Hello,

Right, after some quite extensive reading I believe that a DIY LPG conversion may be the way for me to justify keeping the coupe, and also a really interesting summer project!

It looks like the conversion can be done for £1000 or less for a 'medium' quality sequential Italian kit that will probably be fine for at least 75k miles (the higher quality kits usually last longer but are basically impossible to source for the DIYer). Good enough savings for me given my 16-18k miles a year and projections of petrol rising more and more.

The key issues seem to be difficulties with setup (which don't really appear to be half as complex as those associated with highly tuned coupes), and potential installation difficulties due to lack of room. Nothing that can't be solved though. I'll be looking to do this on with the engine in standard form.

I'll start looking into this in much more detail after June (I have something seriously imporant to finish before then). I'll start by doing a proper assesment of where everything might go (and will probably appreciate some input from the forum in that regard) and then hopefully go for it! I'm hoping to convince the old man to help out with the mechanical bits and I'll stick to the electronics and the laptop :).

At first glance it looks like there is plenty of room for a tank in the boot - not sure about where the filler might go. In the engine bay, removing the airbox will yield enough room for the vaporiser and various other bits and aside from looking at whether appropriate mounting positions for the injectors (drilling into the manifold) can be found, there doesnt seem to be any obviously fatal obstacles.

If any of the Euro forum members are aware of any conversions that have been done on the continent, please let me know it would be very useful.

Cheers!

Scott

This is of course, assuming that my insurance company doesnt vito it (or PF saying they won't touch it with LPG) LOL!

As said before you need to hunt down Kingpleb. Could save you a lot of time and effort.

**stolen off the web about Kingpleb's car***

Well for nearly 20,000 miles ive been running my Fiat Coupe on LPG and
after a few mods recently the 5th piston rings let go so i had a new
piston and rings and associated gubbins put in.

She had been running well for a while and then on my return jurney after
a run she decided to start firing like a dog.

Got home and there is no compression on the 5th cylinder. Im thinking the
exhaust valve has gone or the inlet one. niether of which is good.

Now the head is going to have to come off either way and probably have
some work or be scrapped.

In either case ill want to fit new valves to either my head or a new(er)
head. Now i have heard about valve seat reccession and was wondering if
there is anything i can do to make the head last longer, 3angle valve
seats, different valves?

What are my options in this regard as she is a high miler and does see a
lot of mile so i dont want to be pulling the head off with this issue
again :o( And any advice from you LPG veterans is muchly appreciated on
this toic :o)

PS the car in question is a Fiat Coupe 20vt, running a GT28rs .64 Garrett
turbo, Pro ALloy front mount intercooler, and 3" exhaust(no cat or mid
box) and is running the dream XXI system iirc.

Installed by F1 Injection in bolton who i will need to go to at some
point to check all fuelling anyway :o)

I assume it is an iron head ?
in which case a decent machine shop will fit hardened valve seats and
your troubles with recession will no longer exist .




Hi Guys, as im not sure about the head but i can find out, im sure its alu
though...
Flashlube, i was told i would never need with the system.

Yes i do think it may have run lean but i have to consider that it is
becoming more common in cars my age and newer that the exhaust valves are
letting go, must be an age thing and them maybe not liking increased boost
levels/increased airflow.

Ill ask about the hardened valve seats as well, a rough guide on pricing
from anyone or are we talking a few quid per one or for the lot while the
head is off?

Thanks guys,
Will

********************

the only prob with lpg is the heat
fitting a good fmic will help or even aquamist will help??
because natural gas is not as good soaking up the heat under boost

Do coupe's run hotter than other turbocharged cars then? There are a few Imprezzas running fine on LPG and various other vehicles (200SX etc)...

Blimey, yes I think Wills experiences put a lot off doing a coupe LPG. But I'm sure it can be done fine for a standard car (KP's had a big turbo without custom mapping I believe).

Yeah but it was his LPG setup that was blowing it, as that was what he always used...

Ross

Isn't that just an assumption though Ross? It could equally be that his (petrol) fueling was incorrect.... or various other things.

All to easy to blame the conversion.

Well considering KingPleb was famous for always running on LPG, i reckon it was that. The thing is, even if his petrol fuelling was out, the lack of use of petrol setting would mean that its not gonna be that.

All in my opinion.

If you are gonna do this, you need to do it right.

Ross

To be honest I dont know that much about the mechanics of lpg. But (I hope he wont mind me saying) I think Will's was probably one of the worst cost saving exercises ever. LPG kit plus three(?) engines plus the many Citrons he had to buy when the coop was off the road

On top of that, his coop never looked the minter it should have done with so much money lavished on it because of the high miles it was doing.

I would just buy a second car to be honest.

Agreed. That would be my opinion aswell.

Ross

I think you will find that running LPG and without mapping is what caused the issues for 3 dead engines. If it was mapped correctly it would have been fine.

It's like slapping on a big turbo, cams, FMIC, 3" exhaust and then running a standard chip and expecting it all just to work. No it won't! Mapping mapping mapping is the key issue here and wasn't done, hence the disater KP had!

