I was fascinated about the Tyre and Aerodynamic improvements. Tyres we can fit, like now, once tesla release what they are .. ( and probably at tyre shop prices
)
As for the aerodynamic improvements, a UK owner has
already done loads of mods back in the summer, and get this >
improves on the old Roadster World record of 311 miles
at 28mph set in Australia in 2009, whereas his car is now exceeding this *
but at 50+* mph !
Here is the thread on UK's Speakev >
Roadster for the weekend | Speak EV - Electric Car Forums
Looking forward to seeing the details.
That would be me !
Its nice to know a battery upgrade will finally be made available in the near future, although I'm curious about the cost and if it has an extended battery warranty covering degradation, and whether this also allows Tesla to honour battery replacement contracts. I'm assuming a 70kWh upgrade will see the existing sheets in the ESS removed for future repairs of people who don't upgrade. I'm assuming the upgrade price will be in part-ex for perfectly good existing sheets ? Does it include firmware changes in the PEM or just in the new sheets ? Like others I was hoping this 400mile would be an upgrade using Model S cells alone.
From a personal point of view I find the modifications to the aerodynamics and rolling resistance most interesting ... because I've been driving a Roadster for the past 6 months with some subtle mods that regularly gets doing 250-275 mile trips *at-motorway* speeds of 60-70mph, with a theoretical max of 330 miles on the standard battery and no electrical mods at an average of around 52mph. My car has 30k on the clock now, and the lowest CAC value is around 149 iirc.
My car went in for a routine service a while back and they kept it a suspiciously long time .. it had some of the mods still on it ;-)
Anyway, starting in June 2014 I began a series of subtle experiments on my Roadster involving hundreds of hours of data recording, tuft testing and around 2,500+ miles of R&D on its aerodynamics but only by doing things that are reversible and that do not void the warranty!
After some exhaustive recursive experiments with 11 different modifications areas, I was able to work out the best beneficial combination and also which aero mods tended to cancel each other out. EG, using small aero mirrors actually increased the wh/m because more air was getting into the rear air scoops. But taping up the rear scoops this then provided the reduction in wh/m I was hoping for ! All these tests would be too extensive to write up here as it would be a research paper in itself.
The combination of low rolling resistance tyres and pressure mods yielded around 15+% range improvement alone, with only a small sacrifice in ultimate grip. This can be improved a further 5% just by pumping the tyre pressure up 20% from the 'comfort' settings. Naturally, I have a 2nd set of wheels with the proper sticky tyres on. My aero mods currently add up to a further 15% to 20% or so depending on which combination are "fitted". I also experimented on some more extensive bodywork mods such as wheel covers front and rear, wake boards, deflectors ahead of the front wheel, and so on, all of which were beneficial, but in my view disfigured the car too much so I left these off. I have plenty of photos of this all taking place.
Most of my existing aero mods are to the underside of the car, and to the air intakes, in combination with a number of smaller things like reduced Cda wing mirrors and wiper. I spent some time reducing the vortex that runs up the A-pillar causing much of the wind noise drivers hear, but the mod to fix this is probably not acceptable to most. I also monitored all the motor, PEM and battery temps with zero adverse effects because I've been driving efficiently, and would not be wise on a track day.
Another benefit of all of the above has been an improvement in acceleration because I need less energy to push my way through the air whilst still having the same amount of thrust !
At 60mph, a normal Roadster in ideal conditions uses about 260wh/m and has a max range of around 220miles. At 70mph its 310wh/m and max range of 180miles.
I'm currently running at around 195/200 wh/m at 60mph, and 235wh/m at 70mph, I can reduce this further but at the cost of making some rather more obvious exterior mods which I've been trying to avoid.
But my
Pièce de air-résistaunce will be the final modification that I currently do not have fitted to the car. It will noticeably reduce drag at 60mph which I believe will extend the range by another 15%, but I have not made this permanent yet as its a bit drastic ... and I'm waiting for the warranty to run out ... !
Anyway, throughout all of this I've not touched the electronics or battery. A 70kWh battery could extend the range a further 20-25%,
I started doing my own R&D after learning that a 2009 Roadster owner in Australia had set a distance record of 300 miles back in 2009. But he did it at an average speed of just 28 mph, on bone dry roads in thin air at 30'c. I was convinced I could significantly exceed this but at *normal highway speeds* ..
Below are a few photos showing the energy usage stats after one particular two-way average run up and down a British motorway, in amongst other traffic, moving with the traffic, but always faster than trucks etc, and it shows that I was running at the rate of just 174 wh/m. Flipping the VDS into range mode shows that with approx 51% battery remaining I still had an "ideal" 156 miles left in the tank.
In other words I reckon I could beat the existing world record at an average of over 50mph with a possible 330+ miles assuming full battery capacity usage.
With the new battery upgrade, this might mean my car could do just over 400 miles at highway speeds ( and dry roads, zero head wind, 20'c etc). With my 'final' semi-permanent modification, I think this could become 450+miles ... ;-)
The material cost of my aero modifications and tyre changes are under $1,000 .... The time cost has been huge .. but good fun none the less !
