Maxol E5 - where's the catch?

Elessar

I'd like to try it on my 320ci but according to BMW they don't recommend it. I still cant believe you cant buy actual 98RON fuel in this country.

colm_mcm

E92 wrote: »

You should already know the answer if you have started using it!

I think it was JHMEG who correctly said that the engine management adjusts straight away.

On the GPX it adjusts after around 100km or when you take the battery out I heard.

Henry Ford III

I seem to remember on the Focus ST that 225bhp was available on 95 u/l, and this rose to 237bhp on Optimax (98 u/l).

About a 5% difference. Hardly worth the bother and expense.

richie_rvf

Henry Ford III
I seem to remember on the Focus ST that 225bhp was available on 95 u/l, and this rose to 237bhp on Optimax (98 u/l).

About a 5% difference. Hardly worth the bother and expense.

Isn't the fuel supposed to be the same price? I thought that Maxol have replaced their u/l with E5.


Elessar
I'd like to try it on my 320ci but according to BMW they don't recommend it. I still cant believe you cant buy actual 98RON fuel in this country.

I have used it twice now in my BMW, did not notice any difference in performance but the car certainly runs smoother and from very low rpm seems to pull slightly better, not in power but smoother - if you know what I mean.

Richie.

Henry Ford III

Some confusion here Richie.

Optimax was 99 RON, but has been withdrawn. Replaced by V Power, which appears to be 99 RON in the UK, but only 95RON here.

richie_rvf

Henry Ford III wrote: »

Some confusion here Richie.

Optimax was 99 RON, but has been withdrawn. Replaced by V Power, which appears to be 99 RON in the UK, but only 95RON here.

What I meant was the price of fuel at Maxol garages, I thought they had just replaced their unleaded with E5 so the price should be the same.

Yeah, I knew that about Shell, I used to go across the border to fill up - never made any difference - except in my head :rolleyes:

JHMEG

colm_mcm wrote: »

On the GPX it adjusts after around 100km or when you take the battery out I heard.

It shouldn't do. It should be pretty instant. If you have the tiptronic gearbox that takes a while to adjust to your driving style (eg if you've just bought the car), or disconnect the battery and it will learn as soon as you drive it next.

Also I think that lower power cars will notice an improvement more so than higher power. I know when I put 98 in my 75bhp 1.3 (back when 98 was 49p a litre!) there was a huge difference. As E92 pointed out a difference between 221bhp and 231bhp may not be noticeable, especially if it is a heavy car.

Flaccus

Isn't it calorific content that matters for power output and not just RON. As the E5 calorific content is 30.51 MJ/Litre versus normal 95 unleaded of 31 Mj/Litre won't the power output be the same as 95RON, as opposed to true 98RON which I assume would have a higher calorific content. And if you are using a car setup for 98RON, wouldn't the ECU adapt after a couple of hundred miles and burn through E5 a lot quicker then 95RON ?

Anan1

Flaccus wrote: »

Isn't it calorific content that matters for power output and not just RON. As the E5 calorific content is 30.51 MJ/Litre versus normal 95 unleaded of 31 Mj/Litre won't the power output be the same as 95RON, as opposed to true 98RON which I assume would have a higher calorific content. And if you are using a car setup for 98RON, wouldn't the ECU adapt after a couple of hundred miles and burn through E5 a lot quicker then 95RON ?

I would have thought that the power output would be as per 99RON, but that the fuel consumption would be higher as a result of the lower calorific content. Isn't that what happens with E85?

TychoCaine

Flaccus wrote: »

Isn't it calorific content that matters for power output and not just RON. As the E5 calorific content is 30.51 MJ/Litre versus normal 95 unleaded of 31 Mj/Litre won't the power output be the same as 95RON, as opposed to true 98RON which I assume would have a higher calorific content. And if you are using a car setup for 98RON, wouldn't the ECU adapt after a couple of hundred miles and burn through E5 a lot quicker then 95RON ?

