Record Straight on Prius Convertible

[hill]

Originally Posted by ForTheGlory

Not as safe and weaker, but he also added a hydraulic system for the roof. That's got to add significant weight. Maybe I'm off-base, but my understanding is that convertibles are almost always heavier than their non-convertible counterparts. Maybe that's just for hard-tops?

You're right ... convertables generally weigh more. Did you not read my post, comparing Porsche convertables? The Porsche CAB weighs MORE than the hard top, because the floor has to be stiffened, and that folks who go cheep by simply sawing off the Porsche roof, ultimatly "have problems" ... such as sag in the middle of the body.

I asked weeks ago for clarification ... whether his floor was sturdy'd up, to compensate for the lost structural integrity. Getting no answer I'm guesssing, gives me my answer. And after doing so much work, the stiffening wouldn't be but an extra 10%. That'd be a pity.

[daniel]

I like the looks of it. Very clean-looking job, judging by the pictures. But I'd never do it to my car. I rented a convertible (Sebring, maybe???) in Hawaii and it was fun to drive a convertible. But I spend so little time at home in summer that I'd get little use out of a convertible, and the issues of paying to have my own car converted are many and great: safety, cost, structural integrity, etc.

[WIPriusOwner]

Hmm...what kind of gas milage are you getting now?

[exproducer]

Hill,

Server was down for days then no posts to my email until yesterday so now trying to reply on various questions.

The Prius was, unfortunately, not reinforced underneath. I had to in the weekly then daily updates from Engineering Group, as work was progressing, get possibilities of what could be done, what couldn't be done and what they wouldn't do.

Although the safety reinforcement was a concern, the added expense was way too great to undertake. The same was true in reconfiguring the side air bags although working now to see if a side air bag solution can be brought back in.

This Prius the first one ever done; even with all the CAD drawings and mathematical figures drawn on masking tape covering the car, to work through solutions, various issues were decided on liability, cost and time. (It had already taken 6 months) The same was true for the window frames being removed which they simply refused to do making a more true convertible unless I only agreed to show the vehicle at car shows.

Toyota has issued a statement the car " may" not have warranty coverage in certain areas; I didn't want full car with no warranty at all.

The hydraulic system on the top explained to me is extremely light weight. The whole main section of it, tucked in the trunk behind the rear seats, can be lifted up with one arm easily. Even with the side pump and metal frame of the top, the only question ever was not if lighter than hardtop but as safe.
They took great pains to make every piece as strong as possible keeping the weight to a minimum. The flexibility feel in driving at freeway speeds is similar to other convertibles I have owned by no need for a spoiler for any corrections.

Originally noted gas mileage and comments blasting my figures. Only can say that Prius is still averaging 40 mpg with top down with 1100 miles on odometer. Top up, (infrequently) appears in highway driving to PU a mile or two. The top was designed with German Canvas; lines on drawings as close as original top as possible if not even better.

The bonnet was matched to the car interior color although I had initially requested black. When they showed me various choices; I saw other black covers with light interior, on other vehicles they were converting; decision was easy. Black did not look good as pictured in my head.

The car was taken on flatbed past week for photo sessions to independent journalist/s who along with another Japanese group did some road testing as well to present to main car mags. Future may have as well additional road testing by outside sources if I keep agreeing to give up car again. Hopefully when published by reliable sources will support the information I have been giving on Prius Chat.

exproducer

[Jack66]

Thanks again for showing us your unique modification and your honesty about the ups and downs. Your mods will probably not stop with the convertible so I hope you will continue to show us your progress. I can't afford your modification but hope to install a car PC -- doing my research at the moment. Good luck!

Jack

[Jack66]

This Memorial Day weekend is when I would love to have a Prius convertible! It is sunny, 70 degrees, with a hint of breeze in Northern VA.

[ForTheGlory]

Originally Posted by exproducer

Originally noted gas mileage and comments blasting my figures. Only can say that Prius is still averaging 40 mpg with top down with 1100 miles on odometer. Top up, (infrequently) appears in highway driving to PU a mile or two. The top was designed with German Canvas; lines on drawings as close as original top as possible if not even better.

Not to be difficult, but you said that "The mileage with top down loses approximately 2 miles a gallon". The GreenHybrid.com fuel economy average for the Prius is 47.5 miles per gallon, and most folks on here seem to get 48 or better. If your car is getting 40 mpg, that's more like a 15-20% reduction. Still far better than any other convertible on the road though.

[ZC1]

I'm certain it will be easy to sell, since some people just have to own a convertible.
It looks okay with the top up, but unusual with the top down due to the prominent rear seat window frames.

