RS Liberty Bosch Coil Conversion How-To
Overview:
This document steps through the parts needed and installation steps to convert a Subaru RS Liberty to Bosch coils. The steps given will allow for the installation to be completed without having to drill any extra holes in the car, and provides for a clean, effective installation. This is a common conversion for Subaru RS Liberty's, as it is now common for the factory coils to fail, and genuine Subaru replacements are very expensive
Time taken: A few hours. Can be done in one day without stressing, with time left for a cruise and drinks afterwards.
Parts Required:
• 4 x Bosch HEC-716 Coils, including mounting brackets and electrical connectors. Price is generally AU$50-$60 each.
• 3 x 200mm and 1 x 300mm Long 8mm+ Heavy Duty Coil Leads. Ensure both ends are female conectors. Buy the best you can afford / justify. Top Gun 8mm leads can be bought from most car places for about $30 for the set.
• 8 x 6.4mm Female Blade Connectors. $5 from Jaycar.
• Solder. $2 from Jaycar.
• Heat shrink. $5 from Jaycar.
• 8mm convoluted tubing for wrapping cables. $10 from a car place.
• Wire
Non Standard Tools Required: Soldering Iron
Steps: Pre Work: Disconnect the negative terminal of the battery. It is also a good idea to put the bonnet in the fully upright position, so take the black stick thing out of it's hole, put it through the bracket in the strut top, and open the bonnet right up.
1. Remove the washer bottle - Two bolts at the top, then lift it out, disconnect the electrical connector, and rest the bottle on the top of the engine. No need to disconnect the hose.
2. Remove the air box - Unplug the air flow meter. Undo the hose clamps on the 90 degree bend and remove it from the car. Undo the four bolts that hold the top of the airbox in place and remove it. Remove the filter. Remove the two bolts that hold the bottom section of the airbox to the mounting bracket. Pull the bottom section towards the engine, and it should pop out of the side panel. Remove it from the engine bay. Remove the airbox mounting bracket.
3. Remove the old coils. These are held onto the side of the engine by either one or two 10mm bolts, depending on if the heads were converted to WRX ones. Simply undo the bolts, and pull the coils out. Take note (or better yet, mark) which coil came from which hole because mixing them up will cause problems later on.
4. Check the spark plugs condition and gap and replace if necessary - This is optional, but you've come this far so you may as well do it. Using a ratchet and spark plug socket, remove each plug from it's hole and check it's condition and gap. Standard gap for an RS is 0.8mm. Put the plugs (new or old) back into place.
5. Plug the new leads onto the spark plugs. The end with the 90 degree end is for the coils. The other end gets put into the hole and onto the plugs. The 300mm lead goes in the hole closest to the battery. The others are all 200mm. The leads can be difficult to get into place. Just push them hard and jiggle them around to make sure they are on properly.
6. Fit the electrical connectors onto the coils. In each coil pack, you should have received a packet with two wires prefitted with terminals, plus some nuts etc. Fit one cable to each terminal on the coils, put on a split ring, then a nut. Tighten them up. It's advisable to mark the terminals at the other end of the cable as positive or negative with a permanent marker.
7. Physically install the coils. Mount each coil to it's bracket with the nuts and bolts provided. Now, here comes the fun bit... Coil 1. This is the one closest to the steering wheel. This coil is held in place using the rear mounting bolt for the airbox mounting bracket (AMB). -If you have a pod filter, this bracket is not needed, so you can mount the coil mounting bracket (CMB) directly into place with the bolt. There is nothing else this bolt is used for. Position the CMB however you like (see photos) and bolt it into place. -If you are using the airbox, the AMB still needs to be able to be put back into place. If you position the CMB carefully (see photos), it will sit under the AMB and you can bolt both into place. Coil 2. This is the coil closest to coil 1. This coil mounts in the same way as Coil 1. We have not tested an installation in a car with both an airbox AND ABS, so let us know if you attempt this. Coil 3. Closest to the passenger seat. Looking under where the washer bottle would sit, there is an unused bolt hole in the chassie rail towards the rear of the engine bay. Find a bolt that fits this hole. Bolt the CMB into place using this hole (see photos). You may want to redrill the hole in the CMB if you believe the coil sits too close to the engine. Coil 4. Closest to the battery. In front of the battery, next to the horns, there are two 17mm bolts. These are used to hold the front bumper sub structure in place. We will use the rear of these bolts to mount the final coil. Remove the bolt (could be tight). This bolt will not fit through the mounting hole in the CMB, so you will need to drill the hole out a bit. Bolt the coil into place, ensuring that the horns do not come into contact with the electrical terminals on the coil. Bend the horn out of the way if necessary. 8. Cover the coil leads. Cut and fit some convoluted tubing to the cable part of each coil lead. This is to ensure they do not arc out on the chassie or anything, and makes the install a bit neater. Connect the other end of the leads to their respective coils, ensuring that any slack in the leads is neatly secured into place. Ensure that they have correctly 'snapped' into place.
Now comes the fun part.....
9. Complete this step four times, one at a time... Disconnect the old coil. If you trace the cables back you will find a set of connectors for each coil. Undo the connectors, then cut the cable between the connector and the old coil. Solder new wire onto the end of both wires and cover the join with heatshrink, cut to length (enough to make it to the respective coil), then solder a blade connector to the end. Connect the blade connector on the wire to the blade connector on the coil, keeping in mind that the red cable is positive, and the yellow is negative (VERY IMPORTANT). Connect the connectors again, ensuring that the routing of the cable is neat, then cover the length of the cable with convoluted tubing.
10. When all coils are connected, replace the washer bottle, replace the airbox, replace the 90 degree bend and reconnect the AFM. Reconnect the negative terminal on the battery.
11. Give the car a test kick. If it won't start or backfires or misses or worse, stop it immediately and check that all cables have been connected properly and not mixed up. If you get a check engine light, ensure you have connected the AFM back up. If it starts and runs normally, well done!
12. Take the car for a run, but go gentle until it has warmed up. Ask yourself why you didn't do the conversion ages ago, and be flabbergasted at the improvement it has made...
I didn't write this.
It was originally made and posted on ACTRSLC. I just turned the PDF into a post. Enjoy.
Just thought that his name could be put at the bottom. kind alike a copy write or acknowledgment
