Volvo S70 10v LPG?
 

Hello, I've got a S70 10v 4 speed auto, and I've worked out the predicted mileage that I'll be doing in the future, and automatically I thought of a LPG kit. Now the car does 35MPG on a run, that's why I bought a 10v. But, if I did go down the LPG route I'd want a god job and a good kit. The kit had got to come with a hidden filler, as I don't want hole's in the side of the car. Is this possible? Also what would be the best kit for the money, and what would be the best place to do it.
Also, been doing a bit of research and some people say it increases power, I know the 10v isn't the most powerful option, but is this true?
And final question, how much is a good kit for my car?
Just to say I probably won't be doing this until late this year/ early next year but I'd like to know what's what.
Thanks for looking

Power wise you will loose a fraction, only turbo engines can gain and some other odd engines but teh vast majority will loose a small amount of power. You also use a little bit more fuel but still a significant saving

If you go the hidden filler path you can only get the very small type in and mean you have to screw in the extension each time you fill. What I prefer to do is fit the filler below the bumper opposite side to teh exhaust. This means you can fill from either side.

As to what kit is best there are pros and cons to each kit. Speak to the installers you are considering and ask them what their prefered kit is

Dear 'classic'

I know you allowed me to pick you brains before. Can i have another few questions?

You write words to the effect..."turbo cars and the odd exceptions" will actually gain power.

Do I have the following correct?

1) For optimum fuel:air mix we usually see a drop in power with the gases, simply because LPG (and CNG) has less energy for a given swept volume, which leaves less room for air. Hence because each cycle gets less air, we see less power.

2) So does it follow because turbo-charging can make-up for that air deficit [against petrol] and because LPG and CNG can take a CR way higher, [because of higher octane] greater boost or CR means that gas ultimately gains over petrol?

3) This because now you're shoving in more fuel per cycle than you could with petrol, even over using petrol with a turbo? Hence, Normally aspirated in our theoretical engines, and all else equal, petrol wins, but turbocharged petrol will pre-detonate so can never catch-up?

4) When you convert a turbo-cahrged car, do you ever see more power, and if you don't, is it because you're hobbled with a BiFuel car, and thus the boost set as safest for petrol?

Pretty please?

Very complex question as every engine differs in how the perform but there are some general rules you can apply.

1) basically yes

2) No the boost pressure is going to stay the same so you are still only going to have the same amount of air available. To not loose power you need something else to happen like being able to run more ignition timing

3) Under boost you tend to put in comparitavely less LPG than you would petrol - explination to follow

4) In some turbo engine you will see more power on LPG than petrol keeping teh same amount of boost


We already know that LPG has a lower calorific value than petrol meaning for the same amount of "work" we need to use more fuel. Adding that extra fuel then allows less room for the air charge hence limiting the maximum power available on a typical engine so you normally expect to see a small drop in engine power.

This is still true with turbo engines but a few things happen in turbo engines that can reduce the power lost on LPG to even allowing you to gain.
Many turbo engines add extra petrol under boost for cylinder cooling so are overfueling. LPG does not offer this kind of cooling and adding extra LPG at those levels can cause engine running problems. We will lean the LPG mix back for correct burn thus resulting in the LPG taking up a little less space

The other factor is ignition timing. Some engines are set with very safe igntion timing and LPG will see no gain without the use of a timing advance processor. Other are fairly advanced and teh knock sensors retard the timing back on petrol and will then have more advanced ignition timing on LPG without the use of any extra parts.

If building a dedicated LPG engine then high CR and liquid injection is the way to go

Thanks for your knowledge 'classic'. I've got my knickers in twsit over this. I'm lost:

You write:

We will lean the LPG mix back for correct burn thus resulting in the LPG taking up a little less space

I did grasp that you need heaps of advance with the gases, and CNG needs more than LPG, (I have an old Joker module on my Land Rover for just this reason) but...

P1: If we lean back, then we've shoved in more air, but also less energy per cycle.
P2: With a turbo, we're above atmospheric pressure, the whole charge proportionally increases for the same space, but it's a weaker mix too. This can't be good can it?

Q1: How have we the potential for more power than petrol? More so if we are not keeping the charge at optimum anymore, or are we?

Sorry, I'm lost.

The key part is that petrol is mapped rich for the use of cooling at a minimal loss in power. LPG offers no cooling so overfueling is of no gain so you need to lean it back to correct burn

The injectors on petrol are opening for Xms to fuel the charge and Yms for cooling. We can delete the equal amount to Y as LPG is not going to give any cooling but with its resistance to knock needs the cooling less anyway

Yet again, thank you for that:

t'penny has dropped.