Fuel

[VioletCat]

Firstly HPY everyone
Secondly sorry if this has been covered before, I went back 20 plus pages and could not find anything so asking the group.

What fuel does everyone use?
In an old K series I ran 99 all the time but I feel my 420r was fuelled with 95 before picking it up for the first time. Since then I have refuelled it with 99 and it didn’t like it!
I understand the ECU has to change etc but has anyone else had this experience?
It was almost as if I had lost a cylinder or two for the drive home with a warm engine but fresh fuel. I believe it’s settling down now.
Also it only took 20 litres when I believe it has a 34 litre tank!

Any help/advice would be most welcome

Thanks,

[DCL]

The Duratec installation in the Caterham is quite sensitive to fuel. Not to so much the octane rating but some fuels can cause vaporisation in the fuel rail. Best cure is to fit a fuel line return and regulator, but if not, I would avoid generic supermarket fuels. The winter months can be particularly bad and I would go for a good quality branded fuel such as BP ultimate, or shell V power. I'm not a chemist but believe it is to do with the ethanol and other additives that generic brands tend to get added to up the rating and for ease of use on a seasonal basis.

('nonsense' I hear - all fuels re the same! Experience has proved otherwise for me)

Edited by DCL on Thursday 3rd January 20:07

[BertBert]

Reading about ethanol says that the up to 5% you might/should get in regular unleaded will not make a difference to how your engine runs. It's also pretty hard to tell what's in your petrol even from the main brands. A quick Google says, for example, that Esso's high octane stuff is mostly ethanol free apart from in a few places in the UK! Go figure.

Re the question, I can't see why a duranail in a caterham would be worried about ethanol at the 5% level.

Bert

[VioletCat]

DCL said:

The Duratec installation in the Caterham is quite sensitive to fuel. Not to so much the octane rating but some fuels can cause vaporisation in the fuel rail. Best cure is to fit a fuel line return and regulator, but if not, I would avoid generic supermarket fuels. The winter months can be particularly bad and I would go for a good quality branded fuel such as BP ultimate, or shell V power. I'm not a chemist but believe it is to do with the ethanol and other additives that generic brands tend to get added to up the rating and for ease of use on a seasonal basis.

('nonsense' I hear - all fuels re the same! Experience has proved otherwise for me)

Thank you

Edited by DCL on Thursday 3rd January 20:07

[VioletCat]

BertBert said:

Reading about ethanol says that the up to 5% you might/should get in regular unleaded will not make a difference to how your engine runs. It's also pretty hard to tell what's in your petrol even from the main brands. A quick Google says, for example, that Esso's high octane stuff is mostly ethanol free apart from in a few places in the UK! Go figure.

Re the question, I can't see why a duranail in a caterham would be worried about ethanol at the 5% level.

Bert

Thank you

[fergus]

DCL said:

The Duratec installation in the Caterham is quite sensitive to fuel. Not to so much the octane rating but some fuels can cause vaporisation in the fuel rail. Best cure is to fit a fuel line return and regulator, but if not, I would avoid generic supermarket fuels. ]

I don't have any experience of Duratec installs, but I'd be very surprised if a fuel pressure regulator was not used upstream of the injectors. How would they ensure accurate opening times (fuel delivery amounts) for the regulators, as the pressure to the fuel line can fluctuate? I'm also not sure how fitting a regulator would remove vaporisation issues, if indeed this is the problem? Genuine questions by the way,

[DCL]

fergus said:

I don't have any experience of Duratec installs, but I'd be very surprised if a fuel pressure regulator was not used upstream of the injectors. How would they ensure accurate opening times (fuel delivery amounts) for the regulators, as the pressure to the fuel line can fluctuate? I'm also not sure how fitting a regulator would remove vaporisation issues, if indeed this is the problem? Genuine questions by the way,

The Ford Duratec engines and cars all use a single line fuel feed with a high pressure pump and regulator in the tank. It assumed that the pressure within the line and fuel rail will all be the same (or any systematic pressure drop is mapped out). The problem with in the inline Caterham adaption of this normally transverse engine design, is that the fuel rail is no longer cooled as efficiently and runs hotter. If the car is stopped and started when hot (to fuel it up for example) the fuel rail can boil the ethanol. If you fit a return line, with the regulator at the fuel rail return, any vapor is simply returned to the tank.

[fergus]

DCL said:

The Ford Duratec engines and cars all use a single line fuel feed with a high pressure pump and regulator in the tank. It assumed that the pressure within the line and fuel rail will all be the same (or any systematic pressure drop is mapped out). The problem with in the inline Caterham adaption of this normally transverse engine design, is that the fuel rail is no longer cooled as efficiently and runs hotter. If the car is stopped and started when hot (to fuel it up for example) the fuel rail can boil the ethanol. If you fit a return line, with the regulator at the fuel rail return, any vapor is simply returned to the tank.

