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Discussion Starter · #1 ·
Okay, so couple of months ago I bought a used 335i for cheap. 130000 + miles. Paint work was blistered by the heat. turbos rattling and coolant reservoir was leaking. The thing is, I like the shell of the car, but I dont like the reliability of the engine.

I was recently thinking of selling the engine parts and such, and just converting to EV. I know BMWs and how to pull them apart. I have the tools and I'm a fairly good mechanic.

I'm hoping to get about 200 miles of range, awd preferably if possible, but I'll settle for rwd if it helps with the costs and range.

Enough torque to match 300-400 horsepower. Don't need more than 120mph top speed. Hoping to charge on generic electric chargers you find in parking garages.

The thing is, the car is automatic... Is this going to be a headache, and can I spend less than 10000 to get this done?
 

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200 mile range, 120 MPH top speed, and 300 to 400 HP are all possible but they're ambitious goals; I doubt they're compatible with a $10,000 USD budget. The automatic transmission is unsuitable, but it may be the least of the challenges.
 

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Discussion Starter · #3 ·
200 mile range, 120 MPH top speed, and 300 to 400 HP are all possible but they're ambitious goals; I doubt they're compatible with a $10,000 USD budget. The automatic transmission is unsuitable, but it may be the least of the challenges.
Okay, realistically, what would I need? I saw an Audi S5 I think with the full tesla engine and battery modules. Does anyone know how he did that project? I'm willing to get rid of the transmission in the 3 series. All i need is drive, reverse and neutral.
 

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That's what he did, his auto tranny was just a shell, the motor attached directly to the quattro. And I guarantee he dropped far more than $10k into it. For 200 mile range, with a heavier (than the usual ghias and bugs) vehicle, you'll likely have to spend more than twice that on batteries alone. For those power numbers, you'll need the Tesla drive units, which are going to require higher voltage than other DIY motors. Basically, you're asking for a Tesla in a BMW shell. So be prepared to spend tesla-esque money for that performance.

For $10k, you'll want to check out Rich Rebuilds on YouTube to see how he budget builds. For around $15-20k, you could consider a leaf motor, tune it to around 200hp with an aftermarket controller, leaf or bolt batteries and you could wind up with 80mph and close to 100mi range if you pair a proper diff.
 

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@RayLasko is putting it a lot more realistically for you.
I converted a 2004 BMW 330CiC (convertible) and the highlights of my components are: 6 Tesla S battery modules for a nominal 144V, an HPEVS AC-55 motor with a Curtis 1239e controller coupled to the stock 6 speed manual, with an Orion BMS, and a Stealth combo charger/DC-to-DC converter. I use it as a regular driver, it is pretty slow off the line (was a known trade-off I made with that motor), but once rolling, pulls close to what the old ICE did, it gets up to ~85mph no problem (haven't tried much faster than that), and my range is generally 70 to 100 miles. (There are many, many sources you can find that talk about what "kills" an EV's range: temperature, driving much above 50 mph, your aerodynamic drag, etc.) All-in, was a bit over $20k for the conversion and that doesn't include my labor. All my components were new, except obviously the batteries which I paid a little bit of a premium for to make sure they were good condition, low-mileage units.

I love it, and it is a fun, reliable drive. I rigged-up heat so that I can still have some cold (or at least colder) weather driving, but no AC. I know what it would take to convert to an electric AC compressor and such but just haven't had the time or budget for it. Some of my biggest challenges (and I'm sure they'd be yours also) were "packaging" all of that stuff into a newer BMW (I realize it may not seem like a "newer" car to you, but compared to all the space available in many other conversions that are much older, it's a big difference), and coupling the motor to the transmission. You pretty much have to go custom with that coupling, as no one really sells anything that works with a BMW bell housing.

It's all a long way of saying that $10k is probably a pretty unrealistic budget for any kind of meaningful conversion, and is way off for the specs you initially listed. Sorry to be a buzz-kill. I definitely would not recommend using an automatic, and most especially not a "newer" auto trans that has any kind of electronic controls to it (which I'd be willing to bet yours does). Again, sorry to pour more cold water.

That's not to say I wouldn't recommend converting a BMW, as obviously I'm one that loves his. Just thought I'd give you my experience so you can be more clear-eyed about it. Good luck, and happy to answer other questions.
 

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Discussion Starter · #6 ·
@RayLasko is putting it a lot more realistically for you.
I converted a 2004 BMW 330CiC (convertible) and the highlights of my components are: 6 Tesla S battery modules for a nominal 144V, an HPEVS AC-55 motor with a Curtis 1239e controller coupled to the stock 6 speed manual, with an Orion BMS, and a Stealth combo charger/DC-to-DC converter. I use it as a regular driver, it is pretty slow off the line (was a known trade-off I made with that motor), but once rolling, pulls close to what the old ICE did, it gets up to ~85mph no problem (haven't tried much faster than that), and my range is generally 70 to 100 miles. (There are many, many sources you can find that talk about what "kills" an EV's range: temperature, driving much above 50 mph, your aerodynamic drag, etc.) All-in, was a bit over $20k for the conversion and that doesn't include my labor. All my components were new, except obviously the batteries which I paid a little bit of a premium for to make sure they were good condition, low-mileage units.

