Ethanol base Fuel map

Tuning discussion for all first generation Mazda RX-8 (2004-2008)
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Apex_Thrill
Posts: 2
Joined: September 7th, 2022, 10:33 am

Ethanol base Fuel map

Post by Apex_Thrill »

im looking for someone to help me out with taking the stock fuel map and adding 30% fuel across the board as i don't know how to calculate for that. i suspect im doing something wrong because when i do 0.30 it bottoms out the afr table. just looking for a little more insight.

also if someone has a reliable ethanol fuel map for a stock 6 port please share it here only if its from a reputable tuner.
DSSRotard
Posts: 8
Joined: April 19th, 2020, 3:22 am

Re: Ethanol base Fuel map

Post by DSSRotard »

Apex_Thrill wrote: September 7th, 2022, 10:48 am im looking for someone to help me out with taking the stock fuel map and adding 30% fuel across the board as i don't know how to calculate for that. i suspect im doing something wrong because when i do 0.30 it bottoms out the afr table. just looking for a little more insight.

also if someone has a reliable ethanol fuel map for a stock 6 port please share it here only if its from a reputable tuner.
Copy & paste the whole AFR table to an excel, then select all values, and subtract 30%. Paste it back. You might need to select the option that allows you to enter unsafe values.
riffy
Posts: 9
Joined: October 4th, 2021, 5:19 am

Re: Ethanol base Fuel map

Post by riffy »

they have an e85 calculator native for most of the other vehicle platforms such as the mazdaspeeds, guess they just assumed rx-8s wouldnt be doing this
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wcs
Posts: 61
Joined: May 12th, 2021, 12:46 am

Re: Ethanol base Fuel map

Post by wcs »

Why?

Are you trying running a boosted setup?

What is there to gain otherwise?

All that aside are the hoses and gaskets E85 compliant in the RX8?
Walle
Posts: 51
Joined: August 29th, 2021, 7:27 pm

Re: Ethanol base Fuel map

Post by Walle »

on NA you will lose power with e85 as you will have significantly less space for air in the process.
unless going above 300whp there is absolutely no reason to do so.
the Lambda = 1 will be always the same and that is how our AFR maps are defined (on lambda not AFR). you need to edit the injector maps in this attempt to add fuel. lambda target tables dont care about the fuel nor does the wideband in the exhaust..

they are only (as option) shown with values of 14.7 for petrol.

there is a map (that I suspect) is for this and it is the "air fuel ratio base" map. I assume this is what the ecu uses to calculate how much fuel to add in the first attempt to achieve the desired lambda target ratios.
Apex_Thrill
Posts: 2
Joined: September 7th, 2022, 10:33 am

Re: Ethanol base Fuel map

Post by Apex_Thrill »

DSSRotard wrote: September 8th, 2022, 9:23 am
Apex_Thrill wrote: September 7th, 2022, 10:48 am im looking for someone to help me out with taking the stock fuel map and adding 30% fuel across the board as i don't know how to calculate for that. i suspect im doing something wrong because when i do 0.30 it bottoms out the afr table. just looking for a little more insight.

also if someone has a reliable ethanol fuel map for a stock 6 port please share it here only if its from a reputable tuner.
Copy & paste the whole AFR table to an excel, then select all values, and subtract 30%. Paste it back. You might need to select the option that allows you to enter unsafe values.
thanks for letting me know this answers my question perfectly! and as for everyone else who went off track of my question i will ignore. More R&D needs to be done to the RX8 and that's what I'm doing, ill find all limitations using my own testing standards.
Walle
Posts: 51
Joined: August 29th, 2021, 7:27 pm

Re: Ethanol base Fuel map

Post by Walle »

Apex_Thrill wrote: September 18th, 2022, 1:31 pm
DSSRotard wrote: September 8th, 2022, 9:23 am
Apex_Thrill wrote: September 7th, 2022, 10:48 am im looking for someone to help me out with taking the stock fuel map and adding 30% fuel across the board as i don't know how to calculate for that. i suspect im doing something wrong because when i do 0.30 it bottoms out the afr table. just looking for a little more insight.

also if someone has a reliable ethanol fuel map for a stock 6 port please share it here only if its from a reputable tuner.
Copy & paste the whole AFR table to an excel, then select all values, and subtract 30%. Paste it back. You might need to select the option that allows you to enter unsafe values.

thanks for letting me know this answers my question perfectly! and as for everyone else who went off track of my question i will ignore. More R&D needs to be done to the RX8 and that's what I'm doing, ill find all limitations using my own testing standards.
you wont achieve desired effect with adjusting the AFR table as I already explained. all fuels includint pure methanol will have lambda=1 at stoich ratio, what ever that ratio is. the fact the VT is showinf AFR and not Lambda is just for the ones that are not adjusted to using lambda. you can see in display setup settings that you can use 14.7 or what ever for the AFR stoich. if you set it there for 7:1 in your AFR table, where lambda=1 it will be displayed as 7:1... same as it was before 14.7:1 .. the map didnt change
Tomii
Posts: 2
Joined: February 5th, 2023, 5:00 am

Re: Ethanol base Fuel map

Post by Tomii »

Hi,

I'm new here and I would like to know if anybody has already made a tune map to run with ethanol fuel :)

Many thanks
DSSRotard
Posts: 8
Joined: April 19th, 2020, 3:22 am

Re: Ethanol base Fuel map

Post by DSSRotard »

Apex_Thrill wrote: September 18th, 2022, 1:31 pm
DSSRotard wrote: September 8th, 2022, 9:23 am
Apex_Thrill wrote: September 7th, 2022, 10:48 am im looking for someone to help me out with taking the stock fuel map and adding 30% fuel across the board as i don't know how to calculate for that. i suspect im doing something wrong because when i do 0.30 it bottoms out the afr table. just looking for a little more insight.

also if someone has a reliable ethanol fuel map for a stock 6 port please share it here only if its from a reputable tuner.
Copy & paste the whole AFR table to an excel, then select all values, and subtract 30%. Paste it back. You might need to select the option that allows you to enter unsafe values.
thanks for letting me know this answers my question perfectly! and as for everyone else who went off track of my question i will ignore. More R&D needs to be done to the RX8 and that's what I'm doing, ill find all limitations using my own testing standards.
Also, i recommend changing display values in Versa in lambda, cause lambda 1.0 will always be 1.0, no matter what fuel you use, but AFR values in petrol is not the same as diesel, learn to use Lambda values and you won't miss, no matter what fuel you will use.
Lambda_to_AFR.JPG
Lambda_to_AFR.JPG (34.13 KiB) Viewed 2309 times
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