Electric Caterham

[924s]

23 hours ago, Davemk1 said:

The max allowable weight for a Seven to feel like a Seven is an interesting question. Before I built my Westfield (1220 lbs) I owned a supercharged Lotus Elise (1900 lbs) and while compared to most anything else on the road the Elise felt light it feels heavy compared to my Seven....which of course it is. Both are seriously quick and fun but they are different.

 

What I wonder about is how light could an electric Seven be made. My Westfield has an S2000 engine and trans and they are not light and heavier than most 4 cylinder cars would have. On the other hand an electric motor would be much lighter than the Honda unit and it won't even need the trans. If one takes the weight loss of the engine and trans and put that weight into batteries what would the car end up weighing? I have no idea but I'm sure it would be far south of the ICE Elise.....which is an awesome car. And the torque and throttle response would make the ICE set up feel slow witted.

 

It's an interesting question and I look forward to seeing what Caterham comes up with. My wild-assed-guess would be that to get the needed range that it will weigh about 1400-1500 lbs and do 0-60 in about 3 seconds. Would it be as flickable as a 1250 lbs car? Nope. Would it be wicked fun? Yep....I think it would.

 

Time will tell.

 

dave

An electric car with no batteries and a  gas powered car weigh about the same, the weight savings of no ice engine is offset with with the reinforcements of the car required to carry the weight of the batteries plus the electric motors, controllers etc. that come with electric power.

2008 tesla roadster weight of  batteries = 450 kg  or 992 lb  

A 1200 lb 7 becomes a 2200 lb 7.

[BlueBDA]

Critical to this discussion is the intended use of the car.

 

A Tesla Model 3 Performance is great for the road, and from what I've read and watched it's just about there for HPDE track days.

 

The ID-R is designed for one purpose - Pike's Peak. It's not meant for doing four twenty minute track sessions.

 

What would you want to do with an electric seven?

 

Street: Just a matter of balancing range vs weight. Guessing (maybe someone else can do the math) that an 80 mile e-seven might weight similar to a Cat, and perform similarly or better.

 

Track: The math probably doesn't work here. Need range, which means weight, and aerodynamics, which means not a seven.

 

Autocross: I think an e-seven could be built to excel at this. Aerodynamics don't play as big a role, and runs are short. I've thought about an e-seven with swappable batteries, built for autocross. EV West told me "people have tried swap-able batteries and it doesn't work out", but I think designed for autocross, with a trailer that is equipped to transport and swap the batteries, could be an amazing system. But - there's no SCCA Solo class for this, so after doing all of the work to design and build it, it couldn't compete. But it would be a ton of fun.

 

It would be great if someone can chime in with some kWh/mass math.

[Vovchandr]

54 minutes ago, 924s said:

An electric car with no batteries and a  gas powered car weigh about the same, the weight savings of no ice engine is offset with with the reinforcements of the car required to carry the weight of the batteries plus the electric motors, controllers etc. that come with electric power.

2008 tesla roadster weight of  batteries = 450 kg  or 992 lb  

A 1200 lb 7 becomes a 2200 lb 7.

Chapman's Lotus 7 had its debut at the 1957 Earl's Court Motor Show in London. They were priced at £1,036 including purchase tax but it cost only £536 in kit form as no purchase tax was required. It weighed only 725 lb (329 kg).

Fast and responsive, the Lotus 7 was one of Chapman's masterworks, an advanced machine that surpassed the earlier Lotus 6 as a vehicle that could perform well on the track and be driven legally on the road.

The current replica  7's are already moving away from the first small light 725 lb 7's. Is a 2000 lb 7 still a 7?

An electric 7 will weigh as much as three S1 7's.  call it 7 x 3?

Compared to an S1   7 the electric 7 will probably feel heavy, clumsy, with three times the weight you need bigger brakes, stronger suspension etc.  you lose agility.

 

 

 

What's the weight of a Caterham with no engine, gas tank, radiator, coolant, transmission etc? The average wet Caterham is about 1350 pounds I believe. 

