Ask a Shiter

[Craig the Princess]

So it saves 10p a litre, but there is a reduction in mpg so unless you do mega miles it is a very minimal saving. Interesting how that has changed since diesel was 1.409+ a litre.

[bub2006]

Interesting info but can someone shed light on what is a diesel fuel heater? Reading owners handbook it says diesels are equipped with a fuel heater to eliminate cold weather issues. Not owned a diesel so I'm confused!

[TataBobu]

In the diesel filter there's an electric resistor pretty much like you get in a cheap fan heater. This is used to heat-up the diesel, in order to make it more fluid in cold temperatures, thus having a better spraying in the cylinders.

[bub2006]

Ok thanks for That.

[face]

Why does a car sometimes seem to accelerate faster as you decrease the throttle?

 

Or is it some sort of illusion?

[tooSavvy]

Why does a car sometimes seem to accelerate faster as you decrease the throttle?

 

Or is it some sort of illusion?

My Savvy is 'fly by wire' pedal and often when lifting off (to change up) there is a definite 'upwizz' for a second.

 

It is probably part of the ecu/stepper butterfly control of throttle opening/closing.

 

TS

[castros_bro]

How much is new Veg these days? With diesel at around 1.109 a litre around here is it worth using veg at all currently?

 

Last week I could get  20 litre for Ã‚£12.99 at  Bookers (65p a litre)

 

Today it's £12~39 for 20L.

[bub2006]

My Savvy is 'fly by wire' pedal and often when lifting off (to change up) there is a definite 'upwizz' for a second.

 

It is probably part of the ecu/stepper butterfly control of throttle opening/closing.

 

TS

My vectra and the other2 I've drive all did something similar on gear change. Apparently it's to assist with smoother gearshift so holds revs slightly

[steve_earwig]

The Toyoyos do it, I thought it was yet more emissions bullshit. You get used to it, it just means you release the throttle slightly early (and on these go back on it slightly early too)

[face]

Cheers chaps 

[Richard]

It used to happen with carbs too, I put it down to the carb being badly out of tune.

[LC Torana]

It used to happen with carbs too, I put it down to the carb being badly out of tune.

 

Yes.  That is what is meant by the term "carb loading".

[Pillock]

What is a "classic car" in regards with "classic car insurance"? Does it have to be of a certain age (which one?) or is there more to it than that?

Depends on the insurer.

As a guide, it starts at around 15 years but some will ask for older now, as a few folk realised that a 15 year old car isn't all that old any more and it's a good way to get cheap insurance. Hence the requirement from some insurers for another car, no NCB earned etc just so you're not using it as a daily.

 

I got a 15 year old Golf GTI on classic, but they wanted proof of joining an owners club. I tried a same age Audi and they refused, as there wasn't an "enthusiasts network". E36 BMW was fine. I was using both the BMW and GTI for commuting although the maximum per year was 4500 miles. That insurer didn't demand that I had another car, but they also wouldn't give me any NCB - that is fairly standard across them all.

 

In short - random chance.

[tooSavvy]

My vectra and the other2 I've drive all did something similar on gear change. Apparently it's to assist with smoother gearshift so holds revs slightly

 

From what I've read the program is to open the butterfly 'smoothly' - even when you STOMP on the gas - because the 'snap open' [of old-time cable] causes an emissions pulse = bad news for manufacturers emission numbers {read.. VAG}

 

 

TS

[dome]

Am about to wire in a new electric fuel pump to the Scimitar, at the back beside the tank. I was going to run the wires externally along the chassis rails from the engine bay where the pump is at the moment (I was going to put an earth straight to the battery to ensure good voltage to the pump, hence the two core)

 

Can someone reccomend decent wiring to use? And don't say two core household wiring, I want to make this look vaguely respectable.

 

Edit: got some automotive/marine quality stuff on the way.

