Sheall V Pwer fuel

[dpp]

I was wondering what fuel you use in your classics as I always try to use Shell V Power but I'm not sure if it is actually any better than other fuels.
However I did notice that after using supermarket fuel my 1975 Vauxhalll developed a run on after the ignition was turned off which went away as soon as I refilled with V Power.

Since that I have always tried to use Shelll and if not available another premium fuel from BP or Esso etc but never any more supermarket fuel. Since getting my Jensen back on the road I have never used cheap fuel following my experiance with the Vauxhall.

Have I been suckered into paying for premium fuel or is it actually better for our older cars?

[Mound Dawg]

Sounds like the Vauxhall hasn't had the timing reset to run on modern lower octane fuels. Back in the 70s you could get two star fuel, roughly equivalent to modern 95 or four star which corresponds to the current Nitro/Vpower/Momentum stuff.

Most cars were set to run on four star, you can wind the ignition timing back a few degrees so it'll run ok on 95 octane fuel but you'll lose a bit of performance so I'd fill it with 98/97 octane stuff to be honest.

Ironically, as your Jensen has an American engine it's quite possible that it will be happy on 95, lots of Yankee cars of the era were because they started removing the lead from their fuels in the early 70s.

[BritishRacinGrin]

They stopped selling Sheall V Pwer years ago, it's called 'Nitro +' or something now isn't it?

Higher RON means greater resistance to pinking, which you observed with your vauxhall. Essentially your cars should happily run on 95 or below with the ignition timing set accordingly so it's up to you.

Supermarket fuels aren't inherently bad, they come from the same refineries as the brand names and differ only in additive packages and they way they've been stored.

A final consideration for bioethanol; most pump fuels use bio nowadays, often 10%, and this is said to be bad for some older cars. If I remember correctly BP ultimate has less Bioethanol than the competition.

[PositronicRay]

My local station is Shell so this is where I get most of my fill ups. I tried the posh stuff, normal shell and supermarket fuel. When I first had my Sunbeam I felt Vpower/nitro was better. Once I had given the car a bloody good (long over due)service set up the ignition and carbs it made bugger all difference.

[nta16]

OP, as said if you have your car fully serviced and (when possible) set up to run on 95 octane using good quality and condition ignition and fuel parts then the extra octane should make no difference

two star petrol was 91/93 octane (not 95)

95 octane was three star

97 octane was four star as was 99 octane

I used to use Tesco Momentum99 (99 octane) regularly and occasionally Shell V-Power Nitro+ (99 octane) more for their packages of cleaning additives than the extra octane as my 1973 Midget was designed to run on 97 to 99 octane (and not below 94 octane) but was now set up to run on 95 octane

I'm now trying a test of running on 95 octane and adding STP Complete Fuel System Cleaner every 4k-miles

I think the Tesco Monmentum99 and Shell v-Power Nitro+ gave me a very little more mid-range torque but that could just be a placebo effect on my mind only

if you have an original or reprint copy of the Owner's Manual/Driver's Handbook it should tell you what petrol was originally required

BP Ulitmate is 97 octane with cleaners

Edited by nta16 on Wednesday 18th February 08:56

[lowdrag]

The E-type has run happily of 95RON for over 15 years now. When we took the engine apart the head was dead but that was due to overheating at some point. The valves were fine and there were never any ignition problems if the points were properly set.

[RichB]

Having contacted the main suppliers last summer BP were the only one to confirm that their Ultimate does not contain ethanol. (Unless you're in Wales)

[nta16]

Tesco Momentum99 has a maximum of 5% ethanol and I guess their 95 octane is the same

over many years of use I've had no problems with ethanol even after the car was sat outside this winter for 5 weeks unused

I think for some (many?) classics the problems are more about lack of regular use on reasonable length journeys than ethanol

I've read many stories about ethanol ruining your car and rotting your teeth yet others abroad report that they've been for many years (decades) using much higher levels of ethanol than we have in the UK without problems (and on the same make and model of classic)

[Riley Blue]

Some light reading for you... http://etheses.bham.ac.uk/3675/1/Daniel12PhD.pdf

[jith]

dpp said:

I was wondering what fuel you use in your classics as I always try to use Shell V Power but I'm not sure if it is actually any better than other fuels.
However I did notice that after using supermarket fuel my 1975 Vauxhalll developed a run on after the ignition was turned off which went away as soon as I refilled with V Power.

