Dr4Film Posted October 19, 2022 Share Posted October 19, 2022 I have owned this 2006 Dynasty with a Cummins ISL-400 since last February and have driven it for over 6000 miles now which includes a trip from Salt Lake City Utah to Florida and then up to New Hampshire and back to Florida recently over a wide variety of terrain, etc. I am very impressed with its power and performance especially the two-stage engine brake. i have found that the engines "sweet spot" is around 54-55 mph where it is running at about 1420 rpm and in 6th gear. It will actually stay in 6th gear while dropping mph until it reaches about 53 where the Allsion will kick down to 5th gear. So now my normal highway travel speeds stay around 55-60 mph. Whereas, the Windsor with a Cummins ISC-350 had a sweet spot of 62 mph. When running 55 on mostly level terrain as in South Carolina, Georgia and Florida I was getting over 9 mpg towing loaded coach and towing my car. That drops to about 7.5 when the terrain starts having rolling hills. Then when in mountainous terrain the mpg drops to just under 7 mpg. My previous Windsor would average between 8-9.5 mpg when driving the very same roads. What has impressed me the most is the two-stage engine brake as compared to the PRXB Exhaust Brake in my previous Windsor. I leave the engine brake switch on all of the time and the Hi/Lo switch in the high position. If the High is too much, then I reach over and switch it to Low and then back to High when finished. If anyone has driven on I-77 from I-81 down through Charlotte and Columbia SC you are very familiar with the Fancy Gap area which includes a 4.5% grade that is 7 miles long. Just before I crested the top of the grade, I made sure my speed was under 63 mph as that's where the engine brake really starts to perform well. Anything above that, not so much. Then for 7 miles I never had to touch the service brakes once. I simply toggled between the High & Low settings to control the speed of the coach keeping it between 55 & 60 mph. It was a real pleasure descending that grade with the Dynasty versus the Windsor. What have others with a Cummins ISL- 400 discovered while driving your coaches? Link to comment Share on other sites More sharing options...
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