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\X/ project: Syncro Cabrio EV Citystromer conversion/build

17371 Views 60 Replies 19 Participants Last post by  MortenB
\X/ project: Syncro Cabrio EV Citystromer conversion/build

Background information:
The Golf Mk3 Citystromer was a limited run of approx 200 cars built from 1995 to 1998 model year (rarer than the Harlequin). I have 3 of them, my brother a 4th. Those 4 cars represent 2% of all Mk3 Citystromers ever made.

They were taken off the assembly line in germany and sent to Siemens (in Holland?) for final drivetrain assembly. The drivetrain consists of a 22kw a/c motor, a Simovert inverter, and 16 x 6v, 160ah gel batteries. The front battery box is bolted above the motor up front, and the rear battery box is welded into the trunk floor instead of the tire recess and floor.
I bought the first one in 2008, and I love it! Still going strong, albeit with new batteries. I upgraded to lithium batteries and, using a vintage 486 computer, linked up with the inverter and increased the available power output considerably. It’s not a VR6, but it seems faster than a diesel Golf mk3 :) HP is not my main concern, but a quiet, vibration free ride is.

Here we go:

I am currently in Norway where I have the 3 Citystromers, and two 1.8L Syncro cars. I'm coming back to the States this winter and would like to continue driving my electric cars in the States as well. Unfortunately, I can’t import the cars due to them not having been imported and certified when they were new. (the battery versions). I could go to a car import company, but it could cost $60 grand to get plates on it. I also kind of want to have awd. So, .......

My plan:
Disassemble two Golf Syncros right away
Disassemble two Golf Citystromers right away
Mate electric motor from Citystromer to the awd gearbox
Modify front and rear battery boxes to fit over/behind the Syncro gearbox and rear diff
Disassemble third Citystromer just before moving
Pack everything in container and ship to Minnesota
Once in MN, buy a Mk3
Convert to EV with Syncro
Repeat last 3 steps until I have used up all the parts.

Now, I do think it’s a shame to destroy 3 original rare cars, but they will live on in the conversions I do. Almost all the parts that can be unbolted, and all parts that are different from the gas versions are taken off to be installed in the conversions.

Here is what I am starting with, note the plates. Here in Norway all EV cars get the EL (electric) plates:

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Step one:

1.8 liter motor mated to the syncro gearbox

syncro rear diff setup

Step two:

In this picture you can see the rear battery box in the trunk floor:
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Yes, get your popcorn! This will take some time, since I'm still in Norway. Hopefully the parts will be in Minnesota sometime in February.

Upper part of rear battery box removed. It will have to be shortened in order for the rear syncro axle to fit. That is ok, though, since the new lithium batteries take about 1/2 the space. They also weigh 600 lbs less than the lead/gel batteries.

seats from one of the EV's, driven only 29000km. Look like new, pack 'em up.

Interior is identical, except for the wiring harness and instrument cluster

A peek inside the inverter that controls the motor. It is mounted to the front of the battery box, right behind the bumper.

Rear battery box cut out of the car. It was a bear, since it was welded to the frame on the sides
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Already found the first Cabrio. Paid $350 for it. Problem with the engine, which suits me just fine. It is in storage at my buddys place in Minneapolis, waiting to be converted.

Why a Cabrio, you might ask. Right now I don't have a good solution for a/c in the electric car. It might take some work to find a space for the condenser and the fan. The EV doesn't have a large radiator and fan. There isn't room either, since the inverter is located behind the grille. The inverter and motor are water cooled using a pump and a small radiator mounted just in front of the left front wheel. So...a convertible might make up for the fact that the car doesn't have a/c.

Here's the new car:

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Well this is fresh :popcorn:
These are some of the batteries that I'm using: 3.2v cells @ 90ah each. Probably be using 64 of them.

I was running 96 cells up until recently. 32 of the cells are 8 years old, and due to overdischarging a couple of times, some have been damaged. I am using this setup with a battery management system and a big resistor to draw the power down in each battery to test capacity. Seems that quite a few of the cells are too damaged to use. I will test all of them eventually. It just takes time. About 2-3 hours to discharge each cell using this test.

