Porsche Boxster I just converted

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Porsche Boxster I just converted

#1 Post by LPGC » Sun Sep 14, 2014 8:18 pm

A few pics of the Porsche Boxster I just converted for a customer. I don't often take pics of my work but the owner asked me to in this case. Will probably start to take more pics in future, a few installers seem to do so these days. I would have a mega library of converted vehicles by now if I had taken pics of most of my installs... But I have posted a few pics of BMW M5's, supercharged Rangerovers etc on this forum before.

A few suppliers I spoke to reckon this is probably the first Boxster that has been converted to LPG, I wouldn't know about that but it is the only one I know of - Someone else might know different?

The car's spare wheel stood up in the front boot, after considering all the possible options for tank(s) etc, a 50 litre vertical toroidal LPG tank in the original spare wheel location seemed the best option and to offer the most capacity, at least if we were going to retain some luggage space and only fit one LPG tank. It isn't possible to fit a larger diameter or height (read depth since this is a vertical toroidal) tank - or the front boot (bonnet) wouldn't shut. The bonnet slopes steeply from the area around the front side of the tank. In the pic the white stuff is white Tiger Seal, not really necessary because the overpipe (looks a bit like the pipe I remember was on my mum's 60's hair-dryer) is secured to the tank using proper fittings, but I thought it better to use a bit of Tiger Seal too.

Tank (in front luggage area):

The owner didn't want any holes making in the bodywork when fitting the filler. A lot of my customers these days opt for the small square cap type fill point and mounted centrally at the rear of the vehicle (or just off centrally if a towbar is fitted). This option wouldn't have been practical on the Boxster and would have spoiled the looks. Another location/option considered was to fit a removable type filler which would have been hardly visible behind the drivers side front grill. But after careful measurement we found that a removable type filler would fit behind the petrol fill flap alongside the petrol filler, and this was what the owner decided on. This is the 22mm thread type, so is far stronger than the easily broken 10mm thread type, and the large diameter doesn't restrict the flow (so doesn't slow the fill) like the 10mm thread type. It is (just) possible to use the short type bayonet adaptor and indeed a short adaptor could be left in place even with the petrol fill flap closed, but there isn't much clearance for the forecourt 'gun' with the short adaptor so we supplied the owner with the long type adaptor. The pic shows the short type bayonet adaptor screwed in, apologies for not taking any pics with the long type bayonet adaptor screwed in, it hadn't arrived the day I took the pics!

Removable (22mm adaptor) type fill point behind the petrol filler flap:


This changeover switch was probably the easiest to install that I have ever done on a German car! That's because the wiring (from the LPG ECU which is in the rear boot) to the switch runs through an existing opening between the rear boot and area to the side of the engine bay, then runs under the carpet at the side of the engine bay, under the carpet in the interior, under the middle trim / armrest / handbrake area etc in the vehicle, straight to the switch - It was very easy to route the wire under the carpet. The switch location was chosen because it seemed a very appropriate, easily visible, handy, sensible location and because it is mounted on an easily replaceable and inexpensive section of the vehicle trim. On Mercs you can usually run the switch wire into the vehicle interior along with all the other wires from the under-bonnet mounted fuse box, so that part is easy on Mercs, but then on Mercs you have a dashboard that is built out of girders to contend with, this was easy by comparison and almost as easy as routing the wire / fitting the switch in a Nissan Xtrail :lol:

Switch just in front and just to right of gear stick in easily replaced small plastic panel:


The engine is a bit difficult to access on Boxsters. You have to put the hood 90% towards the up position, remove some clips, remove some trim, remove the engine cover, and then you get a partial view of the engine! It is difficult to see any LPG parts in this engine bay pic but they are definitely all fitted, I had just been out in the car for a test drive (running on LPG) before taking the pic anyway! Incidentally, those 'pipes' running across the top of the engine are not pipes that I fitted - they are the original throttle and clutch cables!

Probably the best view you'd get of the Boxster's engine:

The LPG ECU is in the rear boot mounted just to the right of the petrol ECU. I minimised the number of wires running into the engine bay by connecting some of the wiring that usually connects near the the engine (but runs to the petrol ECU) directly to the petrol ECU instead. There are, of course, still plenty of wires that need to run into the engine bay, and to get them into the engine bay a hole had to be made through the rear boot's front bulkhead (or read the rear engine nay bulkhead). The wires run inside a bulkhead fitting and because we don't want any fumes etc from the engine bay getting into the rear boot, further sealed / protected with 'Tiger Seal'. The wiring goes through the bulkhead fitting which might be visible to the right in the pic. The ECU is attached using one of the same bolts which secures the latch for the soft-top cover. This bolt was originally a stud, the stud was removed to fit a longer bolt which could do both jobs, doing this meant I didn't need to drill another hole to secure the ECU. Worth saying some of the wires in the pic are the interface cable I have attached, and the wire that runs to the interior changeover switch because I hadn't finalised the routing of that wire when the pic was taken. Also worth saying it all looks completely original with the trim back in place - you can't tell there is an extra ECU behind the trim.

LPG ECU next to original petrol ECU:

The reducer is hiding low down in the offside of the engine bay but above the plastic underskirt. All the piping (gas feed to engine and reducer vacuum reference) and wiring between the reducer and the upper engine bay is well clear of the exhaust (both the offside manifold and back pipe) and the inner wheel area, and all runs together inside a single protective over-pipe. Instead of using 4 different sets of wires to run inside this over pipe (i.e. reducer solenoid wires / reducer temp sensor wires / tank solenoid wires / level sender wires), I used a single length of 7 core wire for this purpose... If I hadn't used the 7 core then maybe the vac reference pipe or some of the wiring would have had to have been outside the protective over-pipe. The single length is much neater and will make changing the vapour filter (which is in the engine bay at the top of the over-pipe) a lot easier and that process less likely to break any of the wiring.

The reducer - You wouldn't usually be able to see this even with the car in the air but in the pic the car's plastic under-tray is removed:

This was one of those vehicles where when you do the first one it takes a bit of head scratching, but once you have done one you'd be able to do a second in only two thirds the time though not do it any better... and good installers will know what I mean by that! Customers shouldn't read much into that comment, because a good installer will do a better job of converting a vehicle, even if they haven't previously converted that particular model before, than a bad installer who has converted that particular model before... So the advice to customers is don't ask an installer if they have converted your particular model of vehicle before, bad (and some good) installers always say yes anyway, and even if they really have it doesn't mean they'd do a better job than a good installer who hasn't converted that model but will put the time in and do the head-scratching.

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