BXProject

[Stinkwheel(Matt)]

I posted the below on the CX forum, but i know you guys know your onions, so i will cross post and id welcome your comments please.

"My new CX as you have probably all seen is running on LPG as well as petrol. Its a mixer system and it has caused Adam the previous owner some serious headaches in the past.
I've been looking into LPG systems and really the polish install (certified) back in 2005 should never have been done using a mixer system, the trouble that could potentially develop is massive. (i.e. Exploding car due to lpg vapours in the inlet pipework, one backfire and it could go very wrong indeed, or according to what ive found out/been told) The blos carb setup it was modified too was a step in the right direction, but it does all come back to its the wron type of system.

So, two choices, upgrade to a multi point injection system (suitable for turbo or supercharged cars) or pull out the system and accept that its a Gti T2 and live with the petrol costs.

I think im going to go with pull it all out, for several reasons......

This is never going to be an everyday car for me, I have the BX and 2CV's for that.
Because of the above, the several hundreds of pounds spent on buying the parts to upgrade the system to multi point would be better spent on getting the rest of the car right and how i would like it.

and reason 2, the setup on the CX would be ideal for my carbed BX i believe, so maybe i will transfer the kit to that (and have it inspected afterwards) "

[Philhod]

Seems a reasonable conclusion to me. LPG really is explosive and personally would never use it with a carb set up. Like Hydrogen I would prefer to keep these fuels separate from air until the time they are ignited.
Try looking on the bay of evil for throttle body kits to fit to the BX. Folks are always buying these then can't fit them and sell.

[mat_the_cat]

I wouldn't go as far as saying I know my onions (or LPG systems!) but I reckon that's the best decision. As you probably know LPG will exploit any weaknesses in the ignition system and with a mixer system a backfire is probably only a matter of time, made worse by poor mapping. Once I had replaced a faulty (new!) HT lead on the Disco I only had one backfire in 20k miles when on the overrun for a long period followed by booting it.
On a turbo car there is probably more potential for expensive damage, so the BX should be a better bet for it. A K&N filter on top of the carb (or slightly loose air hose clips) will stop airbox damage from a backfire.
If you have to buy a new tank probably best to go for a 4 hole tank to avoid slow filling. They have a 10 year test frequency so if you plan your BX to be a keeper might be best to go for a new tank as I have heard the cost of testing is similar to a new tank.

Although on the other hand you would only need a new front end to the system on the CX, and a good multi point should work well. But you would still need it certified on top of the front end cost...

[Stinkwheel(Matt)]

Its a tricky one, but im keener on getting the CX standard ish than the BX, so i think that will influence my final decision.

Oddly, i asked my insurance company about the BX and LPG fitting etc. I told them i would get it fitted myself but get them a certificate of inspection if i should decide to go that way. They said they didnt need a certificate, just to know it was fitted, so i started to search on the interweb and it seems there is no legal requirement for you to actually tell anyone whatsoever if you fit an LPG system yourself, this seems very unusual to my mind in these days of health and feckin safety.

[mat_the_cat]

Yeah, I couldn't find any legal requirements to have it certified, just the insurance companies who wanted it so if yours is happy then good news!
If you get a copy of COP 11 and follow that you should have no problems - most of it is common sense anyway from what I know (I don't have a copy of the standard but I do have a checklist somewhere).
If you do transfer it then I'd be happy to try and remember any tips I picked up...

[Stinkwheel(Matt)]

coolio, thanks mat. Im liking this idea more and more.

[Philhod]

Just make sure you use ALL new seals on the fuel side.

When plasma cutters first came out they used Hydrogen to form a flame halo around the arc and as the low pressure cutting medium. A backfire and failed (new) seal managed to set the guy using it, on fire. I put him out without too much damage and immediately banned the thing from use (all powerful shop steward). They use a different arc halo now and compressed air for a higher pressure cutting medium, so now a safe tool.

[mat_the_cat]

It's all rigid copper pipes (new olives) or flexy JIS hoses on the high pressure side, it will be obvious if you have any leaks as the pressure will mean there is no such thing as a small leak! Plus the frost forming will be a giveaway.
Although it looks like microbore tubing for central heating or low pressure gas applications (caravans etc) the walls are thicker so not the same stuff...Tinley Tech or WTV will sort you out with the various fittings you will undoubtedly need.
There is talk of a new standardisation (Europe wide?) of the LPG filler so might be worth looking into that in more detail if/when you go ahead.

[smiffy]

We need to hear from Aerodynamica, I believe his CX has LPG

[Stinkwheel(Matt)]

It does indeed smiffy, he also did his old BX 16 TRS.

They are both carb vehicles and are fine with the mixer type system.

The one thing i kept coming back to all over the place was the warning reading similar to following.........

"Do NOT use a mixer system on a forced induction car, it will backfire, blow your knob off and kill all small children and furry animals in the local area"

seriously, this is not a safe install, i do not mind really as the price of the car didnt really reflect that fact it had LPG fitted. And as a bonus i can (and almost certainly will at some point) fit it to my BX (with all new pipework/unions etc)

It boils down to i use the BX everyday, when the CX is done to how i want, i will use it maybe every other weekend or something. It doesnt need LPG and i'd like it to be safe