Extra Power in a diesel with LPG

[minormatt]

I've got an old 1996 2.5di transit which I am trying to get the most power out of. I have already turbo'd it, fitted the biggest available injectors etc and drag race it occasionally.

I have read that introducing LPG in to the air on a diesel will help the diesel burn and give an increase in power. I am NOT trying to save money with this, just trying to make my 1/4 mile times quicker

Is this true and is it worthwhile? I'm thinking of a very simple install (for racing only), a tank, a filter, a solenoid valve a vapurisor and a power valve. I may make the setup removable so I won't have it installed when on the road

Any thoughts?

[bxman]

Good Luck ,just hope the bottom end will stand it.
Keep us posted Cheers Patrick.

[minormatt]

bottom end will stand it! The engines are absolutely bulletproof - if they have oil in they are fine, coolant is optional

Even if its not, I will get it towed to nearby services/garage etc, ring the RAC for recovery and put one of my spare engines in...

Last time out was 19.5s & 70mph at the 1/4 - which isn't bad for an old van with 240,000 miles

[sijones]

if it's just for fun ...

i'd look at doing it like methanol injection (hole in air intake) using the turbo pressure switch to turn on the extra gas when required with an override off in the van.

maybe using a normal vap that's referenced to intake pressure to vari the gas with pressure etc.... might be well out but in my head it would work!

As far as am aware you have to be very careful how much extra you put in as it will go bang with too much.......

[classicswede]

There has been a lot done with diesel LPG blend and you do gain a reasonable bit of power with improved fuel consumtion.
Nearly all the conversions are done with saving in mind, most of the conversion done for power usualy go bang when you get to gready

[Tubbs]

There has been a lot done with diesel LPG blend and you do gain a reasonable bit of power with improved fuel consumtion.
Nearly all the conversions are done with saving in mind, most of the conversion done for power usualy go bang when you get to gready

So speaks the voice of experience, i have also got a bit greedy in my time

[minormatt]

I will just have to be careful then... Or kill an engine, which would be a feat given how bullet proof they are

Would a normal single point petrol system be the thing to use (open loop)?

I have a spare BRC Just front end system (will need a vapouriser and tank but have everything else)

[minormatt]

Also... does an LPG filler have to be mounted on an external surface of a vehicle, or could I mount it in the door step??

[sijones]

Also... does an LPG filler have to be mounted on an external surface of a vehicle, or could I mount it in the door step??

depends if you need a certificate on it afterwards for insurance purposes.

CoP11 says something like can't be mounted inside the vehicle so another words where the gas can go inside the van.

If you use a single point your going to restrict the airflow and therefore upset the mixture, also diesels don't have a butterfly to control airflow so not sure it's practical to use a mixer...

[classicswede]

The just bits are of no use to you.

I use a nice small little vapouriser and just a basic switch for gas control. I also have a fair selection of tanks about you could make use of.

The filler does need to be externaly mounted or into a well vented area. I uspect the side door step could be ok?

[rossko]

depends if you need a certificate on it afterwards for insurance purposes.

CoP11 doesn't apply to diesel fumigation systems. Plain common sense says its still wise to follow the relevant parts of course.

Car size vap would be overkill except for engnes in the megawatt league.
Best to find out how diesel fumigation works before planning too far ahead - for example a means to shut it off at ilde.

[sijones]

depends if you need a certificate on it afterwards for insurance purposes.

CoP11 doesn't apply to diesel fumigation systems. Plain common sense says its still wise to follow the relevant parts of course.

That surprises me, i wouldn't have thought it differentiated between fuel systems, kinda makes no sense to have a CoP11 for petrol but no regulations for diesels which means they can be dangerous and insurance will insure them!......

[Gilbertd]

I would have though it would

This Code takes due note of progress towards European and International harmonisation, notably:
• European Standard BS EN589 ; "Automotive Fuels - LPG - Requirements and Test
Methods";
• Draft European Standard BS EN 12979 : "Automotive LPG systems - Installation
Requirements";
• Draft European Standard BS EN 13856 : "Operational Requirements for Automotive
LPG Systems";
• Proposal for a draft UN Economic Commission for Europe Regulation : Uniform
Provisions for the Approval of specific LPG (Liquefied Petroleum Gases) retrofit
systems to be installed in motor vehicles for the use of LPG in their propulsion
systems;
• UN Economic Commission for Europe (ЕСЁ) Regulation 67.01: Uniform Provisions
Concerning:
i) Approval of specific equipment of motor vehicles using liquefied petroleum gases in their propulsion system.
ii) Approval of a vehicle fitted with specific equipment for the use of liquefied petroleum gases in its propulsion system with regard to the installation of such equipment.

