Motoring Old Wive's Tales
Discussion
I was having a chat with my Dad (certainly not an old wife) earlier. He was in the van with me when I had to fill up. One of the major differences between our filling up habits is that he does it at a quarter of a tank and I only do it when the red light comes on. By this point the van bleeps and bongs away until I give in and give it another score of that Devil's juice, diesel.
Although I see no problem in either of our approaches. (Apparently, I play fuel light bingo
) He says I'm in the wrong as if I let it go below a quarter, nasty 'bits' will end up in the system and clog up the engine. Despite my arguments that petrol and diesel are highly refined, fuel systems have filters, and that pickups are mostly at the bottom of a tank, he refuses to budge. I guess we're both stubborn sods, really.
It made me wonder, and create this thread, to ask what other old wive's tales do we come across as car enthusiasts? What makes us sigh and roll our eyes when we hear it?
Michael
Although I see no problem in either of our approaches. (Apparently, I play fuel light bingo
) He says I'm in the wrong as if I let it go below a quarter, nasty 'bits' will end up in the system and clog up the engine. Despite my arguments that petrol and diesel are highly refined, fuel systems have filters, and that pickups are mostly at the bottom of a tank, he refuses to budge. I guess we're both stubborn sods, really. It made me wonder, and create this thread, to ask what other old wive's tales do we come across as car enthusiasts? What makes us sigh and roll our eyes when we hear it?
Michael
Whenever the discussion turns to fuel prices, my MIL proudly informs me that she puts her car into neutral downhill to save fuel. I then explain that approach hasn't worked since vehicles by and large became fuel injected at the end of the 80s, give her a brief lesson how it works which seems to go in but then a year later we're having the same discussion again. Don't think I'll bother correcting her next time.
Darkslider said:
Whenever the discussion turns to fuel prices, my MIL proudly informs me that she puts her car into neutral downhill to save fuel. I then explain that approach hasn't worked since vehicles by and large became fuel injected at the end of the 80s, give her a brief lesson how it works which seems to go in but then a year later we're having the same discussion again. Don't think I'll bother correcting her next time.
This was my understanding too, and was certainly oft repeated 20 ish years ago, but having been looking into some of the fuel saving methods of the latest automatic/twin clutch gearboxes, one thing they seem to do is allow the car to 'freewheel' in order to save fuel, which seems to go against that logic 
Perhaps leaving the car in gear only works to save fuel when going downhill or when intentionally wishing to lose speed?
SweptVolume said:
Darkslider said:
Whenever the discussion turns to fuel prices, my MIL proudly informs me that she puts her car into neutral downhill to save fuel. I then explain that approach hasn't worked since vehicles by and large became fuel injected at the end of the 80s, give her a brief lesson how it works which seems to go in but then a year later we're having the same discussion again. Don't think I'll bother correcting her next time.
This was my understanding too, and was certainly oft repeated 20 ish years ago, but having been looking into some of the fuel saving methods of the latest automatic/twin clutch gearboxes, one thing they seem to do is allow the car to 'freewheel' in order to save fuel, which seems to go against that logic Perhaps leaving the car in gear only works to save fuel when going downhill or when intentionally wishing to lose speed?
SweptVolume said:
Darkslider said:
Whenever the discussion turns to fuel prices, my MIL proudly informs me that she puts her car into neutral downhill to save fuel. I then explain that approach hasn't worked since vehicles by and large became fuel injected at the end of the 80s, give her a brief lesson how it works which seems to go in but then a year later we're having the same discussion again. Don't think I'll bother correcting her next time.
This was my understanding too, and was certainly oft repeated 20 ish years ago, but having been looking into some of the fuel saving methods of the latest automatic/twin clutch gearboxes, one thing they seem to do is allow the car to 'freewheel' in order to save fuel, which seems to go against that logic Perhaps leaving the car in gear only works to save fuel when going downhill or when intentionally wishing to lose speed?
SweptVolume said:
Darkslider said:
Whenever the discussion turns to fuel prices, my MIL proudly informs me that she puts her car into neutral downhill to save fuel. I then explain that approach hasn't worked since vehicles by and large became fuel injected at the end of the 80s, give her a brief lesson how it works which seems to go in but then a year later we're having the same discussion again. Don't think I'll bother correcting her next time.
This was my understanding too, and was certainly oft repeated 20 ish years ago, but having been looking into some of the fuel saving methods of the latest automatic/twin clutch gearboxes, one thing they seem to do is allow the car to 'freewheel' in order to save fuel, which seems to go against that logic Perhaps leaving the car in gear only works to save fuel when going downhill or when intentionally wishing to lose speed?
Whilst passengering in a new Fiesta with someone who put their car into neutral down hill to save fuel. I pointed out that leaving it in gear and lifting off the accelerator would be more beneficial and pointed out the live MPG display on the trip computer. Lifted off in gear downhill and it quickly jumped to 99.9 MPG. She did the same putting it in neutral and it jumped back to 99.9MPG, so that kind of ruined my theory!