Since that I have always tried to use Shelll and if not available another premium fuel from BP or Esso etc but never any more supermarket fuel. Since getting my Jensen back on the road I have never used cheap fuel following my experiance with the Vauxhall.

Have I been suckered into paying for premium fuel or is it actually better for our older cars?

Dear me, the misconceptions around unleaded or whatever!

There are two elements to this; the octane rating and whether or not fuel is unleaded. They are two different things and must be viewed as such.

The lead in fuel was used as an additive by way of lubrication mostly on the valve gear. Early unleaded fuel did cause problems in many engines, but the fuel nowadays is a different ball game and has many additives of differing kinds to protect engines, fuel and emission systems.

The octane rating, simply put, is how effectively the fuel burns. The rule of thumb on older engines is the higher the state of tune, i.e. compression ratio, cam profile, ignition timing, etc, the higher the octane should be. Lower octane fuels in the wrong engine cause pinking or pre-ignition, NOT unleaded fuel.

My daily is an Audi A6 2.4 V6. It has full motronic injection and cats. it doesn't matter what octane rating I put in, the ECU simply adjusts the mixture and ignition curve to cope with the combustion properties of that fuel. It does it using the numerous sensors situated on the engine and manifold systems. I use Tesco 99 octane super unleaded and the car drives superbly with full power. if I go to ordinary unleaded the pwer decrease is marked and instantly noticeable; simply due to the ECU protecting the engine by retarding the ignition and reducing the power to prevent pre-ignition.

Your classic has no sensors and no control system, so it has to be set up manually. Judging by some of the disasters I see on a daily basis in my workshop, this is a dying art!

The engine in your 2.3 Vauxhall dpp was pretty much state of the art in its day and was the basis of the droop snoot rally cars and the Lotus powered engine in the Jensen Healey. You should only run it on 99 octane or as high as you can get. Pre-ignition is the number one killer of engines in old cars, so the timing and fuel mixture has to be spot on for the state of tune and the octane of the fuel you are using.

Lastly, if you find that your engine runs on when you switch off it can be that the timing is too retarded and the plugs are running hot causing them to ignite the fuel even after the ignition is dead. If you are forced to retard the timing to stop pinking then it might be wise to change to a different plug type to prevent run on.

Hope this helps.

J

[nta16]

sorry just seen I forgot about Esso, not a fuel I see often so checked their website, from their website -

"Supreme Unleaded (97 octane): Our premium grade, higher octane petrol with double the detergent additives of our standard unleaded (95 octane) to help give you a better engine performance."

[Pixelpeep7r]

Riley Blue said:

Some light reading for you... http://etheses.bham.ac.uk/3675/1/Daniel12PhD.pdf

LIST OF ABBREVIATIONS
aTDC After Top Dead Centre
AFR Air-Fuel Ratio
AFRstoich. Stoichiometric Air-Fuel Ratio bTDC Before Top Dead Centre
BDI n-Butanol in Direct-Injection
BUT n-Butanol
CAD Crank Angle Degrees
CADEOI-SPK Crank Angle Degrees from End of Injection to Ignition
CADSPK-90 Crank Angle Degrees from Ignition to 90% Mass Fraction Burned CAD10-50 Crank Angle Degrees from 10 to 50% Mass Fraction Burned CAD10-90 Combustion Duration (Crank Angle Degrees from 10 to 90% MFB) CAD50-90 Crank Angle Degrees from 50 to 90% Mass Fraction Burned
CA50 Crank Angle at 50% Mass Fraction Burned CLD Chemiluminescence Detector
CO Carbon Monoxide
CO2 Carbon Dioxide
COV Coefficient of Variation
DDI DMF in Direct-Injection
DI Direct-Injection
DISI Direct-Injection Spark-Ignition
DME Dimethyl Ether
DMF 2,5-Dimethylfuran
DNPH 2,4-Dinitrophenylhydrazine EBS Ethanol Boosting Systems LLC EDI Ethanol in Direct-Injection

i guess there won't be one neat summary page that states 'yeh that shell nitro+ stuff is better because there's not as much crap in it' in that 'report' lol.

