sorry I meant opal petrol

Submitted: Tuesday, May 18, 2021 at 21:37
ThreadID: 141778 Views:2093 Replies:11 FollowUps:13
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Hi guys what I meant is how does a 4.8 patrol run on opal petrol.cheers uppy
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Reply By: RMD - Tuesday, May 18, 2021 at 22:24

Tuesday, May 18, 2021 at 22:24
UPPY
Your engine will run on it, BUT, Your engine is designed for 95 octane and opal is 91 octane. Used carefully, no hard driving, it may accept the fuel without pinging/detonation. Low octane fuel 91 burns faster than 95 and therefore more susceptible, more likely to detonate under load. Such detonation is really explosions instead of burning in the cylinders and is to be avoided to prevent engine damage if it is continual.. Perhaps try your rig on std ulp to check it's actual tolerance with load/acceleration. The compression ratio is 10.8 so low octane fuel isn't advised unless the engine can electronically retard ignition to suit. Modern engines usually advance ignition until detonation is detected and so then retard to operate just under the detonation threshold. Not sure if it does ping/detonate will you hear it do it. Some engines definitely let you know with a crackling sound under load/acceleration, others detonate but not easily heard detected. I have no experience with patrol v8's so can't be any more accurate. They are thirsty camels.

EDIT.
I initially thought of the V8 which is 10.8comp ratio, the 4.8 is 9:1 so will accept the lower grade fuel better, ie, more tolerance to opal. You may have to slightly turn the distributor so it is initially less advance than std tune so the fuel doesn't detonate. As other below mentioned, if left in std tune position the detonation will/can wreck the engine. So, if you have to use the fuel. while using it less initial advance may help. If you are not able to accurately make the ignition timing changes it is more of a problem.
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Follow Up By: Member - John - Wednesday, May 19, 2021 at 11:30

Wednesday, May 19, 2021 at 11:30
RMD, no distributor on a 4.8. Electronically controlled.
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Follow Up By: uppy - Monday, May 24, 2021 at 20:35

Monday, May 24, 2021 at 20:35
thanks for taking the time to reply
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Reply By: Rangiephil - Wednesday, May 19, 2021 at 08:21

Wednesday, May 19, 2021 at 08:21
You could always add some octane booster.
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Reply By: Member - nickb "boab" - Wednesday, May 19, 2021 at 09:14

Wednesday, May 19, 2021 at 09:14
Majority of mechanics around Alice Springs would tell you not to use it !! Engine Destroyer.. is what they would tell you and only only as a last resort . The V8 petrol LandCruiser would run best on 98 when you can get it speaking from my experience .
Cheers Nick b
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Follow Up By: uppy - Monday, May 24, 2021 at 20:36

Monday, May 24, 2021 at 20:36
cheers thanks for the reply
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Reply By: Life Member - Woodsy - Wednesday, May 19, 2021 at 10:29

Wednesday, May 19, 2021 at 10:29
Hi Uppy, my experience
My Patrol is a 2011, 4.8 GU petrol auto. Great 4x4 and I love it
Since new it has averaged 20.51 l/100k, running on normal 91 unleaded
In 2016 after completing the Masters Games in Alice Springs I and my passenger travelled to Warburton WA to travel down the Connie Sue and then the Anne Beadell to Coober Pedy. We were towing an 8x4 trailer with one jerry can of fuel, 30l of water an extra spare wheel & camping gear. At this point the average fuel consumption was about 23 l/100k. At Warburton we filled with Opal and off we went.

After a few hours I noticed that the fuel level was dropping dramatically. We stopped and looked for fuel leaks etc but nothing was found.
After a night's sleep we decided that we would not be able to reach any fuel supplies either at Laverton or Ilkurlka so we decided to return to Warburton.
After refilling with Opal the calculated fuel consumption was on the part completed Connie Sue was 45l/100k.
We then continued Laverton without further problem and fuel consumption of 25l/k with Opal. We were able to refuel with unleaded at Laverton.