Here's a picture of the electric motor next to the syncro gearbox. Just checking to make sure there is enough clearance for the motor. Looks good.

Meanwhile, I pulled the motor and all the EV parts out of my electric Blazer. You can see it here mated to the original 4 speed transmission:

You can see the Blazer in the background in one of the above pictures. It was a '92 model S10 Blazer, in baby blue. It had an interesting past. Ordered converted by then wife of actor Robin Williams. Written about in Home Power magazine.

It was a shame I wasn't able to sell it complete. It needed new batteries. The drivetrain was worth more to me than I was selling the whole car for. The motor might someday power a boat, but I digress...
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The motor adapter plate is finished. Here it is mounted to the motor, with clutch installed. Ideally, if I had a lathe, I would turn down the size of the flywheel to make it lighter. There is no need for a flywheel, other than for the clutch to mount to.

The motor adapter plate is made up of two 10mm plates; one that matches the motor screws and one that matches the tranny screws and shape. I already had the aluminum plate that mated to the motor, but couldn't find a piece of aluminium for the tranny adapter, so I made it out of a piece of steel that I had laying around. That was not easy. Steel is f-ing hard as hell!

Syncro gearbox all cleaned up and ready to go

I had to remove the transfer case in order to get enough clearance to install the motor/adapter plate

With the transfer case removed, the gearbox doesn't look all that different from a standard gearbox

Motor attached to gearbox! ....and they said it couldn't be done.

Out with the dirty old technology

In with modern clean tech.

I have only temporarily installed the EV parts in the Syncro car to check compatibility. When I get all this stuff to the States, it will go really fast to install it, since I know everything will fit.

Next: modify the front battery box.
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Something NEW and interesting. Bravo :thumbup::thumbup:
Subscribed! Looks like it's gonna be a hell of a build! Keep us posted

Trimis de pe al meu SM-G930F folosind Tapatalk
This is incredible!

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History in the makin' fellas :popcorn:
The EV Golf has a simple non-ABS brake system. It does not take up a lot of space in the motor compartment. The car I purchased has abs brakes (do all cars in the states have this?). The brake lines and ABS motor sticks much farther forward from the firewall than the plain non-ABS brakes. From pictures, I can see that the brake system on the Syncro is identical to the Cabrio in Minnesota. In order for the rectangular battery box to fit, I will need to make modifications including a cutout in the box for the brake parts and for the shifter linkage that sticks up from the syncro gearbox. I may as well do all fabricating and modifications that can be made here in Norway, since I have a pretty nice garage here. I don't know what I will have to work in once I'm in MN.

Test fitting the battery box in the Syncro donor car. It needs to go about 4 more inches rearward. Need to make space for the brake lines and abs motor.

Here, I have cutout the required areas

Holes covered up. The piece I cutout was just turned around to make the bigger box, for the smaller box I just cut out a piece of the frame from the Syncro donor car.

Here's how it looks from the back

All painted and seam sealed

Had to relocate the mount a little forward to clear ABS
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Subscribed! This is going to be so rad
bump... would love to see a video of this driving once this is all finished. keep us updated m8!
The car I purchased has abs brakes (do all cars in the states have this?).
No. ABS was common but not standard. There are two generations of ABS too, looks like if it's like the syncro it's the later one with the booster. Up to maybe 94/95 they used a vacuum pump design like mk2 and Passat B3.

If you have any questions on what the US models had or were like 9there are differences), I'm glad to help :) Cabrios have extra bracing in the trunk too so I'm really curious to see how syncro works with it!
If you have any questions on what the US models had or were like 9there are differences), I'm glad to help :) Cabrios have extra bracing in the trunk too so I'm really curious to see how syncro works with it!
Do you have a picture of the extra bracing?
There are a bunch all over, not sure what you're going to run into. I know there are extra sheets of steel inside the wheel well adjacent to the chassis leg, as well as the narrow and heavily braced rear seat opening:

It's hard to say what is different from Mk3 without seeing them sixde-by-side (I only own a Cabrio), but in ETKA most of the floor and pillar parts are different part numbers (1Ex), which coudl be for any number of reasons. I don't think it'll affect you much if you are just working on the trunk floor and below, though.
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