My 207whp unported N/A E-85 map. (input from experienced tuners appreciated)
 

Alright, so I just finished up with my first E-85 rotary tune yesterday.

https://i.imgur.com/mM1vcNY.jpg

I'm super happy with the results.

Upper line is after the dyno.

The lower line is before dyno tuning, but after a bunch of street tuning.

'07 RX8. ~85k miles. Original engine. Original coil packs.

E85. Stock injectors. Walboro GSS242 fuel pump. Stock intake. OEM air filter. SOHN OMP adapter. Redline 40504 alcohol specific 2 stroke oil. Turbo XS header. AP catless midpipe. Borla catback. Rear O2 sensor delete.

For reference, this car made 179whp on the same dyno before all of the mods. Dyno Dynamics units typically read a teensy bit low. The engine was healthy as shit at 80k miles when I first got the car. I'm the second owner. First owner was a psychotic about maintenance.


The full load stuff is dead bang on. I'd add fuel, it would lose a bit of power. Go leaner it would lose a bit of power or stay the same. Same story with adding/subtracting timing.

I had a bit of time to do partial load stuff on the dyno. Not a lot of time though.

I know the part throttle stuff could still be better. I'm sure there is a lot of stuff still in the mapping that could still be better.

Attached is my AP map. Feel free to pick it apart and tell me what I can improve. I was seeing some weird closed -> open loop transition stuff on the dyno. I'm going to have to experiment more with that.

How can you make more power with a fuel with a lower energy content?

By burning ~22% more of it.

It's also 105 octane. About 3.5 degrees of timing advance everywhere vs. stock on the leading plug. Almost double that much more advance on the trailing side.

E-85 also has a slower flame front propagation speed. This is very beneficial to the very long combustion cycle against the rotor face.

You should definitely try to properly tune an e5\e10 car.
Ethanol's advantage aren't as great as they seem.

Congrats! By the way, I have not read everything but I must say: Please change those coils. No RX-8 has good coils at 85k miles.

Good luck.

Paul.

I checked them with my o-scope when I first got the car. They still look healthy. Great primary discharge voltage and good spark duration. Firing through alcohol with stock plug gaps would definately expose weakness.

If you do actual math, you will find that fixed amount of air mixed with E85 releases about 6% more heat than same amount of air mixed with gasoline, at given lambda.

Then you have higher engine efficiency, as combustion occurs at lower temperature - lower losses into coolant and oil.

Alcohol fuels have longer initial flame kerner development, but once the flame front is established, burn rate is faster then with gasoline, use of strong ignition system can actualy allow for lower timing advance to reach best torque then with gasoline, which means less negative work in engine, more net output.

Higher knock resistance allows operation without timing retard from MBT and we all know that rotary engine is severely limited platform in this regard, so again, power increase from optimal operation.

And last, but not least, significant evaporative cooling increases volumetric efficiency and again, permits optimal operation in knock limited situation.

Alcohol fuels have only one disadvantage, higher required fuel mass to reach same lambda. Thing is, that engine fully optimized for ethanol fuel would operate at higher compression and boost pressures and without timing retard and fuel enrichment so actual fuel consumption wouldn't be that much higher than with gasoline. E85 requires 50% more fuel mass to reach same lambda, but boosted rotary on gasoline requires as much as 40% enrichment, resuting consumption in such situation would be just 10% higher...

has anyone test with e85 oem map ? Is it works or gains anything ? Great numbers

E-85 in a car with stock ECU mapping would really struggle to stay running. You need to make large fueling changes for things to work.

Thanks for taking the time to write that.

To add a bit of real world anecdote about thermal transfer and evaporative cooling.

My coolant temps average about 10-15 degrees F cooler than on gas.

Another thing you didn't mention is the complete lack of any carbon deposition from E-85. Carbon has always been a huge problem with rotaries. I'm excited for this engine to need a teardown, just so I get to see how clean and shiny everything will be.

Thanks for the explanation. So in his case he is using around 50% more fuel in your opinion?

Are you using cobb ? Which parametres are you change for e85 ?

In case of pure ethanol vs. pure gasoline, comparison of lower heating values reveals that ethanol would need as much as 64% more fuel mass than gasoline to release same amount of heat. But due to higher fuel density of ethanol, it would show up as about 50% higher volume.

In case of usual E10 gasoline vs. E85, later would need 40% more fuel mass which is about 33% more volume.

So we can see that disadvantage of lower fuel economy can be quite significant in conditions which aren't knock limited - low load driving, NA engines, but considering that high boost rotary engines are tuned for about 0.73 Lambda on gasoline, and E85 fueled ones comfortly for 0.85 Lambda, actual difference in used fuel volume would be just 10% higher for E85.

