tazzieman Posted 18August, 2015 Report Share Posted 18August, 2015 Fuel tanks heat up and cool down each day, releasing volatile compounds each time. Maybe the heat differential determines how quickly the fuel goes off.Right now , I am getting 6-10 degrees between max and min each day. And of course not really hot enough to evaporate many fumes. Tassy is a cool place to live after all.Old race cars don't have carbon canisters. Maybe they lose more of the combustible fumes that give fuel its flavout?Old fuel stinks bad , so I suggest you poke your schnozz in the filler and use this as a scientific gauge as to when to refill..Oh , and maybe ethanol in fuel , and the mixing of different brands makes jelly. That would be easy to experiment with , but keep an extinguisher handy. Link to comment Share on other sites More sharing options...
dominicxu1 Posted 18August, 2015 Report Share Posted 18August, 2015 I add about a litre of metho to the tanks of my cars every 6 months, disperses any build up of condensation and burns clean. My cars can sit for months without being used and I've never had a problem. Dominic. Link to comment Share on other sites More sharing options...
TINGY Posted 19August, 2015 Report Share Posted 19August, 2015 Who wants to do a group buy of German air for our tyres?I hear that the depleted ozone in Australia air causes premature hardening of the rubber compounds and therefore could be dangerous. I also read on the internet that our air doesn't have the same shock absorbing properties and those with adjustable Belstein's and Koni's need to run half a notch more rebound front and rear.Isn't it August not April Pete Link to comment Share on other sites More sharing options...
Coastr Posted 20August, 2015 Report Share Posted 20August, 2015 Coolant thread? ? ? Very good!isn`t this what the internet is for, to make you worry about things that you had no idea that you needed to worry about.I think we should call it autochonriasisI have been calling it 'internet hypocardria' for a while.If you ever research buying a used car and decide to look up the 'common' faults of the car, you'll never buy one.Similar to 'if it bleeds, it leads' nobody (hardly) ever posts 'another 50,000 trouble free kms completed'It gets to the point where we basically expect our head studs to fall out, our IMS bearings to grind to powder, our tappets to be worn to skeletons, our sills to be rusted out...etc etc.In the BMW world it's got to the point where people consider full radiator, hose, expansion tank and water pump replacement to be a normal part of a 100,000 km service, irrespective of the condition of the existing equipment.In the Audi world, people just crush their cars after 50,000 kms after reading the internet. Link to comment Share on other sites More sharing options...
tazzieman Posted 21August, 2015 Report Share Posted 21August, 2015 And Frank , I would never buy a Golf , nor a Mini , and certainly not a Jeep! Link to comment Share on other sites More sharing options...
HowardMoon Posted 22August, 2015 Report Share Posted 22August, 2015 He tells me that 98 ULP goes off after a certain period of time, and can cause pinging when the car is driven again after sitting idle for a month or 2 Some of his clients that race 911's have left fuel in the tank for few weeks in between race meetings, then had some pretty major engine problems at the next race. Basically, he advises to only put in what you really need for a particular trip, and not fill it up. Can anyone shed a bit more light on this? Do you fill your cars and leave it sitting? Just thought I'd bring it to your attention if you weren't aware Pardon me for sticking my nose in but this is the exact opposite to my experience, though it does align with the common old wives tales..I have a couple of bike engines that are tuned right on the very edge of detonation. I use only BP 98 purely for consistency, and with either engine I get audible det once the cylinder head temp reaches a certain level. I can eliminate it altogether by compromising the tune (fatter and/or less lead, obviously) but that also reduces the sharpness to some degree so I tune for best performance knowing that once the CHT gets up a bit there will be some light det occurring. It's not enough to hurt parts but I keep a close eye and ear on it, and it's so consistent that it's predictable. In very hot weather I don't lean out the jetting quite as much as you would normally and this is enough to stay safe.I store fuel in plastic containers, and like most people I used to try to not store too much or for too long. But then I noticed a pattern appearing - the CHT det threshold was noticeably higher if I was running fuel that had been stored for a few weeks than if I ran fresh stuff. At first I didn't pay too much attention to this but over the following months the pattern became very clear and quite predictable. I could noticeably reduce the det threshold simply by topping up with fresh fuel.Of course this goes against the common wisdom that says you should only use the freshest fuel available but then common wisdom is so often baseless. And if I stored the fuel too long - as in several months - the engines would take a bit longer to light off from cold but otherwise they ran well. The sweet spot seems to be fuel that has been stored in plastic for 2 - 4 weeks.Not long ago this subject came up in a discussion I had with some sharp builders (and by sharp I mean these blokes routinely build 250-300hp/litre engines; they aren't your typical single marque monkeys) and in effect their response was "Well duh, everyone knows and has to deal with that", only more tactfully put. I know precisely nothing of fuel chemistry or composition but their explanation involved the evaporation and permeation through the plastic of the lighter ends. They also indicated that depending on the type of fuel, they sometimes store it in metal containers with the empty space filled with nitrogen to help preserve its properties.At any rate, it seems my experience with old fuel - BP98 at least - being less rather than more inclined to det isn't at all unusual, even if it isn't widely recognized. Link to comment Share on other sites More sharing options...
