it will take longer for your truck to idle correclty from a cold start as well.
 

Spook50

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Doc said:
I think you will also find that it will take longer for your truck to idle correclty from a cold start as well.
I haven't noticed anything yet, but I kept the original coolant lines just in case. I'll keep 'em throughout winter so I can throw 'em on if I have problems.
 

overhanger

 
 
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Spook50 said:
<snip>
But, DO NOT do this if your EGR system is still installed and working. That coolant passage helps cool the hot exhaust gas entering your intake manifold.
Please explain how you came up with that bit of wisdom.
 

overhanger

 
 
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Hildy said:
Are you saying you can do this with an unmodified rig?
Hildy
Nope, just looking for further enlightenment.
Dual exhaust? Spook was just musing about doing the same thing to his inline 6 and adding a crossover balance tube. Don't know if he did it or was just thinking about it.
 

Spook50

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overhanger said:
Nope, just looking for further enlightenment.
Dual exhaust? Spook was just musing about doing the same thing to his inline 6 and adding a crossover balance tube. Don't know if he did it or was just thinking about it.
Just considered it, and decided against it.

As far as not bypassing the throttle body when the EGR is working, when I first asked about the purpose of the coolant passage in the throttle body, a couple people explained that it was there to help cool the exhaust gas as it entered the intake manifold. If you've pulled your EGR system before, you can see how far the tube extends into the intake. Almost clear back to the TB. I figured it to be just common sense that letting gas that hot enter the intake as that one spot with no coolant flowing around it would damage something over time. Whether it be electronics nearby, or the metal of the TB and/or intake itself.
 
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im not sure if the 3Fe will be desmogged, and i think its the way i want to go, but im really not sue how to or what im even getting my self into with the whole 3FE head on a 2F block, but i know ill figur it out!
 

overhanger

 
 
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So, your admonishment in capital letters, to not do something is based on what a couple of people told you and what you deem common sense? My take, based on what the FSM says about the purpose of the TB heating element, is that it is there to prevent icing of the throttle plate as the very cool air passing the throttle plate is cooled even further by the venturi effect of the TB taper which, when mixed with the humidity of the incoming air, can create icing. With the heating element, icing is avoided. True, the intake air immediately hits the EGR tube upon entering the intake manifold but how can heating the intake air at the TB help cool the EGR gases better than not heating the same air? Yes, I have removed the EGR tube and it is at least a couple of inches away from the TB so how can there be more cooling effect from the heated TB for that tube than without the heating element being in the system?



[/QUOTE]As far as not bypassing the throttle body when the EGR is working, when I first asked about the purpose of the coolant passage in the throttle body, a couple people explained that it was there to help cool the exhaust gas as it entered the intake manifold. If you've pulled your EGR system before, you can see how far the tube extends into the intake. Almost clear back to the TB. I figured it to be just common sense that letting gas that hot enter the intake as that one spot with no coolant flowing around it would damage something over time. Whether it be electronics nearby, or the metal of the TB and/or intake itself.[/QUOTE]
 

Spook50

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overhanger said:
So, your admonishment in capital letters, to not do something is based on what a couple of people told you and what you deem common sense? My take, based on what the FSM says about the purpose of the TB heating element, is that it is there to prevent icing of the throttle plate as the very cool air passing the throttle plate is cooled even further by the venturi effect of the TB taper which, when mixed with the humidity of the incoming air, can create icing. With the heating element, icing is avoided. True, the intake air immediately hits the EGR tube upon entering the intake manifold but how can heating the intake air at the TB help cool the EGR gases better than not heating the same air? Yes, I have removed the EGR tube and it is at least a couple of inches away from the TB so how can there be more cooling effect from the heated TB for that tube than without the heating element being in the system?
Alright, I edited it. Jesus.
 

