Fuel question for older Porga

[cyberpunky]

One of my friends complained how much fuel he was using in his vehicle going to his holiday house on weekends. He was using a tank + another third of a tank on the trip. I suggested he try 98 and he did and came back with a quarter of a tank. The was a vito MB van so would have engine management and yes it is anecdotal but it was a huge difference on a trip he did all the time. I know with my old car if I went below 95 to 91 it pinged it's head off but with 95 was purring like a kitten  

[Uncle]

My owners manual says 91 at a minimum

 

I've placed the relevant part in bold. At a minimum means just that. The very least. Not the best you can do but the least you can do. I am not saying you are going to get 197 more kilometres out of a tank. But you will see an improvement over 91RON in a trial/sample batch of at least 5 tanks.

 

Take my new fangeled wiz bang old XR6T (with granted knock sensors). Driven by my wife who would never see any boost at all. She would go to a servo and fill up with anything that was cheap no matter what I told her. The car would always get 410klms from 50 ltrs. Like clockwork. So I took it upon myself to make sure I filled the car every Sunday before her 380klm weekly commute. Sure enough after getting the rubbish fuel out of the system I would see 450 to 460klms to a tank. This is over a one year time frame and not just the odd tank. 

My point is she would never see any boost so knock sensors do not come into play. This would also come up in an OBD scan that I ran on the car before I sold it.

 

Subjective storys aside I'll put this as simply as I can.

You can run more advance with better IE higher RON fuel. More advance (and yes your 911 has a set maximum advance point) will make more power. The easier it is to make said power even by an almost imperceptible amount the easier it is for the engine to move the mass. 

Let me be clear. The RON rating of fuel is not the single key to more power and in this case more klm's per litre. You need to be able to take advantage of spark timing and flame propagation for it to have any benefit. 

Now look at the photo of my old distributor. Note two things. See that diaphragm at the bottom of it without the hose on it? Thats for the Vacuum advance. Thats right Porsche put that on there to advance the timing under vacuum load. IE higher RPM why I hear you say. Well so you could make a little more power! How nice of the good chaps. 

Next look at the stud poking up in the curved slot. This little fella will allow you to adjust the overall advance you are running on the motor. So if your a clever chook,want a little free power and have some time on your hands you can fiddle with it and a timing light. If you are not running rubbish fuel your motor won't detonate (well to a point it won't) and hey presto good things come to those who look for them. Now remember you won't have a knock sensor to hold your hand so don't get crazy or its going to cost you a lot of money in melted pistons or bent rods. 

 

 

 

Sorry to get off track D but it is an interesting subject. 

 

Same here for the hair D!

[JustJames]

I find if I adjust my tin foil hat correctly it covers up the damage done by the chem trails.

Question is, am I overly advanced, or just a teensy bit retarded?

[tazzieman]

, but it did back up the notion that cheap fuel is more expensive than the good stuff.

Notions , gut feelings, pub stories...gotta love 'em! Remember , the first rule of marketing (fuel , additives , vitamins , cars, muscles , beauty etc) is to create anxiety or the feeling that the user is inferior to others...then let human emotions run riot.

This is about a stock '78 low compression 911. It does not need fuel additives or other magic. The German engineers of the 70s drew on plenty of scientific knowledge . It's quite simple and unless you're a serious racer , get the engine tuned up  & change the oil often and it will give decades of good service. If you abuse it , well not many have got the $20k rainy day cash for a rebuild. 

 

http://wiki.answers.com/Q/Will_using_a_higher_octane_fuel_increase_the_car's_miles-per-gallon_rate

 

I don't quote wiki on the basis that it's full of complicated science - just accessible by most and fairly well peer reviewed.

 

http://abauerporsche.wordpress.com/2011/02/28/higher-octane-fuel-is-it-worth-it/

 

High octane does not give your car better gas mileage

[Doish13]

Awesome play with words and gents, while this has gone back and forth it has been informative.

In short - standard fuel is better for the valves etc however not the stuff with sugar cane added and PULP is also good as it give good mileage however, you may or may not then want to add a lead additive. Chem trails are bad and is making Uncle and I go bald while JJ struts around the northern suburbs with a hub cap on his head.

[SteveT]

So as I advance in years and get closer to eventual detonation, can I rely on high octane fluids to retard my knocked out senselessness?

[Harvs11]

So, are we all just heading towards a state of advanced retardedness? 

[JustJames]

Notions , gut feelings, pub stories...gotta love 'em! Remember , the first rule of marketing (fuel , additives , vitamins , cars, muscles , beauty etc) is to create anxiety or the feeling that the user is inferior to others...then let human emotions run riot.

This is about a stock '78 low compression 911. It does not need fuel additives or other magic. The German engineers of the 70s drew on plenty of scientific knowledge . It's quite simple and unless you're a serious racer , get the engine tuned up  & change the oil often and it will give decades of good service. If you abuse it , well not many have got the $20k rainy day cash for a rebuild. 

 

http://wiki.answers.com/Q/Will_using_a_higher_octane_fuel_increase_the_car's_miles-per-gallon_rate

 

I don't quote wiki on the basis that it's full of complicated science - just accessible by most and fairly well peer reviewed.

 

http://abauerporsche.wordpress.com/2011/02/28/higher-octane-fuel-is-it-worth-it/

 

Tazzie, there's only one thing to do.