[924s]

2 minutes ago, Vovchandr said:

 

What's the weight of a Caterham with no engine, gas tank, radiator, coolant, transmission etc? The average wet Caterham is about 1350 pounds I believe. 

the weight savings of no ice engine and everything it comes with  is offset with with the reinforcements of the car required to carry the weight of the batteries plus the electric motors, controllers etc. that come with electric power.  An electric car with no batteries and a  gas powered car weigh about the same.     http://www.mate.tue.nl/mate/pdfs/12452.pdf

[924s]

13 minutes ago, BlueBDA said:

Critical to this discussion is the intended use of the car.

 

A Tesla Model 3 Performance is great for the road, and from what I've read and watched it's just about there for HPDE track days.

 

The ID-R is designed for one purpose - Pike's Peak. It's not meant for doing four twenty minute track sessions.

 

What would you want to do with an electric seven?

 

Street: Just a matter of balancing range vs weight. Guessing (maybe someone else can do the math) that an 80 mile e-seven might weight similar to a Cat, and perform similarly or better.

 

Track: The math probably doesn't work here. Need range, which means weight, and aerodynamics, which means not a seven.

 

Autocross: I think an e-seven could be built to excel at this. Aerodynamics don't play as big a role, and runs are short. I've thought about an e-seven with swappable batteries, built for autocross. EV West told me "people have tried swap-able batteries and it doesn't work out", but I think designed for autocross, with a trailer that is equipped to transport and swap the batteries, could be an amazing system. But - there's no SCCA Solo class for this, so after doing all of the work to design and build it, it couldn't compete. But it would be a ton of fun.

 

It would be great if someone can chime in with some kWh/mass math.

some math here......http://www.mate.tue.nl/mate/pdfs/12452.pdf

[924s]

5 minutes ago, 924s said:

some math here......http://www.mate.tue.nl/mate/pdfs/12452.pdf

A Tesla Model 3 Performance is great for the road, and from what I've read and watched it's just about there for HPDE track days.

The Tesla is good for one thing, intersections, it launches well, nothing else. Tesla had problems at the ring, making a 5000 lb.  pig stop and go around corners is a nightmare. The ring record holder for production cars in 2003 and 2004 at the ring was a 7 clone, a Donkervoort powered by an Audi 1.8 20vt 4 cyl engine,  it weighed 650 kg, 1400 lb, 1400 lb makes more sense.  (this also proves how good 7's are). I would rather have a new Donkervoort GTO with the Audi 5cyl. turbo than any million $ hypercar, lighter is better.

 

The ID-R is designed for one purpose - Pike's Peak. It's not meant for doing four twenty minute track sessions.  It also is the quickest car in the world at Goodwood hill climb. It is the second quickest car in the world at the ring Nurburgring, the Porsche 919 Evo is quickest. the ID R is useless for track racing because like all electric race cars it has no range, 12 minutes at full throttle, then needs recharge.

[Vovchandr]

1 hour ago, 924s said:

A Tesla Model 3 Performance is great for the road, and from what I've read and watched it's just about there for HPDE track days.

The Tesla is good for one thing, intersections, it launches well, nothing else. Tesla had problems at the ring, making a 5000 lb.  pig stop and go around corners is a nightmare. The ring record holder for production cars in 2003 and 2004 at the ring was a 7 clone, a Donkervoort powered by an Audi 1.8 20vt 4 cyl engine,  it weighed 650 kg, 1400 lb, 1400 lb makes more sense.  (this also proves how good 7's are). I would rather have a new Donkervoort GTO with the Audi 5cyl. turbo than any million $ hypercar, lighter is better.

 

The ID-R is designed for one purpose - Pike's Peak. It's not meant for doing four twenty minute track sessions.  It also is the quickest car in the world at Goodwood hill climb. It is the second quickest car in the world at the ring Nurburgring, the Porsche 919 Evo is quickest. the ID R is useless for track racing because like all electric race cars it has no range, 12 minutes at full throttle, then needs recharge.

 

I understand you clearly don't like electric. I personally don't care for them either but for the sake of discussion lets keep the figures accurate

 

Tesla 3 Performance "electric pig" shows 4250 lbs on Google. 

 

Modern BMW M5 shows 4,345 lbs on Google. 

 

Being a "pig" is more of a modern car problem rather than a purely electric problem. 

 

Any modern production car that's going to have modern safety of plethora of air bags and crash reinforcements, miles of electric cables, creature comforts etc is going to be heavy. Days of Elise are long gone. *minor exceptions of extremely purpose built cars and of course Miata* Civics come in at 3000lbs now a days. 

