high octane fuel question

[Dave92270]

hi guys,

I moved my H3 to Europe, and finally got it licensed here (needed lights modifications and other stuff). anyway, back in Cali I used 87 octane fuel (or was it 86?) which is recommended for H3; here the lowest grade is 95 octane - do I need to reprogram the car computer, or can just let it go? I don't see any diference in engine peerformance...no rough running, idle rpm is same as well....

thanks for advice

[guruerror]

95?! WOW!

I'd think you'd be fine with no programming change...

...however, I'd be temped to put in a 'Performance' tune and spend the weekend mashing the pedal on that fancy Autobahn; especially if you've got the 5.3.

[Dave92270]

Originally Posted by guruerror

95?! WOW!

I'd think you'd be fine with no programming change...

...however, I'd be temped to put in a 'Performance' tune and spend the weekend mashing the pedal on that fancy Autobahn; especially if you've got the 5.3.

I know , high octane sounds fancy and performance promising, but not sure if H3 engine is capable to take advantage of it, BTW, today I bought some 15 gallons (around 60 liters actually here) of 95 octane, but they usually offer 98 octane as well. However today at this particular station I saw 100 octane fuel as well. They market it as "premium high-octane automobile benzin".

I think that I hopefully wont hurt anything using 95 octane without modification of computer. However, I'll give a call to guys who did mods on my H3 to be EU registered, they may offer some performance adjustments in the computer...

well if anyone else has experience with this stuff I'd be glad to hear it, thanks

[Humvee21]

I am not 100% sure, but this is just my opinion/beliefs. The higher the octane is, the better it is. Therefore, as long as you do not put a lower octane than manufacture requirements then you will be fine with no programming changes. However, octane measurements between the US and Europe are measured differently. This means that we could have 87 octane in the US and have 87 octane in Europe, but both are completely different since it is measured differently. Do some research on octane measurements in Europe and see how it compares. Hope I helped some

[RenegadeX]

What you need to do is add a supercharger!

Higher octane just prevents premature detonation (knocking). You need it on high compression engines, supercharger equipped, etc. Your engine is not. You can use it without a problem.

Contrary to popular belief, higher octane is not high performance.

[Dave92270]

Thanks guys,

Sounds like I'm going to be just fine with 95 octane without any modifications, but next time I'll speak with the shop which did EU conversion for me I'll ask them about this.

So far, the engine seems to run exactly the same as it did back in the US on 87 octane.

[fourfourto]

According to wikipedia,
RON is always about 4 to 5 points higher than the equivalent PON (Pump Octane number = AKI):


USA (AKI/PON) --- Europe (RON)

87 = 91
89 = 93
91 = 95
93 = 98

[Dave92270]

Originally Posted by fourfourto

According to wikipedia,
RON is always about 4 to 5 points higher than the equivalent PON (Pump Octane number = AKI):


USA (AKI/PON) --- Europe (RON)

87 = 91
89 = 93
91 = 95
93 = 98

Thanks. That is interesting, I guess there is not much to worry about then.

[wpage]

You could see some benefit from a tune. Timing is important with a hotter burn in you cylinder. Probably not a issue of damage but performance improvement to take advantage of a higher burn rate in combustion...

Good luck in your venue!