Injector scaling is the big one.

Everything else is pretty standard.

FWIW, I ended up having to add about 22% more fuel everywhere when all was said and done. Some places a few % more, some places a few % less.

I tuned to .85 lambda.

I haven't been able to really get an accurate gauge of mileage of gas vs. E-85. Too much time spent driving like a gleeful idiot.

My best tank of E-85 in 100% city driving so far has been ~13mpg. My best tank of gas in the exact same driving environment was around ~16mpg.

With the fuel prices locally, it's actually SLIGHTLY cheaper to run E-85 right now despite the crap mileage. You're talking pennies per gallon though, so it's not a huge deal. When winter rolls around and the price gaps mostly goes away, I will switch back to gas. I'll get back on the dyno then to get a valid comparison.

One of the biggest problems for having a car tuned for e85 is traveling. e85 isn't available at every gas station. You could get yourself into a situation where you need fuel and it isn't available. This would be an even bigger problem once your outside of the corn belt.

The AP has multiple maps.

I have a map for gas, I have a map for E-85, I also have a map for a 50/50 mix. The O2 sensor can do some pretty huge fuel trims for anything between the 3 maps.

The gas maps just haven't been dyno tuned. I used my dyno tuned E-85 map as a starting point, then made changes as appropriate. It's not perfect, but it's probably closer than your average car running a bunch of bolt ons with no tune.

Subbed :)

x2.

nvermind subbed

do you premix as well as inject the redline?

No premix. From all of the reading I have done, I don't see a need for it.

I have increased the OMP oil delivery across the entire operating range. There should be plenty of rotor lubrication. The redline stuff is very clingy.

Lol, i know very little about fuels, that's why I asked.

wouldnt doing this resolve alot of the engne flooding issues from shutting it of when cold? considering it burns fuel at a much faster rate....

E85 would be a dream to use given the same reliability and ease of use. Especially considering the fact that 1 litre of 95 is $2.60 here, and 1 litre of E85 is $1.63.

Indy cars secretly rely on nuclear flux capacitors to go 220 mph, not ethanol fuel

You'd be surprised to know how much E% you can use in an Rx8 with just by tuning the factory components

The biggest issue for street or track is we only have a 13.5 gallon fuel tank, which essentially becomes an 8 gallon tank with the E85 consumption rate

This statement is contradictory.

If an oil is designed to maintain a film when exposed to alcohol, it will not wash out.

the OMP is pointed to the sides, nothing is going to the center of the apex seal, it will wear down without premix or a center oil injector.

did you change all the fuel lines and the fuel pump to handle e85?

Mazda Australia build a turbo Targa car that ran E85 and we believe it produces around 350 hp. It ran really well and at one stage it was within the top three against supercars.

The car is now owned by Ric Shaw. He is a racing driver and owns a specialist rotary workshop in Sydney. He has overhauled the car and now runs it in local events.

E85 has certainly helped with the incredible power output and track reliability. It is a low mount turbo so it must be running well over 1 bar of boost to maintain the power.

I'd love to see detailed pics of that cars setup.

It was built by Pac Performance so the details will be similar

Oh, okay.

Ric's car is for sale for $80k and it is the only RX8 SP available for sale anywhere.

You're absolutely right. That is why unmodified engines never make it to 100k+ with proper care and feeding while still maintaining perfect compression. :rolleyes:

If OMP delivery is increased (which was done as part of the OEM reflashes to increase reliability) you get sufficient lubrication in the center of the housing. The problem is that you are injecting more oil than is strictly needed for lubrication. This leads to hugely increased HC emissions.

With the third injector in the S2 cars, total oil delivery was brought way down, while still maintaining acceptable lubrication.

The only thing contradictory is you listing "input from experienced tuners is appreciated" in your thead title

Nice job and great info! Have an 04 I would love try this map on. Access Tuner Race won't load it though. I'm assuming because of the year differences. Any way to get it to work?

You just don't load someone elses tune into your car and expect it to work .

Brett, what help was that comment? Are you knowledgeable on the topic or just being a .. well.. ?

I tried to load it in Access Tuner Race to view it. I would love to translate what the OP has learned into a tune.

Not to mention that he is using an aftermarket higher output fuel pump which isn't STX class legal and without which you won't have enough fuel supply to handle E85, assuming your motor is making decent output

If the map is unlocked you should be able to view it in the appropriate model year ATR program. IMO it doesn't really offer anything of value if you already understand how to tune with an AP. The OPs method and ability to tune an AP effectively is also in question. Every DD dyno for a Renesis I've ever seen reads high too in my experience, so the value may not be what you think it is. Copy and use it at your own risk. I can already tell you there aren't any secrets in there.

