Project Tow10k Rd2! (best older truck to aeromod)

[stillsearching]

Revisiting some of my past discussions, explorations and similar where i've been asking and trying to figure out ways to basically upgrade a sedan or station wagon which had good natural aero and a modern engine with increased towing ability... and after considering and reconsidering, i'm thinking maybe I do have it bass-ackwards afterall because I was having difficulty seeing the polar opposite strategy as having similar chances for success.

So Round 2 I think i'm going to explore the opposite strategy:

Get an older pickup (or at least chassis) FULLY RATED for towing 10,000lbs, and then aeromod the HELL out of it (including potentially radical things considered like putting the Caprice body on that chassis then slicking down further, someone else actually did this with a 1/2 ton elsewhere - but if I can get a similar CoD and reduce frontal area to the truck body despite the more vertical windshield thats just as good) and then in addition repower it both engine and transmission to bring it much closer to modern specifications for mileage. Instead of trying to tow too much with a Caprice just because the Caprice is so aero and nears 30mpg on the highway with with the LT1 and some careful driving, the goal will be to raise the bar for pickup based aeromodding instead.

I basically realized that all the things I would have to upgrade on say the frame of a caprice, el camino, or similar to try and make it handle 7-10k still to have perhaps either a marginal safety vehicle or something possibly ticketed by those who don't appreciate the careful engineering going into my modifications for safety... it's less work to bolt in a new engine and transmission to an older tow-happy pickup and to find ways to seriously slick it down afterwards. Combined with the extra room under the hood and everything else. I mean making slick bricks is what stuff here is about, what with even semis getting the treatment to double mileage, so that's probably going to be the goal here - take an "old" tow vehicle and more than double it's mileage between engine/trans and aeromodding.



So with that being said, please help me brainstorm a bit for version 2 of this project. Because budget is vital and critical I need to start with much older vehicles - nothing 2000up even worth considering. Think 1980-1999 more likely to be chosen for projects, or even back into the 70's as for instance the earlier chevies had the same body from about 73 to 87. Plus there may be easier fits with such a wide range to have little or no modifications to frame length for instance if I did stick a car body on it. (in the same way rednecks used to throw el camino bodies onto blazer 4x4 frames at the same 116" wheelbase) Nothing older than the 70's due to low availability, skyrocketing price in any decent shape, and way more primitive suspensions and such.

The Chassis Has To Tow 10,000lbs - that's my core metric right now, whether body swapping or not, and it has to do it on a budget to boot. I'm hoping to find a basic running vehicle for maybe $2000 or less for just a chassis/something like a rollover if I did do a body swap. A bit more is okay in cases like already having a bodystyle for easier aeromodding, or already having a suitable diesel in good condition without a swap, but much over $3500 for everything all in starts to seriously push limits. I'm not too concerned about being rust free, "being a looker" or anything else. Just having a suitable and reliable starting point. Since "HD" halftons are new, and many experienced towers still find them iffy for 10k figures, i'll make it easy and just go 3/4 ton and be done with it.


However aerodynamics may not be as hopeless as it seems, case in point - the 1999-2004 Ford Lightning F150 had a coefficient of drag of _0.36_. Vehicle Coefficient of Drag List - EcoModder The 10th generation F150's start in 1997 so i'm wondering, could the parts that make the lightning more aero simply be carried over to or simulated on another F150? (technically 250) Then taken further? The windshield is already raked back nicer than most. This would be preferred to say, the Dodge Rams which show a horrible 0.52 and perhaps are much less fixable... or is it not the nose/would a whaletail smooth it all out? If near vertical windshields don't matter as much I could use almost any other starting pickup however.

If the 150/250 cabs arent the same there's another possibility though - swap cabs. Or like take an older chassis like say a 1993 Ford already with a 7.3 IDI diesel, then sticking one of the newer cabs on from the 10th gen to do the Lightning style slickening. It could even be a Ford cab on a Dodge frame, it doesn't matter, the chassis does the job of towing, the body i'm hoping to choose for it's aeroability. Note I actually like the larger quad cabs and such, provided length doesn't negatively impact aero, so if there's a way to have a 4 door full crew cab plus the 8 foot bed i'm even happier. That reduces part of my other desire to have the Caprice body to bring 5 other people with. However at some length it doesn't fit the garage anymore so this is an iffy maybe - the fact I cant fit any 3/4 ton into my garage AT ALL due to height makes me prefer a shorter vehicle, if I get something too long i'll have the same problem again.