 

Morgan Electric trike I believe was about 1200lbs, which according to your math is unachievable. 

 

Edit: I think I found part of your problem. You're using 1000lbs worth of batteries as math. That's to give a full weight daily driver a range of 300+ miles. That is simply irrelevant for a niche car like a 7. We don't use them as dailys and we don't need to hit 300 miles without stopping for a charge. Most of us most of the time barely go 100 miles a day. Long range will simply not be a goal and in any case, that's not a total day range, that' just until next charge, which can be very quick with a small battery pack. 

 

I'd personally be happy with 100 miles of range or even less, which would require much less battery power in a light car to begin with. Extreme short range versions can be even lighter. Potentially lighter than a fully working 7 is now. Just look at the Locost battery builds. They dont achieve a huge range and remain quite light. 

 

As you're well aware weight makes everything worse. Braking, accelerating handing etc. 

 

However this puts a 7 in a very unique portion where since we don't need much range, weight can be kept down, which means less batteries, which means quicker charging which is also a major problem for big battery banks for regular cars. 

 

Its fair to judge electrics on lack of noise and flair, but if an electric 7 was made as a 1500lbs car it would actually be a very good vehicle with instant torque etc. 

Edited June 8, 2021 by Vovchandr

[Vovchandr]

Without looking into it, just happen to come across this at a perfect time for this argument

 

Video is time stamped to important part for this discussion

 

Tesla etrofitted 308 GTS weights less than stock according to the video (I'm sure range is diminished and pack is smaller, but point stands)

 

 

Edited June 8, 2021 by Vovchandr

[924s]

2 hours ago, Vovchandr said:

 

Tesla 3 Performance "electric pig" shows 4250 lbs on Google.

 

wikipedia tesla  model  S  shows 4,960 lb  with longer range batteries

 

 

Any modern production car that's going to have modern safety of plethora of air bags and crash reinforcements, miles of electric cables, creature comforts etc is going to be heavy. 

 

 

with the government regulations everything is at least 3000 lb.  the lightest mass production  car now is a Miata, at 2400 lb it is two 7's, not light.   i would imagine the electric 7 will be around 2200 lb, will  have to wait to see the specs.

The ultimate sports gt car is the soon to come T50   2200 lb. Not an ultralight like the 7 but lighter than other hypercars.    https://www.roadandtrack.com/new-cars/future-cars/a33370809/gordon-murray-design-t-50-horsepower/

 

2 hours ago, Vovchandr said:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[924s]

one electric car i kind of like is the VW ID R,     I like VAG products.  One issue with electric cars is no sound track.  The other issue is they are slow (an exception is the VW ID R)  The Tesla is good at stop light races only.       Actually the hybrids are the quickest now, see F1 now.   

0 to 200 km in seconds

Porsche  gt2 rs                                     8.3

Caterham 620r    313  hp                    10.1

Donkervoort gto    5cyl  370  hp       7.8

HKT  RS        Audi  1.8 20vt   400 hp              7.5

Tesla                                                            14.1

Chiron                                                         6.3

Mclaren senna                                        6.8

c8 Corvette                                                   12

f40                                                                   10.4

Porsche 919 evo                                        4.5

VW ID R                                                            5.0

F1                                                                        4.1

F2                                                                         6.6

F3                                                                          7.8

 

Donkervoort    ring   record   7:13    Audi  1.8 20vt     had ring record in 2003 and 2004.

 

 

Of all the 7 clones I like the HKT  RS it has close to F3 performance

 

[Vovchandr]

1 hour ago, 924s said:

with the government regulations everything is at least 3000 lb.  the lightest mass production  car now is a Miata, at 2400 lb it is two 7's, not light.   i would imagine the electric 7 will be around 2200 lb, will  have to wait to see the specs.

The ultimate sports gt car is the soon to come T50   2200 lb. Not an ultralight like the 7 but lighter than other hypercars.    https://www.roadandtrack.com/new-cars/future-cars/a33370809/gordon-murray-design-t-50-horsepower/

 

Your quotes are messed up in the post above. I think I pulled your comment.

 

With the government regulation Caterham as is isn't allowed to on the road to begin with as a production car. Why is this part of the argument?

 

Are we talking a 7 that has to comply with all safety or a 7 as is now just electric powered? Two completely different arguments. 