He's right.... The octane rating is a measure of a fuel's knock* resistance. It has nothing to do with the amount of power you get out of it. While a given fuel's power increases in proportion to it's octane rating, different types of fuel don't correspond. Ethanol only has 2/3 the power of petrol (21Mj/L Vs 31Mj/L), even though it's more knock resistant.

Because the mixture is more knock resistant than normal 95RON, the engine can run more aggressive timing, and generate more power for a given quantity of fuel. This compensates for the actual lower energy content of the mixture, but no more, even on JDM cars. The only real benefit is that the CO2 emissions are 3.4% lower than 95RON.

* For those that don't know, Knocking/Pinking/Pre-Detonation is petrol's propensity to spontaneously ignite when compressed (like diesel does), before the spark plug lights it. A high compression engine requires a high octane fuel to run correctly. Otherwise the petrol ignites itself before the piston gets to the top of the cylinder, which would interrupt the smooth rotation of the engine components, causing a "knock".

Flaccus

Octane rating only reflects the ability of unburnt end gasses to resist spontaneous autoignition. When this happens you get a pressure rise as both the spark flame front and ignited end gas are expanding which causes an early pressure peak that is reponsible for the oscilliations which create the so called knocking noise. The Octane rating or antiknock index just measures the ability of these gases to ignite. Higher Octane rating means more efficiency and so potentially more power, but if the calories per litre are substantially less with E5 compared to proper 98RON I would doubt you get more power at all.


<edit>Didn't see above post</edit>

dcGT

Flaccus wrote: »

Octane rating only reflects the ability of unburnt end gasses to resist spontaneous autoignition. When this happens you get a pressure rise as both the spark flame front and ignited end gas are expanding which causes an early pressure peak that is reponsible for the oscilliations which create the so called knocking noise. The Octane rating or antiknock index just measures the ability of these gases to ignite. Higher Octane rating means more efficiency and so potentially more power, but if the calories per litre are substantially less with E5 compared to proper 98RON I would doubt you get more power at all.


<edit>Didn't see above post</edit>

Interesting. So is this stuff a placebo of sorts?

DC.

TychoCaine

Anan1 wrote: »

I would have thought that the power output would be as per 99RON, but that the fuel consumption would be higher as a result of the lower calorific content. Isn't that what happens with E85?

In a given engine you get a certain amount of power per calorie used. You put a fixed quantity of energy into the engine in the form of fuel, you'll get the same out the other end at the flywheel, less the inefficiencies (heat, noise etc.) in the engine. You have to put more energy in to get more energy out.

If we were to forget about ignition timing for a second here, your ECU would decide whether to consume fuel at a higher rate to maintain horsepower, or consume fuel at the normal rate and produce less horsepower. In the latter scenario you'd probably override it anyway by being slightly heavier with your right foot. What will happen in reality is that the ECU will detect 99RON fuel and fuel at the normal rate but change the ignition timing (because it can allow it to get more compressed before having to ignite it) to be more efficient. This will bring the BHP back up in line with normal 95RON, and maintain normal levels of fuel consumption.

Take a look at the Maxol website here. Don't you think they'd be shouting it from the rooftops if they had a fuel they could sell for the same price as 95RON that would give more power or economy?

TychoCaine

dcGT wrote: »

Interesting. So is this stuff a placebo of sorts?

DC.

Not quite. It won't make a difference to performance or efficiency, but it's good for the environment because it lowers CO2 emissions by 3.4%.

Flaccus

I've been using it on my Octavia vRS for a while (local station is on maxols e5 list) and didn't even cop it.

Max_Damage

I haven't read this entire thread, so I don't know if this has been brought up, but meh...

Given that ethanol has approx. 33% less energy per same unit volume than petrol, then this E5 stuff that Maxol are selling will have slightly less energy than unleaded petrol. That's provided they didn't put some additives to the fuel.

