Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

BMW i8

This site may earn commission on affiliate links.
#21
rabar10 said:
It's all about battery discharge rate for EVs.
Click to expand...
"... which is a related to max capacity and chemistry, and less to do with 'energy stored at the moment of discharging'?"

Is this what you're saying? If so, that definitely clarifies. Thanks.

- - - Updated - - -

dennis said:
I found with the Karma that I am less and less willing to drive it with the ICE running. I want it to be electric all the time.
Click to expand...
Sorry for going off-topic a little bit but this is interesting to hear from Dennis and is somewhat related to the other, um, "more than EV" vehicles such as i3 and i8.

1. Are you beginning to think of the Fisker as a gateway vehicle to "only EV" for drivers such as yourself?
2. And, if money was no object, from a driving experience standpoint do you think you would like your Karma better if the drivetrain was replaced with a Model S drivetrain (but keep the style, regen behavior, etc. of the Karma intact)? I'm not suggesting that it's worth doing (for a number of reasons), but I'm curious about your answer to the thought experiment.
 
#22
brianman said:
Sorry for going off-topic a little bit but this is interesting to hear from Dennis and is somewhat related to the other, um, "more than EV" vehicles such as i3 and i8.

1. Are you beginning to think of the Fisker as a gateway vehicle to "only EV" for drivers such as yourself?
2. And, if money was no object, from a driving experience standpoint do you think you would like your Karma better if the drivetrain was replaced with a Model S drivetrain (but keep the style, regen behavior, etc. of the Karma intact)? I'm not suggesting that it's worth doing (for a number of reasons), but I'm curious about your answer to the thought experiment.
Click to expand...
Since you asked...

1. PHEV is definitely a gateway to BEV. As others have pointed out, instead of range anxiety PHEV owners learn to experience "ICE anxiety". You just don't want the ICE to turn on.

2. My previous 3 cars were a couple of M5's with great handling/performance and terrible gas mileage and then 3 years in a Lexus LS600H that I "inherited" from my wife when she decided she didn't like it and breaking the lease would have cost WAY too much money. My initial attraction to the Karma (besides it looks) was to get a 4 passenger high performance sedan with M5-like handling and better environmental characteristics than the Lexus hybrid. While the Karma has delivered BMW-like handling, it failed on the performance side and of course the reliability. So from that standpoint a Model S drivetrain would be better. Having test driven the P+ twice, I can see how upgrading my P85 with that suspension would fulfill what I was looking for and allow me to sell the Karma. In the end I would be trading looks for practicality, but in reality I am a function vs. form kind of guy.
 
#23
Thanks, dennis! You left me with one question...
dennis said:
Having test driven the P+ twice, I can see how upgrading my P85 with that suspension would fulfill what I was looking for and allow me to sell the Karma. In the end I would be trading looks for practicality, but in reality I am a function vs. form kind of guy.
Click to expand...
Why is the underlined unresolved? Cost?
 
#26
rabar10 said:
It's all about battery discharge rate for EVs.
Click to expand...
brianman said:
"... which is a related to max capacity and chemistry, and less to do with 'energy stored at the moment of discharging'?"

Is this what you're saying? If so, that definitely clarifies. Thanks.
Click to expand...
Yes, that's it exactly, and phrased much more succinctly too :biggrin:

The only reason "energy stored at the moment of discharging" would matter is if the battery is so low it's restricted the car to 'limp mode' and artificially limited available power.

From the first drive article (thanks for the link, dennis)
Carsten Breitfeld, project director of the i models explained earlier that day: “ It is the same motor as in the all-electric i3, but in the i8 the power output is 96 kW, while the maximum torque of 184 lb-ft is the same. In the i3 the output is 125kW, which was not necessary in the i8.”
Click to expand...
"not necessary" == "not available from the smaller battery"
 
Last edited:
#28
I definitely rate PHEVs by how likely the owners are to drive electric only (rather than those who lump them all together, but that's another thread). My ranking goes like this:

Plug in Prius and other small battery PHEVs: Electric driving only happens in specific circumstances and is very limited
Fisker Karma: Electric driving works fine, but there is a performance advantage to using the gas engine
Volt: No reason not to do electric only driving inside it's range. However, range is limited and gas engine hugely increases it.
i3: Good range (by non-Tesla standards) and gasoline engine not likely to be used on a regular basis (too limited)

By these standards the i8 is barely above the plug-in Prius. Looked at as an EV, it's an expensive sports car with a 128hp motor and a 22 mile range. In my opinion those who say it's another Fisker Karma are doing a serious disservice to the Karma (at least from an EV point of view).
 
#29
gregincal said:
Fisker Karma: Electric driving works fine, but there is a performance advantage to using the gas engine
Click to expand...

The performance difference is hardly discernible. Most Karma drivers that I know run on the battery unless it is depleted or they are on a highway and are saving some battery capacity for when they reach a city.

gregincal said:
By these standards the i8 is barely above the plug-in Prius. Looked at as an EV, it's an expensive sports car with a 128hp motor and a 22 mile range.
Click to expand...

