Prius 75-91mpg

[Nathan jones]

Ok guys, well I was'nt planning these however the new wheel tyre arrangement required some new arches so as you guys say spats are awesome well..

[Nathan jones]

I could'nt keep the return angle below 17° but well it's a short body, toyota's fault


...also the rivets are countersunk ready for respray, also there are sections underneath ready for a cutout and mounting holes, I'm letting the fibreglass and bondo settle for a week

[Nathan jones]

And the front, reduces the arch by 1 7/8" all the way round

[Nathan jones]

The drive is very quiet, not sure it's the body drop or more likely the spats, but as you guy say it must have done something, todays preliminary is 117.9 mpg combined, although I can hardly believe it so will do more tests and some highway D

Thanks guys

N.b will get a respray again over the bank holiday

[Nathan jones]

These guys going in next month, 3.5 each, should save 9kg altogether once the harnesses and seat airbags are installed, plus I don't have to take dates on the bus..

Also the 117.9 included a very small race with a vw something (it was crap)

[mpg_numbers_guy]

I like the exterior mods! What was your method for attaching them to the car? Are they painted carbon fiber?

What wheels and tire size are you running? Are they 15s or larger? Your tires seem to have a bit less sidewall than normal on a Prius.

What seats are those? I imagine they're pretty uncomfortable without any padding or bolstering!

[Nathan jones]

Hi numbers guy, thanks for the wheel advice. They are 15's, 5.5j with 185 45's on. It was hard to beat the stock wheel weight

[Nathan jones]

The seats are hand made fibreglass (not by me) a guy in cornwall makes them I think lotus molds. Really impressed, they're very light and strong and were £245 inc carriage. I will have to get brackets made so they fit. I made closed cell foam layouts to go on for comfort, but more for passengers than me. I'll upload pictures when they're done, should be sweet. They may go in after the MOT as there's already a lot for the guy to assimilate..

The skirts are woven roving, glued with panel bond and flat riveted. I was going to make carbon ones but I used the fibre glass mould instead with bondo as I ran out of time. I will make some carbon ones next year. I'm really impressed with the difference!!

Also I noted after a day of driving the soc has reduced to compensate for the lower load, annoying as I was expecting a 221 bhp ratio equivalent. I find if you drive with the brakes on for a while before warp speed 10 sections it's not so bad..

n.b I should have bought and butchered an insight like you said months ago but at the time there were no tax free ones about

[mpg_numbers_guy]

Originally Posted by Nathan jones

I noted after a day of driving the soc has reduced to compensate for the lower load, annoying as I was expecting a 221 bhp ratio equivalent. I find if you drive with the brakes on for a while before warp speed 10 sections it's not so bad..

I recently hooked up the Dr. Prius app to my mom's 08 Prius to see how the battery functions while driving. The car seems to strive to keep the battery between a 60% and 65% state of charge - indicated by 6/8 bars on the display. Any higher than 63% means that you have either gone downhill, or have driven inefficiently by braking a lot, so the car will use more battery to try to get your mpg back up. Any lower than 60% means that you've used a lot of EV range or a lot of battery power, so the car will burn more gas to get the charge back up, also reducing efficiency.

Improving aerodynamics and reducing weight won't make the battery stay at a higher charge - the 60%-65% is optimized for best battery life and efficiency. Reducing weight will help keep the battery at that charge state better, which will allow the car to get better fuel economy overall.

It's a myth that hybrids get better fuel economy - most of their efficiency is due to their aerodynamic shape and smaller engine. The electric system works mostly to offset inefficient driving patterns, such as braking.

Originally Posted by Nathan jones

Hi numbers guy, thanks for the wheel advice. They are 15's, 5.5j with 185 45's on. It was hard to beat the stock wheel weight

The shorter wheels theoretically should give you shorter gearing, but I'm not entirely sure how the Prius CVT works - it may be completely load based and not have any kind of rubber band style gear ratios (i.e., min RPM for a given speed). It would be interesting to see speed vs MPH on level ground with the old wheels/tires versus the new wheels/tires - using RPM monitoring through Torque or a Scangauge, and a GPS speedometer.

[Ecky]

Originally Posted by mpg_numbers_guy

The shorter wheels theoretically should give you shorter gearing, but I'm not entirely sure how the Prius CVT works - it may be completely load based and not have any kind of rubber band style gear ratios (i.e., min RPM for a given speed). It would be interesting to see speed vs MPH on level ground with the old wheels/tires versus the new wheels/tires - using RPM monitoring through Torque or a Scangauge, and a GPS speedometer.

I think it's somewhat fallacious to call the Prius transmission a CVT. I mean, it is continuously variable, but it's an entirely different beast than the CVTs used on every other car (except the Chevy Volt, which has a nearly identical box).




I'd argue it's the ultimate gearbox for mating a gasoline engine and electric motor, though Honda's approach in their new hybrids is proving surprisingly effective.

The idea is this: You have three parts - a Sun gear (center), planet gears (between center and ring), and a ring gear. You connect the engine to one, the electric motors to another, and the wheels to the last one.

Let's say you have the engine spinning the sun gear and the electric motors spinning the planet gear(s). You can leave the gas engine at a single speed and load (let's say, the peak efficiency speed and load), and vary the speed of the car (even into reverse) by spinning the electric motor faster or slower. If you need more power, you spin the gas engine faster and the electric motor slower. You can really get any RPM/load/vehicle speed combination you want, and the gearbox has no clutches or wear parts.

The benefits of Honda's approach (no gearbox at all) are that it's lighter, less expensive, and marginally more efficient when the engine is directly driving the wheels, since there are fewer gears.