SteveT Posted 22August, 2015 Report Share Posted 22August, 2015 I had some product training through work during the week regarding this very topic. Apparently all fuel starts to evaporate in its container and then condense again. In this process it loses some of it's octane somehow, the exact science wasn't explained to a bunch of sales reps for obvious reasons, and this process continues. The big news was that 98 actually loses it faster than the lower octane fuels. Might be because there's more to lose? So the best way to eliminate this is to use a fuel stabiliser (Sta-Bil or similar) which, when used to recommended dosage, gives 12 months storage without loss of octane. It also reduces or even stops the ethanol in all our Aussie fuel from absorbing moisture, again through condensation in containers. The fuel companies are allowed to sell us up to 10% ethanol in Aussie fuel without telling us it's in there. Also recommended to store fuel in fuller containers as there isn't then as much space for it to evaporate. Link to comment Share on other sites More sharing options...
HowardMoon Posted 23August, 2015 Report Share Posted 23August, 2015 So what we have here are the producers own people disseminating information that is at best not entirely correct, and provably so.I'd like to say this is unbelievable and surprising. But unfortunately it isn't in the least. Link to comment Share on other sites More sharing options...
SteveT Posted 23August, 2015 Report Share Posted 23August, 2015 So what we have here are the producers own people disseminating information that is at best not entirely correct, and provably so.I'd like to say this is unbelievable and surprising. But unfortunately it isn't in the least. Feel free to give us a small insight into your vast knowledge on the subject, I am awaiting enlightenment from any informed source. Link to comment Share on other sites More sharing options...
LeeM Posted 23August, 2015 Author Report Share Posted 23August, 2015 I have no idea what anyone is talking about! :-) Link to comment Share on other sites More sharing options...
HowardMoon Posted 23August, 2015 Report Share Posted 23August, 2015 Understandable comment, but to be fair Steve I did say I have zero knowledge of fuel chemistry. And to be honest I know very little about anything - just barely enough to know how much I don't know.. I think I'm just tired of wading through bullshit.But anyhow, as I said before I found that this particular fuels det resistance actually increased after some period of storage. And after some discussions with others I found that they and many many others had known about this and dealt with it for a long time. It's not just my opinion - it's something that's been recognized for a long time.Here's the thing: as you know a fuels equivalent octane rating is essentially its resistance to det - nothing more, nothing less. The fuel company rep says the octane rating decreases with storage yet I and many others find that it quite often goes the other way. I don't really care what he says; I just know what happens in my case and those I've discussed this with.I don't mean to be a smart-arse, I'm just weary of every damn subject that's related to engine building being cloaked in so many layers of goddamn bullshit... Link to comment Share on other sites More sharing options...
tazzieman Posted 24August, 2015 Report Share Posted 24August, 2015 I never found a reference that said Stabil was snake oil. That's why I use it if I have to leave fuel sitting around in my garage or car or boat. Link to comment Share on other sites More sharing options...
Tit Posted 24August, 2015 Report Share Posted 24August, 2015 Very good!I have been calling it 'internet hypocardria' for a while.If you ever research buying a used car and decide to look up the 'common' faults of the car, you'll never buy one.Similar to 'if it bleeds, it leads' nobody (hardly) ever posts 'another 50,000 trouble free kms completed'It gets to the point where we basically expect our head studs to fall out, our IMS bearings to grind to powder, our tappets to be worn to skeletons, our sills to be rusted out...etc etc.In the BMW world it's got to the point where people consider full radiator, hose, expansion tank and water pump replacement to be a normal part of a 100,000 km service, irrespective of the condition of the existing equipment.In the Audi world, people just crush their cars after 50,000 kms after reading the internet. lol@audi comment. Link to comment Share on other sites More sharing options...
Rob Posted 24August, 2015 Report Share Posted 24August, 2015 I add about a litre of metho to the tanks of my cars every 6 months, disperses any build up of condensation and burns clean. My cars can sit for months without being used and I've never had a problem. Dominic.Dominic - just a heads-up for you, that "metho" is the same as the ethanol in E10 petrol that some are pointing fingers at for causing woes in engines and ancillary equipment. It's called "metho" as it is denatured, or made undrinkable, by the addition of a denaturant such as methanol, acetone, methyl isobutyl ketone or isopropyl alcohol, amongst others, at about 10% by volume. Link to comment Share on other sites More sharing options...
ANF Posted 25August, 2015 Report Share Posted 25August, 2015 As a side question to this, how do older Porsche, pre 86 and older, go on unleaded petrol?Are they the same as old Mercs and the valves are fine (Mercs are fine back to the late 50s)?Cheers Link to comment Share on other sites More sharing options...
Peter M Posted 25August, 2015 Report Share Posted 25August, 2015 Adam,Provided the octane is adequate, these cars with aluminium heads have hardened valve seat inserts so do not miss the lead additive. Link to comment Share on other sites More sharing options...
ANF Posted 25August, 2015 Report Share Posted 25August, 2015 Thanks Peter I thought as much and would only ever run 98 (95 in a pinch) same as my Mercs when I do finally park one in my driveway! Cheers Link to comment Share on other sites More sharing options...
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