Unfortunately I could not locate the BTU rating of the Derale D13501 but it looks like the Tru-Cool LPD 4452 and B&M 70264 are 14.5k and 9.8k respectively.
While the Tru-Cool and Derale units are 3/4" deep, the B&M is twice that much at 1" 1/2. All three are 11" wide. The Derale and Tru-Cool are 5" 3/4 tall. The B&M is 6" tall.
So aside from depth, all units are about the same physical dimensions.
I wrote to etraler and Derale themselves to obtain the BTU rating of the D13501.
Beside physical dimensions and BTU rating, what should I check? Beside the etrailer specs on the Derale unit, I could not locate warranty statements.
B&M 70264:
http://bmracing.com/?wpsc-product=autom ... -11x6x1-12" onclick="window.open(this.href);return false;
B&M 70255:
http://bmracing.com/?wpsc-product=autom ... 11x5-34x34" onclick="window.open(this.href);return false;
Derale D13501:
http://www.etrailer.com/Transmission-Co ... 13501.html" onclick="window.open(this.href);return false;
Tru-Cool LPD 4452:
http://www.transmissioncoolers.us/categ ... -thin.html" onclick="window.open(this.href);return false;
Thanks!
EDIT: Forgot to check the Hayden Automotive 676. Apparently, same dimensions as the Derale and Tru-Cool units. No BTU specs. However, I notice that some units mention also a GVW(R) which, I asume is Gross Vehicule Weight (Rating). The Hayden is 18k pounds. Derale 15.5k, Tru-Cool 14.5k. B&M does not seems to provide that specification.
From Hayden web site, I could not locate the 676 and from their catalog, the model numbers are five digits long. They do have a lot of options:
http://www.haydenauto.com/upload/Hayden ... oolers.pdf" onclick="window.open(this.href);return false;
Also, while browsing I found from B&M product #70255 which have the same physical dimensions and BTU rating as the Derale and Tru-Cool units.