Further to No power...LPG

[ytt105]

As a follow up to the Need more towing power badly thread, I inspected my LPG system on my 96 4.6 V8.

http://lh4.ggpht.com/_Dceot1dyG8Y/TS...MG_8463sml.JPG

http://lh5.ggpht.com/_Dceot1dyG8Y/TS...MG_8464sml.JPG

http://lh4.ggpht.com/_Dceot1dyG8Y/TS...MG_8465sml.JPG

This is an Impco 425 mixer, and the general feeling is that it is restricting my air intake and therefore my towing performance.

To confirm the theories, I removed the mixer, turned off the LPG, and went for a tow up the hill towards Cooma, from Canberra.

From the bottom of the hill, with no runup, I climbed the hill in 3rd gear at 80 - 100kph. Previously, with the LPG fitted, the same run would be done in 2nd gear at 60kph the whole way, on petrol or LPG.

So, it seems I definitely need to do something.

Bee Utey, and others have suggested I replace the Impco restrictor with a large gas ring. However, to do this I would also have to replace my convertor because it doesn't have any adjusters on it, their on the Impco instead. Makes the conversion far more expensive.

This got me thinking, what about an injection system?

The adjustments are handled by the computer, so maybe I could retain my convertor and spend the money saved on the injection.

Although it will be more money, it may well be better value.

Any comments?

[bee utey]

double post

[bee utey]

The bigger gas ring (AMR part no. M352) is under $80 and will require a slight remachining. A suitable converter can be sourced from ebay for around $100 or less, second hand. Probably the most common converter for a fixed mixer is the OMVL. If you find a low mileage used one you will not be out of pocket by too much.

A second hand one, eg this one:

LPG Convertor OMVL used famous & sought after (eBay item 170601681529 end time 21-Feb-11 00:50:27 AEDST) : Cars, Bikes, Boats

may work well enough, or re-kit it.

A gas injection kit will cost you over $1000, this one has been installed successfully by forumites here:

MARRELLI 8 CYL LPG INJECTION LPG KIT - Fit it yourself (eBay item 190492735397 end time 19-Feb-11 08:25:16 AEDST) : Cars, Bikes, Boats

[ytt105]

2nd hand is a good idea Bee Utey!

Is my idea of using my existing non adjustable convertor for an injection system feasible or just wishful thinking?

[bee utey]

Is my idea of using my existing non adjustable convertor for an injection system feasible or just wishful thinking?

Definitely a waste of time. Your Impco converter doesn't produce any gas pressure, which you need to inject the gas! It's like using a 2psi carby fuel pump to run your EFI. No go. Unless you modify its internals. Anyway you normally wouldn't get an injection kit without a converter.