what mpg on lpg ???????

[chorley]

volvo v70 bi-fuel 2.4 ltr (2004)

what mpg should i expect to achieve running on lpg around town ???????

(at the moment im only getting 13 mpg )

no wonder im skint.

[classicswede]

What gearbox auto or man?

My T5 Auto on local driving and short runs is going around 16MPG but much better on a longer run.

I'm not sure what you should expect with twon driving. How old is teh thermostat? If it is stuck open end the engine takes a long time to warm up that would cause poor MPG but still drive perfectly fine

[DC850]

I have a 850 2.0ltr had LPG on it for 4.5 years and drive 110 miles per day. Since fitting done 123k (205K on car) I have always had aroung 23-24mpg so your 13mpg even with a large engine is poor. What do you get on petrol as I get around 28-30mpg with average driving.

[chorley]

its an automatic gearbox-- ive just been ringing round locally for a service quote
been quoted £220 +vat to service the lpg. also they said you cant get parts for 2004 fac/fit volvos, they are obsolete.

im thinking i might scrap it lol

[DXMachina]

DC850 and Classicswede both run cars which have aftermarket LPG systems - probably multi-point injection systems with a separate ECU which takes instruction from the petrol ECU

Your factory-fitted system was probably a Necam CGi made by Necam Koltec. It is essentially identical to the LPG system available in Vauxhalls. Its an older and cruder system and usually runs in open-loop mode, IE without reading sensor feedback and adjusting itself the way a well-adjusted fuel system does.

Searching this board for info on problems with Factory fitted LPG may be more useful than my recollections from a while of reading here

Also they were apparently known for causing valve seat recession through poor running, potentially your valves are leaking which would cause poor economy through loss of compression? (I'm guessing here)

That said, an auto box on a big engined car isnt an obvious route to good economy....

[classicswede]

God what are they going to do for £220+vat? Service should cost no more than £100

You can still get parts for the factory fit but they are expensive and you are often better off replacing with another system if anything major has failed.

[reggit]

My factory S60 auto returns about 25mpg on a run, obviously less around town (20ish but not checked).

The £220 sounds like the quote I had from F1 automotive 2 years ago to service/repair a factory fit corsa - it had a bust solenoid that for love nor money I couldn't get undone.

Run yours on petrol for a tank around town and compare the consumption figures. I'd expect the same + 10%ish mpg on petrol.

[DC850]

Yes DXMachina mine is a after marked Prims system and does take the initial timings from the standard ECU and then modified by the LPG ECU just as you said.

And by the way my 850 is an Auto also and still get 23mpg without a light foot.

[BrianH]

The Groot open loop went in on a B200E engine at 155k miles. This usually did 20 to 21 mpg.

I rebuilt the evaporater at about 350k with a kit that cost me £34 (mostly gaskets and o rings). One burnt exhaust valve at 403k

Replaced B200E (1986cc) with a B230E second-hand with 127k recorded (2316cc) engine at 495k and mpg went to 23.5mpg. The performance and manners are a lot better.

Alway runs 100% gas.

Love it.

BrianH 512k

[The Thong]

I have a BRC system. If I keep off the looney pedal I can get 27mpg on my 2ltr Auto S60 but on average I get 24mpg. I have been quoted £140 inc vat to service my system, someone's having you on mate.

TT