Which Petrol?

Contigo said:

Which bit? The redex or the Sul vs Unleaded?

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15-20% better fuel consumption, or even any significantly better performance in proper double blind controlled testing. From SUL.

Mined ewe I'd be interested in any proper evidence that Redex helps these days as well

C

I think Super is a must. It's bit like eating fresh food, you like to think that it's doing your insides some good when compared to processed rubbish. I'm convinced after many quick cars that it makes for a smoother, quicker drive. I don't care what it does to economy but suspect it doesn't hurt. To me it's a bit like using hgh quality oil. Sure they will all do the job but there are some fine tolerances in a modern engine, especially one with such touchy Italian electronics running the show!

I think there's probably some more evidence that fresh food is better for you than processed (typically high fat / high sugar / high salt)

However, I could well be wrong (again)

C

I do not use redex to boost performance, it won't do that..!! For example, when in Europe and I come across a garage with fuel I have never used, I will stick redex in with that fuel, redex only keeps stuff clean, just like V-Power but which has extra boost..!!

Ok for the redex stuff I was not convinced but after watching this when it was aired a few months ago it changed my opinion.

https://m.youtube.com/watch?v=03nL8Z0dRkI

I have a few articles regarding tests on SUL vs Unleaded on my computer so will reference them once I fire it up.

Interesting.
Sort of
3% increase in power, but it's in no way a scientific test.

I'd still be interested in the SUL stuff

C

Redex only cleans up what is already there, if the system has a build of say a toxin type coating, it will take it off and you will get back to the power you were supposed to have..!! Super on the other hand burns better and results in more power for a cleaner burn, the engine has to do slightly less for the same result, so in effect the performance is better..!! 95 Ron is the minimum for a reason..!!

Why do you think a fuel that is more resistant to pinking burns better? It contains *less* energy that regular unleaded.

I am genuinely curious as to people's views. The science is pretty clear on the whole matter, but it's a fascinating discussion


C

Won't it be tricky with modern engines capable of adjusting ignition timing on the fly based on knock sensors? One reason the Maser ECU can be remapped for more power is that it's conservatively mapped in the first instance, running rich with a default retarded ignition to cater for poor fuel and hot running. Putting in a higher octane fuel will allow the controller to optimise burning the fuel, so it's not a simple test directly of the properties of each batch. Same end effects though.

Yes and no. You can run higher compression up to the point the ECU will let you. That gives a theoretical increase in efficiency. *But* the fuel has less energy, so you're reducing the maximum amount of energy for the same level of efficiency.

Some cars will see a *moderate* increase in power and mpg (Certainly I'd be very surprised if there were properly measured gains even getting close to 10%), but it's most interesting to me the glaring lack of proper research demonstrating the claims.

The redex video is interesting. *But* it fails on the first, most basic standards of scientific rigour. There's no control, so there's absolutely no way to tie the observations to the redex and nothing else.

Now, *if* this stuff is as good as the petrol companies would have us believe, surely they'd have studies coming out of their ears which they could trot out every time someone pointed at their marketing and said 'hang on, where's your evidence?'

Instead we have nebulous claims about 'Friction Modification technology (Shell) 'Corrosion inhibitors' (BP, when was the last time you saw a corroded fuel system?) and similar.

Interestingly (to me at least) the least hyped is Tesco who even publish some reasonable ish study results and make sensible claims, and publish some specs.

The advertising for the original Optimax was withdrawn on (I understand) the instructions of the ASA.

Now I'm going to buy a tank of it, as (I said up there) I'm detecting some very slight hesitation. I *expect* that confirmation bias will either make me
1) Feel an improvement
2) Feel no improvement
3) Feel things get worse.

Gonna be tricky

C

Why are some cars designed to run on a minimum 98 RON then? Some cars do have the ability to deal with the knock using very clever methods and adjusting timing on the fly without any degradation of performance.

CatmanV2 said:

Now I'm going to buy a tank of it, as (I said up there) I'm detecting some very slight hesitation. I *expect* that confirmation bias will either make me
1) Feel an improvement
2) Feel no improvement
3) Feel things get worse.

Gonna be tricky

C

Click to expand...

experimenter effect in action

Evo magazine did a test on a Golf GTi a few years ago and the test results were interesting. The test car was run on each fuel until its onboard computer showed a range of 3 miles or less, filled with 10 litres or more of the test fuel, then run down to a range of 3 miles or less again and filled with 20 litres or more of the same fuel.

The quoted figures for the Golf GTi are 197 bhp and 207lb/ft. Tests were done at WRC technologies in Silverstone.

Some results:

Shell Optimax: 209 bhp, 242lb/ft.

