Fuel additives

[kalniel]

Now I know how these threads usually go - someone asks 'does fuel additive X really work?', several people reply with links to articles testing them with no significant result, and a couple of people swear they work for them.

So I'm going blab on about what I tried

My astra dti hasn't ever failed a smoke test, but that's probably because whenever it's under light load it's absolutely spotless. What I do get though is under heavy acceleration, especially up hills when the turbo has enough load, I get the nice clouds of black smoke coming out the back. Of course this is just unburned fuel and nothing to really worry about, except for the expression on the face of whoever is following me However over the winter I noticed my fuel economy drop from 60-65mpg to 50-55. Nothing too much to worry about there and possibly explained by the conditions. But on the off chance I decided to plug for a bottle of diesel injector cleaner (redex).

A double dose and 300 miles of motorway driving later what's changed?

Well for starters there's no miracle 'car suddenly feels like new' - the throttle response is identical. I still have the same flat spot at around 1300, and still have a surge of power at 2000. The engine sounds slightly noisier if anything, but it's not a bad noise - just sounds a bit more like a burbly diesel when before it sounded more like a rough petrol engine.

But I've yet to see any smoke under hard acceleration. I need someone to follow me with headlights on to be really sure, but so far there I haven't seen a spot. Result

It's too early to tell on the fuel economy front. A half tank top-up indicated 60mpg for motorway driving, which matched what I'd get before winter. We'll see what happens with country driving in a few weeks.

I'll also stop adding it to the tank and see if the effect remains or whether I need to constantly use it - the price at Wilkos is so good that it works out much cheaper per tank than the difference between normal diesel and Ultimate/V-Power, which is presumably diesel with this kind of stuff added anyway.

So are there any problems I should be looking out for having tried it? I assume it's just diesel with a high concentration of detergents.

[filbert]

Additives do work, but like you've said there not wonder cures.
Look out for the filter blocking up as I've known additives to turn diesel to treacle.

[Wh@l3fish]

I don't think you'll notice any difference using an additive, as you say it's mostly just detergents. That's not to say they won't do anything - just unlikely that you'll notice it.

A couple of years ago my golf diesel failed it's MOT on emissions. Bunged a bottle of Redex in the tank and a quick hundred mile blast up the motorway and it passed. It could also have been the engine getting a good run of course!

Fuel economy is a funny thing though and is dependent on a number of factors - weight in the car, driving style, weather, cleanliness of the engine. You *might* notice a slight difference in economy using the redex, but something on the order of 5-10 mpg as you suggest seems quite high and there could be something else at play. (Combination of cold weather, extra weight in the car, heater on e.t.c.)

I think you're right about the Ultimate and VPower being normal fuels with detergents added, although if you read either BP or Shell's websites they're loke vintage wines! My GF uses BP Ultimate diesel (she doesn't have to pay for fuel!) and swears she gets better mileage, but I haven't seen it myself, i think its mostly psychological.

I think in conclusion, the Redex is useful for older cars or cars that do a lot of miles for a quick cleanout every now and then. I certainly wouldn't use it all the time, maybe every 6 months or so.

[adam212]

Fuel addatives are like cars some work well, some work realy good and some dont wort at all. Alot fo them claim to do this that and the other the only one i have come accross that writes it on the bottle is howes meaner power kleaner (big american out let), they have started distrubation in the uk, i tryed a few bottles my self and it good value for money.

[Konan555]

I don't hold much faith in most of the additives that sit on the shelf at the motor-factors, however, I don't see cleaner as an additive as much as a one off treatment.

Many a flat spot has been cured with a shot of the stuff, although I like to add it into my fuel at the same time as changing the filter as part of a service.