Previously I had travelled the Connie Sue from Warburton to Cocklebiddy in an unleaded GQ Patrol with a consumption of about 25l/100k.

No reason was found for this massive increase in fuel consumption so our guess was that the fairly poor highway? conditions caused the GU fuel computer to pour in heaps of Opal to get the power needed.

Hope this is of some help.
Happy 4 wheeling

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Follow Up By: RMD - Wednesday, May 19, 2021 at 12:09

Wednesday, May 19, 2021 at 12:09
Wow, 21 L/100 normally is only a little better than a 22 ton diesel coach I used to drive. 45l/100 is way worse than the coach. I wouldn't be able to afford the fuel costs for any outback trip.
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Reply By: Member - John - Wednesday, May 19, 2021 at 11:35

Wednesday, May 19, 2021 at 11:35
Uppy, 4.8's run best on 91, unless tuned for 95 or 98.

This is from the BP website. "Opal fuel has a minimum 91 octane rating and meets all the specifications for regular unleaded 91.
Opal fuel meets the National Fuel Quality Standards Act 2000 which provides the legislative basis for national fuel quality and fuel quality information standards for Australia."

So should not be a problem.
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Follow Up By: Member - nickb "boab" - Wednesday, May 19, 2021 at 20:27

Wednesday, May 19, 2021 at 20:27
Hmmm well you can't change the tuning on a 100 series v8 petrol ..
Toyota service department told me (in 2016) to use BP 98 & you will notice the difference.. at that stage i could agree .
Cheers Nick b
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Reply By: Life Member - Woodsy - Wednesday, May 19, 2021 at 14:57

Wednesday, May 19, 2021 at 14:57
Hi Uppy

My experience was a real experience and the extreme fuel useage with Opal fuel on a very poor Connie Sue highway was also real so please take care

If any of the ExplorOz members would like to help diagnose this problem I had let's talk here
Happy 4 wheeling

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Follow Up By: RMD - Thursday, May 20, 2021 at 09:35

Thursday, May 20, 2021 at 09:35
Woodsy
If a 4.8 normally runs on 91 and timed to do so then all ok. With the "Outback Experience" of using Opal which is said to be also 91 or better, the fuel which you received may have been stored for a while and much of the most volatile molecules had left the scene through evaporation in Aussie heat. That leaves lower volatile fractions of fuel to make up the fluid fuel you received. When used, MORE fuel has to be injected to make up the energy/power required to drive the vehicle forward. That may explain why very high fuel use. If there was any contamination in the fuel the OXY sensor may have received a blast of rubbish and not sensed OXYGEN levels very well. Most times they then cause the ECU to overfuel until the sensor is replaced or the crap is burnt off the sensor by long hot running. Just a thought.

Might also explain why some of the community folk think they have enough fuel to travel to see mates and find they run out somewhere and search parties then become involved.

If fuel has deteriorated through evaporation the fuel burning rate will be slower when ignited by the plug. That means the fuel is still burning when leaving the the cylinder, a bit like late spark timing, and so causes overheating and engine failures if extreme or driven hard while it is happening. Burns exhaust valves!

Any fuel which is still burning upon exit from cylinder is total lost fuel efficiency as that portion contributes nothing to gas expansion in the cylinder to push pistons. If the burn hasn't happened by 2/3 of downward piston travel, then in the last 1/3 or beyond nothing much is gained. All fuel should be burnt before exhaust valve opens. Best if it is!
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Reply By: Bazooka - Wednesday, May 19, 2021 at 17:15

Wednesday, May 19, 2021 at 17:15
Not really what you were asking about uppy but fwiw here's an earlier thread on unsubstantiated OPAL fuel problems.
Opal Fuel Warning

