4l80e cooler line question

[ak diesel driver]

So my question is if a later model 4l80 is used, that has the bigger lines, is it an issue to use the smaller line cooler in the radiator?
@THEFERMANATOR
I'm mostly worried about flow and lubrication

 

[THEFERMANATOR]

I'm not a fan of it myself, but most of your radiators today only have a 5/16" cooler and use adapters to go up to the bigger lines. I know in 97 GM went from 5/16" to 3/8" for cooler lines, and in 99 with the nbs went to a 1/2" cooler line for the 4l80e, so GM felt flow was important.

 

[ak diesel driver]

Buddy of mine said when he worked at the dealer they had to flow test the cooler, if it didn't pass they replaced it

 

[ak diesel driver]

Frostbite FB286 Frostbite Aluminum Radiator- 3 Row

High-Horsepower street cars and trucks can be a challenge to keep cool. A proper cooling system starts with the right radiator. Aluminum Radiators cool more effectively and weigh less than older OEM style brass units. Choose from a variety of popular application specific fitments. Holley is...

www.holley.com

Am I reading this right? Says 1/2 x20

 

[Will L.]

Frostbite FB286 Frostbite Aluminum Radiator- 3 Row

High-Horsepower street cars and trucks can be a challenge to keep cool. A proper cooling system starts with the right radiator. Aluminum Radiators cool more effectively and weigh less than older OEM style brass units. Choose from a variety of popular application specific fitments. Holley is...

www.holley.com

Am I reading this right? Says 1/2 x20

yes, 1/2” tube fittings and comes with adapters up to 5/8”. One would think that means 1/2” tube inside, butthey could stuff anything inside. As to the -20 thread on the 1/2” fittings and the -18 thread on the 5/8” fittings- seems straight foreword what it comes with- but idk what GM decided on, so another adapter might be needed.

the spec of how its built is good that it’s Tig. But they don’t give spec to fin per inch or core row spacing or core size that I saw.

 

[THEFERMANATOR]

Frostbite FB286 Frostbite Aluminum Radiator- 3 Row

High-Horsepower street cars and trucks can be a challenge to keep cool. A proper cooling system starts with the right radiator. Aluminum Radiators cool more effectively and weigh less than older OEM style brass units. Choose from a variety of popular application specific fitments. Holley is...

www.holley.com

Am I reading this right? Says 1/2 x20

1/2"x20 is the thread size used for 5/16" hard line fittings. The 5/8"x18 fittings are to use 3/8" hard line.

 

[Will L.]

So reducing the line in the radiator where it sheds heat, then expanding to larger size, then return to transmission...
The net pressure should be the same. The rate of flow could change. Or if flow gets regulated the pressure would spike in the reduction area but drop off again as it returns- if I understand boyles law properly. Any time fluid volume area expands, some aeration is possible.

Is there functionality issue from any alteration in volume (flow rate) back into the trans? Where does the line feed to once itcomes back?

 

[ak diesel driver]

From some stuff I read the return line from the coolers should be the rear one and it lubes/pressurizes from the back forward. The older units feed into the middle instead of the back

 

[denata]

 

[ak diesel driver]

So it turns out Holley is just a reseller of champion

 

[THEFERMANATOR]

91-96 has both lines in front, in 97 GM went to the rear luber and moved the return line to the middle of the case. The cooler return flow lubes most everything from the middle back(the output bushing and slip yoke for 4x2's are lubed by the afl circuit). This is why I do not like the reducers at the radiator. GM ended up going up to a 1/2" line for the 4l80e, but the radiator reduces it down to that of a 5/16" line. That's 2 big choking orifices in the flow is how I see it. Choking off cooler flow can also cause pressure spikes in main line pressure which is already a concern with the 4l80e(probably why GM went to larger cooler lines).