Fuel Economy

[marynamo]

I have to admit I never heard of lpg in cars before joining the forum. Never seen it at a fuel station in South Africa either.

 

[SQUIZ]

I have to admit I never heard of lpg in cars before joining the forum. Never seen it at a fuel station in South Africa either.

Fuel is cheap in S.A. compared to europe so no real need for LPG. I used to live in Springs many years ago.

 

[Lpgc]

I think the best thing to get the maximum mpg is to put something like Redex fuel cleaner into your tank it's proved to work. I only do town work and in the summer I roughly get 21 miles to the gallon in winter it goes down to 18 to the gallon and that's not taking it particularly easy. I haven't done any long runs yet so I can't comment on that.
Watch the video give you some insight.
If you have never used it put twice as much in a couple of tank fill don't expect it to work straightaway it will take time but it's definitely worth doing.

The vid made it look as though they poured the stuff in the tank, put the car straight back on the rolling road and saw immediate results... but the stuff would need to go through the injectors (meaning best part of a tank of fuel would need to be used between rolling road tests) for the stuff to be able to go through injectors and have any effect on injectors anyway. By the time a tank of fuel had been used other variables (including weather) could make more of a difference to bhp than the cleaner did. Petrol injector cleaning potions can work (and the trade has better ones than Redex) but I reckon they intentionally picked a car which they knew had slightly gummed injectors ('when I previously tested this car I noticed it had hesitation between 3000/4000 rpm, but the hesitation seems to have gone now') and knew injector cleaner would have a good chance of working on that specific car. When injector cleaning potions don't work ultrasonic cleaning can, when that doesn't work you're looking at new injectors. The trade wouldn't add a bottle to a full tank, would wait until the tank was nearly empty, add to the tank and go for a blast to concentrate the potion going through injectors - Wouldn't expect the potion to have that much effect except for on a car where injectors were known to be gummed / spray pattern off, where cleaning potions have best chance of improving matters.

 

[marynamo]

Fuel is cheap in S.A. compared to europe so no real need for LPG. I used to live in Springs many years ago.

How much is petrol there? Next month it will be more than R17 per litre here.

 

[Harvo]

How much is petrol there? Next month it will be more than R17 per litre here.

Averaging at £1.30 for petrol.

 

[marynamo]

Averaging at £1.30 for petrol.

Oh gosh ouch.

 

[Easy Rider]

I have been told locally by quite a big garage that when a vehicle is converted to LPG it causes more heat in the engine which was originally designed to run on petrol and This extra heating contributes to the catalytic breakdown. Is this potentially correct? (Im only asking!!)

 

[George322]

I used some ZX1 on mine some time ago. I gave my kids a bottle to use on their cars too.
It won't affect the valve seats for the reasons that Simon has mentioned, but adding it to the gearbox, the engine oil and the water pump should give some protection from wear.
http://www.team-zx1.com/

 

[Lpgc]

I have been told locally by quite a big garage that when a vehicle is converted to LPG it causes more heat in the engine which was originally designed to run on petrol and This extra heating contributes to the catalytic breakdown. Is this potentially correct? (Im only asking!!)

Most Elgrands that suffered cat problems on this forum only ever ran on petrol (were not even LPG converted).
Cats have to be above a certain temperature to even work, when they are working (doing their job as normal) the catalytic action creates more heat (so the cats effectively get hotter than the exhaust gas that feeds them anyway). One of the biggest factors effecting how hot the cats get is contents of the exhaust gas feeding them, regardless of what fuel the engine is running on the cats get hotter the richer the engine mixture and the more exhaust gas that goes through them (more you put your foot down).
If cats get too hot they will fail - But overheated cats doesn't seem to be the usual cause of Elgrand cat problems... They break anyway.

Edit - On Elgrands the cat issue is different to on the majority of other vehicles that suffer cat problems. Elgrands have 4 cats - 2 at the front in the exhaust downpipes (usual place for cats) and 2 a bit further back in the exhaust (so one cat feeds into another - which is an unusual setup). The issue on Elgrands is that any debris from front cats (if/when the front cats start to break up) the debris then clogs up the entrance to the rear cats (entrance to hundreds of very narrow tubes through which exhaust gasses are supposed to pass) making it very difficult for exhaust gasses to escape and leading to lots of exhaust back pressure (and even hotter front cats, which will cause remaining intact bits of front cats to break up even faster)... and under these conditions cat debris can then make it's way into the engine.

