Project Tow10k Rd2! (best older truck to aeromod)

[cRiPpLe_rOoStEr]

I was looking at those racing fiberglass body shells. Some have aerodynamically-improved noses that are worth to look at...

[aardvarcus]

You are correct Cripple Rooster, that was the engine I was referring to.

Still Searching, because that engine is fairly common commercially, I doubt the rebuild kits would be that much to keep it going, but I don't have any hard figures. As to putting 10k in the back, technically you would put the vehicle over the GVWR and the GAWR listed on the vehicle. I will edit my earlier post to clear this up.

(If you look at the actual capability of the axles used, you would see that the vehicle would be able to handle the 10k weight, although you are eating into your margin of safety.)

One last thing to keep in mind is also not just what is legal, but what looks legal. I would feel more comfortable pulling a loaded 10k trailer with a vehicle that looks like it can handle it, than one that doesn’t look like it can.

[oil pan 4]

The GM 14 bolt truck axle would be easier to find than an old 12 bolt car axle.
They have "floated axles" and are designed to carry a lot of weight.
12 bolt car rear ends are semi float, like the GM 10 bolt.

Originally Posted by IRingTwyce

The tow ratings for the 6.5 are deceptive. I know, as I own one, and there have been MANY discussions over tow ratings over on the diesel forum I frequent. Driven properly, you can reliably tow 14k with the 6.5.

I get very good fuel milage empty even at 4000 feet above sea level. But it takes a TH700, 3.08 gears and a 6.5L with a big HE351VE turbo.
The setup conducive to good fuel milage isn't the best towing rig. I have had no problem towing between 6k and 7k when I was non-turbo with the factory setup using no more than a U-haul installed transmission cooler.

[pvan93]

How about an older cummins repowered gm based stepvan with 16" wheels. Chop the top, get rid of the passenger windshield, shorten the frame if you want, and aeromod everything behind the drivers windshield.

A 3.9 bta (105hp) can push a 7'wide by 10' tall 6000# brick around 60mph and get 13-13.5 mpg. With out the intercooler (ie the 3.9bt( you can get 15mpg or better (no wind and a level road). I've lately been thinking of chopping the top off at the base of the windshield. That would that would drop the cross section area by 30-35%, and get rid of the highest front drag section of the body. you could then aero mod the front and back. Of course I live in Tx where windshields are not required, and all the speed limits keep rising. With a top speed of 60 I've parked the van for my own safety or until its moded to keep up with traffic

[pvan93]

With a little looking you could also find one with a Cummins 6 or the 7.3 liter V8 for more power. With any of them you get the heavy frame, axles, transmission, and cooling systems to start. Don't like the body, the aluminum body has scrap value. Think of it as a street legal tractor.

With 14-16' behind the drivers seat you have space for a small galley and double 30" bunk beds. (I keep thinking about a cross between a 'teardrop trailer' and a small sailboat galley.) Want to park in a grassy field after a rain. Find a limited slip axle. The 16" wheels make it easier to find heavy rated mud tires. Then shorten the frame to fit cargo.

[cRiPpLe_rOoStEr]

Originally Posted by pvan93

How about an older cummins repowered gm based stepvan with 16" wheels. Chop the top, get rid of the passenger windshield, shorten the frame if you want, and aeromod everything behind the drivers windshield.

Lowering the cockpit would also ease the aerodynamic enhancements

[stillsearching]

Finally getting caught up after two months computer problems. I already answered some in my initial followup post but i'll try to reclarify a bit plus my plans have clarified a little more anyway.

Originally Posted by slowmover

Defining the trailer is far more important than defining the tow vehicle. It truly is the cart before the horse.

The ratio of towing miles to solo miles is more important yet. It dictates what is feasible and what isn't..

I have other vehicles figured out for towing up to 3500lbs with a 4x8 trailer to replace the need for a pickup bed, so this would tow anywhere from 3600-10,000lbs for it's normal use. The split i'm deciding on, but it could spend nearly all it's time towing, say 90% of miles with a trailer, just not with full load - most loads would be one way, with an empty low slung trailer riding the way back. Occasional use without any load is possible but unlikely to exceed 10% - even if I drive it on the weekend it wont be for alot of miles. Total yearly miles i'd guesstimate 7000 just to start with for a rule of thumb, probably not under 5000, probably not over 10,000 though.

Road conditions would include light hills but not mountains - the ability to eventually, at some point, go through the rockies with a full 10k load is needed. It would not be regular at all. (10% of the loads at worst, probably 5% but it will eventually happen so a safety reserve needed)

Aero load I cannot predict 100%... but i'm hoping to have a special trailer for it probably 16ft long, 6-6.5ft wide max, and I would try to aero-couple it to the tow vehicle body as much as possible - a 55mph tow speed is expected and rarely needing to exceed, the majority of loads (65% or more maybe 80%) would be as low as the vehicle/under 60 inches. Ie the trailer would be used for hauling fairly low and dense stuff (construction wood, scrap metal, 2 cords firewood at a time), occasional loads a combination of less dense stuff (4x8 styrofoam sheet stacked up 10ft since it's light), a 3 ton utility tractor or skid steer (which might have some kind of custom aero-cap put on it to be used during towing if it's done regularily - ie a collapsable boattail behind its cab), other project vehicles usually just cars but possibly a few loads as tall as an additional pickup on top of the low riding trailer like a parts truck, etc. Though picking up a couple of travel trailers IS possible at some point in it's life for one way trips.