 

Also why are you bringing a low production number 2.1 million car as your example? Especially after saying that with regulation everything is at least 3000lbs. So is it or is it not? 

 

I'm losing track of your point.

 

 

Lets review

1) Electric cars can be built light

2) Electric Caterham can potentially be made light

 

We hope that it does to stay with the ethos but without noise. That's the whole point of the thread. 

 

You keep bringing multi million dollar cars in comparison to sub $100k electrics and are surprised that they are slower?

 

You need to compare them to Lotus Evija and Rimac Nevera. 

 

2000hp electric cars won't be slow and now the price is comparable to the multi million dollar cars you bring into the argument. 

 

You're all over the place in a thread where the point is how an electric Caterham can be in the future. 

Edited June 8, 2021 by Vovchandr

[panamericano]

If the Tesla is such a pig, why did SCCA move it UP 2 classes for autocross after its first season?

[Kitcat]

The Tesla is super fast, short distance, like at an auto-x. Ask Brightonuk about it’s brakes during a track day though.

[Croc]

 

1 hour ago, Kitcat said:

The Tesla is super fast, short distance, like at an auto-x. Ask Brightonuk about it’s brakes during a track day though.

 

Yes the brakes fade on a road circuit.  Top speed is not particularly high so overall lap time is not brilliant.  I did particularly enjoy watching the poor owner stuck in the pits trying get enough charge from a regular power socket to make a 40 mile drive home.  It took quite a while!  

[Twerd68]

I really enjoyed this discussion. I didn’t take the plunge on buying a seven (and regretted it as I did not enjoy the heaviness of the Mustang at track days). I later enjoyed a Miata much more.  I hope that Caterham gets the intent of this thread and gets their version of an electric racer as light as they can. To add to vovchandr’s thoughts from reviewing track (and towing for trucks) range: track range is far, far different from EPA range. Frankly, I think the best we can hope for is that approx. 2k lbs weight discussed. If they can pull off 1,800 lbs then maybe we are really talking. In the mid-term energy density of batteries keep getting better. 

 

oh and by way of PS I do like the very mechanical sound of some electric cars. The video on the racing version of the electric “Mustang” is a good example:

https://media.ford.com/content/fordmedia/fna/us/en/news/2020/07/21/all-electric-mustang-mach-e-1400-prototype.html

 

Let’s all hope racing and 7s to live on with an ever-shifting but still exciting future. 
 

[JeffersonRaley]

I think an electric Seven under 2k lbs is realistic, especially given that 100 miles of range is probably more than enough and it doesn't need to power AC, power brakes, power steering and all the rest.  Plus that weight would be very low and concentrated near the center of rotation.  With the insta-torque of electric, it could be even more of a slide monster than my 2.5L ICE Seven.  I'll keep the ICE motor'ed Seven for sure because battery power density is way too low for a track rat.  But I totally see the appeal of an electric.  (And I'll be jealous of the way it would start every time.)

[DavidL]

folks interested in electric track cars should look at Dennis Palotov's thinking.  Palotov has made a name for themselves creating tiny but incredibly effective track cars using motorcycle engines.  They starting building a larger LS-powered car, and then built avery very powerful electric version of that car for Pikes Peak.  Palotov's thinking for the future is heavily electric, working in partnership with Cascadia Motion, another Portland (Oregon) company that makes the motor/controllers.  As usual, Palotov has a creative take on how to implement this using fast swappable battery packs.  Anyway, here is a link to his blog, organized by model (including a Europa chassis he built for a customer, not electric).

 

http://www.dpcars.net/

 

click on D8 and D9 for electric car info.....

[924s]

Future french electric Super 7 replica.   cool looking car           https://www.autotimesnews.com/in-france-develop-electric-competitor-caterham-seven/

[924s]

Westfield electric Super 7 replica kit available     https://www.roadandtrack.com/car-culture/buying-maintenance/news/a4227/aftermarket-westfield-lotus-seven-replica-kit-car/

[JohnCh]

I believe Westfield ceased iRacer production quite some time ago (it was released in 2013).  However, I did hear rumors within the last two years they are working on an electric road car.  Given the 2030 edict in the UK, I don't expect Westfield, Caterham, Morgan, and other UK-based fun car manufacturers have much of a choice.

 

-John