Mercky said:
SweptVolume said:
Darkslider said:
Whenever the discussion turns to fuel prices, my MIL proudly informs me that she puts her car into neutral downhill to save fuel. I then explain that approach hasn't worked since vehicles by and large became fuel injected at the end of the 80s, give her a brief lesson how it works which seems to go in but then a year later we're having the same discussion again. Don't think I'll bother correcting her next time.
This was my understanding too, and was certainly oft repeated 20 ish years ago, but having been looking into some of the fuel saving methods of the latest automatic/twin clutch gearboxes, one thing they seem to do is allow the car to 'freewheel' in order to save fuel, which seems to go against that logic Perhaps leaving the car in gear only works to save fuel when going downhill or when intentionally wishing to lose speed?
AIUI, the engine management leaves the fuel injectors on when in neutral, but turns them off when engine braking. If this is correct, she is actually using more fuel by doing what she does.
pingu393 said:
I wouldn't do it going downhill, but I do it approaching a stop.
AIUI, the engine management leaves the fuel injectors on when in neutral, but turns them off when engine braking. If this is correct, she is actually using more fuel by doing what she does.
This is correct, can't say in 100% of cars, but certainly many and all of those I've owned for many years.AIUI, the engine management leaves the fuel injectors on when in neutral, but turns them off when engine braking. If this is correct, she is actually using more fuel by doing what she does.
Got4wheels said:
I was having a chat with my Dad (certainly not an old wife) earlier. He was in the van with me when I had to fill up. One of the major differences between our filling up habits is that he does it at a quarter of a tank and I only do it when the red light comes on. By this point the van bleeps and bongs away until I give in and give it another score of that Devil's juice, diesel.
Although I see no problem in either of our approaches. (Apparently, I play fuel light bingo) He says I'm in the wrong as if I let it go below a quarter, nasty 'bits' will end up in the system and clog up the engine. Despite my arguments that petrol and diesel are highly refined, fuel systems have filters, and that pickups are mostly at the bottom of a tank, he refuses to budge. I guess we're both stubborn sods, really.
It made me wonder, and create this thread, to ask what other old wive's tales do we come across as car enthusiasts? What makes us sigh and roll our eyes when we hear it?
Michael
AIUI though a lot of fuel pumps use petrol to lubricate, run too low too often and you can be setting yourself up for problems?Although I see no problem in either of our approaches. (Apparently, I play fuel light bingo
) He says I'm in the wrong as if I let it go below a quarter, nasty 'bits' will end up in the system and clog up the engine. Despite my arguments that petrol and diesel are highly refined, fuel systems have filters, and that pickups are mostly at the bottom of a tank, he refuses to budge. I guess we're both stubborn sods, really. It made me wonder, and create this thread, to ask what other old wive's tales do we come across as car enthusiasts? What makes us sigh and roll our eyes when we hear it?
Michael
Mercky said:
SweptVolume said:
Darkslider said:
Whenever the discussion turns to fuel prices, my MIL proudly informs me that she puts her car into neutral downhill to save fuel. I then explain that approach hasn't worked since vehicles by and large became fuel injected at the end of the 80s, give her a brief lesson how it works which seems to go in but then a year later we're having the same discussion again. Don't think I'll bother correcting her next time.
This was my understanding too, and was certainly oft repeated 20 ish years ago, but having been looking into some of the fuel saving methods of the latest automatic/twin clutch gearboxes, one thing they seem to do is allow the car to 'freewheel' in order to save fuel, which seems to go against that logic Perhaps leaving the car in gear only works to save fuel when going downhill or when intentionally wishing to lose speed?
Quite a simple concept but one a lot of people (my mother in law included) can't seem to grasp or remember.
DodgyGeezer said:
AIUI though a lot of fuel pumps use petrol to lubricate, run too low too often and you can be setting yourself up for problems?
This is true - I always avoid running to 0 unless it's a steady state cruise; Fuel pumps are submerged in fuel for cooling - Running below 1/4 frequently shortens the pump life a fair bit as it's running hotter. That and a number of cars (less now, but still not uncommon) can run into surge / supply issues with heavy cornering with low fuel levels, admittedly more of a problem on track but still, having a choppy fuel supply wouldn't be the best for the road either.
Ryyy said:
A car thats done around the 100k mark is absolutely toast and time to get rid.
My uncle has been saying this for decades and is always aghast when I tell him (when he asks, which is all the time) that my current daily is at 164k. According to him it should have exploded a rod out the block at 100k, that was 3 years ago and it's actually running better than new! Flies through the MOT every year and hasn't once even slightly hindered a journey's progress. Forums | General Gassing | Top of Page | What's New | My Stuff