I love it, and it is a fun, reliable drive. I rigged-up heat so that I can still have some cold (or at least colder) weather driving, but no AC. I know what it would take to convert to an electric AC compressor and such but just haven't had the time or budget for it. Some of my biggest challenges (and I'm sure they'd be yours also) were "packaging" all of that stuff into a newer BMW (I realize it may not seem like a "newer" car to you, but compared to all the space available in many other conversions that are much older, it's a big difference), and coupling the motor to the transmission. You pretty much have to go custom with that coupling, as no one really sells anything that works with a BMW bell housing.

It's all a long way of saying that $10k is probably a pretty unrealistic budget for any kind of meaningful conversion, and is way off for the specs you initially listed. Sorry to be a buzz-kill. I definitely would not recommend using an automatic, and most especially not a "newer" auto trans that has any kind of electronic controls to it (which I'd be willing to bet yours does). Again, sorry to pour more cold water.

That's not to say I wouldn't recommend converting a BMW, as obviously I'm one that loves his. Just thought I'd give you my experience so you can be more clear-eyed about it. Good luck, and happy to answer other questions.
Thank you
At this point, feel like the engine and the interior is done. willing to strip the insides, and the bells and whistles to do this conversion. going to start collecting what is needed to make this possible.
 

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Discussion Starter · #7 ·
Wow, I'm looking at the cost to convert it to actually be usable, and I estimated just under 40,000. That's crazy.

I'd actually do it if I had the money to. The car is beautiful and I got it at a decent price.
 

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Wow, I'm looking at the cost to convert it to actually be usable, and I estimated just under 40,000. That's crazy.

I'd actually do it if I had the money to. The car is beautiful and I got it at a decent price.
Would be curious as to what you based it on and calculated as that sounds somewhat high, but yes, definitely not that far from the realm of reasonable options for a "usable" conversion of a car like this. I'm willing to bet a lot of that is in the batteries.
 

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Discussion Starter · #9 ·
Would be curious as to what you based it on and calculated as that sounds somewhat high, but yes, definitely not that far from the realm of reasonable options for a "usable" conversion of a car like this. I'm willing to bet a lot of that is in the batteries.
Well, to get the 200 mile range 15000-20000 in batteries with a cooling unit.
10000 ish for the motor and controller.

Because my car is automatic, I'll need to probably do something crazy for the drivetrain instead of bolting directly to the gearbox. I estimated 5000.

5000 for miscellaneous speed and charge monitoring parts, digital dash, chargeports, labor, wires, tools for the conversion, shipping, unforeseen circumstances...etc.

It's honestly a "worst case scenario estimate".

I'd honestly love to do it.

The twin turbo was nice, but I'm sold on electric for a personal car.
 

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I hate to be a downer, but when you say you like the 'shell' of the car, are you OK with literally just keeping that? Because the amount of engineering required to make anything else work will be a nightmare. The dashboard, the center console, navigation, heads-up-display, the automatic transmission, the traction control and the ABS... everything is very complicated and very integrated in any modern vehicle, especially a modern German vehicle. Your only hope is probably to rip out everything and fabricate your own track-car interior. But why bother? You could get a well-handling, older vehicle which would be far less work and end up with the same level of performance.
 

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Discussion Starter · #11 ·
I hate to be a downer, but when you say you like the 'shell' of the car, are you OK with literally just keeping that? Because the amount of engineering required to make anything else work will be a nightmare. The dashboard, the center console, navigation, heads-up-display, the automatic transmission, the traction control and the ABS... everything is very complicated and very integrated in any modern vehicle, especially a modern German vehicle. Your only hope is probably to rip out everything and fabricate your own track-car interior. But why bother? You could get a well-handling, older vehicle which would be far less work and end up with the same level of performance.
The interior is pretty shabby and sunburnt anyway, so I'd discard it. Wouldnt even want the steering wheel....
The only thing good on this is the shell.The interior door grip handles have melted into a somewhat cream wax.
Traction control I can do without. Also dont need ABS. Just the right brake tuning.

I am okay with a track interior. I watched Rich Rebuilds and saw a company called EV West do that to an M3 and I'm okay with that. Bucket seats, switches, the whole works. It would also allow me to place the batteries much lower for a better centre of gravity.

I have been searching for shells and the prices are insane. Converting this car wasn't my first option I considered.
 
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