Project EXI

The building of a Marlin 5EXi kit car, using a Seat Leon 1.8T 20v Donor

Mar 16 2010

Fuse and relay plate

I have started to fabricate a plate to hold the fuse boxes, and relays. It is easier going forwards to mount all the fuses and relays, so that if needed in the future it can be removed and serviced outside of the chassis.
Using some 2.5mm thick aluminium plate, the battery terminal hole and indicator relay mount were drilled M6.
The fuses and relays were drilled M4, I have made another hole in case I needed to fit another relay at a later time. While the plate is being fabricated I may increase the number of relay holes.
I intend to countersink the holes from the rear, so using M4 counter sink screws, this plate can then site flush against the front bulkhead. The photos show the grey plate, i intend to remove this grey paint, to leave a brushed aluminium finish.


Posted by Steve | Permanent link | File under: electrical

Mar 14 2010

Removing the SAI combi valve

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I have removed the combi valve from the engine block and crafted and aluminium plate to cover the hole. The combi valve had a small gasket on it, I cut this to a different shape to sit neatly under the plate.
I also removed the SAI pipes that feed the combi valve, there is a SAI solenoid that is connected to the Vacuum system, for now this is still in place, but I will leave it unplugged from the ECU.
I've indentified all the ECU wires, and documented them in a PDF, from this it is easier to work out what wire of the ECU goes to what wire on the Marlin Loom.
I've added into the Wiring loom document a wiring map, showing the lengths and distance between connections for the wiring loom. From this I can make up a wiring Jig so that making future looms will be easier and more consistant.
Ive also run the power feed cable (20mm2) cable along the side of the passenger area, to provide all power to the front fuse boxes.
I hope sometime this week I can get around to soldering up some of the fuse box and relay wires.


Posted by Steve | Permanent link

Mar 12 2010

Removing the secondary air pump - Part 1

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Fitted to a VAG engine there is a system referred to as the secondary air injection (or SAI for short). This is a system where fresh air is pumped into the exhaust, when the engine is cold.
The idea is to burn off any unburnt fuel, to speed up the performance of the catalytic converter.
For the 5EXi this is not really needed. Its not really needed in the VAg engines, the main reason here is so the VAG group meet emission requirements in the north american markets. You will find that BAM engine in the VA group dont have the SAI system fitted. Main reason is these engine are not shipped to north america.
With this in mind the 5EXi does not need the SAI system. So for my Kit this will be removed.
This involves removing the Pump, Relay, associated electrical wires, combi valve, and vacuum hose connections.
When the combi valve is remove a small plate will be need to fill the hole into the exhaust. I intend to make a homebrew plate out of 2.5mm think aluminium plate I have and a couple of M6 bolts.


Posted by Steve | Permanent link

Mar 09 2010

Understanding how to connect to the donor loom

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The wiring loom is still moving forwards. One thing I had to overcome is the power requirements for the fuses and relays, which are now some distance from the battery. In a convential setup this is not a problem, particulary in a front wheel drive, front mounted engine.
There are a number of ways to solve this problem.
Run small invidual cables from the battery, rated at the capcity the device being powered needs.
Run a large cable with capcity to power all devices, with some overhead for future expansion. This route is the more costly route, but in my opinion is the better option, it will allow other devices, such as a radio, electric heater etc, to be added later without the need to add more power circuits.
Given the seat donor also this method, with a 110A interior feed, this is the route the marlin loom will take.This then adds another problem, how to get a 10mm diameter cable to connect to 6.3mm terminal on the fuse box? Simple answer is you cant, so I need to get a battery terminal distribution connector. This two M8 studs, one for a the battery cable, using a 20mm2 M8 connector, the other is for smaller wires, stacked up, but using 6mm2 connectors with an M8 stud. using smaller wires with 6.3mm spades on the end to power the fuses box system.
In total this adds about £15 to the total cost of the wiring, but worth it in my opinion.
So another AES order has gone in, for battery cable, terminal connector, terminals, washer bottle and some slipon terminal id markers.
I have now identified the Mass Air Meter, and associated cable to the ECU. Just one connector left near the Air inlet manifold.
I will create a Marlin loom to VAG loom interface document, so all the wires that need to be connected up are easily identifable. !!
Also to fit the fuse box and relays to the front, it has been suggested to mount all the components onto an aluminium sheet, then mount the sheet to the front bulkhead. That way the switch gear can be removed and serviced outside of the marlin, awesome. Means I can solder inthe warmth indoors :)


