LPG V Petrol performance figures

Submitted: Monday, May 05, 2008 at 21:29
ThreadID: 57312 Views:5089 Replies:11 FollowUps:8
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I promised this weeks ago and here are the results.


-4L V6 Manual Ford Courier fitted with "Parnell Sequential LPG"

-Against the stopwatch the car goes ffom 60 to 100 (in third gear): 6.9 sec on LPG and 7.8 sec on LPG.

That is huge. Whilst I'm happy with the fuel saving, The Seq LPG is supposed to be better than that.

I suppose it needs expert adjustment/tuning. Are you reading this Erfic???


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Reply By: Mainey (wa) - Monday, May 05, 2008 at 21:44

Monday, May 05, 2008 at 21:44
you say:-> ""Against the stopwatch the car goes from 60 to 100 (in third gear): 6.9 sec on LPG and 7.8 sec on LPG""

How does LPG compare to Petrol ??

So what is the low down torque like at low revs replicating the use in towing a load at normal road speed.

Mainey . . .
AnswerID: 302230

Follow Up By: Best Off Road - Tuesday, May 06, 2008 at 07:12

Tuesday, May 06, 2008 at 07:12

Oops, should have been 6.9 on ULP.

When I find time with the camper on the back I'll do the numbers again. It's bloody hard slowing to 60 on a Melbourne Freeway without upsetting people LOL.

I went for the 60 to 100 in third as 60 in third is quite low in the rev range and it was a torque exercise, as even at 100 in third it still hadn't hit the peak kW output.


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Reply By: PajeroTD - Tuesday, May 06, 2008 at 03:41

Tuesday, May 06, 2008 at 03:41
I think we should be going to CNG. It's like 15c per litre, doesn't come from oil, it's more abundant, cleaner burning, and doesn't need to be transported by trucks. Plus you can install your own pump at home, it doesn't substitute for food as corn grown ethanol does. It's only downside seems to be it is non-renewable, and not quite as emissions friendly as hydrogen.
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Follow Up By: Member - Davoe (Yalgoo) - Tuesday, May 06, 2008 at 18:09

Tuesday, May 06, 2008 at 18:09
Imagine that being fuel sufficient for the next 100 years (if we wernt flogging it all off to china. Would need a fair bit of infrastucture pluss a few hurdles but the benifits would be immense
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Reply By: Krakka - Tuesday, May 06, 2008 at 05:15

Tuesday, May 06, 2008 at 05:15
Yeah Jim, Very useful figures in the Simpson Desert, or anywhere offroad.
My Ferrari does................................................................
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Reply By: Best Off Road - Tuesday, May 06, 2008 at 07:14

Tuesday, May 06, 2008 at 07:14

Original post should have read 6.9 seconds on ULP.

Thanks Mainey.


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Reply By: Top End Explorer Tours - Tuesday, May 06, 2008 at 09:25

Tuesday, May 06, 2008 at 09:25
Whoo Hoo internet drag racing.

I just did a drag race in the TD 100 series (on my own) (in 3rd) I didn't have a stop watch I counted 1001 1002 etc, a I went from 60 to 100 before I finished 1005, by the way the aircon was on as well.

Hey Roachie do you want to line up the Chevnissan.

Cheers Steve.
AnswerID: 302284

Follow Up By: stefan P (Penrith NSW) - Tuesday, May 06, 2008 at 17:05

Tuesday, May 06, 2008 at 17:05
Yeah well thats nothing!!!!!

I started this test on the way to work this morning in the POWER HOUSE 2.8 Patrol........and I'll let you know the results when it gets to a 100.....LOL

Cheers Stefan
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Reply By: Member - Barnesy - Tuesday, May 06, 2008 at 10:04

Tuesday, May 06, 2008 at 10:04
Thanks for that totally useless info Jim. That 0.9 of a second would influence a lot including..............well nothing!

Time with a stopwatch the extra time you spend filling up at the bowser with lpg and factor that in. Do it when towing the CT out bush using lpg and then do the same with somebody elses diesel. Don't forget to include the number of times needed to fill up lpg versus a diesel tank.

That would be the only time a diesel looks fast when time spent at the bowser it factored in!

AnswerID: 302289

Reply By: Best Off Road - Tuesday, May 06, 2008 at 10:36

Tuesday, May 06, 2008 at 10:36
The purpose of the post was this.

Those who are intereted in LPG often ask how well a vehicle performs on LPG and what influence it has on consumption.

Also the latest Sequential Injection System is purported to perform as well as ULP. Mine isn't.

I have previously posted that consumption seems to be up by about 10% and I can now state that based on my performance test, power is down by, say, 10-15%.

I will now endeavour to have it expert tuned to see if the suggested figures are achievable. I will then report again FOR THOSE WHO ARE INTERESTED.


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Follow Up By: John S (NSW) - Friday, May 30, 2008 at 05:08

Friday, May 30, 2008 at 05:08

Good to see that you are still keen on LPG perfection. Most people don't get that once LPG is setup properly, it can return savings of more than 35% irrespective of how hard you drive and how loaded your vehicle is.

Even with seq injection, LPG is still sluggish under 2500rpm.

LPG fuel consumption will always be a bit higher than ULP - this comes down to the octane ratings.

