[LS1] LS1 Vapour injection conversion results

[sleepa]

Just had my VX LS1 wagon converted to a Vapour Injection system and wanted to post some results if anyone else was interested in doing similar.
For more details my car only has a 2.5inch catback at the moment, I will be installing an OTR CAI with maffless tune in the next couple of months so the results will change then as well.

It still needs to be retuned after 1000km to get the best economy/power.

The system has been in for 2 days so far, first impressions are.

It runs smoother then petrol
It feels like it has more torque off the line then petrol
Driveabilty around town is actually better then petrol.
On cruise it is the same as petrol.
Doesnt quite have as much punch as petrol in the upper rev range. Noticeable, but there is still PLENTY of power to overtake.
Oh, and the tank is in the spare wheel, i didn't have a spare so no loss of space.

The first tank of 38l used 250km, which works out at around 15.2 lper 100km mixed town/highway driving, also some gas was used to initially tune the engine on the dyno. So that figure is not accurate enough.

Second tank will get better results.

Overall I am pretty please with the results. I will update this thread when i get more results.

 

[Munz]

thats sweet - except for the spare wheel part, but keen to see the what kind of power it would make - more or less?

 

[HamaTime™]

Vapour injection is a decent LPG system. Did you do a complete conversion (i.e. straight gas) or is it still a dual fuel system? Straight gas would probably yield some better figures.

Anyway, JTG Liquid injection systems are fantastic as far as I have heard. I would half consider running straight JTG Liquid Injection on a new V8 if this issue over LPG prices gets sorted out. At the moment it's hardly a viable option for me so I run petrol these days ... :/ ridiculous prices.

 

[yxyx64]

... I will be installing an OTR CAI with maffless tune in the next couple of months so the results will change then as well.

interested in why you are getting a maffless tune

 

[one_and_only2004]

interested in why you are getting a maffless tune

Less restriction in the intake - pretty much why everyone else does it too.

 

[sleepa]

Vapour injection is a decent LPG system. Did you do a complete conversion (i.e. straight gas) or is it still a dual fuel system? Straight gas would probably yield some better figures.

Anyway, JTG Liquid injection systems are fantastic as far as I have heard. I would half consider running straight JTG Liquid Injection on a new V8 if this issue over LPG prices gets sorted out. At the moment it's hardly a viable option for me so I run petrol these days ... :/ ridiculous prices.

Still running petrol as well, it needs to warm up on petrol in the morning, LPG is a pain to start on. Although I am looking for ways to increase the power of lpg. Liquid injection is meant to be a fair bit better than vapor injection, only reason I didn't is because they haven't got the tunes entirely right in my area yet.

 

[sleepa]

thats sweet - except for the spare wheel part, but keen to see the what kind of power it would make - more or less?

They put in a bracket so I can still have a spare if I want.

I'm very interested in seeing if it makes more or less. Considering LPG is meant to be 100 octane, with some supporting mods it should in theory make as much power as pulp

 

[HamaTime™]

They put in a bracket so I can still have a spare if I want.

I'm very interested in seeing if it makes more or less. Considering LPG is meant to be 100 octane, with some supporting mods it should in theory make as much power as pulp

In theory yes, in reality no. Whilst LPG has a higher octane rating (usually 108 Octane) than say Premium 98 ULP, it does have a significantly lower energy per Mili joule content.

• PULP - 34.8 MJ/L
• 26.8 MJ/L

This means that your LPG usage will be higher than that of PULP due to the lower energy per MJ content. Throttle response and pickup up higher in the rev range also reflects this. However, this should be easily fixed via a tune.

Now despite Vapour Injection being an inferior technology to that of Liquid Injection, Vapour will still yield similar numbers to Petrol as it is direct injection. However, the car is still disadvantaged by running two fuel systems due to extra weight, a tune for each fuel. The engine will run far better when it is set up and tuned solely for one fuel. (Putting the cold start issues to the side).

 

[sleepa]

In theory yes, in reality no. Whilst LPG has a higher octane rating (usually 108 Octane) than say Premium 98 ULP, it does have a significantly lower energy per Mili joule content.

• PULP - 34.8 MJ/L
• 26.8 MJ/L

This means that your LPG usage will be higher than that of PULP due to the lower energy per MJ content. Throttle response and pickup up higher in the rev range also reflects this. However, this should be easily fixed via a tune.

Now despite Vapour Injection being an inferior technology to that of Liquid Injection, Vapour will still yield similar numbers to Petrol as it is direct injection. However, the car is still disadvantaged by running two fuel systems due to extra weight, a tune for each fuel. The engine will run far better when it is set up and tuned solely for one fuel. (Putting the cold start issues to the side).

Completely agree with you. I know with liquid injection you can get more power then petrol with a tune. (from what I have heard 10rwk on LS1s).
And I know vapour injection will use a bit more fuel to get similar numbers as petrol.

My aim is to use LPG as the sole fuel, (with a few litres of petrol for starting) and change the tune,plugs and perhaps cam to get more performance out of LPG at the expense of petrol which i wouldn't use anyway.

 

[yxyx64]

interested in why you are getting a maffless tune

OP, still interested in why you are getting a maffless tune.

(BTW: energy is measured in joules with a Mj being a million of the suckers)