Posted by Steve | Permanent link | File under: ecu, electrical

Mar 06 2010

Making the first wiring loom

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Over the last 2 nights I made my wiring loom.
I removed the rope mock-up and used this as a template to route the cables.
Where I had a jucntion in the wiring loom, I fixed cable ties to the rope, then routed each cable around the rope and added heat shrink cable ID markers as each cable went into the loom.
I didnt label any black cables as it was obvious these are intended to be ground, and these route to one of three places.
Once in place I taped the cables together, every 6cm or so, until I had bundle of cables, this is the loom!!
After 2 nights work, about 7 hours in total, sore knees and a bad back, the first marlin VAG loom was made. Ive taken some pictures of the completed loom, laid out my driveway,the same way it would end up the chassis.
The loom then went into the chassis and cable tied, just to hold it place. I was quite pleased as it fitted easily enough, and I might not have to move any junctions. I will use the rope to create a wiring board, to develop future looms from.
Now the loom was in place, it was time take another look at the donor wiring and drive down another level of iidentifying what cable was what.
I found out some more about the relay box that was attached, to the exisiting donor. One is for the secondary air pump, and the other is for a voltage supply relay. I looked on my engine and the secondary air pump isnt there, it is supposed be under the alternator? I guess Mark at Marlin has removed it. Will have to have a chat to see if the idea was to remove it, or its just been forgotten about. From what I can tell the APP engine is the only one to have this fitted. So hopefully its not needed. I labelled the cable for this on the ECU (single purple wire), just in case it is fitted later, and cut the remainding cables and relay out.
The marlin loom wont have the voltage supply relay, so again labelled before cutting and removed from the cirucit. That makes the donor wiring a little simpler to look at, although there is a huge mass of unknown wires at the moment.
Once these two relays were out of the way, the rest of the ECU wiring loom is pretty striaght forward. It all ends up being mostly single wires, that need to be connected. This section is all the ECU input side. There is a connector for the lambda sensor, knock sensors etc.
The lambda sensor is a brown 4 way connector.
The rest is mainly for throttle fly-by-wire inputs and such like
There is a 14 way connector on the donor wiring ECU putput side, which when idenitfying wires, has things like oil level / oil temp senders, Speed signal, so these are needed.
Almost all of the ECU wires are now identified and label with masking tape. Its a matter of finding the corresponding input/output wire and joining them up.
You'll be pleased to know that the donor alternator cable will reach the battery fuse plate. This cable has a 2 way connector on it at the end which connects to the alternator. At the other end this connects to a 4 way connector. The other 2 way connector connects to the now, hopefully, defunct 2nd air pump, so this can be removed/or ignored.
The 4 way connector on this alternator loom, connects with the 4 way connector that goes off to the fan control resistor, we dont need this, so I cut the out, my 4 way connector now has only 2 wires on it, that complete the alternator circuit. I think this end up going to pin 30 on the ECU.
There are alot more cables to identify. I think i may end up making a new page, to document the above notes, and include the ECU pinout page I have at the moment. This may make integrating the Marlin loom and VAG donor loom a little simpler.


Posted by Steve | Permanent link | File under: electrical

Mar 03 2010

Switches, relays and wires for loom have arrived

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The order for all my Wires, switches, relays, fuses has arrived!!!
This is a major milestone in my build as I can now focus on all the electrical systems for the 5EXi.
Over the next few days, I will take many photos of the loom, as if you are building an EXi yourself, you will need to follow these steps.