 

[Easy Rider]

Most Elgrands that suffered cat problems on this forum only ever ran on petrol (were not even LPG converted).
Cats have to be above a certain temperature to even work, when they are working (doing their job as normal) the catalytic action creates more heat (so the cats effectively get hotter than the exhaust gas that feeds them anyway). One of the biggest factors effecting how hot the cats get is contents of the exhaust gas feeding them, regardless of what fuel the engine is running on the cats get hotter the richer the engine mixture and the more exhaust gas that goes through them.
If cats get too hot they will fail - But overheated cats doesn't seem to be the usual cause of Elgrand cat problems.

Thanks for that @Lpgc ;-)

 

[Eltuese]

Expect poor economy. Really. I'm not gonna lie to you.

They are a 2 tonne bus with pretty appalling aerodynamics and large engines. They are designed for comfort and luxury, not for cheap motoring.

As a brief run down:

E50 QD32 3.2 Diesel - 26mpg average. 18mpg around the doors. 36mpg on long runs at 55.

E50 ZD30 3.0 Diesel - 28mpg average. 20mpg around the doors. 40mpg on long runs at 55.

E50 VG33 3.3 V6 - 18mpg average. 14mpg around the doors. 28mpg on long runs at 55.

E50 VQ35 3.5 V6 - 16mpg average. 12mpg around the doors. 28mpg on long runs at 55.

E51 VQ25 2.5 V6 - 22mpg average. 18mpg around the doors. 32mpg on long runs at 55.

E51 VQ35 3.5 V6 - 20mpg average. 16mpg around the doors. 30mpg on long runs at 55.

These are worst case scenarios. If you are getting less than this, you have a problem (either with your engine or your right foot). If you go into buying an Elgrand with these figures in mind, then you won't be swearing 6 months down the line when you are on first name terms with every petrol station attendant within 30 miles of your house.

Thanks for the information

 

[Robbo]

Has anyone got a picture of a front catalyst without heat shield? I'm wondering just how restrictive they are and if replacing them with sport cats nets an economy improvement.
Don't want a bigger exhaust, just better efficiency.

 

[Ralph Barnett]

We converted our E50 to LPG as soon as we bought it three years ago and having done appx 30k miles since then we are now out of the pay back and into the Profit phase. We got there sooner than expected as although we also had it converted to a camper I use as a day van cos I just love driving it. Overall our total outlay still makes it a far more cost effective option than a VW equivalent and I really like the quirkyness and sense of being part of something a bit different.

 

[SQUIZ]

How much is petrol there? Next month it will be more than R17 per litre here.

R17 per litre is roughly equal to 90 pence and we are paying £1.40 for premium unleaded ouch !!!

 

[dave_s13]

Yeah but. We don't need to put premium in so its more like 1.30

 

[Lpgc]

Either Premium or Super. Should beg the question where is the Basic option... but we know Premium is really the Basic option. Bit like at fast food outfits where you can only buy medium or large, nothing is described as small, kids size is Happy. Even supermarkets are moving away from calling stuff Basic / Value now.

 

[ReidBenner]

Any feedback from E51 owners in Canada? I would guess 91 octane would be sufficient for the VQ35.

 

[SQUIZ]

Yeah but. We don't need to put premium in so its more like 1.30

I go for the higher octane on a refill . I get the same miles for the same amount of cash so why use lower octane unleaded ?

 

[Andy700]

I wasn't expecting much for fuel economy, and so far I've pretty much exclusively made short trips through town, plus I've been getting excited and sticking my foot down now and again, just to test it obviously, but my fuel economy seems lower than I was expecting. It's reading 3.6km/l, which is really 3.6m/l, which works out at about 16.4mpg. However the chipped speedo reads a few miles faster than sat nav reality, maybe up to 10% out, so I could be covering even less ground than the van thinks I am, which would put me more around 15mpg! Although if it's just a misaligned needle that wouldn't be the case.

 

[Cemmy074]

I have been told locally by quite a big garage that when a vehicle is converted to LPG it causes more heat in the engine which was originally designed to run on petrol and This extra heating contributes to the catalytic breakdown. Is this potentially correct? (Im only asking!!)

Yes only %5 heat more