[BertBert]

DCL said:

The Duratec installation in the Caterham is quite sensitive to fuel. Not to so much the octane rating but some fuels can cause vaporisation in the fuel rail. Best cure is to fit a fuel line return and regulator, but if not, I would avoid generic supermarket fuels. The winter months can be particularly bad and I would go for a good quality branded fuel such as BP ultimate, or shell V power. I'm not a chemist but believe it is to do with the ethanol and other additives that generic brands tend to get added to up the rating and for ease of use on a seasonal basis.

('nonsense' I hear - all fuels re the same! Experience has proved otherwise for me)

So if boiling ethanol in the fuel rail is a problem to the fuel system (and it does have a lower boiling point than petroleum), filling with good quality branded fuel is not the solution as they are very likely to contain ethanol as well. You will indeed need another solution such as the fuel return system you describe.

Although is that what the OP is experiencing, or have we gone off at a tangent?

Bert

[DCL]

BertBert said:

. . .good quality branded fuel is not the solution as they are very likely to contain ethanol as well.

As I said I'm no chemist and wouldn't want to get into arguments about the make up of modern fuels. My comment is purely from experience of using different fuels. I suspect the branded fuels are just tested and quality controlled a little more and that buys a bit of a bigger margin before this issue show itself. And, again, it seems to have a seasonal element to it, and I guess it may be regional too, and probably some will never experience any issues.

[mike150]

I just came across this thread and thought it relevant………………..

My 620S has ran perfectly since I got and I put it up on axle stands 2 months ago for a through clean top to bottom, at the time it had a half tank of fuel.

Yesterday I couldn't resist taking it down our half mile lane as it was dry...………...basically it ran like a pig at low revs and light throttle kangarooing as it went, it was ok with a bit more throttle so I'm assuming its the 2 month old petrol!

Edited by mike150 on Friday 4th January 16:29

[BertBert]

DCL said:

As I said I'm no chemist and wouldn't want to get into arguments about the make up of modern fuels. My comment is purely from experience of using different fuels. I suspect the branded fuels are just tested and quality controlled a little more and that buys a bit of a bigger margin before this issue show itself. And, again, it seems to have a seasonal element to it, and I guess it may be regional too, and probably some will never experience any issues.

Yes, there seems to be huge unravel-able complexity around petrol and the brands. The idea for example that the blend of a specific fuel varies by region is mad. Or that the amount of ethanol in a brand just varies as the (major) suppliers have to achieve their obligations under the Renewable Transport Fuel Obligation (RTFO). Then there's all the stuff about additives, quality, age, water and contaminants in tanks etc.

It's a wonder that it all works really. Having said that, with a variety of cars over the years and relatively few of them being normal, I can only think of one issue that I thought was bad fuel.

Hey ho.

If the OP thinks his Duranail runs better on normal unleaded rather than premium, that's what I would go with! What 99 did you use by the way?

Bert

[downsman]

From reading various internet threads, I believe that (almost?) always, 97 octane will contain less ethanol than 95, and although all (modern) fuel will "go off" after a while, the higher octane stuff should last longer.

My Seven gets tucked away in an air chamber for winter servicing and to keep it off the road salt every winter. I'm usually driving until the end of October and then don't get out until late March or early April. I always have esso 97 in the tank, and so far have had no problems with restarting and running in the spring, so for the fuel to go off that much in 2 months seems unlikely.

[BertBert]

Never had problems with fuel going off over the winter, but others have, so more petrol mysteries!
Bert

[tomwoodis]

Shortly after I built mine (duratec) I filled it with Shell V Power for the first time and mine also ran like a pig whilst driving home one day. It was like it was down a cylinder or something, ran very erratically, under powered and I noticed a lot of black soot had come out of the exhaust.

At the time I didn’t think it was the fuel but perhaps it was. In the end I unplugged all the leads/ sensors I could find under the bonnet and plugged it all in again. That seemed to cure it as it’s never come back again and I’ve run the car on V Power almost exclusively since then.

The jury is still out on what was the exact cause.

Tom

[MK3 Dan]

Is the 99 stuff from Tesco?

That has a high ethanol content and I am sure they used to advertise that. We cannot get on with it in some bike engine'd stuff.

We stick with Shell/BP.

[BertBert]

So if the Tesco momentum is 5%, what are % in the ones that work better in bike engined stuff?

[coppice]

Re tank - my Duratec S3 car allegedly had a 35 litre tank. But the Stack fuel gauge never registered more than 29 litres and I never pumped more than 25litres in , even when gauge showing 3- 4litres left and warning light on. Range anxiety is not enjoyed exclusively by Nissan Leaf drivers ..

[VioletCat]

MK3 Dan said:

Is the 99 stuff from Tesco?

That has a high ethanol content and I am sure they used to advertise that. We cannot get on with it in some bike engine'd stuff.

We stick with Shell/BP.

Yes it is Tesco

[VioletCat]

So I have since spoken with service at Caterham South.
They claim it could be the Cam in the Duratec engine and is typical in 420’s at this time of year. So basically I shouldn’t be driving it in the cold as the Cam doesn’t like it.
However it doesn’t matter how long I drive it for or even if I get it fully up to temperature it still behaves the same.
It’s booked in soon to have this issue and a number of others investigated I will keep you updated on the outcome.