Looked at as an expensive sports car, it has an anemic 3 cylinder engine. If they are counting on the combined EV + ICE for the 4.8 second 0-60 time, I wonder how many miles you can travel in that mode before the battery is depleted.
 
Last edited:
#30
dennis said:
The performance difference is hardly discernible. Most Karma drivers that I know run on the battery unless it is depleted or they are on a highway and are saving some battery capacity for when they reach a city.
Click to expand...
I think his point was that in both cases you need the ICE on to have max performance out of either car.

In the Karma's case you have a 260hp 4 cylinder engine that goes through a 235hp generator plus a 20.1kWh/200kW (268hp) battery feeding into the dual 150kW (202hp) traction motors. With battery only you have 268hp on tap. With the ICE on you have the full 404hp available.

In the i8's case you have a 131 hp (96 kW) electric motor and a 231 hp (170 kW) 3 cylinder engine that can operate in parallel for a combined 266kW/362hp. Without the motor, you are left with that 231 hp engine. However, the curb weight of the i8 is under 3300lbs, so it'll still be quick without the motor on.
 
#33
stopcrazypp said:
In the Karma's case you have a 260hp 4 cylinder engine that goes through a 235hp generator plus a 20.1kWh/200kW (268hp) battery feeding into the dual 150kW (202hp) traction motors. With battery only you have 268hp on tap. With the ICE on you have the full 404hp available.
Click to expand...

Unfortunately, that is not true. When operating with the ICE on, the electric motors are still drawing from the battery and the ICE/generator is replenishing it. The two inverters feeding the motors can provide a maximum of 120kw each for a total of 240kw (320hp). But the inverters are only allowed to transfer full power for a few seconds because of overheating issues. One owner dyno'd his Karma with the ICE running and saw 202-205hp at the wheels.

This could explain why the 415hp/4600 lb. P85 has a 0-60 time of 4.0-4.2 seconds, and the "403hp"/5300 lb. Karma has a 0-60 time of 6.3 seconds. :biggrin:

- - - Updated - - -

Doug_G said:
Odd, I've driven a Karma and the difference felt like night and day.
Click to expand...

Odd, I've driven my Karma 10,000 miles and wish it were that noticeable.
 
#35
dennis said:
Unfortunately, that is not true..120kw each for a total of 240kw (320hp)...One owner dyno'd his Karma with the ICE running and saw 202-205hp at the wheels.

This could explain why the 415hp/4600 lb. P85 has a 0-60 time of 4.0-4.2 seconds, and the "403hp"/5300 lb. Karma has a 0-60 time of 6.3 seconds.
Click to expand...
Wow, I didn't realize the actual specs were that far from the paper ones. The Karma is still widely advertised as a 400hp car. If what you are saying is true, there's only a 40kW/50hp deficit between the two modes.

gregincal said:
To bring this back to topic, though, my point is that a Karma in stealth mode will smoke an i8 in EcoPro mode. The i8 is totally dependent on its ICE for any level of performance.
Click to expand...
According BMW from the BMWBlog link, it's the other way around (i8 is dependent on electric motors for any level of performance):
0-62 mph pure electric: less than 4.5sec
0-62 mph full system: less than 4.5sec
0-62 mph system running on just gas with no battery: not available
 
#36
BMW Blog's info is not correct.

The i8 is a plug-in hybrid. It can drive on electric only,on gasoline only and with the 2 modes combined.

Maximum Performance is achieved only with both engines working.

It's not really a competitor to the Tesla Model S, but nevertheless a truly unique car with it's wide range of talents.
 
#37
Yeah, the i3 with the range extender weighs 2900 lbs and goes 0-60 in 7.8 seconds. The i8 weighs 3300 lbs and has the same electric motor, except detuned to provide 130 hp instead of 170 hp (because of the smaller battery). I'm sure it will do 0-60 eventually.
 
#38
gregincal said:
To bring this back to topic, though, my point is that a Karma in stealth mode will smoke an i8 in EcoPro mode. The i8 is totally dependent on its ICE for any level of performance.
Click to expand...

The i8 drivetrain is much more akin to the Porsche 918 than the Karma - ICE is the main source of power, electric motor(s) provide additional power and AWD, limited all electric range for city driving.
 
You must log in or register to reply here.

Similar threads

JetFalcon
Used BMW i8 for $50k-60k?
Replies
1
Views
285
Electric Vehicles
Watts_Up
Watts_Up
C
  • Article
Thoughts on the i4 M50 from a former M3P owner
Replies
58
Views
5K
Electric Vehicles
voxel
V
P
Hello from Ipswich, UK
Replies
1
Views
469
Introductions
ewoodrick
E
fholbert
Tesla aside, EV buyers aren’t staying loyal to EVs
Replies
10
Views
946
Electric Vehicles
E90alex
E90alex
M
Switching BMW X5 G05 40i full option (2019, 150.000 KM or 93.000 miles) to Tesla Model S Raven Long Range 2020 (60.000km)?
Replies
2
Views
219
Model S
KalJoMoS
KalJoMoS
Top
Back
Blog
New
Forum list
Marketplace
Menu