Moderator: volvite
That's all true (although power/weight ratio isn't usually a factor in setting a tow rating..it's usually axles, suspension, chassis, etc). You could pull these loads with a lot less power than either V6 or V8....just not as quickly. Recall many far less powerful vehicles in the past were used for towing loads like this.volvite wrote:The overall structrue of the pathfinder is not changed for a V6 to V8. Most parts are the same. However there are the differences on power to weight ratio. Look at any vehicle and it's the same way. Your bigger engine is going to give you the better of the two in towing capacity. Less work involved in towing higher amouts of weight. Also that bigger engine is going to give your vehicle an overall heavier weight to help compensate for the bigger load. This might help:
Maximum Trailer Weight=
The absolute maximum that the trailer should weigh is the difference between GVW and GCWR. If the manufacturer-specified Maximum Trailer Weight is lower, then it takes precedence.
GVW=Gross Vehicle Weight
GCWR=Gross Combination Weight Rating is the maximum number that the tow vehicle GVW plus the trailer GVW should never exceed
Hope that helps.
Several assumptions you are making are not correct here:hfrez wrote:I think you are all forgetting the importance of the transmission in towing. I cannot believe or assume that the V8 has the same tranny as the V6. Gearing becomes a big issue also and the amount of them. I do not know how many gears are in the V8 tranny but I must believe that it is a bigger transmission and holds more fluids and may also have a bigger radiator up front.
One thing I already noticed is that rear drive axle ratio for the 2011 V6 is 3.13 and for the 2011 V8 it is 2.93. This may not seem like much but it makes a big difference. The smaller the number the better for towing the worse the Mpg's.
Trucks are the same way. They mostly have the same frame and body setup but the engine in conjunction with the transmission and rear end is what gives an F150 different towing capabilities. It is not just all about weight either but the tow vehicle must have a minimum weight for it to tow a certain capacity.
Actually the numerically lower ratio will negativly affect the v8 pathy not positivly affect. since it will be more difficult for the engine to turn the wheels (better for fuel economy) which is why i think the v8 only gains you 1k lbs towing capacity of the v6. Same with the rear diff, numerically higher gear rations make it easier for the engine to spin the wheels etc.hfrez wrote:I guess the point I'm trying to make is that there are differences between the V6 & V8 other than just engines that affect the towing. You would have to agree with that!
Just look at the specs of the two transmissions. They may have the same factory code but they are geared different and this will affect towing.
Transmission V6
Drivetrain Rear Wheel Drive
Trans Type 5
Trans Description Cont. Automatic
First Gear Ratio (:1) 3.84
Second Gear Ratio (:1) 2.35
Third Gear Ratio (:1) 1.52
Fourth Gear Ratio (:1) 1.00
Fifth Gear Ratio (:1) 0.83
Reverse Ratio (:1) 2.76
Final Drive Axle Ratio (:1) 3.13
Transmission V8
Drivetrain Four Wheel Drive
Trans Type 5
Trans Description Cont. Automatic w/manual mode
First Gear Ratio (:1) 3.82
Second Gear Ratio (:1) 2.36
Third Gear Ratio (:1) 1.52
Fourth Gear Ratio (:1) 1.00
Fifth Gear Ratio (:1) 0.83
Reverse Ratio (:1) 2.61
Final Drive Axle Ratio (:1) 2.93
In 1st gear, the engine makes 3.82 revolutions for every revolution of the transmission’s output. In 4th gear, the gear ratio of 1:1 means that the engine and the transmission’s output are moving at the same speed. 5th and 6th gears are known as overdrive gears, in which the output of the transmission is revolving faster than the engine.
+1, totally agree.found wrote:Your main factors are power to weight, axle ratio, and brakes.
the v8 and v6 have the same trans (slightly diff ratios), same drive shaft, and same rear diff assembly (slightly diff ratios). which leads me to believe the additional 50 hp 100lb/ft torque are the difference. In all the specs i have read the brakes are the same between the two as well. I think I also saw a post somewhere saying that the v8 rear springs are stiffer then v6 springs, but who knows if that is true.
anyway, after towing 6k lbs with my v6 pathy i can see its limitation was hp/tq related. . .particularly in the mountains. brakes were just fine, fantastic actually and nothing got too warm it was just struggling to maintain 65mph
This is what I (unsuccessfully) was trying to get across.found wrote:Actually the numerically lower ratio will negativly affect the v8 pathy not positivly affect. since it will be more difficult for the engine to turn the wheels (better for fuel economy) which is why i think the v8 only gains you 1k lbs towing capacity of the v6. Same with the rear diff, numerically higher gear rations make it easier for the engine to spin the wheels etc.hfrez wrote:I guess the point I'm trying to make is that there are differences between the V6 & V8 other than just engines that affect the towing. You would have to agree with that!
Just look at the specs of the two transmissions. They may have the same factory code but they are geared different and this will affect towing.
Transmission V6
Drivetrain Rear Wheel Drive
Trans Type 5
Trans Description Cont. Automatic
First Gear Ratio (:1) 3.84
Second Gear Ratio (:1) 2.35
Third Gear Ratio (:1) 1.52
Fourth Gear Ratio (:1) 1.00
Fifth Gear Ratio (:1) 0.83
Reverse Ratio (:1) 2.76
Final Drive Axle Ratio (:1) 3.13
Transmission V8
Drivetrain Four Wheel Drive
Trans Type 5
Trans Description Cont. Automatic w/manual mode
First Gear Ratio (:1) 3.82
Second Gear Ratio (:1) 2.36
Third Gear Ratio (:1) 1.52
Fourth Gear Ratio (:1) 1.00
Fifth Gear Ratio (:1) 0.83
Reverse Ratio (:1) 2.61
Final Drive Axle Ratio (:1) 2.93
In 1st gear, the engine makes 3.82 revolutions for every revolution of the transmission’s output. In 4th gear, the gear ratio of 1:1 means that the engine and the transmission’s output are moving at the same speed. 5th and 6th gears are known as overdrive gears, in which the output of the transmission is revolving faster than the engine.
18 wheelers for example, the rear diff is around a 5.90:1 and are typically set up behind atleast a 10 speed trans. which has a starting ratio of 15:1 ish all the way to 1:1