Moby

 
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This is a common trick with EFI chevys as well. It's usually listed in articles like "10 cheap horsepower tricks". Whenever I've read about it its always been in relation to icing on the throttle body. I've consider this mod using a tee that I can turn on to allow stock flow when I'm in cold weather. But that just seemed like too much work. However based on this thread I may reconsider :)
 

Spook50

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Moby said:
This is a common trick with EFI chevys as well. It's usually listed in articles like "10 cheap horsepower tricks". Whenever I've read about it its always been in relation to icing on the throttle body. I've consider this mod using a tee that I can turn on to allow stock flow when I'm in cold weather. But that just seemed like too much work. However based on this thread I may reconsider :)
My engine definately seemed to like it. I like the idea of a valve to control it. Once I make a throttle body spacer (yet another experiment I can do on the cheap), it'll be insulated for the most part from the heat of the intake manifold, so I'll have to be more careful in winter driving conditions.
 

Moby

 
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Good to know, I will put this back on my list of mods.

TB spacer, huh? I never really consider that for this engine but might be worth a try. My throttle body did like the porting it got :)
 

Spook50

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Moby said:
Good to know, I will put this back on my list of mods.

TB spacer, huh? I never really consider that for this engine but might be worth a try. My throttle body did like the porting it got :)
Yeah that's another reason for doing the spacer, is being able to easily sand out the phenolic to match the ports on the intake and TB. I'm really not sure if having a spacer will make a difference, but I figure if all it costs is the work to cut it out, it's worth a try. I still need to dig out my extra TB and send it into Downey to be bored out. Problem is when I do that I'll want to match up the port on my intake as well, and that'll be a good deal of work :doh:
 

overhanger

 
 
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Send the TB to RC Engineering for the boring - they do Downey's work and you can save a few $. As I recall it, there is no need to match the engine side of the TB to the intake as the intake manifold opening is larger than the TB outlet even after porting.
Spook, I still want to know how you figure the TB coolant helps cool the EGR gases. Not trying to be a smart ass just trying to have a discussion of the facts and not opinions.
 

KLF

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I'm with Steve on this one. That coolant line is there to keep the TB from icing up. My 22RE has the same thing, and the EGR is nowhere near the TB. I can't imagine that the intake air is warmed very much by that coolant line keeping the TB warm enough to stop the icing, can't be more than a couple of degrees difference.
 

Godwin

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On the TB spacer -

Squeezing the intake hose back on between the air filter and throttle body is already a tight fit. I would expect that adding even a small TB spacer would only make this task more difficult and increase the risk of cracking an older hose. To get everything back together may require pulling the air filter housing, attaching the hose at the TB and then reinstalling the housing to the other end of the hose.
 

Moby

 
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overhanger said:
As I recall it, there is no need to match the engine side of the TB to the intake as the intake manifold opening is larger than the TB outlet even after porting.
I had to port mine but it's soft and easy to do even with a lower power Dremel. I also trimmed the gasket to match.
 

overhanger

 
 
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Moby said:
I had to port mine but it's soft and easy to do even with a lower power Dremel. I also trimmed the gasket to match.
It's been a couple of years since RC Engineering bored my TB but they increased the bore 3mm and the stock gasket worked fine without trimming. Who did the work on your TB? The aluminum intake manifold does make for easy porting, especially when compared to grinding the iron of the head. A dremel won't work there!
 

Spook50

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overhanger said:
Send the TB to RC Engineering for the boring - they do Downey's work and you can save a few $. As I recall it, there is no need to match the engine side of the TB to the intake as the intake manifold opening is larger than the TB outlet even after porting.
Spook, I still want to know how you figure the TB coolant helps cool the EGR gases. Not trying to be a smart ass just trying to have a discussion of the facts and not opinions.
Only going off what I was told (by people who usually know more than I do) when I asked around about it. I just don't like to chance having someone fxxx up their truck by doing a certaintrick or mod and then blaming me for it because I'm the one who posted about it.

Godwin, that's something that I haven't quite figured out a workaround for yet. I'm thinking I can cut an inch (that's the width of the spacer I'll be making) from the metal section of the intake hose and put a new groove in it with one of the machines they have at the shop on base. I haven't taken a close enough look yet to see if there's even enough material to cut an inch from it, but if there is, that's probably what I'll try.

Moby, glad to know that it's a softer metal. I didn't realize that the manifold is aluminum. That'll make working on it much easier.
 
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