I just just found your post now - today Dec. 14,2007- and noticed that it actually dated from June & July 2007! - so I apologize if my reply here is out of date. How is this project going? Did you get the engine fitted? Did you get a rad built for it yet? This is truly an amazing project! I love those old "Deetroit 'Buzzen"Dozens"!! I've had some first hand experience with a truck somewhat similar to what your doing. Back in the early 1990's - for a brief time, (a couple dozen or so Toronto ON to Bakersfield CA round trips hauling refrigerated meat and produce), I drove an 85' 9370 International Eagle that had a twin-turbo 12V71 gen-set engine swapped into it. What a truck! Fuel mileage wasn't the greatest, about 5.5 mpg loaded and pulling hard - down to about 4 in the mountains - and maybe 7 mpg if you drove it easy and real carefully. But talk about power - and with dual 6 inch straights the sound was absolute music...albeit somewhat loud music! Absolutely nothing sounds as sweet as V12 Detroit at full chat!l The truck had originally been equipped with a tired 425 hp 3406 Cat that finally threw a rod out the side of the block. The owner - (not me I only drove the thing!) found a deal on a very low hours, surplus 540 hp at 1800 rpm 12V71TT industrial engine that had been used as stand-by generator and decided to put that into the truck. For a rad - he had a rad shop build a custom unit that was externally, loosely based on an OEM rad for an International with an 475 hp 8V92 Silver Detroit motor, but with two extra cores added. Basically, you want/need the biggest rad with the thickest core your rad shop can fit into your Mack. While maybe not absolutely necessary - to help keep things cool, he also added a pair of externally mounted Lubrifiner bypass oil filters as well. Being mounted outside the hood they definatly helped lower peak oil temperatures -which meant that much less heat having to be handled by the rad. As for CAC- while most Detroit truck installations didn't use CAC- it's still a good thing to have on any turbocharged engine if you can fit it. Even "high flow but low - in fact, almost neglable boost pressure" conditions that a turbo- 2-stroke Detroit typicaly operates at , cooler charge air still contributes to cleaner runninsg and better fuel mileage. Fit it if you can. On the International .we kept the "original CAC unit used with the 425 Cat in front of the rad and had the rad shop modify the tanks to accept a second inlet, fed by the right bank turbo. The cooler air from the CAC allowed the engine to be turned up with oversize #96 injectors ( the originals were #90's) and still run clean without loading up, slobbering or excessive smoke. With the 96's and CAC - and with the governor set 2300 rpm - the truck dyno'd at 525 hp -at the ground! ( Not bad considering the engine was originally rated at 540 hp at the fltwheel) Another thing with Detroit 2-strokes - they inhale lots of air - almost twice as much as a 4-stroke diesel for the same hp, so both for clean running,power and mileage, it's important to use high capacity, low restriction air cleaners. On the International, we fitted a pair of large Donadlson external units, originally spec'd for a KW off-road logging truck with a 3408 Cat. I'm sure these contributed to the power and relatively clean running. Also, being external, they brought in much cooler outside air which helped a lot too. Likewise with exhaust flow too. Detroits put out a lot of exhaust flow and don't like restriction in the exhaust. We used 6 inch straight pipes. With the turbos, the noise wasn't too bad - unless and until you where really gouging on it. If dual 6 inch straights are too loud for you, or will cause problems at the scales, at least use the biggest diamiter pipes - and the largest capacity, low restriction mufflers you can fit. Good luck with your project! Please do keep us informed of your progress! Feel free to e-mail me either on or off list too if you want. Mart ===============================