In any case i'd like to get it under 0.29 and then work on combining that with an aeromodded trailer to be figured out later. Also dropping frontal area and ride height - I know most 3/4 tons sit up noticibly higher, but do they have to? Can they drop back down again and still do their job?


A diesel engine would either need to be included in the likely model choice or swapped in. As this is a huge part of the expense in most trucks, older model diesels are perfectly fine and nothing is off the table. Anything from a GM 6.2/6.5, to the Ford 6.9/7.3 IDI's, to even things like mercedes RWD car engines boosted in power. This is not intended to be a barn burner, nor is it expecting to tear up mountainsides pulling 10k at 70mph with throttle to spare - pulling 10k would be so rare that the rest of this build is oriented towards economy unladen and while deadheading, and only transmission leverage even makes the tow possible. Power may well be less than what the factory shipped for pulling 10k almost assuredly under 200hp perhaps well under as low as 130hp or so. But at least it will be capable of handling and stopping the weight safely unlike my Caprice-chassis project idea. It may only be going 40mph uphill in the rockies with it but it will not be overheating, or fishtailing out of control while doing so. The vehicle will spend most of it's time unladen and far more moderate loads will be the norm. Anyone replicating the project may choose more power but I wont need it, I mean 10,000lb Unimogs had 82hp in WW2 so I think most peoples perceived cravings for power is a little overrated. I'll go slow the few times I have those loads but i'll get there without endangering others, just annoying them, putting on my John Deere hat, and looking back at them all bitter. :^)


Furthermore i'm actually a big fan of the older IDI diesels because this will eventually be experimenting with SVO, hopefully heavily. They tolerate the viscosity differences far better than modern engines and the lack of computer means one less thing to worry about in the swap.


Transmission trickery is one vital area of exploration, but since it's a pickup some of my original ideas of using transfer cases are alot more appropriate since those come in pickups just not normally in 2wd. I'm alot more interested in having what amounts to range box ability, with a fairly close ratio transmission, then some radical new 6 speed. Afterall the biggest thing to change in normal use would be the "mode" of the car - it has to have the power to start in 1st gear, and will generally cruise in drive since towing doesn't happen in OD anyways so why have it at all? Either a closer ratio 4-5 speed stick even if there's no OD, or a 3spd automatic like a TH400/C6 will probably be fine. But I want to play with range boxes and axle ratios so that the vehicle at rest can simply be put into the most appropriate driving condition:
- High speed cruise would be the numerically lowest gearing of course, if i'm unladen i'm probably in a hurry and have alot of miles to cover.
- A step up from that would be more appropriate for around town, steep hills, slower 55mph cruise, or light tow loads of maybe say 2000lbs or something. I've seen people say that for a Caprice like fullsize car, going from a 2.56 ratio to a 3.73 ratio IMPROVES mileage by 2mpg around town because the engine doesnt have to work as hard. I may not jump that far but then it may depend on how I work up a range box too.
- A possible second step up if a four range is possible would ideally be for notably heavier towing say around 6000lbs or so, or more steep hilly areas with a lighter tow load.
- The highest numerical ratios would be solely designed for the goal of towing 10,000lbs even up 6-7% grades without alot of engine power, not really expecting to get much over 40mph while doing so.

Two possibilities exist for a range box that i know of so far, if you have others i'm all ears but there's no way i'm spending $2000 on a friggin Gear Vendors just for a mere 0.30 overdrive or underdrive:
- The hot rodders used to connect two TH400 transmissions in series, in effect the rear one becomes a range box for the front one. Similar options could be done with others like a Powerglide, or even hooking a manual transmission of some sort behind an automatic or vice versa as long as it is tough.
- 4x4 people already have 'dual range boxes' by adding an NP203 divorced range box to usually an existing NP205 transfer case. The 1.96:1 ratio is steep but appropriate and the boxes are tough as hell rated for 5500lb/ft input shaft torque. What i'm hoping is to use two range boxes but with one of them reversed so in essence it becomes a 0.50:1 overdrive. This has already been done on a 4x4 project BC4x4.COM four wheel drive, 4x4, offroad and fourwheeling site. and that the boxes must be shifted while not in motion doesn't bother me, as whenever I change loads or radically change driving situations it's no big deal to park at the foot of the rockies for instance. It's possible that other gear options could make it a 4 range instead of a 3 range, still researching it, but this is near as I can tell a cheap and effective way to seriously increase the flexibility of an inexpensive 3spd automatic or close ratio manual. Each range box weighs about 81lbs by itself.


