Coolant through the TB?
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
To keep it warm so it doesn't freeze up. Many have bypassed it for whatever reasons. I do it so I don't get coolant all over when I am cleaning my throttle body every few years.
It is also seen on the L98 TBs for the F-body
It is also seen on the L98 TBs for the F-body
Melting Slicks
Joined: Sep 2008
Posts: 2,376
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From: Cherokee National Forest TN
If operating in the snow belt the TB will frost if it is not kept warm.
Carbed cars from the 60's on had exhaust manifold heat tubes connected to the air filter it served 2 purposes, kept the carb from icing + lessened warm up time.
Carbed cars from the 60's on had exhaust manifold heat tubes connected to the air filter it served 2 purposes, kept the carb from icing + lessened warm up time.
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
I suppose it depends. I haven't had it ice up in WI yet and from 91 to 04, I drove the F-body all year long regardless of condition. Even in snow.
Safety Car
Joined: Aug 2013
Posts: 4,427
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From: Minneapolis Mn
I suppose if you want to try it without anything, you could put a valve in the line to shut it off and see what happens. It gets cold here so even though not driven in winter I still run it on occasion to keep the fluids and seals up. I can't say I've seen a big difference either way but I keep it on anyway.
Team Owner
Joined: Dec 1999
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
You could bypass the TB, but GM engineers that developed the L98 must have ran coolant under the TB for a reason. GM tested the Corvette with the L98 in all sorts of climates from as high as 120 degrees down to temps like -40 so they must have had a good idea as to why that coolant line was put there.
It does help with warmup and the ECM may even go into closed loop quicker as the warm coolant flows thru the TB lower housing. The IAC also gets coolant thru the lower housing and that may also help with warmup and emissions.
IMHO, if there are no coolant leaks and the hoses are in good shape, there is no real reason to do a bypass on a stock engine especially if it's running fine.
It does help with warmup and the ECM may even go into closed loop quicker as the warm coolant flows thru the TB lower housing. The IAC also gets coolant thru the lower housing and that may also help with warmup and emissions.
IMHO, if there are no coolant leaks and the hoses are in good shape, there is no real reason to do a bypass on a stock engine especially if it's running fine.
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
I suppose if you want to try it without anything, you could put a valve in the line to shut it off and see what happens. It gets cold here so even though not driven in winter I still run it on occasion to keep the fluids and seals up. I can't say I've seen a big difference either way but I keep it on anyway.
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Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
You could bypass the TB, but GM engineers that developed the L98 must have ran coolant under the TB for a reason. GM tested the Corvette with the L98 in all sorts of climates from as high as 120 degrees down to temps like -40 so they must have had a good idea as to why that coolant line was put there.
It does help with warmup and the ECM may even go into closed loop quicker as the warm coolant flows thru the TB lower housing. The IAC also gets coolant thru the lower housing and that may also help with warmup and emissions.
IMHO, if there are no coolant leaks and the hoses are in good shape, there is no real reason to do a bypass on a stock engine especially if it's running fine.
It does help with warmup and the ECM may even go into closed loop quicker as the warm coolant flows thru the TB lower housing. The IAC also gets coolant thru the lower housing and that may also help with warmup and emissions.
IMHO, if there are no coolant leaks and the hoses are in good shape, there is no real reason to do a bypass on a stock engine especially if it's running fine.
According to THIS, O2 has to have varying output, CTS has to be above 104 and it has to have a certain run time.
A good reason is if you are cleaning your TB regularly and you don't want to mess with coolant leaking out
Pro
Joined: Mar 2004
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From: Linthicum MD
Safety Car
Joined: Aug 2013
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From: Minneapolis Mn
Racer
Joined: Aug 2015
Posts: 383
Likes: 143
From: Pine Ridge FL
Coolant through the throttle body is actually quite common. I've seen it on several makes. Pretty much the conventional wisdom is that if you don't live in a place with extreme cold then you can bypass it and get more HP. Don't know if that is true or not but how many people who modify their Corvette for performance drive it in weather below freezing anyway?
Team Owner
Joined: Jul 2004
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From: Hartford WI
That is worth more than any SOTP dyno reading.
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
However, I have not had a freeze up or any unstable idle once when we dipped to 20 below and I used to drive a L98 motor F-body every day since it was my one and only daily driver. Depends. Would there be snow on the ground? No snow I'd do it and am doing it.
Racer
Joined: Aug 2015
Posts: 383
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From: Pine Ridge FL
I think you have to have the right atmospheric conditions in regards to temperature and humidity for the throttle to freeze up. And since a stuck open throttle really sucks I can see why manufacturers err on the side of caution.
Team Owner
Joined: Aug 2004
Posts: 21,543
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From: Park City Utah
Now I'm not saying that it can not happen; The OEM has to engineer for the worst possible case, and that is probably for those folks driving Corvettes in Antarctica. Or some criteria similar to that. For 99.9% of us, it's a non issue.
It doesn't affect warm up time in a meaningful way. It speeds and improves atomization. Fuel vaporizes in warm air better than cold air so that feature primarily improved cold running performance, faster.
Team Owner
Joined: Jul 2004
Posts: 28,422
Likes: 3,275
From: Hartford WI
I agree and disagree. If the motor is running, there is enough heat where I can't realistically see how the TB can be stuck in the open position. Any movement would unstick the ice around the shaft. I would agree that it can be stuck close where the blades stick to the opening if there is enough moisture around the blades and the temp is right for it. In which case, you'd have to run the engine for maybe a half hour in that temperature to get it hot since it would be an extreme cold. Not sure how you'd get that much water around the blades but you're right. It would have to be something wild and weird. I'm always curious how we could achieve that crazy condition. Any ideas?
Team Owner
Joined: Aug 2004
Posts: 21,543
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From: Park City Utah
No, it doesn't help with warm up, OR emissions. It's sole purpose is to prevent icing when those extremely rare conditions present themselves.
Safety Car
Joined: Aug 2008
Posts: 4,344
Likes: 48
From: San Marcos CA
Although the exact conditions are actually sort of rare, a throttle intake can ice up. It can be a problem on aircraft..I think the condition is more likely at lower atmospheric pressures (higher elevations) while flying through clouds.
It has never happened to me, but I think it would be rare on a port injected car...a little less so on a throttle body or carburetor where the fuel itself will evaporate off the heat of the throttle plate and cause humidity to instantly frost the works up.
It has never happened to me, but I think it would be rare on a port injected car...a little less so on a throttle body or carburetor where the fuel itself will evaporate off the heat of the throttle plate and cause humidity to instantly frost the works up.