# Thinking about converting a Subaru



## Bochek (Sep 24, 2009)

First off, a little about me and my background.

I am an Automotive Technician, and have been an electric car enthusiast my entire life.

Recently i have done some work on a few Subaru's Mainly Forresters with the 2.5L engine, to me it seams like the near perfect platform for an electric car. 

So im looking for someone to give me a reason why it would be a bad idea, the only one i can think of is the drive-line efficiency of AWD.


Secondly, if i where to want a minimum range of 30km and a minimum top speed of 80mph, what would be the cheapest battery/motor technology combination to get the job done?

Thanks,
-Bochek


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## Bowser330 (Jun 15, 2008)

Bochek said:


> First off, a little about me and my background.
> 
> I am an Automotive Technician, and have been an electric car enthusiast my entire life.
> 
> ...


Bocheck, your skills will come in handy so thats good to hear.

Important things to check for a good donor car:
(1) Price
(2) Weight
(3) Drag Coefficient (aerodynamics)

AWD in my personal opinion is great! and I want you to keep us posted on your results once you are on the road.

your minimum range is VERY small, you can definitely get 18 miles of range (30km) and the 80mph top speed is also very attainable.

I suggest you use john's "blue meanie" as a template for your conversion, yours may weigh a little more, but he's getting over 80mph and 30mile range with the setup.

Motor = 1500
Controller = 2000 
Batteries = 3700
Total = 7200 + misc other parts like charger, dc-dc converter, etc.
I would say finished total is 10K$ 

http://www.tnrbatteries.com/odpcbgr35.html
14 of these would be 700lbs total. (50lbs each)
168V and about 45AH = 7.5kwh, if your car gets 250wh/mile then thats about 30 miles range (100% DoD)

*Edit*: The setup mentioned above simply compares a setup similar to John's Blue Meanie. Personally speaking I am +1 for the setup NZero and MR. T have explained below.


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## NZero (Jan 30, 2010)

Bochek said:


> Recently i have done some work on a few Subaru's Mainly Forresters with the 2.5L engine, to me it seams like the near perfect platform for an electric car.
> 
> So im looking for someone to give me a reason why it would be a bad idea, the only one i can think of is the drive-line efficiency of AWD.
> 
> ...


Subaru forester you are looking at is auto? If not then your fine, if it is you will want a Soliton controller that can "idle" to keep your subaru box happy.

Would say a good platform if you know what you are doing, that is "know they handle well because a boxer is low slung" keep batteries etc low low low low low low low!
Take up the whole front and most of the rear if you can. 
You will want a Kostov 11 to push the weight around so $2000 motor.
Soliton1 $3000 ish.
Batteries you want 144 to 156v MINIMUM. for 100ah your looking at maybe $5000.
Then just power steer pump from a BMW (japanese one if possible)
and a brake booster, dc-dc charger, pot box, some welding so I would say $14k for a half decent set up.
Good tuff car with solid chassis, good well ok driveline (you can remove rwd parts if you wanted or even remove the FWD parts and go direct drive but then you wont get your speed up very quickly). lots of info on the forester and best of all the boxers usually blow head gaskets around 180,000kms so cheap as chips in most places.


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## Tesseract (Sep 27, 2008)

Bochek said:


> ...Subaru's Mainly Forresters with the 2.5L engine, to me it seams like the near perfect platform for an electric car.
> 
> So im looking for someone to give me a reason why it would be a bad idea, the only one i can think of is the drive-line efficiency of AWD.
> 
> Secondly, if i where to want a minimum range of 30km and a minimum top speed of 80mph, what would be the cheapest battery/motor technology combination to get the job done?


You didn't specify a year so I selected 2002 at random. According to various websites, a 2002 Subaru Forester has a dismal drag coefficient of 0.39, a staggering frontal area of 30.8 sq. ft., and a downright gluttonous GVWR of 4120lb.

Which according to my favorite hp calculator means you will need 50.3hp to drive at 80mph. To account for the motor's efficiency make that 50.3kW in electrical power.

You only need to go 19 miles (30km), though, so your battery pack won't be too large. It's laborious to explain, but you would essentially need 15kWh to drive the entire 19 miles at 80mph and only use 80% of the battery pack's capacity (which is the rule of thumb for lithium; if using lead that ratio is often 50% or less, which is one of the many reasons why lead is NOT any cheaper than lithium when all is said and done).


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## TigerNut (Dec 18, 2009)

The Forester has a high GVW because it can actually carry a lot of stuff. The curb weight is 3150 pounds according to Wikipedia. You should look at stripping out as much of the non-essential stuff as possible to lower the weight.

For the aerodynamics, you can install Impreza suspension components and lower the whole car a couple of inches, which will buy you valuable handling as well as reduced drag. You can then also use high-rate springs and struts intended for Impreza rally applications.

We sold my wife's '98 Forester last spring, replaced it with a 2006 Impreza. We'd replaced the head gaskets a few months before... the '95 to about '99 2.5L, four-cam models had a design issue that essentially guarantees you're going to be replacing the head gaskets, as reported by NZero. Fortunately for you all those first-gen Foresters are getting up there in mileage and you can probably find one where the owner just doesn't want to deal with that job. It's an engine-out fix unless you're really committed.

Another thing that you should look out for if you're shopping, is toasted rear wheel bearings. They can get wrecked from curbing the rear wheels, and they make a real din when they've gone bad. The repair requires a large press and the correct procedures, or else the new bearings will also fail in short order.


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## Bochek (Sep 24, 2009)

TigerNut said:


> The Forester has a high GVW because it can actually carry a lot of stuff. The curb weight is 3150 pounds according to Wikipedia. You should look at stripping out as much of the non-essential stuff as possible to lower the weight.
> 
> Correct!
> 
> ...


One thing i will add, The first thing i do when traveling to AND from work is climb a big hill. then obviously there is a big downhill at the other end.

- Bochek


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