Fuel

Engine, Exhaust, Drivetrain, ECU Issues and Fixes
John_M
Posts: 353
Joined: Sat Jan 21, 2017 9:43 am

Fuel

Post by John_M » Mon May 01, 2017 11:41 pm

I remember reading a review by Porsche years ago on high quality fuels v ordinary stuff. They reckoned there would be no difference in performance because the on-board computers would analyse the burn and adjust all settings as required. They firmly believed that there was no performance advantage to be gained.

I am not sure whether there was much difference in performance - but I found one car would run rougher when I filled up at some garages, so I stopped using supermarket and some local garages and used the local BP or Shell ones and it run far more consistently smoothly (I do recall having to fill up once from local Esso garage and it run badly until I filled up again).

I often wondered whether more than the additives whether there were other factors like condition of tanks, amount of turnover of garage's stock that were causing issues.

When I got a diesel (because of 20k commute) I continued until I moved and there was no sensibly located Shell or BP garage on route so started using supermarket stuff and tbh couldn't tell the difference.


goron59
Posts: 5368
Joined: Sun Aug 09, 2015 10:15 am

Fuel

Post by goron59 » Tue May 02, 2017 12:04 am

Interesting. As the macan manual taylks about using 98 RON fuel, and not 95 RON if you can avoid it. So odd that they'd say the car will be happy with whatever fuel!

Either way, we're feeding our GTS with premium as its what we've put in all our cars! shell V power does seem to give the cars a little more oof, but could be nothing!


I wouldn't say "happy" as such.

The engine management system has knock and other sensors so can use as little as 95 without issue, but is designed to work best with higher rating. How high, I don't know. I know previous cars have been particular frisky with 102RON but others seemed indifferent to it.

The additives in more expensive fuels is nice for those that keep their cars for more than 5 minutes (or the second owners).

And fuel from cheapo supermarkets might "come from the same hole in the ground" but the way it's treated/transported/stored/delivered can be quite different.
2016 Macan Turbo PHCKCL70


User avatar
jesim1
Posts: 287
Joined: Mon Dec 29, 2014 10:26 pm
Location: Nr Wigan

Fuel

Post by jesim1 » Tue May 02, 2017 2:25 am

It's hard to tell just how much of this is our thoughts rather than actual real data? I remember watching 5th gear do a thing on premium fuel (petrol) and they concluded over five fuels they tried that a couple made a measurable, but unfeelable difference in performance - about a couple of percent - but it did not justify the cost.

I use whatever diesel I'm close to at the time after trying a back to back full tank premium diesel against the cheapest supermarket stuff I could find and I could not notice any difference at all - my car has certainly never ran "rough" as some people suggest?

James
Functional & fun, ooh err missus: http://www.porsche-code.com/PGCJ9I91


User avatar
Ray G
Posts: 201
Joined: Wed Feb 10, 2016 11:45 am

Fuel

Post by Ray G » Tue May 02, 2017 8:10 am

For some reason best known to Esso, "synergie" is rated at 97 RON" but mine runs just fine on that from my local station

Off to France / Belgium (Spa) at the end of the month so not quite sure what I'll be able to find....it'll be interesting to see if I can feel any difference whatsoever, and if the mpg is noticeably different.


If they quote 97 then that is probably what it is. Esso tend to try to source their own production in the UK as much as possible (from Fawley) but exchange fuel where distribution costs can be reduced. They possibly supply 98 octane to the higher grade tanks then mix 98 with 95 (2/1) to get the advertised 97 octane.
Previous: Cayenne D then Cayenne S petrol
Current: Macan S Diesel VG


Kasfranks99
Posts: 2350
Joined: Thu Jul 28, 2016 8:38 pm

Fuel

Post by Kasfranks99 » Tue May 02, 2017 8:37 am

I have only used BP ultimate and only at a petrol station that has high turnover.
That was advice I have read up and given by a few people to use high turnover petrol stations.

BP ultimate has been very smooth indeed in all my cars.
GTS 😀


User avatar
Ray G
Posts: 201
Joined: Wed Feb 10, 2016 11:45 am

Fuel

Post by Ray G » Tue May 02, 2017 9:15 am

I remember reading a review by Porsche years ago on high quality fuels v ordinary stuff. They reckoned there would be no difference in performance because the on-board computers would analyse the burn and adjust all settings as required. They firmly believed that there was no performance advantage to be gained.