One question is does it make more sense to start with the really slick 0.31 Chevy Caprice and either boattail that (though it almost has one already) or connect the aero of the caprice to the front of the trailer, or stick with the pickup cab and boattail that instead/connect that tailend to the trailer front - even though aerohead points out comparable coefficient of drag is probably obtainable, the frontal area remains alot more for a pickup, so i'm still open to consideration there. One thing I DO like about the idea of using the Caprice is that I still have six passenger capacity since I don't care about the pickup bed anymore, though that's not the sole reason.

Originally Posted by slowmover

By 10k travel trailer you dont mean 10,000lbs behind a Charger..??

Yes, I am. But it depends on decent aerodynamics.

I have page upon page of angry posts saying i'm endangering others to even consider, ridicule, and panning that idea due to lawsuit risks if something ever goes wrong for being radically beyond it's designed tow weight. I couldn't find one single person in support of it on any towing related, Caprice related, or diesel related board - even people with stouter HD chassis half tons say that's almost too much for them to safely stop or handle, let alone normal 1/2 tons which are still stouter than any Charger or Caprice. :-/ Most don't even think the 7k rating of the Fleetwood is safe and that's from guys moving these weights all the time. So i'm pretty set on just using a 3/4 ton chassis, if not pickup cab for the underpinnings for safety.

Plus slickest aero is no longer a guarantee for all loads, just many.

Originally Posted by aardvarcus

As to putting 10k in the back, technically you would put the vehicle over the GVWR and the GAWR listed on the vehicle.

One last thing to keep in mind is also not just what is legal, but what looks legal. I would feel more comfortable pulling a loaded 10k trailer with a vehicle that looks like it can handle it, than one that doesn’t look like it can.

The 10k will be in the trailer, not on the rear axle, not sure where that came from. Even if it doesn't "look" like it can handle it, as long as it's legal for pulling i'm fine.

FWIW i've already talked to quite a few people hauling 10k through the Rockies and everything with 6.5's and even with 6.2's with the mildest of improvements - as long as you don't need to go super fast it will get it moving, the problem everyone tells me is stopping and vehicle dynamics under the load. It wont make modern guys wanting 75mph uphill happy. I consider both that, and a 3/4 ton chassis to be doable. (though it could just as well end up a Ford or Cummins too, I just mean the rest of the discussion is still open to being GM, Ford or Dodge chassis, GM Ford or Cummins engines, etc. though still favoring 6.2/6.5 GM or 6.0/7.3 IDI Ford for engines)


Not so sure on the van idea.. :-/ Not looking to completely chop, channel, and resection a body... one reason i'd considered a car body swap is that from the one other person I heard who did it, it wasn't even all that hard.

[JRMichler]

Originally Posted by stillsearching

a 3 ton utility tractor or skid steer (which might have some kind of custom aero-cap put on it to be used during towing if it's done regularily - ie a collapsable boattail behind its cab),

Plus slickest aero is no longer a guarantee for all loads, just many.

Try laying 2 or 3 long poles over the top of the skid steer, then pulling a tarp over the top of the poles. Tie down the tarp hard enough to flex the poles and end up with a smooth curve. The result won't be an ideal teardrop, but will be far better than a naked skid steer (think parachute).

[slowmover]

I have page upon page of angry posts saying i'm endangering others to even consider, ridicule, and panning that idea due to lawsuit risks if something ever goes wrong for being radically beyond it's designed tow weight. I couldn't find one single person in support of it on any towing related, Caprice related, or diesel related board - even people with stouter HD chassis half tons say that's almost too much for them to safely stop or handle, let alone normal 1/2 tons which are still stouter than any Charger or Caprice. :-/ Most don't even think the 7k rating of the Fleetwood is safe and that's from guys moving these weights all the time. So i'm pretty set on just using a 3/4 ton chassis, if not pickup cab for the underpinnings for safety.

Don't know what they're talking about from the standpoint of loads, of law, or what their not-so-cowardly forefathers have done with plenty of margin. One can see this on RV boards as well. A world of ignorance. In the meantime, those who know what they are about fit the vehicles, optimize the lash-up and get down the road. And have for more than fifty years.

But it's more expensive up front.

Aero changes the equation of what is wanted as it is primary for a highway vehicle. Weight is the secondary consideration. In all cases it will be the tow vehicle with the most accurate steering, and suspension most resistant to the vehicle being moved from it's path that makes it the better choice. A pickup -- especially 4WD with live axles -- is at the wrong end of the spectrum. The rollover propensity, alone, makes it the worst choice. As to braking, any trailer that cannot stop itself under any conditions is defective in design or maintenance or both. The tow vehicle and the trailer ought to be able to stop each other without the brakes of the other working. Etc.

Any vehicle chosen as tow vehicle has limitations. But the one which starts with the best design will return the best performance whether on the road or for dollars spent.

You still need, IMO, to narrow down your definition:

- 10K payload across the Continental Divide

is completely different than

- Running around a major metro region with a fairly economical combined rig.

You won't have both in one rig. Spec your rig for your climate, terrain, use. Not the outliers. That's where you hire out the load.

And

10k miles per year isn't enough to re-invent the wheel as you are trying to do. Not enough savings to justify expense (especially time). Towing is generally a 30-40% penalty over solo miles. Best aero might bring that to a 20% penalty. Do the math.

In which case a sedan with an open trailer and some hard panels/shells and tarps for aero & all-weather will do well enough. Costs go up from there with quickly diminishing returns.

What you want to do, and what you ought to do, still haven't met up.

.