Which fuel additive to use?

[JonathanT]

Hello I've read the existing threads but not sure which additive is the best for an R4 GTL 1100 I'm hoping to own one day soon.

Thinking of adding each time I fill up as cost doesn't seem to be prohibitive. In order to look after the Valve seats.
the additive added in!

Thanks a lot folks


Jonathan

 

[harbourseal]

I use no fuel additive at all. My 956cc runs on undoped regular 95 unleaded petrol.
I make excellent mileage last weekend 1ltr:18.6 km
I do use TSL in my motor oil and gearbox as an additive.
My 1978 renault 5TL motor runs really smooth on it.

 

[mojobaby]

Hi JonathanT
After "Super" petrol was phased out, a Renault dealer here told me to use SP95 with a lead additive, which I've done for the past 10 years. It costs about 8Euro for a bottle and keeps me going for 6 months at least. Any auto place will sell it.

In a previous thread, Malcolm suggested that you wouldn't need a lead additive unless you did a lot of highway driving (high speed probably)

I make a point of not using SP95-E10 which has a 10% ethanol content.

 

[pepper]

I use texaco additive in my tank, (found a bulk buy on eBay a few years ago).

 

[jjad]

And I use 'Castrol Valvemaster' (the ordinary type, not 'Valvemaster Plus').

 

[Cornish4]

I do use Valvemaster Plus, mostly for prolonged motorway use at higher speed. The extra octanes are said to be kinder to an engine under these conditions.

 

[jonigel]

Nearly all Aluminum heads have hard valve seats fitted as normal,no need for additives,it is the iron heads which suffer from valve seat recession and so that does not apply to Renault 4s. But you still need to use good petrol, not the stuff with ethanol in it as it causes rust in the tank and fuel lines,espeically
if the car is not used a lot.Where i live now i have to use sp98 which is quite a bit more as all the 95 is E10 ,but the van is used daily and goes well on it.

 

[Cornish4]

It's not so much the lead replacement properties of Valvemaster Plus, as you say the little 4L engine doesn't need that, it's the fact that the engine runs much better on higher octane fuel. I try to use Shell 98 octane when I can. This doesn't contain ethanol. So if I can't get that I bung in a drop of additive.

 

[iMacThere4iAm]

With my recent experience of burning out an exhaust valve while using unleaded 95 without additive, I would advise caution and use it in future!

 

[Cornish4]

Your burnt out valve could have been a weak fuel-air mixture Tom, or maybe too far retarded ignition timing. In future perhaps use a higher octane fuel such as Esso 97 or Shells 98 octane. Chucking in a drop of additive now and then won't do any harm either.

 

[jonigel]

A burnt valve is genarally caused by ignition problems or too lean a mixture as the chap above suggested,but some of the 1100 engines are meant to run on 98 octane ,depending on the compression ratio, if you have a handbook it gives you the info regarding which engine needs 98.octane

 

[malcolm]

I've had burnt valves in the 1108 GTL twice (different cars, different carburettors). For me both times were due to valve seat recession on long high speed trips across France. About 1000 miles is enough to do it. Though 10,000 miles at much more sedate speeds doesn't seem to be a problem.

The viewpoint on whether to use an additive tends to depend on whether you've had valve seat recession in the past or not.

 

[Bobble]

Fortunately i've not had that problem as yet and i have done considerable mileage in all our R4's but i do use 98 octane and
have done urban and long motorway driving, personalty i think if you drive sensibly it's not a problem, lets face it there not
built as speed machines anyway, just a practical economical all purpose car.