After all, it comes out of the same hole in the ground, it's just the additives that make the difference.


The engine management system will adjust to whatever fuel is supplied...but 98 gives higher output so should give better performance.

Have to correct the second statement: It does not come out of the same hole in the ground. Crude oil and gas is formed from dead sea creatures, underground and under intense pressure and temperature (coal is formed from dead plants). Crude oils that come from different parts of the world differ in both density and sulphur (and a host of other less important qualities). A quote:

"The variety of oils sometime seems as variable as the minds of man. Each source rock is unique and can vary geographically as well as geologically across it's extent. The kerogen (pre-oil) contained within these rocks have a chemistry determined by the origin of the organics originally buried millennia ago. A second influence is the chemical makeup of the rock.
One of the main differences is sweet and sour crude. Sour crude usually originates in a carbonate prone source which contributes the materials, usually sulphur, necessary for H2S or other compounds found in sour crude.
Another is the 'weight' of the hydrocarbon. It varies from a near pure methane gas to a bitumen thicker than the tar used to build roads. Much of this is caused by the orininal organic composition but further complicated by the heat and time acting on that material.
The higher prices go to lighter oils mostly found in the North Sea, Africa and the Gulf of Mexico. The Canadian oil sands are much thicker and therefore less valuable all the way around - higher production, transportation and refining costs."

If you then add into the mix the type of refinery used to process the crude oil (with/without reformers, cat-crackers, hydro-crackers, thermal crackers, isomers, with/without chemical plants etc) then the petrol produced can vary enormously...even within the constraints of high EU specifications.

Add to that the proprietary additives and you finally get the petrol you want...or not!
Previous: Cayenne D then Cayenne S petrol
Current: Macan S Diesel VG


User avatar
VanB
Posts: 2602
Joined: Wed Sep 21, 2016 6:58 pm

Fuel

Post by VanB » Tue May 02, 2017 9:31 am

I have no idea whether the premium fuels improve performance or not but I do know that the manual says 98 RON is the preferred choice and having spent the amount I did on the car that's what I'm going to feed it.

I also suspect the additives in premium fuels are likely to benefit the engine over the longer term so worth the few ppl extra
Current - 991.2 GTS C4 GT Silver
Previous: Macan GTS Night Blue
Previous: 981 Cayman S Agate


User avatar
Ray G
Posts: 201
Joined: Wed Feb 10, 2016 11:45 am

Fuel

Post by Ray G » Tue May 02, 2017 10:19 am

Previous: Cayenne D then Cayenne S petrol
Current: Macan S Diesel VG


User avatar
Mistertoad
Posts: 1378
Joined: Thu Mar 06, 2014 9:52 am
Location: West Sussex

Fuel

Post by Mistertoad » Tue May 02, 2017 10:39 am

BP ultimate is 97 RON. Tesco Momentum is 99 Ron. Perhaps refuelling alternatively with cooking then premium might be the best compromise. Assuming the need to save a few pennies.
2015 Cayenne S - Sold
2016 718 Boxster - Sold
2016 Bentley Continental GT V8 S


User avatar
Tim92gts
Posts: 350
Joined: Wed Dec 28, 2016 6:01 pm
Location: Essex

Fuel

Post by Tim92gts » Tue May 02, 2017 3:36 pm

I have no idea whether the premium fuels improve performance or not but I do know that the manual says 98 RON is the preferred choice and having spent the amount I did on the car that's what I'm going to feed it.

I also suspect the additives in premium fuels are likely to benefit the engine over the longer term so worth the few ppl extra


If the knock prevention is still by retarding the ignition a touch you'd expect the higher quality fuel to allow slightly more advance of the order of two degrees.
This tends to give a bit more power at high rpm.
I think the systems respond if the sensors detect more than one knock per 10,000 or so, YMMV obviously.

Tim
PP Turbo, LED PTV ACC Pano 20"Macans collected 6th September
1992 928GTS
2003 996 Cab


Post Reply

Return to “Engine and Drivetrain”