That's what i've explored so far, if you have unique ideas or analysis i'm all ears.

[slowmover]

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

A 10K travel trailer ( I have one) can be pulled by anything from a Jeep JK Wrangler on up. A Dodge Charger, for example, if the TT is aero in design, with low ground clearance and has correspondingly low COG, can fit the tow vehicle bill.

The better tow vehicle is more reliable if closer to stock spec. Not to mention use-able.

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

If you have done these defintions, then link them.

I enjoy this sort of brainstorm . . but my skills, time & money rule out most all of them.

Note the average mpg and cpm calcs in my sig. This is what it all comes down to, IMO.

.

[aerohead]

*With less than a foot added for a nose 'cleanup' a 'comprehensive' streamlining kit should net you around a 35% HWY-only mpg improvement.
*If your willing to put up with 3-feet of boat tail on top of that,you could see a 45% HWY-only mpg improvement.
*A little longer tail might net you a bit more.
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*Gearing will push your mileage higher.
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*I know nothing of what radials might be out there which might show up,mileage-wise.
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*Radials,O.D.transmission,and taller rear axle pushed my '62 Dodge D100 from 11mpg at 50 mph,to 16 mpg at 65 mph.
*A nose,full wheelcovers,,front gap-fillers,rear skirts,fan delete,and aero shell got it to 21 mpg at 65 mph,nearly doubling the HWY mpg.A belly pan would have pushed it over 2X.
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Rings are shot and I've probably got a burnt exhaust valve on one cylinder.She'd no doubt do better with a fresh engine.
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*The T-100 will do 36.5 mpg @ 65 mph with the 30" boat tail.
*31.8 mpg @ 75 mph.
*Originally,she was returning 23.3 mpg @ 70 mpg.
*No mods have been done to truck other than aero.

[oil pan 4]

If you want an older 3/4 ton truck rated for 10,000 lb you are going to have to get something with huge gas murdering big block V8.

The 6.5L turbodiesels were only rated for 8500 at their highest.

All trucks had gas sucking 4.10 rear ends.

See:
Tow Ratings Database - Tow Vehicle Ratings | Camping Life Magazine

[aardvarcus]

Get an old Isuzu NPR cab over box truck with the 3 liter 4 cylinder diesel. [Edited to remove sentence incorrectly stating the capacity of an NPR Box truck.] I have seen the late 80s early 90s ones within your budget in working condition. Remove the box off of the back (sell it as a storage box to recoup some investment), and shorten the frame to “pickup” length. From the cab back build a fairing that tapers in all dimensions simultaneously down to the back bottom to match the template, making an integrated storage box. That would get you pretty good right off the bat. From there, your next steps would be weight loss, changing rear axles (narrower, single tire), gearing, etcetera. Do a little research on people who have transplanted those engines into non-aerodynamic heavy vehicles with good results (stock land rovers at 26 mpg).

[stillsearching]

The trailer will be perhaps the one variable which will change without much control. :P This is what I call an "opportunistic tow vehicle" - it's designed for pulling things, that pop up in availability, being an incredible deal if you have the cash to get it, if you are looking for... whatever that happens to be. It just so happens there's a very large shopping list as this would be the main fetch vehicle for an intentional community that would like everything from someone's decommissioned ham radio antenna (I saw an antenna rig free for the taking that must've cost $6000 new on craigslist once) to decorative tile to free firewood to an inexpensive travel trailer to be someone's temporary housing.

The main tow trailer I hope to get/build/modify to basically be a flatbed with a low profile (low as the car/truck) with aeromodding to most often tow things like 2.5 cords of wood at a time, move a skidsteer or utility tractor/old farm tractor around, be able to move a wrecked car/pickup around, haul alot of scrap wood at once, move 5 tons of brick at a time, etc. It's kind of a nice size between the 3500lb small trailer level, and the truly large Class 6/7/8 type stuff, the max legal weight you can move without a CDL, probably the max weight most people would ever dare attempt without more specialized training and similar. Over this weight the trailers get so damn heavy and the loads would be rare I would think.

