# Planning Subaru Impreza 2.5RS Conversion



## teksimian (Jul 29, 2014)

First of all, I just like to say how impressed I am with what I'm seeing on these forums. Some of these projects are just mind blowing.

I have an my old daily driver sitting in the driveway that I still use as a winter beater. I've always intended on turning it into a project car and doing a drivetrain swap, and now I really like the idea of turning it into an EV.

This EV conversion would then be used as my summer daily to work and back, and maybe a few medium range trips. ~200KM range would be great, but I'd settle for 120KM. And I'd definitely want some performance out of this toy. I'd be aiming for ~300ft lbs. The idea of this much instantaneous torque on an AWD platform really excites me.

The obvious disadvantage of AWD drivetrain power loss makes me think an AWD platform is counter productive for an EV. One solution would be to use subaru's 6speed with a DCCD box which allows for adjusting AWD/RWD bias. I believe it allows for split ranges between 25/75 and 50/50. Other options would be the CVT, or a full RWD conversion. What other transmissions are commonly used with electric motors?

I'm located in Ontario, GTA area. unfortunately I couldnt find any local retailers or distributors of EV components. I'd love to check out an EV before taking the dive. The only distributors I've found in Canada are in BC, 3000KM away on the other side of the continent.

Let me know what your thoughts. I think these are some lofty goals but anything is doable with enough time and money. I'd like to commit 10-15K to this project. What components or setups would be most workable?


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## browncamaroz28 (May 14, 2014)

teksimian said:


> First of all, I just like to say how impressed I am with what I'm seeing on these forums. Some of these projects are just mind blowing.
> 
> I have an my old daily driver sitting in the driveway that I still use as a winter beater. I've always intended on turning it into a project car and doing a drivetrain swap, and now I really like the idea of turning it into an EV.
> 
> ...


Sounds like it could be a really cool project. One thing to note, the 6-speed with DCCD only transfers torque. You are still rotating all of those parts regardless (that is unless the rear's are spinning). The good thing about that car is the STI rearend bolts right in (with a minor mod to the strut towers) and I've seen that rear in stock form running down the quarter mile in the 9's. What year is your 2.5rs?


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## Old.DSMer (May 18, 2012)

Hey teksimian, you will be very happy with instant torque and AWD 

I brought in my components from the US, tough to find retailers for reasonable prices in Canada.

To get 100+km and full performance, you'll need a larger budget. Unless you can access 2nd-hand components and call in fabrication favours.

Have you seen the Electric Subaru site?

I'm very interested in AWD builds - hope yours works out! Let us know when you start that build thread!!!


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## browncamaroz28 (May 14, 2014)

Old.DSMer said:


> Hey teksimian, you will be very happy with instant torque and AWD
> 
> I brought in my components from the US, tough to find retailers for reasonable prices in Canada.
> 
> ...


Man that Electric Subaru site is thorough. If I still had my wrx that would be my conversion bible.

I agree with DSMer on the performance vs range vs price, its hard to have all three until battery price per performance comes down significantly. 4-5 years from now all three might be easier to abtain.


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## teksimian (Jul 29, 2014)

browncamaroz28 said:


> Sounds like it could be a really cool project. One thing to note, the 6-speed with DCCD only transfers torque. You are still rotating all of those parts regardless (that is unless the rear's are spinning). The good thing about that car is the STI rearend bolts right in (with a minor mod to the strut towers) and I've seen that rear in stock form running down the quarter mile in the 9's. What year is your 2.5rs?


1999 GM6.

I also neglected to mention in my first post that I would definitely want include a generator, just in case.


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## teksimian (Jul 29, 2014)

browncamaroz28 said:


> Man that Electric Subaru site is thorough. If I still had my wrx that would be my conversion bible.
> 
> I agree with DSMer on the performance vs range vs price, its hard to have all three until battery price per performance comes down significantly. 4-5 years from now all three might be easier to abtain.


Thanks for all the replies.

I would be willing to skimp on range for the interim, as long as it is extensible in the future.


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## teksimian (Jul 29, 2014)

Old.DSMer said:


> Hey teksimian, you will be very happy with instant torque and AWD
> 
> I brought in my components from the US, tough to find retailers for reasonable prices in Canada.
> 
> ...



Nice Talon! Thanks for the electic subaru link, very nicely documented. Looks like he barely crammed that warp11 in there. Not even enough clearance for a pulley!


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## Old.DSMer (May 18, 2012)

Thanks.

Yep, that guy documented his build nicely. He's using only 50 of the CA100 cells and is pretty tight on space.

I managed to cram in 86. But I can tell you, there isn't a millimeter of spare space. Definitely no room for a generator.

Sounds like you might be thinking of a semi-hybrid system? Drive electric and stop to recharge? So your single-charge range might only be 40 km. But if you're not in a hurry, you could probably fully recharge in 2-3hrs with a 10 kW gas or diesel generator. Lots of range then....interesting concept.


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## arklan (Dec 10, 2012)

imprezzas weigh about 300 pounds so 300wh per mile
120km is about 75 miles
300 x 75 = 22500wh traction pack which is reasonable

200km is about 125miles
300 x 125 = 37500 which is starting to get towards the impossible area

if u r running a 200v pack youll need 113ah and 188ah

using pouch cells which r about 2.2kg per 100ah at 3.2v nom
63s to get 201.6v
between $110 to $150 per 100ah 3.2v cell
will say $130 per 100ah

$156 for 120ah cell x63 =$9828 166kg
$260 for 200ah cell x63 =$16380 277kg

prismatics and pouch cells r the cheapest if u buy new
at 5c rate burst ur 120ah pack will be able to put out 600amps aanand tththe 200ah can put out 1000amps

performance and range are the same thing in an ev, u cant have one without the other

just some envelope maths 

edit: i suggested 200v because netgains are rated for 170v (192max) and will allow some for sag


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## browncamaroz28 (May 14, 2014)

arklan said:


> imprezzas weigh about 300 pounds so 300wh per mile
> 120km is about 75 miles
> 300 x 75 = 22500wh traction pack which is reasonable
> 
> ...


I agree with everything in your post except I think John Metric has shown that performance and range can be two very separate things. When your pack is capable of 100C bursts you could have 15 miles of range from an 9 second car.


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## arklan (Dec 10, 2012)

i was referring to both range and performance needing higher kwh packs, so youll get both range and performance

just depends how u drive it
evil grin


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