NB8 91 or 95 ron fuel?

miata · Postby **miata** » Thu Jul 07, 2011 1:41 pm

NitroDann wrote:GP maybe some people think that the forum is a place for giving good correct information when you have it and reading good correct information when you dont. And telling people info you just pulled out of your ass because it sounds about right down at the pub is NOT what the forum is for.

If the info was regarding door trims who cares but not steering brakes or engines please, because thats just negligent.

Dann

Who died and made you Moderator? Please refrain from lowering the tone of this forum.

93_Clubman · Postby **93_Clubman** » Thu Jul 07, 2011 1:41 pm

BadBong wrote:Back to a more technical question - why does NB8B require better fuel?

Does it have anything to do with VVT?

Higher compression:
viewtopic.php?f=18&t=17082&p=200449

magenb · Postby **magenb** » Thu Jul 07, 2011 1:50 pm

93_Clubman wrote:
magenb wrote:
93_Clubman wrote:According to Redbook 91 RON:
http://www.redbook.com.au/used-cars/det ... 1040CF8DDF

Redbook is a good guide. If you lookup 2000 and 2001 models, it says 91 ron, which Dale says is wrong

Indeed, RB is only a guide, & it's wrong for the NB8B, but it's not wrong for the NB8A.
viewtopic.php?f=18&t=36865&p=478938#p478938
viewtopic.php?f=29&t=35915&p=466405

The NB8A spanned 1998-2000 & the NB8B spanned 2000-2002.

Awesome info there.

On a side note, the first link has a compat guide for E10 which is from Caltex, suggesting Mx5s older than 2005 shouldn't use it. The BP site says just about everything will work lol http://www.bp.com/genericarticle.do?cat ... Id=7038421

JBT · Postby **JBT** » Thu Jul 07, 2011 1:58 pm

magenb wrote:Was the Aus spec 99 model tuned from factory on 91 or 95 ron fuel?

Same as the NA i.e. ULP - 91 RON. The NB8B and NC use 95 RON. Only the NC is recommended by Mazda to use E10 (min 95 RON).

I'm not sure of the factory (handbook) minimum recommended RON for the SP or SE.

93_Clubman · Postby **93_Clubman** » Thu Jul 07, 2011 2:12 pm

magenb wrote:On a side note, the first link has a compat guide for E10 which is from Caltex, suggesting Mx5s older than 2005 shouldn't use it. The BP site says just about everything will work lol http://www.bp.com/genericarticle.do?cat ... Id=7038421

Here's Mazda's view:
http://www.mazda.com.au/Owners/Motoring ... Chart.aspx

Postby **Boyracer** » Thu Jul 07, 2011 2:15 pm

NB8B runs a higher compression ratio therefore they will recommend the higher octane fuel.

All the NB series engines run a knock sensor so even if you do run lower grade fuels the engine sould be safe... The only effects would be less performance and higher fuel consumption.

Old Dude · Postby **Old Dude** » Thu Jul 07, 2011 4:01 pm

Interesting how manufacturers decide what is suitable fuel..........I have a 2008 X trail, that Nissan told me do not run it on E10, now you would think that such a relative new car it would be designed to run on E10

Cheers
Dale

Question for those in the know, is E10 a higher octane than 91? I was told it was because ethnol is higher octane. But I would really like to know for sure.

Postby **NitroDann** » Thu Jul 07, 2011 4:03 pm

miata wrote:
NitroDann wrote:GP maybe some people think that the forum is a place for giving good correct information when you have it and reading good correct information when you dont. And telling people info you just pulled out of your ass because it sounds about right down at the pub is NOT what the forum is for.

If the info was regarding door trims who cares but not steering brakes or engines please, because thats just negligent.

Dann

Who died and made you Moderator? Please refrain from lowering the tone of this forum.

Everytime I post you show up, it used to be 1red5 before he looked stupid in Joshs thread.
If you indulge in giving wrong info like its real info great, but im going to call people out who make things up and post it like fact. :shock:

Dann

Postby **NitroDann** » Thu Jul 07, 2011 4:04 pm

BadBong wrote:Back to a more technical question - why does NB8B require better fuel?

Does it have anything to do with VVT?

It has to do with higher compression, higher compression improves combustion efficiency hence emissions (and power..).

Boyracer wrote:NB8B runs a higher compression ratio therefore they will recommend the higher octane fuel.

All the NB series engines run a knock sensor so even if you do run lower grade fuels the engine sould be safe... The only effects would be less performance and higher fuel consumption

Knock sensors only pull back timing after they sense knock. To prevent knock run better fuel/less timing. Just because it wont do it non stop doesnt mean its a good thing and the ecu wont learn to pull timing every time a hill approaches.

Dann

miata · Postby **miata** » Thu Jul 07, 2011 4:06 pm

NitroDann wrote:
miata wrote:
NitroDann wrote:GP maybe some people think that the forum is a place for giving good correct information when you have it and reading good correct information when you dont. And telling people info you just pulled out of your ass because it sounds about right down at the pub is NOT what the forum is for.

If the info was regarding door trims who cares but not steering brakes or engines please, because thats just negligent.

Dann

Who died and made you Moderator? Please refrain from lowering the tone of this forum.

Everytime I post you show up, it used to be 1red5 before he looked stupid in Joshs thread.
If you indulge in giving wrong info like its real info great, but im going to call people out who make things up and post it like fact.

Dann

If that was aimed at me, I might remind you, that I AM the moderator, you are not. It's not up to you to tell people what they can or cannot post. You are annoying people and we don't like that here.

Postby **NitroDann** » Thu Jul 07, 2011 4:09 pm

Old Dude wrote:Interesting how manufacturers decide what is suitable fuel..........I have a 2008 X trail, that Nissan told me do not run it on E10, now you would think that such a relative new car it would be designed to run on E10

Cheers
Dale

Question for those in the know, is E10 a higher octane than 91? I was told it was because ethnol is higher octane. But I would really like to know for sure.

E10 is a slightly complicated thing here. And for the record I ran my car on E10 (tuned for it...by me) and now run E85 (Only oz mx5 i think, also tuned by me, going for 6 months strong now).

It cant be 'designed' to run on e10 and 'designed' to run on regular petrol also. (I know I know, flex fuel sensors... but thats getting too far into it for this question I think)

Ethanol has a different stoichiometric ratio than petrol, and Its knock resistance is much higher.
If the car is tuned for petrol then it will be both too lean to be optimised for E10 AND will be running too retarded.

Obviously E85 has so much ethanol your car simply wont run on it without a full retune where as e10 is close enough that it will run not perfect, but good enough most people wont notice.

theres nothing wrong with E10. It is USUALLY 95 octane (ethanol is 115 octane or close to it so adding it will increase octane) but many manufacturers ddont take 91 and add 10% ethanol improving the octane, instead take 87 and add the e10 to get it back to 91. United is all 95 Octane for the record.

E85 is 105-110 octane depending on the exact percentage of ethanol in use (eg united is 90% and winter blend of caltex like right now is just 70%, with it hitting 85% at caltex in summer).

I hope this answers your question.

Dann