B&M trans cooler

[greenmachine]

My inlet/outlet is 1/2" npt. Should run 1/2" ID lines or is that OD? 1/2" ID seems huge, but 3000 stall on the street is gonna make a lot of heat.

 

[wyrmrider]

MA mopar went to half inch lines on the diesels for a reason
even the OD trans have 3/8
bends kill you
the good coolers have half inch in and out
etc
our tests showed that going from 3/8 to half inch reduced back pressure measured at the trans by 15 lbs for each line and about the same when eliminating the in radiator cooler big difference
stock flow has to be 1 quart in 20 seconds at idle- more is better

 

[greenmachine]

I hear what your saying. My question is the nipples/fittings that screw into the trans (front side to cooler, rear fitting return), both only have .200 openings, not even 1/4 (.250). Isn't that my bottleneck no matter how big of trans cooler lines I run? I think I'm gonna run braided stainless lines also. This is all good info. Thanks!

 

[greenmachine]

My lines will be 3/8 braided minimum. Possibly 1/2 depending on cost. Does flow increase between .375 to .500 that dramatically?

 

[wyrmrider]

the small restriction is for a very short distance- and you can drill them out if you are not going to go up a size
and yes do a pie r squared on 5/16 3/8 and 1/2 there are plumbers tables that include bends and length friction but simple area works
also if you have a cable shift with a screen filter put a transdapt or other adapter in the out line and a spin on filter= I consider this also a must for any converter clutch build- a blown converter clutch trashes your trans cooler (s)

 

[greenmachine]

Ok. Did homework. You got me there. .375 is .0057 volume per foot. Vs. .500 is .0102 vol. per foot. 20 feet of hose with .375 gets you .114 total gallons vs. 20 feet of .500 hose gets you .204. I could possibly drill the fittings from .200 to .250, but unless I wanna drill and tap the trans I don't think the fittings have enough material to be opened up bigger.
I like the spin on filter idea to save my monster trans cooler. I appreciate all the insight.

 

[wyrmrider]

just a little bigger but you have to r&r the fittings
hose makes the biggest difference
we tested with 3 temp gauges and 6 pressure gauges on he famous Death Valley route "Baker Grade" two tube sizes and three hose sizes
Baker is home for the worlds largest thermometer for a reason

 

[493 Mike]

One other item to consider is that metal lines will radiate extra heat while rubber is an insulator.
Mike