Why didn't LPG take off?

[Havard]

i havent done one but someone must have.I know a few soarers have been done and only one other aristo that i know of.

 

You know that I have one!!

 

I will be down to see you soon.

 

H.

[Chris Wilson]

I had a multi point LPG converted MKIV TT in a few months ago, for turbos I recall? VERY tight fit in there, but apparently it worked OK. I didn't try it on gas. I would be warey of LPG on a big HP turbo engine myself, unless I had a wide band on it, and could SEE it didn't get weak.

[Guest munchie]

DO YOU ALL know its exactly the same stuff you get in the big red 47kg bottles.....?

47kg = 108 litres

I sell them for £30 which is 27p per litre

 

now how much sense does that make!

 

GSW - dont fancy doing one on site in Cornwall???

[ivan]

Why didn't LPG take off?

Perhaps nobody wants to be seen with a gas bottle in their car these days?

 

 

[dangerous brain]

Perhaps nobody wants to be seen with a gas bottle in their car these days?

 

 

 

What even those big shiny NOS ones??

[carl0s]

Here's my question.

 

If the calorific value of LPG is 14% less than petrol, and this means you need to inject 14% more of the stuff into the motor, then what happens to the injector duty cycle, which is already pushed almost too far on an 18psi-boosted stockish Jap motor?

 

Or does the LPG system have its own injectors?

[Kranz]

Has its own injectors drilled & tapped into the inlet manifold.

 

And even though the calorific value is lower, its octane is much higher and its mixing cam be more homogeneous, so advancing the ignition can recover this defecit.

[dangerous brain]

For guys that keep their cars for years as long as you can find somewhere to stick the tank its well well worth the money. Lets put it this way its the only modification that will leave you effectively in profit after 20k miles

[carl0s]

Interesting, thanks guys. And these injectors are pretty beefy are they? They're able to supply enough juice for 400hp, reliably?

What sort of system is controlling them? How can somebody fit an LPG system and have the air/fuel mix correct yet so many fail to do it on a petrol Supra (i.e. mapping an aftermarket EMS)?

[dangerous brain]

Basically from what I can gather all it does is follow the stock ecu and add whatever milisecond LPG needs extra to the equation. Its a bit more complicated but not much. GSW has run it on the aristo for over 2 years I believe with no problems and makes more power on gas than on petrol.

[Ian R]

I run my car on Gas now and again N20

[carl0s]

Basically from what I can gather all it does is follow the stock ecu and add whatever milisecond LPG needs extra to the equation. Its a bit more complicated but not much. GSW has run it on the aristo for over 2 years I believe with no problems and makes more power on gas than on petrol.

 

That's very interesting, and an elegant solution to the problem. Cool.

If I end up buying a house far away from my customers, then I might go the LPG route. I've already ruled out larger turbo etc due to the autobox.

 

I wonder how it would work on a BPU car where the ECU is going all-out on the injectors anyway due to >15psi and no fuel-cut (FCD fitted).

[dangerous brain]

PM the guy his car is BPU also. I think he quoted me a ballpark figure of 2 grand fitted. He has also said if I keep the boost down on my single he couldn't see a reason why it couldn't be fitted. Basic rule of thumb is max ability is 100bhp per cylinder with todays technology.