[dpp]

Thanks for the great replies, I think I will continue with the Shell fuel as it is not the small additional cost that is my problem but more the fact that I have to purposefully drive to a Shell garage even though I visit the supermarket station for my classic car weekly and don't get fuel.

The Vauxhall has a very low mileage engine so I use a lead additive as I don't want to pull apart a healthy engine, and after 5000 miles use the plugs were a perfect colour when replaced at service and the car runs really nice so Im not going to risk any problems for a minor inconvenience and an extra couple of quid at the pumps.

The Jensen is running on a fresh engine with hardened valve seat inserts so has no additive but seems to run well on Shell fuel so again i think I will keep it as it is.

[roscobbc]

Guy who built the engine in my Vette only ever dyno's using Shell VPower Nitro (which I continue to use) he sees a real 2%+ increase in BHP - OK, so not too significant with 100 bhp - it was probably worth an additional 10 to 12 bhp on mine. With 10.5 to 1 comp ratio the engine most definately ran smoother with VPower and was less likely to 'run-on'

[Mopar440]

dpp said:

The Jensen is running on a fresh engine with hardened valve seat inserts so has no additive but seems to run well on Shell fuel so again i think I will keep it as it is.

If you've had hardened valve seats fitted then presumably your engine id a 383? If so, that's got a higher compression ratio that the later 440, so may benefit from the better fuel.

[BGarside]

My BMW M50 engine apparently has a CR of 10.5:1 but is supposedly happy running 95 octane. I wonder if the ECU is pulling timing to prevent pre-ignition?

My first car was an '85 Fiat Uno 60S and despite only producing a massive 58hp, used to pink like a bh on unleaded unless the timing was retarded so far that what little performance it had was basically killed off...

[dpp]

Mopar440 said:

If you've had hardened valve seats fitted then presumably your engine id a 383? If so, that's got a higher compression ratio that the later 440, so may benefit from the better fuel.

Yes its a G series 383 so needed new valve seats unlike the later 440, i don't think the G series is as high a compression ratio as the earlier engines though. ive also got an E series 383 thats needs rebuilding but thats for another project but I have been told this is the better than the later engines.

[dpp]

Mopar440 said:

If you've had hardened valve seats fitted then presumably your engine id a 383? If so, that's got a higher compression ratio that the later 440, so may benefit from the better fuel.

Yes its a G series 383 so needed new valve seats unlike the later 440, i don't think the G series is as high a compression ratio as the earlier engines though. ive also got an E series 383 thats needs rebuilding but thats for another project but I have been told this is the better than the later engines.

[Mopar440]

Yes, the E-Series is the one to go for, lovely, lovely engine.

[Andy 308GTB]

jith said:

Early unleaded fuel did cause problems in many engines, but the fuel nowadays is a different ball game and has many additives of differing kinds to protect engines, fuel and emission systems.

There was some confusion as to whether my car had hardened valve seats, so for a few years I would source Leaded petrol.
As the availability dried up, I switched to Unleaded and the Valvemaster additive (when I remembered).
Are you saying that there is now no need for additives when using Unleaded petrol with un-hardened valve seats?
I'm just curious because I now believe my car to have hardened valve seats

Other than that thanks very much for an excellent post. I have seen Ferrari owners drive miles out of their way to get Shell petrol - stating that Ferrari recommends it for their cars. Blatantly, ignoring the fact that Ferrari could hardly recommend BP when Shell is one of their longest standing major sponsors. Also I do believe that there is a certain snobbery and elitism about insisting that your car needs the highest octane petrol available - i.e. other drivers don't need to be so choosy because their cars are less powerful etc. Again ignoring the fact that the higher octane rating will prevent pre-detonation/pinking but does not provide more energy...