Shows useful gains compared to Shell 95. Compared with other high octane fuels, it's on a par with Tesco 99 low down but lacks its mid-range (and that of Bp ultimate) with torque fading slightly earlier. Driver notes: (Tried after the 1st batch of bp ultimate) The Golf suddenly discovers a top end - you want to rev it right to the redline. Of all the fuels the GTI felt the crispest and most fun to drive on this. It would be my choice.

Tesco 99: 212 bhp, 242 lb/ft.

Highest octane rating of the pump fuels didn't quite give the top results. Massive gains over our sample of Tesco 95. Doesn't deliver like the BP ultimate low down but then gets ever stronger matching its power and staying stronger for longer. A fine result, and its part bio-ethanol. Driver notes (After Shell optimax) Mega mid range but feels a little laboured to the redline. Somehow less clean feeling. Sound was less positive too.

BP ultimate: 212 bhp, 250 lb/ft.

Level pegged with Tesco 99 on peak bhp but significantly out performed it and every other pump fuel in terms of torque (and even matched the race fuel into the mid-range) Very strong right from the off and stays ahead of the others right up to 5000rpm. Drivers notes (Tried after a 95) Explosive low down - really quick on boost and sharp response too. Wooly top end though - the last 1000rpm is a struggle, strange.

Some other quotes from the article:


It's worth noting that in WRC's experience some cars respond better to Optimax (turbocharged Subaru's for instance) and some to Bp ultimate (Mitsubishi Evo's) so its possible your car will prefer one or the other, or Tesco 99.


Drivers perceptions are interesting: Some fuels make the engine FEEL a lot keener to fly to the redline.

The next test they did was on an E60 M5 and the results are interesting. One note is the sophisticated ECU and the way it adapts timing using the spark plugs!!!!!!



I think after reading the outcome of the M5 article where they said putting 95 RON in a car designed for 98 RON and there being no difference really does throw a spanner in the works but it could be down to simple things like batches of fuel. Sometime even though you are putting 95 RON into a car it is minimum 95 ie not going to be 94 but could be 97RON. When BMW tested it in their labs they noted 501bhp on 95 RON and 515bhp on Optimax, hardly a 20% gain but certainly something which would be noticeable by most drivers. The one thing which should be true is that:

If you put 95 RON into a production car designed to run on 97 RON it will detect knock and change the timing to compensate. You will get less power / efficiency.

If you put 99 RON into a production car designed to run on 97 RON, it will not notice that there is no knock and change the timing until detonation starts to occur.

But as Cat says above it's a fine art and there really are no proven or reliable stats out there. I know one thing,my seat dyno tells me if the old girl is going well so I always use BP Ultimate and that's my choice. It's up to you guys and gals

I have commented on it here previously however, I always put Tesco 99RON super unleaded in the Maserati. I have not even tried running it on anything else to make a comparison so I'm probably chucking money down the drain.... Now to explain; I have my own company and I run fuel cards for the family and it is a FuelGenie account which limits me to Tesco and Morrisons. I can live with that

Why do I use super unleaded over standard without testing it? Well around 2000 I bought an old Mercedes 123 230e that at the time was 18 + years old and had 105,000 miles on it. I drove it for a while and then rebuilt the engine completely, it didn't need re boring or rings but the bottom end was shot because of oil sludging I hadn't picked up on (didn't realize how long it had been sat around for prior to my buying it). I took the opportunity to 'breath' on anything and everything internally, including gas flowing and running gold vanadium plugs etc. It was fitted with the Bosh mechanical fuel injection and I discovered in the books it was designed to run on higher octane (4* 98RON equiv' as opposed to 2* 95RON equiv') but would run on low if needed. I at that time put some tanks of Optimax into it and found great results so I had it tuned to be optimized for Optimax... Results were very impressive, as I recall:

95 Ron / 98Ron Optimax
Range on a tank full
260miles / 390miles
0-60mph
14 seconds / <8 seconds
starting
Hmmm... / perfect

This represented a genuine massive gain in power, reliability and more than 12mpg such that it easily paid for the difference in cost of a tank full...

I strongly suspect that the Maserati just says thank you for feeding me nice stuff and dials it all back rather than giving you the full benefit of it...

General concensus then is higher octane gives you more power, but for Mr.C, we can't prove it, but if it works don't fix it..!!

Interestingly the owners manual/handbook for the 3200 (probably same for Coupe too) says Super Petrol unleaded octane no lower than 95 R.O.N for recommended fuel.

Doesn't it say that in virtually every petrol car sold in Europe? That's the most commonly available petrol, so I'm certain they are factory tuned to deal with that fuel.

Super and 95 don't really go together do they..??

You ever bought petrol in America Rob? 95 isn't the starting point...

Anyway... there's 100 available in Italy at Shell and Tamoil stations