I don't understand what you mean Ross. The system I'm looking at is a *slave* - as long as the petrol map is spot on and the calibration between the petrol injector duty cycle and the gas injector setup is correct then it should be fine (aside from heat issues possibly).

If you modify the car after the installation you need to double check both the petrol map and the gas calibration...

And I don't want a second car

I got in contact with Will. This is straight from the horses mouth:

'I dont think the LPG directly killed the engine, most likely what killed it was not running it on a correctly mapped ECU as i just stuck in a GTEC then a GTEC2 with a bit more advance as the LPG burns better with more advance.'

I was always under the impression that the LPG was mapped...

Ross

Not typically I don't think. You let the petrol ECU system take care of the mapping, and then instead of injecting petrol, you inject gas. So the calibration is all about ensuring that you put the right amount of gas in for the current petrol injector duty cycle. Apparently the calibration can be done using the stock o2 sensor so I presume its based on some kind of extrapolation (i.e. its just an offset or bias you need to estimate and compensate for).

Any mods subsequent to the calibration which change the amount of fuel that goes in for the same duty cycle will mean that the gas needs to be re-calibrated. Any mods that effect the optimality of the petrol ECU system will mean the petrol system needs checking / mapping as well.

So basically, if its done properly, the only problem I can forsee is that when running on gas, the combustion temperatures will be higher, but as someone has said, this can be improved in various ways.

The other issue is valve problems - some people use 'flashlube' systems which squirts lead like stuff into the intake to minimise valve problems. Looks a bit naff to me but worth looking into.

Scott

dunno where all that stuff came from as have only skimmed the thread but the head is ally, the exhaust valves are absolutely the highest quality OE valves there are and are sodium filled, and there have been no reported problems ever of 20VTs having valve seat failure under normal circumstances.

As I see it the problem is that you should run less boost on LPG because the combustion temps are higher. You should use a colder spark plug and should run aquamist as well if possible. I would use 0.8 bar max on a std turbo and if you want 300+BHP get an oversized turbine housing so a GT28R with 0.86 A/R housing for instance. Or even the std turbo with a GTiR turbine housing. Also match your exhaust manifold to the cylinder head

hi warnysouth,new to this but bear with me!iv ran an lpg car for years,and when i say that i mean,i bought it new in 1996,converted it,and to this day has NEVER!broken down---i know,i didnt believe me either!But more to the point heres my experience with it.

a.it doesnt need mapping! because the gas comes from the tank as a liquid,its then fed into an evaporator unit which turns it straight into a gas,which is in turn fed down the inlet,NOT INJECTORS to the engine,the ecu plays a minimal part in the burn,in fact,i liken it much to a carb set up!simple.

b.it runs cooler! my temprature gauge used to sit on 90 c when i ran on petrol,on gas it sat at 75 - 80,your basically breathing cold dense gas?after all it was a liquid half a second ago,and it was -200 degrees then!

c:reliability. now while i cant vouch for a turbo aplication,i ran gas on a 1.6 vauxhall 8v lump,originally a nova engine i believe,they dont run past 100,000 miles without failing,this ones done 168000 mile! take from this wot u may .

the only problem i ever had was the valve stem seals had to be replaced,at 100,000 this is because the temprature difference wears them in someway,but trust me,dnt do one yourself!ur lambda sensor will have a heart attack!hehe

have you investigated the posibility of alternative fuel sources,a group of artisans in india are having some success with chicken shit!i personally have always felt thjere was a lot of scope for a consomme of turpentine and black treackle,dont know about boost levels,but it wont half give u the shits lol

or you could steal the fuel?or pherhaps run next to your car while it does the quarter mi8le run to save wieght!hehe

Oh dear, erm there are one or two inaccuracies in that post I fear.

Vauxhall 8v engines most definitely do run past 100k miles

LPG does burn hotter, this matters a lot more for a turbo'ed car because its breathing hotter air from the turbo.

You do need SOME kind of mapping, you cant just inject gas into the intake and hope for the best. Even carburetter cars maintain an air/fuel mix.

When saying it runs hotter, people mean the EGT (Exhaust gas Temperature), as in when burnt in the cylinders it creates more heat. Not oil or whatever temperature that you're reading off the gauges.

duly noted!but u must admit,why the hell does it run with a lowetr coolant temp?

I have absolutely no idea

Apologies for the thread dredge, but did you get any further with this Scott?

Cheers

Ben

my bro's 2.5 mgzt had a seperate map for the lpg for it to run safely.Was super reliable and very quick still.

The LPG systems that have been fitted to a coupe, how do they inject the fuel? do they just use a mixing ring?

The LPG gas from the vapouriser has to be a higher pressure than he charged air. If not the right amount of fuel is not injected. Just got a Coop 16v Turbo and think ing of a conversion. I have a V70 and Range rover both on gas and run fine. Dirty gas (oily) can make injectors stick as it dries hard. Change filters every 5000 miles. Check lpg pressure out of vapouriser. Must be at least 2 bar or higher for turbo depending on spec. Your vapouriser may not be able to keep up with demand so maybe a 2 vapouriser set up is required (as per my rangie)

What you talkin' 'bout Willos ?

...sorry couldn't resist