This one is for the MTH experts....

I'm currently running an MCS with just an Alta intake and the MTH tuner file. I still don't have the 'flat-spot fix' on the car...

In Australia, Shell has just released a product called "Optimax Extreme" - Basically it's 100 Octane (I think we use RON here in Australia) Unleaded Petrol with 5% ethanol.

Fuel Info Link Here

I understand that this sort of fuel has probably been in Europe and parts of Asia for some time, but it's just coming into use here. I have some questions about it's use with MTH: As I understand it (and please correct me if i'm wrong), Ethanol treated fuels tend to run a bit leaner than fuels without ethanol. Also, as far as I understand, part of the way MTH maps release more power in the MCS engine, is by running slightly leaner across certain parts of the fuel map. Does this mean, that if I run this sort of fuel, I could be running dangerously lean?

So, specifically, are your maps safe to use with this fuel? Or will I need to order new ones to account for their use?

Also, if I do that, will I be restricted to 100 octane? There aren't many outlets (yet), so there's a strong chance I'd have to continue filling up with 98 RON occasionally...

Your advice would be much appriciated - there are several Aussie Mini owners with MTH who are 'sitting on the fence' about the use of ethanol treated fuels at the moment.....

 

If you have a file created for 98-100 Octane you must use this premium fuel only. No prob with 5% ethanol though. If you want to be safe just ask us to send you different files for different fuel qualities. Do not run a 98-100 file with lower Octane !!!

 

Thanks for the quick reply Volker...I currently have a 98 RON map (I never mentioned 100 RON when ordering)- and ONLY use 98 RON octane....I suppose what I was asking was, can I safely use the 100 octane with this current map? (or do all your "98RON" Maps include the use of 100RON?) I know it may sound strange, but I've read that the ethanol based 100 octane runs leaner....to your knowledge, is that true?

 

My second post here !

Yee ha,
Anyways Im not sure I can help with the answer but I can tell you
that ethanol burns cooler and needs to have a higher fuel to air
ratio then gas. Gas is 14/1 and ethanol is 18/1, I think

I know in my modified kart, I need a larger jet for
ethanol, and head temps are so low, we tape off fins to keep her warm.
Same engine, smaller jet with no taped off fins will run gas normaly.

Now Im wondering if more gas by volume is being used ?
the mix, that now has ethanol added to it still needs to run 14/1
so now mix a little water in it, and you now need even more gas
to get the 14/1. I know that ethanol is not water, but just a
mind bar...

Im now thinking thats why our milage goes down every winter here,
more fuel is needed ....

The only thing that would deflate my idea is if the burnt ethanol
gasses changed the O2 sensor readings...


Food for thought anyway !
HoopsCoop

 

Volker,

You sent two mappings, one for 95 Octane and one for 98-100 octane. I live in California, USA and the premium here is 91-92 octane, I always use premium fuel. Which mapping should I use? Thanks for your reply.

retroom

 

Here's a reference that lists USA octane (PON) and the RON counterpart (use the second chart down the page): http://www.btinternet.com/~madmole/R...RONMONPON.html

Looks like you need to stick with the 95 octane program.

 

Good article...the 95 mapping is what I have installed. It works great. I was wondering what might happen if I used the 100 octane mapping.

retroom

 

There is generally no problem running on higher Octane fuel than what your file has been programmed for. But it will not give you much more power - if any. If you ask when ordering, we will always do files for you for different fuel qualities. No extra charge.