MacGregorSailors.com

Bit of a surprise to report

I pull my 2002 X with a 2001 VW Eurovan ..it has a 200 HP V6

I usually drive at 70 on the I90 with the tow rig and observe 13 mph.

Trip back from the Cape I set the cruise on 60 to see if I could help the mileage figure

On a 170 mile run - observed 13 mpg!!

Surprised that the mileage didnt go up a bit

At constant speed, there are two primary forces the engine must overcome.

1) Mechanical friction, proportional to speed. 2) Aerodynamic friction proportional to speed squared.

When not pulling the trailer, the mechanical term is relatively smaller, and though it dominates at lower speed, at higher speed the aerodynamic term (remember proportional to speed squared) takes over.

When pulling the trailer, the mechanical friction term is relatively higher, so that even at relatively higher speeds, the aerodynamic term never gets a chance to dominate. Eventually of course, if you take the speed still higher the aero term will take over.

I've got a 02 Quad cab Ram 1500 w/ 4.7l v8. I got just under 10 at 70mph and get 12 at 55mph. I seem to do best in hilly areas w/ no cruise being I can anticipate hills and accelerate down them to keep it out of passing gear going up them. Wonder if anyone gets much more than we can get? Mike

Catigale wrote:Bit of a surprise to report

I pull my 2002 X with a 2001 VW Eurovan ..it has a 200 HP V6

I usually drive at 70 on the I90 with the tow rig and observe 13 mph.

Trip back from the Cape I set the cruise on 60 to see if I could help the mileage figure

On a 170 mile run - observed 13 mpg!!

Surprised that the mileage didnt go up a bit

Hmm, what was the wind for each trip? That can have a significant effect as well. Other things like tire pressure are important factors as well. Assuming they are all the same- that is interesting. Colder air will help too- more dense for the engine so less fuel required. Were you in the same gear for both speeds?

My truck gets about 14-15 mpg towing the Mac. If it is a lot of stop and go that drops to about 12, but as long as I have some highway driving it seems to settle in the mid 14s. It is a diesel Dodge Ram 2500 with a manual transmission and doesn't work too hard pulling the Mac. 13 is pretty good for the eurovan.

Jeff S
Jeff S

My 72 f-250 gets 11.8 on the highway without a trailer behind it. 13+ pulling a boat sounds good to me

I think what we're getting out of this is that the mileage of vehicles pulling the Mac is remarkably similar, regardless of the tow vehicle. Statistically, the difference between 10 and 13 mpg in an uncontrolled test is probably somewhere down in the noise.

Yep, agree Chip. My Toyota Sienna gets around 13-14 mpg, too.

The MACs are amazingly easy to tow...but occasionally making turns with such a "LONG" pull behind kinda causes bumps...and WATCH those low hanging Tree Limbs... I Tow with an F150, V6, with good results. Sometimes tires "SPIN" when pulling out of the WATER...even with empty BALLAST.

I get around 70 mpg with my Trailblazer when I idle over from the fenced storage yard to the marina 70 yards away.

I got one of those propellers that you mount in the hitch receiver. Obviously can't use it when towing the Mac, but the rest of the time it's good for at least 2mpg hiway.

The spinning prop sets up favorable air vortices aft that literally push the truck forward.

I'm trying to figure out how to mount a receiver on the back of the trailer. Then I could just move it there when towing and get the benefit at all times.

I suppose I could just glass a receiver onto the bottom of the boat aft. Probably wouldn't help the boat much when in the water, but for the extra 2mpg when towing it would be worth it. I could probably get the same effect by putting the motor down, but that would hang too far below the bottom of the boat and I'd be afraid of dragging in driveways and like that.

And no, it's not blue, but chrome. I was going to paint it blue but I heard that chrome is even better.

Chip,

Get a receiver for the front of your vehicle. Put the prop there and get a double benefit: propulsion and engine cooling.

Actually a triple benefit: move the receiver ball up front when you need to maneuver the mac in tight quarters around the house.

Fourth benefit: prop sucks in and chops up bugs/rocks/debris so less vehicle damage.

I better quit before things really get out of hand (though #3 has been used by others).

I like the front receiver idea. Instead of just moving the propeller up there I could get a second one, so I'd have better cooling plus an additional 2 mpg; 4 mpg total.

I don't now about putting the ball up there, though. I'm pretty good at backing at low speed, but on the road at 65 mph it might be pretty difficult. Plus the trailer wiring harness won't reach the receptacle. I don't think the back up lights would be powerful enough for night driving.

Chip,

Get one of those big screen flat TVs at discount while most are evacuated following the hurricane whereever it hits. Mount the big flat screen on your boarding ladder.
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Next, get one of those network security cameras, mount the cammera on the top of the mast pointed up, so you can see behind the trailer when the mast is down.
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While picking up the big flat screen, also acquire an in dash DVD player.
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Then hook the output of the DVD player to the big flat screen main input, and the security camera to the aux input.
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Now you can use that front hitch to push your Mac26 (surge brakes dissabled) down the highway, while watching a DVD on the big screen and keeping an eye on where you are going with the security camera in the "picture-in-picture" display.
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Note: This will test your steering skills especially in heavy high speed trafic on very narrow lanes (where they added a lane just by painting new lines on the existing pavement)
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And don't forget to install the low resistance wires, resistorless plugs and the DiretHits for a little extra MPG towing and more torque needed to push the Mac26 backwards down the highway. http://www.directhits.com/ I just sent a request to DirectHits asking for kits for 50hp outboards, Tohastsu in particular. The kits can be made with blue low resistance spark plug wires to make the boats go faster. I'll post about it if they reply with a kit.