Although I was exploring the possibility of hotshotting a dozen empty sealand containers on a 40ft flatbed somewhere or school bus shells stripped of engine there are few loads over 10k which seem to justify a customized tow rig to haul them. There's also not any SVO suitable engines for moving well over 10k without going up to larger trucks and that by itself is the majority of the potential savings here. Something that can pull 10k efficiently off almost free fuel I believe would pay for itself even though it's only it's part time infrequent job. Saving $500 or more per load of fuel, trailer rental fees and vehicle rental fees (let alone hiring a driver) adds up pretty quick is my logic. Many jobs can be done by the 3500lb class trailer but some just flat out cant like moving a skid steer around, one which only needs to be moved a handful of times anyways. No one job makes it pay for itself, it's a number of smaller jobs that are all solved by this one 7-10k class vehicle which if you can DIY solve everything, especially if the vehicle is SVO fueled and a separate project for low cost plant oils works out. (the vehicle is planned now but may not be built unless the plant oils are able to be produced cheaply - if they are not it just takes 3x longer to pay for itself so it needs more careful analysis to really work well)

Other trailers would include eventually a heavy car/pickup dolly suitable for moving 4x4 1 tons around at the stouter end of the scale. But also things like a travel trailer to pull one way to a destination are on the table - a great deal on one wouldn't be turned away I mean, so it's not exclusively about one trailer. It would probably be used with the 3500lb rated single axle trailer for lighter loads as well.


By 10k travel trailer you dont mean 10,000lbs behind a Charger..?? People were heckling the crap out of me for considering 7000lbs behind an even larger Caprice. Thats why I finally crapcanned it and changed to a pickup framed idea.

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To aerohead: whether car or pickup body adding 1 foot to the nose, and 3 feet to the tail not a problem. Hope to couple the aero of the tow rig to trailers as well insofar as possible, and aeromod the trailer rears to boot. May well aeromod individual loads on a flatbed like some kind of temporary boattail on the utility tractor... all depends how cheaply such things can be done on the quick since they either have to work for multiple objects being pulled or be cheap enough to be disposible. If reinforced cardboaard boattails would work that might solve the cheapness problem but I don't think it'd take the load even at just 55mph.

And btw your pickup is actually my inspiration. I've seen your pic around before. My main question is would I be even better off starting with a Caprice sedan/wagon body due to lower overall profile, steeper windshield rake and similar? Or do you think, with the same above mods that a pickup probably be about as good as the car? (the pickup actually preferred if possible - such a twist may even allow a fifth wheel or gooseneck) Do you think the starting pickup body is likely to make a huge design? I don't know how much of the Ford F150 lightning is due to the center section being aero or due to other things (lowering, skirts), but it seems better than the horribly unaero dodge rams. But maybe even those, with the 1 foot nose extension and 3 foot boattail would turn out similar numbers, i've no clue... thats what i'm trying to narrow down, what vehicle body to START with.



Oil_pan - I know, thats why a diesel would be swapped into there unless it was one that came with one in there. And note my wacky idea for a 0.50:1 shiftable overdrive with a reversed NP203 rangebox so it wouldn't matter if they only came with a 4.10 or worse, even if I used a TH400 or 1:1 stickshift on there. Low gear is needed to get 10k weight moving, yet unladen tolerable cruise rpm's are obtainable with the range box. Alternately i'd explore the use of late 70's full size passenger car 12 bolt rear ends with 2-series axles, and use the NP203 rangebox as an underdrive. Even if the axles are not exceptionally strong and don't last under 10k towing they are so cheap and unwanted in wrecking yards I could bring home half a dozen. Cheapness of replacement parts is as much a part of the design as other things, since you have to build off used parts, but the odds are in favor that even if one is bad they all wont be bad.


Aardvarcus - hmm, I wasn't aware of that. I'll have to research it a bit more. I'd never heard they could stick 10k in the back, are you sure on that figure? Can it run off SVO is a critical question though, I expected to need IDI to run it because that's 2/3 of the financial savings right there. It may still get built without SVO fueling but planning for it there is important right now. I'm also curious what kind of mpg (the 30 unladen i hope to exceed?) and reliability I could expect from such a vehicle, within my budget I plan to pretty much have rebuilt the engine for instance (GM 6.2's have been available as crate engines for a little over $2k for awhile, a rebuild should cost even less) and if it ever craps out replacements are not unobtainably expensive. The same reason i'd be leery to buy a big semi to haul other loads (if it craps out I can't afford to fix it, cant afford to rebuild it, have to run it til it breaks) make me less enthusiastic about some of the other medium truck diesels.

