Discussion
There's probably been several threads on this before, apologies if I'm going over old ground.
I normally fill up with Super from my local supermarket (87p/litre). Every time I fill up on a Sunday one of the blokes there always admires the car and says I should fill up with LRP/4 star as it has more lubricants in it and it has slightly more Octane (think it is 98 RON).
Should I try putting LRP/4 star in?
Also after reading the article in this months sprint I hadn't realised how different BP Ultimate/ Optimax is with additives to supermarket's Super. Might try putting Optimax in for a few tanks and see if it makes any difference. Pity its a pain to know the tank is full of any particular petrol as I can only get 30 litres in from the empty mark (i.e. I think the gauge reads empty with 20 litres in it).
I normally fill up with Super from my local supermarket (87p/litre). Every time I fill up on a Sunday one of the blokes there always admires the car and says I should fill up with LRP/4 star as it has more lubricants in it and it has slightly more Octane (think it is 98 RON).
Should I try putting LRP/4 star in?
Also after reading the article in this months sprint I hadn't realised how different BP Ultimate/ Optimax is with additives to supermarket's Super. Might try putting Optimax in for a few tanks and see if it makes any difference. Pity its a pain to know the tank is full of any particular petrol as I can only get 30 litres in from the empty mark (i.e. I think the gauge reads empty with 20 litres in it).
When it is full and the pump has 'clicked' off, once I tried a few clicks more then parked in on my Dad's drive about 5 miles away, at an angle and had petrol flowing out from around the filler. So I can only assume the tank was fairly full at that point.
It is amazing how long the petrol smell takes to go away when that happens. Made the same mistake filling up before going on an airfield.
It is amazing how long the petrol smell takes to go away when that happens. Made the same mistake filling up before going on an airfield.
I used to put that LRP into the 280, but I haven't seen that grade up here for about a year anyway.(No longer at Tesco)
390 only has Optimax, or BP Ultra if the Optimax queue too long.
I believe compression ratios varied amongst the V8s, so I'd have thought that would have a bearing on any benefits realised from the higher octane.
I do like the idea of the engine getting a clean on the dear stuff too.
390 only has Optimax, or BP Ultra if the Optimax queue too long.
I believe compression ratios varied amongst the V8s, so I'd have thought that would have a bearing on any benefits realised from the higher octane.
I do like the idea of the engine getting a clean on the dear stuff too.
tallbloke said:
Don't use LRP. Rover V8 injection engines were designed to run unleaded. If it runs happily without pinking on 95RON cooking unleaded, you are wasting money puttinbg optimax in unless you advance the timing a degree or two to take advantage of the higher octane rating.
The owners handbook says "Leaded fuel only (98 RON minimum)", so wasn't the engine designed to run on leaded fuel and isn't the timing set for higher octane petrol? It does seem to run quite happily on 95 RON, but its always been mixed with half a tank of super or so.
This is covered in the bible and in the unleaded FAQ on my website www.tvrbooks.co.uk.
tallbloke said:
Don't use LRP. Rover V8 injection engines were designed to run unleaded. If it runs happily without pinking on 95RON cooking unleaded, you are wasting money puttinbg optimax in unless you advance the timing a degree or two to take advantage of the higher octane rating.
Bit of a over simplification there. Rover V8s were out before unleaded appeared on our shores. For many years 4* was de rigeur. The problem with LRP is that there is no standard chemistry for it but I have used it in an emergency and had no problems with it.
Most tweaked Wedges need 98 RON unless they have been adjusted.
Hi,
I've found a balance between the normal unleaded and optimax in terms of performance and price. Tesco super - 97 RON, I know this is probably already been talked about but I've found this to be the most cost effective, gives better performance and provides the listener with more frequent and deeper pops and bangs on the over run. YEEHAH!
I've found a balance between the normal unleaded and optimax in terms of performance and price. Tesco super - 97 RON, I know this is probably already been talked about but I've found this to be the most cost effective, gives better performance and provides the listener with more frequent and deeper pops and bangs on the over run. YEEHAH!
There's really only three things to take into considersation when choosing petrol for this age of car. The first is the octane rating; the second is the anti-seating capability and the thrird is the amount of detergent additives. The original V8 engines were set for 98 octane, as that was what the typical 4* petrol was in those long ago days. So ideally that's what you should put in. However, as conventional petrol is now 95 octane, this can be used if you back off the ignition a little. You will, however, get marginally less power. The older petrol had lead added to increase the octane rating and this had the added advantage that it provided a 'lubricant' to stop valve seat wear. In the US however engines were using unleaded by that time and the heads on these engines had hardened valve seats to overcome the lack of lead. The Wedge V8 had the hardened valve seats so lead is not required. There is no advantage from the valve seat were point of view in using LRP or bottled additives or 4*. The final issue is the amount of detergents. There is no standard by which you can assess the amount of detergents in petrol as it's not part of the UK spec. There is a global spec known as the World Wide Fuels Charter, which is supported by the vast majority of the worlds cart and truck makers, but you will rarely, if ever, see this mentioned on forecourts. In practice, it is believed by many that the supermarket petrol stations don't put as much or any detergent into the fuel, so helping to keep the cost down. The result of having no detergents in the fuel will be that the injectors will tend to foul up over a period of time and may eventually stick. You may also see more deposits on the valve faces and the cylider head. The trouble is that, as there were few detergents around in the late 80s early 90's, engine builders designed their injection systems to allow for some deposits being present on the injectors. If the deposits are removed the fuel consumption goes up, the emissions go up and the engine is overfuelled.
So what to use? Unless you want every last ounce of power, there is little point in using Optimax or similar. The drawback in going the Optimax route is that if you set up the engine to take advantage of the power (ie advance the ignition) you'll have to keep running on Optimax. If you put 95 octane in it, it will pink. Even if you can't hear it; as is often the case at high speeds; the engine will be knocking and you may do a lot of damage. The choice is then between supermarket 95 octane and that from the petrol companies. The latter will tend to have more detergents, but unless the engine has run many miles these will be of little advantage, as they will only overfuel the engine (possibly reducing power).
Personally, I use Tesco 95 all the time, and once a year, around Christmas, I dump in a double dose of engine cleaner to remove the majority of the deposits and ensure the injectors don't stick.
So what to use? Unless you want every last ounce of power, there is little point in using Optimax or similar. The drawback in going the Optimax route is that if you set up the engine to take advantage of the power (ie advance the ignition) you'll have to keep running on Optimax. If you put 95 octane in it, it will pink. Even if you can't hear it; as is often the case at high speeds; the engine will be knocking and you may do a lot of damage. The choice is then between supermarket 95 octane and that from the petrol companies. The latter will tend to have more detergents, but unless the engine has run many miles these will be of little advantage, as they will only overfuel the engine (possibly reducing power).
Personally, I use Tesco 95 all the time, and once a year, around Christmas, I dump in a double dose of engine cleaner to remove the majority of the deposits and ensure the injectors don't stick.
I've been trying optimax again and the car definetly has a deeper sound using it, or maybe my temporary exhaust fix has a hole opening up again ... will see when the exhaust is fixed properly.
I've just found out a garage 10-15 mins from where I live still sells proper 4 star - is this worth using over Super? (The garage is the one by the 'tunnel' in the BBWF convoy route)
I've just found out a garage 10-15 mins from where I live still sells proper 4 star - is this worth using over Super? (The garage is the one by the 'tunnel' in the BBWF convoy route)
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