Generally speaking there's little benefit in using petrol with a higher RON than that recommended by the manufacturer. You could try some Opal then fill it with higher octane fuel if it pings.
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Follow Up By: RMD - Thursday, May 20, 2021 at 09:38

Thursday, May 20, 2021 at 09:38
Bazooka
When only OPAL is allowed out there, an owner cannot fill with a higher RON fuel because it isn't available.
Why? Sniff Sniff.
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Follow Up By: Bazooka - Thursday, May 20, 2021 at 10:19

Thursday, May 20, 2021 at 10:19
No kidding RMD. Not much call for swimming coaches for fish but if I come across a vacancy I'll let you know.
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Reply By: Member - nickb "boab" - Wednesday, May 19, 2021 at 20:34

Wednesday, May 19, 2021 at 20:34
Opal fuel
Cheers Nick b
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Reply By: Life Member - Woodsy - Thursday, May 20, 2021 at 09:50

Thursday, May 20, 2021 at 09:50
Hi RMD

Warburton appeared to be a fairly busy fuel stop so I am unsure about about it being old Opal fuel.

When I refilled with Opal after abandoning our Connie Sue trip our fuel consumption from there to Laverton halved (approx)

However I am open to all ideas
Happy 4 wheeling

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Reply By: Robin Miller - Thursday, May 20, 2021 at 14:46

Thursday, May 20, 2021 at 14:46
Had 3 4.8s Manual and currently an auto and all ran with little (5%) difference on Opal or 91/95/98 also.

Never had anywhere your 45lt figure - my most ever was 30lt hotfootingit across Simpson (Typ. 24lt).

Typical for us was Gunbarrel trip towing a lite trailer.
Ayers rock (full of opal) to Wiluna was about 1400km and used 21lt/100km.

Next section of trip was mostly highway to Geraldton using 18lt/100km.
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Reply By: Zippo - Thursday, May 20, 2021 at 18:10

Thursday, May 20, 2021 at 18:10
Short/simple answer: same as it does/would on "normal 91".

Whether that's good or bad is a separate matter, as is whether the Opal has any deleterious effects on the fuel system components themselves (as ethanol-added blends do on some vehicles).

I should add that I've only done a few thousand km on Opal (in a 91-specced vehicle). I'm anal about keeping accurate fuel usage/consumption records and have never been able to see any noticeable difference. As always "your mileage may vary" ...
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Follow Up By: Member - David M (SA) - Friday, May 21, 2021 at 11:07

Friday, May 21, 2021 at 11:07
G,day Zippo.
" I'm anal about keeping accurate fuel usage" May you someday, as I did after many years, reach the state of Nirvana re this problem. This consists of filling the tank and just driving off into the sunset. :)
Dave.
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Follow Up By: Member - Bigfish - Friday, May 21, 2021 at 13:08

Friday, May 21, 2021 at 13:08
Hahaha...I did exactly that for several years. Then I relised what a complete waste of time and effort. Now I couldnt care less about price or mileage. If the car needs diesel I just pull in and fill it up..
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Follow Up By: Zippo - Monday, May 24, 2021 at 19:37

Monday, May 24, 2021 at 19:37
I only do this while touring around remote country, not in the burbs. It serves to allow sensible range projection (and avoiding troubles) as well as warning of anything untoward in the engine behaviour. About of a third of that running was/is on Opal.

Elsewhere I do as you guys do, just fill and drive.
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Follow Up By: Bazooka - Wednesday, May 26, 2021 at 10:49

Wednesday, May 26, 2021 at 10:49
> About of a third of that running was/is on Opal.

And no engine destroyed Zippo? Amazing how myths can live on in this day and age of 'fingertip info'.
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Follow Up By: Zippo - Wednesday, May 26, 2021 at 19:31

Wednesday, May 26, 2021 at 19:31
Nah, still running on the same engine after four past trips around "Opal territory". Currently in Alice and heading back via GCR next week. [Maybe this trip Scotty will be right - "she's gonna blow, Captain".]
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