 

Try some of the full fat high caffeine stuff in your car.  It may not do any good, it's true, but it won't do any harm and it won't cost much.

 

Try it for a tank or two and see if it makes any difference.

 

The worst that can happen is that you could add to the body of unreliable anecdotal evidence out there.  

[Uncle]

Knock on wood!

[tazzieman]

Tazzie, there's only one thing to do.

 

Try some of the full fat high caffeine stuff in your car.  It may not do any good, it's true, but it won't do any harm and it won't cost much.

 

Try it for a tank or two and see if it makes any difference.

 

The worst that can happen is that you could add to the body of unreliable anecdotal evidence out there.  

The cost is irrelevant ; I'd pay $3/l to keep the car running on a day to day basis.

I used 98 for 18 months and switched to 95 then regular. There was no "appreciable" difference and yes that included track days on both. If I was chasing economy , I'd heed Mr Sensible Motorist and use higher tyre pressures , thinner oil (Russian roulette for some) and a soft right boot - using the brakes as little as possible.. If I worried about economy I'd buy a Prius , act all greenie and certainly not own a old S3 Landrover 

[tazzieman]

Knock on wood!

Dendrochronology is a fascinating pastime!

[Harvs11]

The cost is irrelevant ; I'd pay $3/l to keep the car running on a day to day basis.

I used 98 for 18 months and switched to 95 then regular. There was no "appreciable" difference and yes that included track days on both. If I was chasing economy , I'd heed Mr Sensible Motorist and use higher tyre pressures , thinner oil (Russian roulette for some) and a soft right boot - using the brakes as little as possible.. If I worried about economy I'd buy a Prius , act all greenie and certainly not own a old S3 Landrover 

Tazzieman, you're a greenie and you just don't know it.  Rather than contributing to the energy spend of producing a new car like a Prius or new Landy you are recycling the old cars.

[tazzieman]

Tazzieman, you're a greenie and you just don't know it.  Rather than contributing to the energy spend of producing a new car like a Prius or new Landy you are recycling the old cars.

I grow my own vegetables and generate my own bodyheat as well. There's a lot people don't know about me but it's there on the interwebs. 

[Uncle]

I am doing my part by getting rid of all this old oil before it gets spilt on a beach or some such place.

[tazzieman]

I am doing my part by getting rid of all this old oil before it gets spilt on a beach or some such place.

Highly responsible attitude and when you think about it , our beaches are easily amongst the best in the world. Keep those tankers away from the GBR though.

When the LR gets a diesel (eventually and probably a 200)) I'll be reusing the fat from my deep fryer in a further extension to get off the grid..

I don't buy into the marketing schtick of modern cars http://environment.about.com/od/environmentfriendlyautos/a/new_old_cars.htm Why spend on marketing when you can spend the difference on fuel!

[Coastr]

This is all very interesting, but does not answer the age-old question.  Which develops the most passionate arguments - fuel octanes and additives, or oil viscosity and additives?

[tazzieman]

This is all very interesting, but does not answer the age-old question.  Which develops the most passionate arguments - fuel octanes and additives, or oil viscosity and additives?

Well science is about reproducible fact and religion is based on beliefs. When is a discussion an argument? When emotion takes over! 

[wasserkuhl]

Oil is like religion, believe and use whatever you think makes sense(To you or to someone who does your thinking for you)

 

Same goes for Fuel.

 

I use 98 Octane BP Ultimate in all 3 Porsches and they all run well on it.

 

I used some 91 in the Carrera 3.0 for a couple of tanks but went back to 98 as, if anything , it felt better and did get better economy, by a small margin I would suspect. Performance gain would be NIL.

 

Is 98 Better for your older Porsche engine? YES. Does it need it? NO.

 

Do you need to add an additive to avoid valves being mashed up against their seats? Only on pre '86 Water cooled Porsches. Air cooleds do have hardened valve seats in them so Unleaded works just fine.

 

My Work Car, a 2012 Camry Hybrid, gets better economy on 91 Octane than it does on 98 Octane......because its designed specifically to run on the cheaper, more frugal stuff. It Does feel much perkier on 98 though.....

 

So here are my religious beliefs regarding consumables:

 

Use 98 as its the best you can buy for your special car(s)

 

Use Thicker Dino oils with more frequent drain intervals, because it works. For me anyway. Its bloody hot down here.

 

The big Magic man in the sky told me the above, so it must be true.

[Mike]

Almost every car I have been involved with runs better and happier on BP Ultimate regardless of what model.

In fact the earlier the better they respond to it!

 

As far as a lead substitute goes regardless of whether the engine has hardened seats or not, it will not harm the engine. In the majority of instances these days it really is optional becausein the past 15 or so years most engines that have been rebuilt have had the hardened seats etc fitted!

[wasserkuhl]

Yeah but 98 Ultimate costs too much.

 

91 and retreads are where its at! then you can spend more money on a stereo!!!

 

SIGH.

[privatepang]

I tried half tank BP 91 octane in my 75S(said it was ethanol free) and car would stumble if reved above 4000 revs. Filled up the remainder with 98 and its running fine now. Could have been a bad batch of fuel but I'm sticking to 98 octane and 95 if I have to

[Harvs11]

I've recently started using 98 in my SC. Manual says use 91. It's running well and no longer has that little run on when I switch off.

Avoid ANY ethanol if your car isn't built for it. It will destroy the plastic parts and hoses in your fuel system if they are not the correct material for ethanol.