Turbo diesel engine sizing?
I presently own a 4000 pound 18 foot RV and pull it with a gasoline fueled, normally aspirated, truck rated to pull a 6000 pound trailer. However, when towing at 10,000 feet altitude, up a mountain, t...
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Most forced induction motors be them gas or diesel will perform to sea level specs up to around 10K ft elevations plus or minus 1-2K ft depending upon the type and style of forced induction etc. Otherwise, you lose 2-3% of sealevel HP per 1000' of elevation gain. A forced induction motor, also starts to lose this same 2-3% of its HP above 10K feet or there abouts.
This will be the key if you spend a lot of time in the 6-10K range, you will notice a turbo style motor begins to really leave a non turbo behind.
TO get up really steep grades, HP is not the true test, oveall low gearing and torque multiplication. Most rigs will get to the point they can not hold 60 mph on certain grades. If you want to go up a 30% grade at 20K lbs, have 400 lb ft to work with, you need an overall low ration around 24-1. a current model diesel, ala a dmax as I had with 600 lb ft, and its 16-1 low, will only do a 24% grade at 20K lbs. Yet the two motors which I had with these two specs, were rated at 12500 for the 400 lb motor, and over 23K for the dmax.....if you have to go up a >25% grade, you are at 20K, one will make it, the other will not......it is NOT the one rated to be at 20K lbs......so tow ratings and gvwr's may or may not truly tell you WHAT you rig will do either.
Marty
This will be the key if you spend a lot of time in the 6-10K range, you will notice a turbo style motor begins to really leave a non turbo behind.
TO get up really steep grades, HP is not the true test, oveall low gearing and torque multiplication. Most rigs will get to the point they can not hold 60 mph on certain grades. If you want to go up a 30% grade at 20K lbs, have 400 lb ft to work with, you need an overall low ration around 24-1. a current model diesel, ala a dmax as I had with 600 lb ft, and its 16-1 low, will only do a 24% grade at 20K lbs. Yet the two motors which I had with these two specs, were rated at 12500 for the 400 lb motor, and over 23K for the dmax.....if you have to go up a >25% grade, you are at 20K, one will make it, the other will not......it is NOT the one rated to be at 20K lbs......so tow ratings and gvwr's may or may not truly tell you WHAT you rig will do either.
Marty
