100 Octane Petrol in N54

[R.E92]

Who knows what safety features have been disabled by the mapper, not worth the risk IMO

Kinda boils down to know what is being done to your car

AFAIK, most 'commodity level' N54 tunes change the fuelling tables and boost tables and leave much of the rest alone..

The argument I guess since so many people have tweaked this engine, and relatively speaking so few have blown them up that its a pretty tough engine and runs out of steam before it can blow up, unless you start adding bigger turbos and meths /ethanol etc..

I went with the N54 and then MHD Flasher precisely because so many people had been down that route.

That was one of the issues with the N20..there was precious little UK experience of tweaking it and in the US people had blown a few motors asking it to do too much.

Those guys doing the really silly tunes and they have now taken the N54 past 1000bhp are into a world of expensive adds ons or very careful monitoing.

That's why some folks use tools like JB4 (a piggy back device) AND an ECU flash as the JB4 can save the engine from a major issue if something goes wrong..whilst a pure flash will keep going till it goes bang.

So yes it can go wrong, but if the guy says 380 bjp on stock parts then it doesn't set the alarm bell ringing (directly)..IMHO

The JB4 is more likely to cause your engine to blow than save it. I saw a person recently who blew their low mileage engine using just a JB4. They were fortunate enough to be logging the car at the time and the logs showed the engine detecting an issue and trying to reduce boost pressure but the JB4 overrides the engines requested boost and keeps targetting the full amount. Because of the way the JB4 lies about the actual engine load the engine thought the boost had been lowered therefore started to target a really lean afr which caused the engine to blow.

I know they use the JB4 safety features as a selling point but realistically it's marketing BS. One thing that struck me about the JB4 forums was the number of people on their second or third engine, it was almost like a rite of passage.

[B21]

Kinda boils down to know what is being done to your car

AFAIK, most 'commodity level' N54 tunes change the fuelling tables and boost tables and leave much of the rest alone..

The argument I guess since so many people have tweaked this engine, and relatively speaking so few have blown them up that its a pretty tough engine and runs out of steam before it can blow up, unless you start adding bigger turbos and meths /ethanol etc..

I went with the N54 and then MHD Flasher precisely because so many people had been down that route.

That was one of the issues with the N20..there was precious little UK experience of tweaking it and in the US people had blown a few motors asking it to do too much.

Those guys doing the really silly tunes and they have now taken the N54 past 1000bhp are into a world of expensive adds ons or very careful monitoing.

That's why some folks use tools like JB4 (a piggy back device) AND an ECU flash as the JB4 can save the engine from a major issue if something goes wrong..whilst a pure flash will keep going till it goes bang.

So yes it can go wrong, but if the guy says 380 bjp on stock parts then it doesn't set the alarm bell ringing (directly)..IMHO

The JB4 is more likely to cause your engine to blow than save it. I saw a person recently who blew their low mileage engine using just a JB4. They were fortunate enough to be logging the car at the time and the logs showed the engine detecting an issue and trying to reduce boost pressure but the JB4 overrides the engines requested boost and keeps targetting the full amount. Because of the way the JB4 lies about the actual engine load the engine thought the boost had been lowered therefore started to target a really lean afr which caused the engine to blow.

I know they use the JB4 safety features as a selling point but realistically it's marketing BS. One thing that struck me about the JB4 forums was the number of people on their second or third engine, it was almost like a rite of passage.

Well R.E92, I bow to your accumulated knowledge and experience..good to know..that's another goody struck of the list!

I was re-circulating what appears to be garbage from the BMW tuning web site..

https://bmwtuning.co/n54-tuning-guide-beginners/

Some guys on spoolstreet had also contradicted some aspects of their posts..

[R.E92]

That site is a good reference for some things but it's little more than a distillation of forum topics, better to get the info directly.

[Marcoose]

91 Octane is basically our 95RON which is your basic bitch fuel, I would not however run 95RON in my turbo cars though admittedly they were mapped to run on 99RON and didnt run well at all on 95RON (there is a noticeable difference in performance as well when map accounts for fuel quality)

But bitch fuel is better than no fuel, right mate? Just sayin'.

As Richard said, vehicles in American are tuned to meet California 'bitch/s**t' fuel regulations. Given there are millions of high-end street cars in America running on 91 daily and nobody is complaining, it's far to assume it isn't a problem. I had taken the old E85 to other states with different fuel ratings. (Other vehicles too.) As far as street driving goes, even spirited, there was no noticeable difference in performance.

So US 91 is our 95!

Unusally for a nation so keen on bigging it up why is their gallon less than ours and their octane rating?

Yeah, I had to and still am getting used to American 'exceptionalism'. Even after more than half of my life here and now a bone fide gringo, I still say aluminium and potahto.

[Flyingfifer]

But bitch fuel is better than no fuel, right mate? Just sayin'.

As Richard said, vehicles in American are tuned to meet California 'bitch/s**t' fuel regulations. Given there are millions of high-end street cars in America running on 91 daily and nobody is complaining, it's far to assume it isn't a problem. I had taken the old E85 to other states with different fuel ratings. (Other vehicles too.) As far as street driving goes, even spirited, there was no noticeable difference in performance.

You seem to have mistaken my comment for some sort of slight, I was simply pointing out that 91OCT is the same as our 95RON and is the basic level of fuel quality.
The reason millions of "high end street cars" run 91 is that most cars are mapped for 91 though I would point out that not all of them will, when you start getting into GTR/Ferrari territory unless again they are mapped to take the lesser fuel. The same is the case with the Z4 I run my coupe on 95RON (91OCT) most of the time as it is a NA car that is mapped to take 95RON, my Evo and Glanza however were mapped for 99RON and would be a bag of bolts on 95 with a noticeable dip in performance.

[Marcoose]

Well, then guess what? Ferrari’s and Porsche’s #1 market is America. I don’t have sales figures and the following is pulled out of my fat arse, but I bet California is their flagship market. It is after all the 7th largest economy in the world. And in the San Francisco Bay Area and Silicon Valley, with so many folk with far more money than sense, you cannot swing a dead cat without hitting a Ferrari or a Porsche. It’s an embarrassment of riches. (But then my home country is even worse.)

And everybody runs on s**t fuel. Sure, all tuned accordingly. But not a single owner complains about performance. Zero. Full stop. They complain about ‘performance awards’, but that’s another story.

He who cannot find happiness with a 300bhp street car … is not a very happy bloke.

That’s all I have to say.

[Flyingfifer]

There is a difference between "complains [sic] about performance" and the simple fact that should they be run and mapped for better fuel they would run and perform better on better fuel.
You have a bunch of bananas and give one to a monkey its going to be happy it got a banana if it doesnt know there is a whole bunch

Im not sure why you're trying to argue here, we actually agree, if your car isnt tuned for premium fuel its not going to make a bit of difference.

If your vehicle isn’t tuned for 100 octane, it won’t do anything. My track car and bike are not tuned for 100 octane. I’ve never felt fuel was the winning/losing factor.

BUT if you have a car mapped for 99RON or 100OCT (which is frequently the case here with tuned/enthusiast cars) if you run that car on 95 believe me you know that its on 95.