All Smiles for Mgrant Too!!

[Mgrant]

Well, I took the plunge and installed the 12cm wastegated housing. What made me decide to go with the smaller hot end was to assist with gear changes and high altitude towing, and get rid of some smoke. My first impression after replacing the 16cm, with exact pump settings, was a very noticeable increase in throttle response and the left corner of the hood rose higher on acceleration with the 12 versus the 16. I did not notice any falling off at high RPMs like I expected, but the governor is still at stock and the wastegate is set to dump at 24 psi. With the 16, EGTs would go to 750 post at 23psi on acceleration up to highway speed. With the 12, it would not go above 600 on acceleration. I will find out more the next time I tow, but I suspect that the EGTs will be lower. Cool down, no change, but lots more turbo whine and pipe whistling while cruising around town Conclusion, lots more low end and peak torque, perfect for moving heavy loads. The 12cm should be perfect for stock injectors or PWs, but I would think that stretching the rubberband above 3000 with PODs to achieve horsepower numbers would get one into trouble with the 12cm, in which a HX40 should probably be used anyway. Since this is not a race truck, but a workhorse, the 12cm is the way to go and I'm all smiles here



Mike

 

[formula]

sounds good

Let us know how the EGT reads when you're fully loaded. How big of a load do you plan to tow?



Sean

 

[Mgrant]

I tow a 4 place gooseneck Charmac. The trailer usually weighs 11,000 with four horses. I haven't towed with the 12cm yet, but I can tell a major difference when "lugging" empty up some of the steep hill around here, say 45 -50 mph in 5th. With the 16, I can easily peg 900* with lots of smoke, but with the 12cm it's hard to get it to 700* and nearly zero smoke. Boost is much higher and the engine is much more esponsive and doesn't feel like it's lugging, but the Getrag bellers and bawls. The torque rise is much steeper with the 12 versus the 16. The engine reminds me of the newer high torque, low rpm truck engines like the E7 Mack; where Mack suggest not downshifting until RPM drops below 1000.



Mike