OK, yes I know this will make it less crashworthy, void warranty etc.
I'm extremely fond of our Prius, we(mainly my 21yo son) get an honest 42+mpg in pure stop and go city driving. To show just how good that is, we get just 23mpg with our 2001 Prizm (a dead copy of a Corolla built on the same assemble line,same workers, same parts-just different badges). It almost doubles the MPG of a Corolla-a pretty efficient car of about the same size/weight!!

We now use a Honda Pilot for a trip vehicle; on the 3000 mile roundtrip -NO to Flagstaff,AZ- it gets 22.25 mpg(10 trips) .The trip is 1150 miles of interstate(I-10,I-49,I-20,I-40) with about 350 miles of Hy 287(a very good Tx hy-).We travel kinda heavy-2 adults, one or two greyhounds(75 lbs long legs), one or 2 mtbs, ice chest etc. We also sleep in the back at rest stops to save time and $$, and to avoid having to unload at motels.

I want to trun the Prius into an American Road Trip vehicle. Yes, the perfect answer would be to wait for the Sienna Hybrid.The problem is the wait,and the $$$.We own the Prius, but are short of $$(another story).

We get 51 mpg at 65-70 mph with the Prius at sea level( you get better Hy mpg as you gain altitude). Nothing else gets this mpg; the Jetta diesel might get within 10% but diesel costs 20% more so it is effectively down at least 13mpg vs the Prius.

I'm sure it has occurred to others that if the Prius was 12" longer and 5" wider it would be a near perfect trip vehicle.A Camry Hatchback hybrid would be perfect.

My point,I can add 12-14" in length with plywood/fiberglass/plexiglass etc by leaving the rear hatch up about 14", and extending the floor about 14" rearward. Just fill in the openings left by the hatch being open, noise/water insulate everything and Voile ! You could use a support in a 2" hitch-the sort you use to carry long lumber in a pickup or SUV to support the extended floor.

It would be quickly, and completely reversible of course.

The Prius has about 68" in length behind the front seat now.I fill in the space between the folded down back seats, and the front seat backs with foam, and plywood to get a full 68" in sleep room now. We will probably take it-unmodified- on the next Flagstaff trip.

A crude guess is that the mod might cost 10 mpg at 65mph-strictly a guess. I would probably try to smooth out the "bent" roofline to improve that.
Still, 40 mpg is at least 14 mpg better than any minivan, and probably about 8 mpg better than a Ford Focus stationwagon(not a bad little car). The Diesel VW would be nice, but $$ and reliability make that a non starter.
What do you think? Ignore the loss in crashworthiness-that is undisputed, but we will be riding in the front two seats.The back would be for the dog/cargo, and for rest stop sleeping.
Thanks,
Charlie
PS-Yes, and Hybrid Camry hatchback would be perfect, and a 4cyl HH would be a distant second(sits too high to get really great hy mpg-but it is a VERY, VERY nice vehicle as a V-6 Hybrid)

 

Hi,

Let me suggest another approach, look at changing the front seats or at least the passenger seat:


Both of our Prius suffer from a fixed size, seat back and absence of heigth and tilt for the bottom cushion. When I took out my passenger seat last year, it gave me a huge amount of space and I realized what is needed:

1. height and tilt on the seat cusion
2. two-part, seat back with an upper section that can be removed

On a cross-country trip, you can already fold down the rear seats. With a sectional, seat back on the passenger side, you could: remove the upper half of the passenger seat back; slide the bottom forward; and fold the remaining passenger seat back horizontal to make a flat platform to the rear.

In this configuration, the passenger can stretch out and take a cat-nap while the duty driver makes miles. The vehicle profile has not changed and the side-impact bags, located on the seat bottom, are still there for side impact, accident protection.

Now if you still want to change the vehicle profile, I'd recommend replacing the rear hatch with a foam-and-fiberglass structure. This will let you make a smoothly flaired surface.

You start by removing the rear hatch and use foam block, toothpicks and glue to rough out the shape. Then take it out on the road with little pieces of ribbon on it to get a rough idea of the air flow. You want flow separation to occur at the rear, not earlier. Just cut, sand and glue until you have a shape that 'is less bad.'

The next step is to apply fiberglass and epoxie to build up the outer shape. Then cut out the windows and glass in the window mounting rims. Trim the inside and glass it and you're ready to mount the glass. If you do it right, you should be able to swap your extension for the rear hatch. However, I'm not sure the extra height at that end of the Prius is all that useful.

I really think the first approach should be to fix the passenger side seat. Then I'd look at extending the rear.