.

I'm not sure if that's a correct statement.

that it remains to be seen

I'm willing to give it a try with a stock pump to see where I end up.

Unable to install 06-08 ATR with my Accessport. Says it's incompatible. If I extract the files from the .exe and try to run it says it's missing the license file. Am I'm missing something?

No-coast, any chance you can post this in spreadsheet or .csv format?

You'll end up worse than what I already told you since the OE pump output won't come any where close to the pressure and flow of the pump he is using.

The AP for the RX8 is not model year specific, only the maps and ATR software are. You need to request ATR for the model year of the map, then install it on your desktop/laptop computer using your AP. You can then open the map and copy info from that map into the ATR program/map for your car.

That you feel the need to use that map only demonstrates a lack of basic understanding and insight for the process you're attempting to engage in and as further demonstrated in your previous reply to Brettus. You may be better served to have someone more knowledgable doing this for you instead.

I've always found it easier to reverse engineer than to engineer something. I have enough of an understanding to get this one. Been tuning cars for over 15 years one way or another.

ATR says it's not compatible.

http://genxracer.blogspot.com/2013/08/blog-post.html

Edit: Will try uninstalling from my car first.

No-coast.. tested the map on my 04. Dropped timing down a few degrees to start and zeroed the oil metering. Ran pre-mix to compensate.

Overall I had moderate success with it. The idle was poor but driveability was great. Open loop was lean down low to mid range and rich up top. Tried your method of VE tuning but was not able to fully compensate. Have to see if the ecu will report fuel pressure. If not then I'll connect a gauge. First time using ATR so it's a learning process.

there is no way you can run full E85 on the OE fuel system and be rich up top, the only exception is if the motor is way down on potential power output. A good motor on E85 will be way lean as neither the OE pump or injectors have the flow capacity for it.

pre-mix is also not STX legal

but generally speaking, you clearly haven't researched any of what's necessary and seem to have little understanding in general, so I was only trying to warn you off from possibly f'ing something up right before Nats

I can't highlight enough an understanding of what's necessary to run the fuel.

I won't disagree that the stock fuel system as a package doesn't have enough overhead. I've yet to find that it does. I do find it odd though that it's only occurring at low RPMs. Every indication I've had so far with the car is that the motor is not soft. Log below:

https://docs.google.com/spreadsheet/...VE&usp=sharing

Most are aware pre-mix is not legal. Then again, I hope no one has run fuel injector cleaner or any other additive either. ;) I won't use it for competition runs if I were to run E85.

It looks pretty weak, are you sure that this mod isn't costing you power?

Off the shelf additive cleaners and such are not the same thing. Given the emphasis on the fuel rules this year it won't be any surprise if fuel samples are collected/analyzed, fuel systems inspected, or paper filed in ST this year.

Are these additive rules just for STX or all ST* classes?

Can you elaborate further? Would you say down by 5%..10%? What should I be looking for? Even with the poor tune on E85, it showed slight gains.

It may be the car. Comparibly it's only power mod is a cat back though. The cat on wasn't very high flow at 4" in diameter and 300cpi. Logs done back in January (new coils in August) show slightly lower g/sec values with stock air box as well with arguably better conditions. Time intervals between RPM were similar.

Without diverting too far off topic, from rule book:

"Stock and Street Touring® category vehicles will use fuel is which is
“Federally approved for use on public highways.” This includes the
pump fuel known as E85, but does not allow racing-type fuels which
are available at service station pumps."

Done a bit of research on oils that will not break down or turn to sludge. Seems Pennzoil Ultra, Castrol Edge, Amsoil are a few that have potential. Diesel oils have been recommended as well. Shell couldn't provide any info though. There have been a few in the Mazdaspeed 3 forums who have had sludge build up but are not sure if it was related to Rotella T.

I won't be using E85 on the street as gas mileage takes a pretty big hit.

Sorry to respond so late. Work has been straight up stupid.

From what I have seen, the premix thing is a serious grey area. The SCCA rules simply state:

A. Stock and Street Touring® category vehicles will use fuel is which is
“Federally approved for use on public highways.” This includes the
pump fuel known as E85, but does not allow racing-type fuels which
are available at service station pumps.

Technically, the addition of two stroke oil does not make a fuel illegal for highway use. There is literally ZERO in the 2013 rules about this.

To the exact letter of the rules, there is nothing that prohibits premixing. It really confers no performance benefit at all other than engine longevity. It is still in keeping with the spirit of the STX rules that allow for oil pan modifications for the same reasons.