The last bits only say that it applies to vehicles using LPG in their propulsion system so surely it does still apply as it doesn't say vehicles ONLY using LPG just using. I would read that to mean as a fuel or as an additive, you are still using it.

[minormatt]

well an idle/throttle switch is easy to put in, at idle stop the solenoid.

Dai, so am I right in thinking running without an ECU, an on/off switch to switch it on above idle which controls the solenoid valve and control it via a power valve?

As its turbo'd there is at least 1 Bar pressure in the manifold, will the pressure in the LPG system (after the vap) be sufficient to overcome this, or would I need to plumb it in before the turbo (I don't particularly like that idea)

[sijones]

well an idle/throttle switch is easy to put in, at idle stop the solenoid.

Dai, so am I right in thinking running without an ECU, an on/off switch to switch it on above idle which controls the solenoid valve and control it via a power valve?

As its turbo'd there is at least 1 Bar pressure in the manifold, will the pressure in the LPG system (after the vap) be sufficient to overcome this, or would I need to plumb it in before the turbo (I don't particularly like that idea)

If you used some sort of nipple in the inlet manifold, a vap from normal injection lpg system, you take a feed from the intake to reference the vap output, you can then make this a little bit above positive pressure or 1 bar but it's controllable, you would most likely need another varible valve between nipple and vap.

using turbo pressure switch, which may need to be added, it's going to turn on the lpg when in positive pressure, am sure you could get some switch that will only happen when at 1 bar, so turbo full pressure - full throttle or at least putting a heavy load on triggers lpg, when cruising and no load turbo pressure is dropped and you not using lpg...

That's i'd say a simple and cheapish setup for fun use rather than economy which is what you wanted!

[rossko]

well an idle/throttle switch is easy to put in, at idle stop the solenoid.

Which for a conventional pre-vap solenoid leaves a half-litre or so of gas in the vap and hosework ...

I'd want an RPM safety stop as well - maybe as simple as oil pressure switch.
But it might be worth exploring a proper RPM sensing gizmo that could act on overspeed as well?

As its turbo'd there is at least 1 Bar pressure in the manifold, will the pressure in the LPG system (after the vap) be sufficient to overcome this

No, you'd reference the vap to manifold like you would in a petrol turbo

or would I need to plumb it in before the turbo (I don't particularly like that idea)

me niether, that'd be another large volume of fuel to be burnt after you 'throttle off' which could be a nasty suprise. Or it might all be over in just a rev or two.
I must say I've never played with this kind of setup, but some of the potential drawbacks to be dealt with are evident.

[minormatt]

No, you'd reference the vap to manifold like you would in a petrol turbo

I have to say, that means nothing to me...

The injection pump of this particular engine stops injecting diesel at approx 4250 RPM, surely if there is no diesel then the LPG cannot ignite? But rev limiters are easy enough to get e.g. http://www.ebay.co.uk/itm/AccuSpark-Sof ... 2a1e4bbc78 could almost definately be wired to suit

[classicswede]

Hi Matt, best bet is to give me a call and I will fully explain to you how its done.

[SimonHobson]

No, you'd reference the vap to manifold like you would in a petrol turbo

I have to say, that means nothing to me...

On a non-turbo setup, the air side of the diaphragm in the reducer is open to atmosphere - and the suction from the mixture draws gas in. Obviously, if you fit a mixer after a turbo, then on boost it would push air back up the hose and you'd get no gas.

For for a turbo, they do reducers which have the diaphragm enclosed and connected to a hose fitting which you plumb to the intake just upstream of the mixer where it picks up the intake pressure (boosted by the turbo). Thus, as the turbo boosts the intake pressure, the reducer adjusts it's output to match.

So for your setup, you'd use a turbo reducer - this will supply "unpressurised" gas which will track the pressure in the intake. Then you fit a spud pipe into the intake - it needs to be where there'll be enough turbulence for it to mix well before the intake splits to the individual cylinders. You'll probably need to tweak the reducer to provide some positive pressure since (unlike a mixer system) you won't have a venturi to create any suck.

[bxman]

As you only want it on the drag strip. and then only for 10-12 seconds at a time when you already have a full turbo boost of 1 atm.

Why not feed liquid lpg direct into a drilling in the manifold .
Your gas bottle should provide the required pressure.
If you were to use something like a gas cooker jet you would have a large choice of jet sizes.
A simple electronic timer would open a standard cut-off valve for the required time.
manually operated when you needed the additional boost
you would only need a minute bottle and everything could be removed before gong back to roadwork.
High pressure braided SS hose should satisfy the scrutineers.

just a thought.
No doubt attract derision for the health and safety brigade.