How to run E85 on stock 86 BRZ FRS with OFT tune

[steve99]

Originally Posted by Robbierayy1

Hey Steve I read back through our posts and may have missed it, but how or is there a way I could check the commanded afr and the measured afr. Can I check with the OFT? Im assuming the commanded on the e70-75 tune would be somewhere between 10.6 - 10.41 based on my calculations. Going back to your example of e50 in a car which made sense to me except for the rich part. If the commanded afr on the tune is 10.6 - 10.41 then shouldn't the e50 in the tank make the car have a lean exhaust since it has an afr of 11.8? The ecu would have to compensate and add fuel to achieve the e70-75 afr ("go rich command") which would in turn show positive fuel trims.

Ues oft will log afr ( measured) and Commanded afr.


The ecu and all logging will always show petrol afr no matter if your on petrol or e85 or any mix even if you had flex kit.


The 02 sensor measures lambda but the ecu works in petrol afr and so does logging.


So at idle say lambda is usually 1 so afr and commanded afr will be 14.7 petrol afr even if your running e85. The real afr is different but ecu alwats works in petrol scaled afr. Commanded afr will always be in petrol afr as well, ecu doesnt know anytging about ethanol afr even if you have flex kit

[Robbierayy1]

Originally Posted by steve99

Ues oft will log afr ( measured) and Commanded afr.


The ecu and all logging will always show petrol afr no matter if your on petrol or e85 or any mix even if you had flex kit.


The 02 sensor measures lambda but the ecu works in petrol afr and so does logging.


So at idle say lambda is usually 1 so afr and commanded afr will be 14.7 petrol afr even if your running e85. The real afr is different but ecu alwats works in petrol scaled afr. Commanded afr will always be in petrol afr as well, ecu doesnt know anytging about ethanol afr even if you have flex kit

Very interesting! So it is the O2 sensor that is the key here? It can recognize the afr and relay the information to the ecu to compensate with the correct fuel trims? So all the oft tune does is advance the ignition timing right?, which I understand in how it produces more power

[pym19109]

Originally Posted by Tor

You need an absolutely flat road, and you need to do the pulls starting at the same spot. Looks more like you are messuring the bumps in the road as none of these pulls have a curve as would be expected.

You need to do a few pulls on each tune as well, and discard the ones that have a strange progress.

Unfortunately, the road around my area is quit bumpy . I will find the flat road for accurate result.

[steve99]

Originally Posted by Robbierayy1

Very interesting! So it is the O2 sensor that is the key here? It can recognize the afr and relay the information to the ecu to compensate with the correct fuel trims? So all the oft tune does is advance the ignition timing right?, which I understand in how it produces more power

Stock tune runs very Rich


Most tunes from any vendor will run leaner in 12 afr rarther than 11 or high 10


Most will adjust intake and exhaust cam timing as well as fueling amd ignition timing

[Kodename47]

Originally Posted by Robbierayy1

Very interesting! So it is the O2 sensor that is the key here? It can recognize the afr and relay the information to the ecu to compensate with the correct fuel trims? So all the oft tune does is advance the ignition timing right?, which I understand in how it produces more power

The simple way of looking at it is that an O2 sensor only works in lambda. Lambda 1 of petrol has a different AFR to lambda 1 of E85. However the logging of commanded AFR and O2 sensor outputs are Lambda x 14.7.

Here's a good chart to demonstrate:


The OFT does increase fuel delivery for E85 tunes, not just advancing timing.

[churchx]

Lol. Guys are getting more creative on banning image hotlinking

[Robbierayy1]

Thanks Steve and Kodename47 for the info, much appreciated!

[Robbierayy1]

Hey Steve I did more research on this topic and I am understanding this much more! Your posts have helped a ton. My whole goal is to be able to approximate the ethanol percentage in my car by observing the fuel trims on the oft. I was confused so much because I didn't really understand lambda vs afr. Everything would be a lot easier if it was in lambda.

What is the commanded afr for the e70-75% tune in terms of petrol afr since you explained that the ecu and oft read petrol afr?

When I go check my real time display on my oft I see the measured afr right? where would I go to see commanded afr if possible?

[ermax]

If you want to know the E% you can put water in a graduated cylinder and then add some E85. The ethanol mixes with the water but the petrol will separate. So you put the water in and note the volume. Then you add the E85 and note the total volume along with the separation line. Then you do the math to remove the water and then find the ratio. They sell premarked test tubes that eliminate the need for math. $24 for a test tube is silly so I did my own thing.

[sroby]

Steve or kodename47, I’ve been running E85, now everytankfull for a year next month. Do you guys no off any long term effects of the E85 on the fuel lines and system in so much as corrosiveness. Anything in particular to watch? Just curious. Best regards Steve

[pcguru2000]

1. So last night I binged watched people with stock 86/frs/BRZ's that got OFT, switch to e85 fuel, got dynoed and were producing close to 200 HP at the wheels through a dyno. It seems that the gains were 35-50HP at the wheel for just switching to e85. It was hard to find videos with dyno numbers of just stock frs/86/brz's that had minimal mods other than sri, or a catback/axle back, or other minor things.

Is this BS?

2. People claim that it removed the torque dip from 2500-3500rpm.

All the dynos I saw still showed the torque dip with e85, but the dip looked a little smaller and the overall curve of the dip was 5-10hp higher than a stock on 91 gas. So technically, if you were to cut and paste the dyno result of just the dip on e85 to the dyno result of the 91, it would appear that the dip get smaller. Is this the but dyno interpretation that "the torque dip is gone" based on just getting adequate torque numbers in the dip range?

[steve99]

Originally Posted by pcguru2000

1. So last night I binged watched people with stock 86/frs/BRZ's that got OFT, switch to e85 fuel, got dynoed and were producing close to 200 HP at the wheels through a dyno. It seems that the gains were 35-50HP at the wheel for just switching to e85. It was hard to find videos with dyno numbers of just stock frs/86/brz's that had minimal mods other than sri, or a catback/axle back, or other minor things.

Is this BS?

2. People claim that it removed the torque dip from 2500-3500rpm.

All the dynos I saw still showed the torque dip with e85, but the dip looked a little smaller and the overall curve of the dip was 5-10hp higher than a stock on 91 gas. So technically, if you were to cut and paste the dyno result of just the dip on e85 to the dyno result of the 91, it would appear that the dip get smaller. Is this the but dyno interpretation that "the torque dip is gone" based on just getting adequate torque numbers in the dip range?

stock car stock tune to stock car with E85 tune and E85 is about 20hp add header and maybe 30hp vs stock on 91 octane. probably a few hp less if you use 93 as stock car will produce more hp on 93.


E85 and tune even on stock car will also reduce torque dip a lot


best bang for buck mod is tuning for E85 even stock

[pcguru2000]

Originally Posted by steve99

stock car stock tune to stock car with E85 tune and E85 is about 20hp add header and maybe 30hp vs stock

Those numbers are "at the wheels" measure correct?

[pcguru2000]

Any idea why there is a torque dip?

I've heard people claim that it was to get better gas mileage around town. To make higher max HP numbers. To meet pollution standards?

Will the car stock, with oft e85 tune, pass california smog test?