Posted by Steve | Permanent link | File under: electrical, lighting

Feb 28 2010

Fitting Battery plate

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Time to fix the battery mounting plate to the chassis. I am locating the battery as to close the original place in the Donor as possible.
This then allows you to use the same thick cables for the starter motor and the alternator. Having said that the battery plate will fit better turned through 90 degreess, the starter motor will still reach the +ve on the battery (+ve rearmost on the EXi)
The ground cable should also reach, the eyelet halfway along is the chassis ground. The big question is if the alternator cable which connects to Pin5 on the battery fuse plate will reach. If it doesn't then it a 150Amp cable 2m long with an eyelet on each each.
I had to make up two securing plates, to hold the underside of the battery plate in place. I had some 2.5mm think aluminium sheet. So I used that.
To stop the mount plate from twisting around the chassis member, I use the recessed hole on the top of the chassis plate and drilled into the chassis beam. Using an M6 counter sunk screw and aa Rivnut. This seems to hold everything in place.
Not to sure about the long term fatigue here (with just one bolt), so I have also drilled a hole from the inside of the battery plate at 45 degreess into the chassis beam, and used another RivNut and M6 bolt.
I lost two rivnuts in the process, these fell into the chassis beam when tightening then bolt, I hope they dont make a horrible rattle, particulary when braking when the car is on the road. Hopefully they will get stuck somewhere :)
I put some high density foam between the plates and the chassis to increase the friction.
I placed an order today from AES, for the reels of cable and switch gear that I need to build the wiring loom That should arrive mid week. Then its onto the wiring !! If I get my ECU from Marlin, I might be able to fire the engine up in a few weeks!!!
I also need to get some Nuts & Bolts, I need replacement bolts for the driveshafts, I need 12 but only have 10, so I will replace them all.
I also need some M6x20mm dome head bolts, for the tunnels, using domeheads will allow me not to fail on IVA due to sharp edges, particulary if I dont carpet the inside. I am planning on carpetting. But the dome heads will also prevent the bolts heads cutting the top of the carpet.


Posted by Steve | Permanent link | File under: electrical

Feb 27 2010

Rivnutting the front tunnel sections

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I bought a RivNut tool from MemFast. I ordered it one day and received it the next, without Rivnuts, so ordered them on friday and got them in the post this morning. Superb delivery from MemFast, and what is a very sturdy design (has a liftime gurantee).
Being a newbie with RivNuts I was quite keen to try it out, and see how it all works.
As I hadnt fitted the two tunnels yet, these made an Ideal candidate to experiment on. For the front tunnel section I though 6 x M6 bolts would do the job, so it was drill time, once the tunnel was drilled I could then drill the chassis, so this was drilled with a 9 mm drill.
Once drilled the RivNuts were inserted and the memfast riv nut tool put into action. It was brillant, simple, no knucles smashed (Unlike Blin/Pop Rivets) and job done. The tunnels now have a secure non permanent fixings, so once installed I can get access to service anything that runs through the tunnels.
I think I may be a RivNut convert. :)


Posted by Steve | Permanent link | File under: structual

Feb 25 2010

Front uprights

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I received the replacement front wheel bearing and found out that you have to mount the free spindle from the inside of the front upright. I torqued the bolts to 100Nm, dont know what they should be.
The bearing fitted very easily so that was good.
I had to get hold of an M6x16 Countersunk screw to hold the front brake disc in place.
I had to re-tap one of the caliper thread on the upright, as the internal thread was caked in powder coat.
Got holf of 2 M10x60 bolts to secure the Willwood 4 pot calipers. Installing the brake pads was a breeze, and eveything lined up with the caliper mount points on the Marlin supplied upright.
I repeated the same for the other side.
The 5EXI now has front hub, discs and calipers !!! Excellent


Posted by Steve | Permanent link | File under: suspension

Feb 21 2010

Painting the driveshafts

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Today was a good day to start the next big job, and that was to refurbish the driveshafts. Using a drill with wire brush attachments I cleaned up the driveshafts, removde all the rust from each end, to give them a really good clean. Removed the bad paint from the shaft and cleaned up.
A wipe over with some cleaning spirit and the drive shafts were ready for some paint.
When I installed the engine, some of the engine mounts lost their paint, so I also wire brushed these areas ready for a paint touch up.
The starter motor was also cleaned and ready to be given a new lease of live.
I used Hammerite Smooth black, touched up the engine mounts, and the drive shafts.
For the starter motor I Used some left over VHT paint from the engine block. I did not want the starter motor to paint to burn, so VHT was the safer option. Given they can get hot when running, plus its mounted to the enginer block, so heat transfer would be quite high.


Posted by Steve | Permanent link | File under: powertrain
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