I mean case in point schoolbusses are commonly available for under $2000 - I could aero one and they handle the weight, but I wont be hitting 30mpg with one towing 7k. Ever. Yet a diesel converted Cadillac Fleetwood is rated for the weight and should hit 30mpg unladen. I'm just realizing that I really do need more than 7k once tare weight of all available trailers is taken into account. The skid steers I might want to move around probably 5500lbs plus some implements. 7k is just not enough towing ability, I have to take risks and compromise safety stretching above a limit that many consider marginal in stock form despite our normally paranoid US tow ratings. If I could move 8500lbs without raising hackles i'd still do a sedan though. FWIW my proposed 'bulk material tow' vehicle for getting over 10k would be a schoolbus with 10k on it's back and another 10k in a trailer behind it both aeromodded. There are no single item objects that need more than 10k in weight, just huge masses of firewood, brick, scrap metal and whatever. That's also legal without a CDL. It just needs enough gear and power to move the load.

[IRingTwyce]

Originally Posted by oil pan 4

If you want an older 3/4 ton truck rated for 10,000 lb you are going to have to get something with huge gas murdering big block V8.

The 6.5L turbodiesels were only rated for 8500 at their highest.

All trucks had gas sucking 4.10 rear ends.

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.

Think on this:

Yes, those figures sound about right - laughably low for a 1-ton, but of course those figures are also based upon the staying within the declared GCWR which of course is not a legally enforceable figure.

So, as long as you are within axle ratings (which ARE) legally enforceable and within the ratings of your license, aren't a menace on the road (in other words don't try to pull 30,000# and not even be able to maintain 30mph, much less be able to stop it) then your probably fine so long as you use your head.

There is a misconception that the 6.2/6.5 GM motors are bad motors. They're not. They ARE misunderstood, and often poorly maintained. These turbo diesels were never designed for heavy towing. They were designed for good fuel economy. With a 6.5 and 3.73 gearing, you can expect 22+ mpg highway in a Suburban right off the lot. If you have the more tow-friendly 4.11 rear end, you're not going to get that high a rating (I manage about 15 mpg highway running empty, not towing, but I've got a 1 ton 4 door dually). You'll never tow as much with a 6.5 as you will with a Duramax or a Cummins. But you'll probably get a lot better mileage in the long run.

[aerohead]

The Caprice,as a body-on-frame structure is enticing unless you wanted the extra height( forward visibility) of the pickup cab.
Without any tail,but short nose and comprehensive streamlining you'd be looking at Cd 0.19 territory,no matter who's truck you start with.
With boat-tailing,the Cd will begin to fall off as you add length.
My T-100 started at Cd 0.44 and with the 'kit',and 30" of tail on it,the mpg/Cd relationship published by GM suggests Cd 0.168.
Finishing out the tail might get her to 0.12-13.I hope to have those numbers by next September.
When Hucho was at Volkswagen,they tried really hard to get the Golf/Rabbit drag down by smoothing the front and after just a tiny bit of rounding saw no real benefit with extreme radii.
They did see real drag reduction when they 'Templated' the rear end.
My opinion would be to forget about the Caprice and go directly to the pickup.
Hucho's own pumpkin seed 'car' of 1978 achieved Cd 0.15,and that was with an 'illegal' rear contour,and nothing done to fair in the wheels.

[cRiPpLe_rOoStEr]

Originally Posted by aardvarcus

Get an old Isuzu NPR cab over box truck with the 3 liter 4 cylinder diesel.

I assume you were talking about the 3.9L 4BD1-T engine. That's a good option, and so is the Cummins 4BT, altough this one still has more aftermarket support than the Isuzu, including some fuel-saving camshafts

Another nice option to consider would be a Deutz 912 or 913-series

[slowmover]

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

Yes, I am. But it depends on decent aerodynamics (a Silver Streak travel trailer, in this instance). The only real question is V8 or V6 engine. Once up to speed the weight isn't so much of a consideration. Moving from a stop or on an ascent is about the penalty for a smaller tow vehicle.

As before, defining the trailer is everything. You might post up some pics of what you have in mind.

.