I guess anything can be done with sufficient money and desire. Nice job.

Thanks for posting!

ZC1

[exproducer]

Originally Posted by ForTheGlory

Not to be difficult, but you said that "The mileage with top down loses approximately 2 miles a gallon". The GreenHybrid.com fuel economy average for the Prius is 47.5 miles per gallon, and most folks on here seem to get 48 or better. If your car is getting 40 mpg, that's more like a 15-20% reduction. Still far better than any other convertible on the road though.

For the Glory,

On the mileage figures, Los Angeles is a bit different than many cities MPG driving stats. I'd be interested in hearing from other hardtop hybrid LA Drivers mpg but here is what I have found in about 5 years hybrid driving. (1000 miles convertible)

It is near impossible, now almost at any time of the day, particularly work time mornings commute and evenings from work traffic flow, to drive with any consistent pace for the Prius to get mpg in the 47.5 mpg range, even with a very light foot on the gas. Someone will probably write and say they do, but I've found it's impossible in normal driving conditions around Los Angeles.

The vacillation of stop and go traffic, on the freeway, from 60 mph to 10 mph back and forth constantly has the graph inside the Prius bouncing from 50 mpg to 30 mpg into average mpg zones that end up at 40 mpg averaging freeway and street.

To give you an idea, from the downtown Los Angeles area the distance is approximately 25 miles to the Pacific Ocean in Santa Monica. The main route, across the 10 freeway, is directly West from these points, to the beach. This is the route most people would take to get to the beach and back. A Google map check will give you 30 minutes (impossible) and 1 1/2 hours in traffic (more likely in rush hour now which extends for hours). From 3 PM on heading back, from the ocean, you are in rush hour traffic stop and go. You could also take Wilshire Boulevard or other direct side streets the entire length of the same route and make the trip in approximately 1 hour hitting traffic lights every few blocks.

No matter which way you drive it, generally, you are looking at a 1 hour minimum, to go 25 miles, at the speed limit, to achieve 40 mpg. I don't believe in a hardtop you could ever get the 47.5 mpg. This plays havoc with getting maximum potential mpg hardtop or convertible from the vehicle.

There are other freeways in Los Angeles obviously that flow, at various times, at the speed limit which could let the convertible possibly get the higher range at 47.5 mpg in course of open freeway driving but not short hop street traffic/ short freeway commutes anywhere in Los Angeles.

I previously owned another hard top Prius (2003) and although a different hybrid system averaged around Los Angeles 38 - 40 mpg. Some freeways 45 mpg. Understand though, this vehicle was equipped with special diamond lane stickers, issued in small quantities by the state of California, which gave the vehicle the right to use special highway lanes, on some roads, basically only reserved for hybrids etc.), in which traffic flowed quickly to get maximum mpg while the rest of the freeway was at a painful stop and go flow. Those stickers could only be issued for one specific hybrid car, not moved to a new hybrid and were limited to believe somewhere to the first 50,000 or so of the first hybrids who applied for them. They are no longer available for anyone with a new hybrid so without these stickers you are in normal (watching paint dry) traffic most days in Los Angeles. If you go in the diamond lanes without the stickers it is a date for traffic court and a big fine.

My wife owns a 2003 Honda Civic Hybrid (with the CA State stickers) and makes similar trips daily via diamond lane freeway and also on side streets getting 42.5 - 45 mpg hardtop. Back East or Midwest open highway assume both cars, convertible or hardtop average your figures realisticly at the 47.5 mpg or better.

I'm sure there will always be questions concerning loss of mpg in the convertible but all I can tell you is, it sure is nice, to at least have the top down, when you still get 40 mpg and are stuck getting to the beach.

exproducer

[rapunzelrides]

I saw this car coming up my hill the other day and thought “This car ROCKS!” I checked out the Toyota website, wondering if this was the next big thing, and found that it is a one-off. I love your mod. But then, I love the way the stock Prius looks.

I’m a Los Angeles hardtop driver. I’d have to agree with you about “normal” driving conditions in LA, which is to say there aren’t any! I rarely use the freeway. At my previous job in Hollywood (12 miles, no freeway), I was averaging about 50-52mpg. I now work in Burbank (10 miles), about 4 miles each way on I-5 during off-peak hours. It is a considerably flatter commute, and my mileage is 52-54mpg. Having owned your previous car, you do have some basis for your mileage claims, however I wonder what your mileage would have been in the newer model Prius. Did you drive your convertible prior to its customization?

BTW, I think you are my neighbor. Do you have a young golden retriever? I'm the cyclist with the silver '05. Enjoy your beautiful new car!