LPG, if setup properly and tuned properly can and will produce more power than ULP.

Different brands of LPG will give you different consumption and power figures. For us, Shell LPG seems to be the best brand for our AU Falcon. My WB V8 ute is less fussy and doesn't seem to care what brand is runs on, as it's consumption and power is almost constant on every brand.

CNG is just Natural Gas. LPG vehicles can easily be modified to run CNG. The cost per litre is really cheap, but your consumption is very high compared to other fuels including LPG. I researched this a few years ago, 100ltrs of CNG will get you around 200kms. This is a Metro only fuel solution due to this limited range per tank.

LPG starts its life as CNG, then its refined further to produce the final product. Both LPG & CNG are by products on oil refining.

So before I get roasted over this let me say that, each fuel has its place. I use LPG for my city and highway vehicles as this tends to be the highest area of my running costs, and ULP only in my Cruiser for offroad - I didn't get a diesel Crusier due to vehicle cost and the fact that diesel still can't give you instant power which I prefer as we do alot of high country/mountain driving. I know my consumption is higher than diesels, but that is my choice and I am happy to pay for it at the pump.
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Reply By: Philip A - Tuesday, May 06, 2008 at 11:33

Tuesday, May 06, 2008 at 11:33
Thanks for your useful post.
a bit better than
"I can't notice any difference"
I wonder how they can optimise the ignition timing on modern ECU controlled engines to take advantage of LPG slower burn time. In your case it seems the fitter didn't.
Regards Philip A
AnswerID: 302298

Follow Up By: Member - Tour Boy Springsure- Tuesday, May 06, 2008 at 16:26

Tuesday, May 06, 2008 at 16:26
Hi all,
You can get dual mapped aftermarket chips for all petrol/gas vehicles so that they run at the optimum on both.
2010 Isuzu FTS800 Expedition camper
2015 Fortuner
Had 72 cruisers in my time

Lifetime Member
My Profile  My Blog  Send Message
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FollowupID: 568370

Reply By: Member - Warfer (VIC) - Tuesday, May 06, 2008 at 13:46

Tuesday, May 06, 2008 at 13:46
How do you expect me to keep up Jim when we go 4wd ! lol
Let me guess an hours head start..

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Reply By: Member - Serg (VIC) - Tuesday, May 06, 2008 at 14:15

Tuesday, May 06, 2008 at 14:15

Confess to us, you love to have diesel, but either cannot afford one or your missus does not like it smell :-)))))

Seriously though I do not know what are “Parnell Sequential LPG” and “The Seq LPG”, but what I do know that direct LPG injection may outperform ULP depending on setup. Do not expect huge savings on fuel though because it consumes much more LPG then ULP. And nothing can be done about this because energy stored in LPG less then in ULP, while diesel has highest one – main reason diesel consumes less then petrol. Some questions remains – run from single tank and engine longevity without special LPG-related valve lubrication found in some factory LPG engines.

AnswerID: 302325

Follow Up By: Tippa - Wednesday, May 21, 2008 at 18:10

Wednesday, May 21, 2008 at 18:10
My 80 series cruiser averaged 16L/100 easy fwy/city driving. I recently had electronic gas injection fitted and it now uses 20L/100kms with similar driving. So you are right, it does use more (not much though!) but with gas costing 62c instead of $1.59, it now litterally costs half to drive if not less than half. Absolutely massive saving with no power loss.
Also get more range too since i never got 400kms out of my sub tank which it replaced!
Extra time spent pumping the gas gives me enough time to clean the windscreen before it auto shut-offs. Best thing i ever did for a truck which spends 80% of its life on the blacktop.
Especially since it still has more power and more torque than a TD, and is cheaper to run. (waiting bites ha ha).
Just my 2c!
FollowupID: 571121

Follow Up By: Member - Serg (VIC) - Friday, May 23, 2008 at 09:03

Friday, May 23, 2008 at 09:03
I have a look at numbers and find out that petrol contains about 1.2 more energy per volume compared to LPG (I thought that it much bigger difference). So theoretically speaking in ideal situation car that consume 16L of petrol should consume 19.2L of LPG to perform similar. Thus your numbers looks to me very right. Therefore my previous statement about “much more” not that related to proper installation, but rather to simplified one where gas injected into inlet manifold.

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Reply By: Tippa - Thursday, May 22, 2008 at 22:02

Thursday, May 22, 2008 at 22:02
Just have to update my previous figures... gas gets 400kms from 70 or so L so it comes in at 16L/100 which is the same as ULP. Guess its the new ECU controled injected gas systems which have made them so efficient (20% increase over previous systems). So no, you dont burn more gas than ULP, and gas is 60% cheaper. So the savings are directly relevent to the price of gas compared to ULP... 62c compared to $1.60.
AnswerID: 305365

Follow Up By: Tippa - Thursday, May 29, 2008 at 22:45

Thursday, May 29, 2008 at 22:45
But when we are talking over such small differences, the difference can be how you use your right foot.... Power is similar and economy is about the same, so its pretty much comparing price at the pump as to the savings as i mentioned, give or take.
Still, i'd have a multivalve TD anyday for the range and fuel availability in remote locations...
FollowupID: 572580

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