[Cavcraft]

Craig the Princess, on 16 Nov 2015 - 12:27 PM, said:

How much is new Veg these days? With diesel at around 1.109 a litre around here is it worth using veg at all currently?

 

 

65p in Costco. Yes, very well worth using the stuff.

[bub2006]

Where's Costco? Is it a nationwide place?

[Tayne]

It's a cash and carry, you need some sort of business type excuse to be in there.

If you don't have a Costco near you, look for a Booker or a Makro.

If you don't have some sort of business, or some way of pretending, ask friends if they have a way in.

[dome]

If you've got a Chinese supermarket near you they can be worth a try, my local one wasn't quite as cheap as Costco but I didn't have to pay a subscription fee.

[Pillock]

You can sign people in to Costco though so ask your mates if they have a card.

Also, their criteria is not exactly strict, and they don't really check stuff over. I've got a Costco card FFS, Mrs_Pillock used to work for a government agency and just keeps renewing it.

I reckon non-profit organisations can get them, it says stuff like "Church groups" on their website. Get some headed paper printed out on a laser printer or summat and try your luck. 

[D Spares & Tyres]

try your luck.

 

Don't bother ☺

[Stanky]

I have a stupid question, triggered by Dome's post re fuel pumps.

 

In a car with a fuel gauge which is operated by a float on am arm in the tank, how does the signal get back to the sender without electricity causing the fuel vapour in the tank to ignite. I can't get my head around how this could work without being a massive fire risk - if not necessarily when the car is new, but as the car ages and the shielding on any wiring becoming perished due to the hostile environment it lives in.

 

I'm sure it isn't and I'm being stupid, but how do they work without blowing cars up?

[HH-R]

If I understand it right, the float is just pushing an arm of metal across another piece and varying the resistance of a loop of wire, say high when it's full and low when it's empty. The gauge on the dashboard is like a multimeter that's measuring the resistance of the wire at that time, which equals the level of fuel left, so the gauge is the thing that's powered rather than the sender.

[Stanky]

But surely the concept of varying resistance means that electricity is passing through the arm, otherwise what does the multimeter/gauge measure?

 

I am genuinely intrigued by this, obviously it doesn't blow cars up but I dont understand how.

 

Or is it like when scientists* proved bees can't fly and I shouldn't inspect this matter any further otherwise I'll inherit Bub2006's luck and my car will explode?

[bub2006]

Please take it!

[HH-R]

Again could be RONG but any current flowing through the sender would be tiny, the contact bit of the arm is probably outside of the tank too, in case there were any rogue sparks.

[HH-R]

From Wiki:

 

However, this system has a potential risk associated with it. An electric current is sent through the variable resistor to which a float is connected, so that the value of resistance depends on the fuel level. In most automotive fuel gauges such resistors are on the inward side of the gauge, i.e., inside the fuel tank. Sending current through such a resistor has a fire hazard and an explosion risk associated with it.

 

So looks like OMG DEATH is very possible.

[Stanky]

I've just been reading up on this and through a lot of general confusion (and some digress on the subject of solar flares) it seems that current does indeed flow through the arm, but as you say its such a low current that ignition is all but impossible, especially as the sealed tank is unlikely to have much air in it, or have the cap off allowing air and vapour to mix.

 

still, I'd rather have read that '"it cannot possibly happen you cretin, because the patented Mangrovewarbler-Hypotenuse harmonic stabiliser detects the level of fuel in the tank without the need for electricity" or something.

[spike60]

I always thought electric fuel pumps inside tanks were a greater risk than senders because of the higher current involved. I'm thinking SD1 here, probably because it's the only time I've had to roll my sleeves up and remove one from under 12 gallons of petrol!

[Richard]

All flammable gases, vapours and powders have a minimum ignition energy. If the spark contains less energy than the minimum it will not ignite- a phenomenon that is frequently demonstrated at the other end of the car. Tank senders will be designed in such a way that they cannot produce a spark with enough energy to cause ignition.