LPG Question

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Khryztal

Khryztal

New Member
Posts
725
Location
Felcourt. Surrey
Evening y'all. I have a 3.9 V8 rrc on LPG. Question is. Can I remove the gas ring/collar thing and fit a fogger type valve directly into the air intake of plenum housing. Before the throttle butterfly.

If so any ideas on size of valve?

Cheers guys
 
A Fogger, is a way of very finely atomising a gas for injection.

They are typically used in Direct Port Nitrous systems as a way of injecting the Nitrous Oxide into the engine.

In theory they *may* be used for LPG...BUT and it is a very crucial safety point....the LPG 'mist' created could in effect be too volatile and could ignite inside the fogger or plenum chamber with nasty results.

The way Nitrous Oxide works, is it doesn't itself sustain combustion so can *safely* be finely misted, but when it is heated in the combustion chamber the Nitrous Oxide splits and increases the Oxygen concentration by a significant amount, and Oxygen burn very well so it increase the explosive power of the current fuel/air burn by introducing extra pure oxygen into the reaction.

A fogger with LPG *could* create a perfect storm combination of a very fuel rich vapour in a hot space with inducted air, and as we all know from GCSE Science, that a fuel vapour ignites at a much lower flash point temperature than a heavier fuel vapour density.

Also the LPG ring has been calibrated to introduce a measured quantity of gas over a given amount of time.....trying to matc hthis with a fogger could be difficult and dangerous....

Just my opinion...if you want to increase gas efficency, I would look elsewhere in the system, mixture, water jacket temperature on the Gas expansion valve etc....
 
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Lol, I get the principles of Nitros. and not looking to improve the effiecency of the LPG system per se. What we were looking at was removing the bottle neck that the gas ring and blow back valve create.
We were thinking of the nos type fogger to replace the gas ring as it removes one bottle neck in the air pipe.
As you say the fogger creates a gas vapour. does the gas ring not create the same effect? the evap unit turns the LPG from liquid into a gas and this flows through the gas ring. On my system it is regulated by a turn in valve on the pipe from evap to gas ring.

If it can't be done it can't be done.

Going to be betting another car end of the month so RRC will become my second car and only used for holidays, green lane etc.
 
Down to one RRC. It's the one with the brooklands kit. But now has most of the panels changed to the ones from the white one.

It's not a true brooklands, it was modified by ovefinch and then had the brooklands kit fitted by someone else.(badly)
 
The Gas Ring does introduce the Gas vapour into the induction system, but the vapour molecule size is larger than that created by a fogger, if you look at the nozzle of a fogger and compare it to waht is essentially a Gas Stove Ring on your LPG gas ring, the nozzle size is different.

I am not saying it won't work, just concerned over the vapour density and ignition flash point at a smaller molecule size due to a more fine mist that will be created.

the LPG system on my old '93 RRC, used a similar mixture valve in the pipe from the vapouriser to the gas ring also..!!

You are dead right in the fact that the Vapouriser/evaporator does expand the Liquid into a gas, but the gas ring feeds this gas into the induction air at a set rate and turns the gas into a vapour of a certain size to ensure a clean burn (a gas and a vapour are two technically different beasts although there considered matter state is the same....!!).

I would be intrigued by the results....BUT I would have to point out to exercise caution as you will be playing with finely atomised highly flammable gas that could be accidently introduced at just right ratio to the inducted air to have a flash over and that could be dangerous if not fatal.....
 
Although it would be a good idea if it worked, I do agree that the mixture may be volatile after reading your post. I have looked at other ways of introducing the gas into system, gas cooker valves, welding nozzles etc.

May just remove the gas system lol. That would solve all the problems of bottle necks. Either that or try to get over sized gas ring and blow back valve made up.
 
Sorry to butt in, but on my '94 Classic with LPG the air filter stinks of gas - is this normal? I guess you must get some blow-back, as there's also an "exhaust" flap on the airbox which I assume is stop a build up of gas pressure.

Any thoughts?
 
As far as I'm aware you only get blow back during low engine vacuum, giving you a back fire on LPG. There should be a blow back valve thing that slams shut in this case saving your AFM. sometimes they put a vent flap in to releave the pressure
 
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