Flaccus

Yeah...mentioned in a post above in detail by Tycho

Anan1

TychoCaine wrote: »

In a given engine you get a certain amount of power per calorie used. You put a fixed quantity of energy into the engine in the form of fuel, you'll get the same out the other end at the flywheel, less the inefficiencies (heat, noise etc.) in the engine. You have to put more energy in to get more energy out.

If we were to forget about ignition timing for a second here, your ECU would decide whether to consume fuel at a higher rate to maintain horsepower, or consume fuel at the normal rate and produce less horsepower. In the latter scenario you'd probably override it anyway by being slightly heavier with your right foot. What will happen in reality is that the ECU will detect 99RON fuel and fuel at the normal rate but change the ignition timing (because it can allow it to get more compressed before having to ignite it) to be more efficient. This will bring the BHP back up in line with normal 95RON, and maintain normal levels of fuel consumption.

Take a look at the Maxol website here. Don't you think they'd be shouting it from the rooftops if they had a fuel they could sell for the same price as 95RON that would give more power or economy?

So what you're saying is that the lower calorific value of the fuel is compensated for by the fact that it can be burnt more efficiently because the ignition can run more advance? This makes sense for an engine that's set up for 98, ie one that will advance ignition timing when the fuel allows. What about most cars though, which are set up for 95? Won't they just get poorer economy with nothing to show for it?

TychoCaine

Anan1 wrote: »

So what you're saying is that the lower calorific value of the fuel is compensated for by the fact that it can be burnt more efficiently because the ignition can run more advance? This makes sense for an engine that's set up for 98, ie one that will advance ignition timing when the fuel allows. What about most cars though, which are set up for 95? Won't they just get poorer economy with nothing to show for it?

Even my old 1.4l Focus had a "98RON recommended" note in the manual, and I can't ever remember driving a car where 95RON was recommended. I'd have thought anything with electronic fuel injection and ignition would adapt just fine.

Spit62500

Flaccus wrote: »

I've been using it on my Octavia vRS for a while (local station is on maxols e5 list) and didn't even cop it.

Your local station may be on the list but not yet stock it. The Maxol in Newbridge is on the list for a few weeks but doesn't yet stock it. They have started to install a designated E85 pump (as of last weekend) so its on its way. The Maxol in Naas has it - you can tell because there are stickers proclaiming it on the pump.

Flaccus

Must ask the owner. Only 2 stations in Clare are on the list.

zilog_jones

TychoCaine wrote: »

Even my old 1.4l Focus had a "98RON recommended" note in the manual, and I can't ever remember driving a car where 95RON was recommended. I'd have thought anything with electronic fuel injection and ignition would adapt just fine.

The manual for my '98 Fiesta recommends 95RON - it says it will run on higher but will gain no benefit, and it can run in 91 if you take out some fuse. This applies to all the petrol engines available in it at the time (1.25, 1.3, 1.4 and 1.6 if it existed then), not just my crappy pushrod. I assume this was the same up until at least 2002.

EuroR

From what I've read so far the opinion is that there is no huge gain running e5 versus standard unleaded other than the environmental benefit (all good).

Moving back to Ireland soon and want to find a decent fuel to put in the car. Am i right in saying the options are:

>Maxol e5
>Standard unleaded

and??

Is there a none biofuel alternative to standard unleaded?

Is the two the same price?

Japan rocks for fuel by the way. High octane every station 95c/l (euro)

L1011

Theres E85 on sale quite a few places, as well as 98 RON non-biofuel. However, most cars won't take E85 without modification....

nialler

I've had 2 tanks of it in now, my car prefers 98 RON, with the E5 it runs a lot smoother and certainly has more pickup, fuel economy I'm not sure yet, only did a reset on the 1st tank so I'll give it a few and report back.

EuroR

MYOB wrote: »

Theres E85 on sale quite a few places, as well as 98 RON non-biofuel. However, most cars won't take E85 without modification....

Cool so who does 98RON non-biofuel hardcore heat the world petrol?

Apologies for drifting from the thread but your the guys who know.

bennyx_o

Theres no petrol stations south of the border selling 98RON petrol (except E5)