GOOD LUCK!
Bob Wilson

 

Bob,
I like that idea. I have a Prius 2, and I think the side airbags are in the seatback.
However, I like the idea of using room that the front passenger seat "steals" even when not in use.I like your idea enough to go out in the cold, pouring rain-12:20 am-and have a look. I discovered that if I move the passengers seat as far forward as possible, and remove the headrest from the back seat and the ft seat, the the ft seat will tilt back to just about flush with the back seat.You have to bounce the front seat just past the last detent, but it ends up just about flat.
I could do that, put down some plywood to make it essentially flat, cover the plywood with dense foam, and put the air mattress on top of that-INSTANT 3' WIDE 9' LONG BED.I would have to fill the bottom of the front seat with something-maybe an ice chest, or luggage-to make the plywood level, but that should be easy enough.The plywood could slip into the back when the seat is being used as a seat.
I would like to fit a tight fitting baggage "bubble" to the rear of the Prius.I could use a hitch support to support it,and if it blended into the rear of the Prius, it might not hit the MPG too badly.Making it with fiberglass would fit the bill.
The only shortcoming the Prius has is that it just doesn't have enough room for the American Road Trip.
Thanks,
Charlie

 

I have a 2" receiver hitch on my NHW11 and what is called an 'oversized load carrier'. The only thing I don't like is stuff can obscure the license plate and the lights:

http://www.harborfreight.com/cpi/cta...emnumber=34313
http://www.harborfreight.com/cpi/cta...emnumber=92655

If you put a plate carrier and light on the carrier, I think you'd have a winner. Caution, you need to keep the loads 'light', < 100 lbs.

I think a better answer is a small, light weight trailer or better yet, a 12 ft. jon boat. You can put a lot of stuff in a 12 ft. jon boat and a tight-fitting cover held on with bungie cords would be a great way to haul stuff around. Then once a year or so, you could even go fishing.

Bob Wilson

 

How about this?



(From a PriusChat post)

 

Hey,I like that stretch limo. It gets me thinking; how are Limos made from unibody vehicles? I can see how you do it with a body on frame design-just weld in some more frame rail, cut the body behind the front door,and add sheetmetal. I guess they just cut it in half at some strategic point, weld add a huge amount of bracing to both ends, and weld in sheet metal.Of course, you have to upgrade the suspension, and increase the strength at suspension points.(yes,I understand that this is a photoshopped picture-right???).
I think stretched TCHs, or an Escape Hybrids would make great taxies. Prius might be even better! I have always wondered about the,"We only use rear drive vehicles-Crown Vics- because FWD vehicles can't take the pounding city streets hand out," that Police Depts and Cab companies give as the reason for using Crown Vics??
Bob, any idea on the FWD durability vs RWD on beat up city streets??
The claim used to be that the CV joints would give out etc.So what, they are usually just a $450 wear item that lasts about to 80,000 miles.A Crown Vic costs maybe $17000 new-a Prius maybe $22000 now. The 12mpg vs 35mpg of it VS a Prius would make up the $5000 in fuel pretty quickly. Oh well.
Bob, here is a picture-crude- of the over 100" sleeping space done with your suggestion to lay the front seat all the way back.With plywood under the foam, and an air mattress on top- and the right icechest on the ft seat(with the ice in a watertight bag so it can be on its side),- it would be pretty comfortable. The same thing can be done with the driver's side.
Thanks,
Charlie
PS I'll have to work on the picture-won't let me.

 

No idea.

On the photos, I always put them up on a personal web site and grab the URL. Then I use the photo tool to identify the URL source.

I and probably half a dozen other folks would be interested in the photos, here and in PriusChat. Heck, even the gear heads in Prius_Technical_Stuff would enjoy them.

Bob Wilson

 

Bob,
When I get some time,I'll work on the pictures.

The Prius could be such a perfect road trip vehicle , if it was just a little bigger-maybe 14" longer and 7" wider-essentially a Camry Hatchback. I really don't see any reason that all cars aren't made as hatchbacks.
Still,I haven't given up on making the Prius a bit bigger. Your idea on the front seats will make it suitable for long trips; the comfortable sleeping capability saves lots of time and $$. No stopping and unloading in motels, and no $80 a night to stay in Amarillo while on the way to Flagstaff.The loading unloading usually chews up a good 1.5 hours.Being able to switch off drivers saves about 6 more hours, and you arrived refreshed.
I might haunt salvage yards and see if I can find the rear 6" of a Prius cabin. If I can, I can add about 15" of fiberglass to it, and attach it to the original rear where the hatch closes.I can then use the original hatch and retain a hatch. It would need support from below, of course, but one of those oversized hitch mounted lumber carriers would work for that.
Thanks,
Charlie

 

Okay, but some of us would actually appreciate a smaller Prius. We're after fuel economy as our top priority, and the existing Prius is bigger than it needs to be.

Harry

 

Hi,
I would recommend a through stress analysis. A unibody avoids stressing weld-points and shimming in an extension would require serious changes, high quality welding, and non-trivial wiring changes. It becomes a permanent change so even in local driving, the extra weight has to be transported.

One of the reasons I like using a trailer or external rear carrier is the extra capacity is added only when needed. Otherwise, it is stored and doesn't impact normal driving.

GOOD LUCK!
Bob Wilson