Anyone tuned on a 91 octane tune?

[nastang87xx]

I'm running a Lund Flex tune now with the Ngauge. great tune and I have had no issues. I will run e85, then switch back to 93 to "clean up". I have good power on both tunes.

Dyno done inthe good ol FLorida heat August..
Dyno chart

It's nice to see some torque down there in the 3000 range. 325 tq at that RPM level is very much LS2 type of low end grunt and that's not an insult.

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[Ninjak]

It's nice to see some torque down there in the 3000 range. 325 tq at that RPM level is very much LS2 type of low end grunt and that's not an insult.

Agreed. The tune truly woke up my low end TQ. I can feel the difference. I guess that's why I never complained about it

 

[snaproll]

Yeah I believe you can actually put 87 in it and the knock sensors are good enough to compensate. But why would you do that??? :lol:

I’m gonna second your comment. I think they can run on all kinds of stuff for a short time and get away with it, but after seeing about 4 coyotes melted down on pump gas, the guys that I know have all switched to 98 for race duty. No problems since (knock on wood). I hate spending the money on $10/gal gas but I hate paying the engine guy more.

 

[superman07]

The ECU's programmed behavior could be different depending on the tune and or tuner. Typically there is a threshold and limit to how many degrees can be pulled out of the base maps. Add in the other tables for various readings and getting to the timing actually commanded can be tricky. Combine this with the other programmable items for thresholds and how quickly to revert back to the base and a bad tune will still blow your motor. Doesn't take that much to blow the boundry gasses from the piston.

I would never run 87, ever, stock or aftermarket tune, or just trust the knock sensors running hard. Just asking for it in my opinion.

I’m gonna second your comment. I think they can run on all kinds of stuff for a short time and get away with it, but after seeing about 4 coyotes melted down on pump gas, the guys that I know have all switched to 98 for race duty. No problems since (knock on wood). I hate spending the money on $10/gal gas but I hate paying the engine guy more.

 

[snaproll]

The ECU's programmed behavior could be different depending on the tune and or tuner. Typically there is a threshold and limit to how many degrees can be pulled out of the base maps. Add in the other tables for various readings and getting to the timing actually commanded can be tricky. Combine this with the other programmable items for thresholds and how quickly to revert back to the base and a bad tune will still blow your motor. Doesn't take that much to blow the boundry gasses from the piston.

I would never run 87, ever, stock or aftermarket tune, or just trust the knock sensors running hard. Just asking for it in my opinion.

Yes - I probably wasn’t clear. I agree with you. I would have thought the engines would be more able to compensate with all the technology but the results in my corner of the world haven’t been good.

 

[superman07]

Indeed, I understand. I think its easy to believe this because they really can do amazing things. But racing is a different animal. What do they say, trust but verify. Not enough people review logs.

 

[Zitrosounds]

I’m gonna second your comment. I think they can run on all kinds of stuff for a short time and get away with it, but after seeing about 4 coyotes melted down on pump gas, the guys that I know have all switched to 98 for race duty. No problems since (knock on wood). I hate spending the money on $10/gal gas but I hate paying the engine guy more.

93 on street ans 98 260GTX at the track.

 

[65sohc]

They will give you a hardcoded E85 tune or a hardcoded gas tune which has 3 octane levels. You can choose from 87 up to 100 octane. Anything above 100 is considered a race tune and costs additional money.

That is way more complicated than the Lund flex fuel tune. With Lund you fill the tank with whatever premium you can find and drive wherever and however you want (after the 4-5 mile ETOH% calculation phase). e40 is about 96 octane so anything above that effectively eliminates detonation from the picture and allows full timing advance. I also pay $1.95/gal. vs $3.35+ for 91.

 

[nastang87xx]

That is way more complicated than the Lund flex fuel tune. With Lund you fill the tank with whatever premium you can find and drive wherever and however you want (after the 4-5 mile ETOH% calculation phase). e40 is about 96 octane so anything above that effectively eliminates detonation from the picture and allows full timing advance. I also pay $1.95/gal. vs $3.35+ for 91.

This is actually what I'm considering now. So basically you just need to take it easy for a bit after you blend E85 in your fuel tank and then you go for it?

 

[65sohc]

This is actually what I'm considering now. So basically you just need to take it easy for a bit after you blend E85 in your fuel tank and then you go for it?

Yes. The nGauge tells you exactly what's going on. When you start the car after fill the Alcohol Learn value will read 0. After ~30 sec. of driving the Alcohol% value will start to fluctuate and AFR will change as the PCM computes. You can actually feel and hear as the adjustments take place. After 3-5 miles it locks in and the Alc. Learn switches to 1. Then you're good to go. I enjoy watching it do its thing and look forward to filling up.

 

[nastang87xx]

So that doesn't degrade engine durability then? Sounds like it would be a little rough as the engine is trying to figure out what's going on. Does it end up knocking quite a bit during that 3 or so miles?

 

[superman07]

When the ECU sees the refueling event (10%) it turns off trims and quickly adjust the target stoich based on the inferred content. The process is very susceptible to the general health of the vehicle. Bad fuel, dirty injectors, fuel pressure, O2 accuracy all matter a great deal. Vacuum or exhaust leaks even minor will cause the vehicle to infer a incorrect value. You will run pig rich and knock if bad enough.

You are supposed to drive the car very carefully as it learns the fuel. The Nguage can track the target ALC percentage in realtime. The tune itself has fueling and timing targets based on e-10 and e-85. The ecu must then calculate values that are in between. It is unclear if lund actually mapped values of ethanol in between. A lot of tuners will map and confirm other mix points usually in 10-20 percent increments to provide a bit more safety.

But yes, if a moron decided to go to WOT right after a refuel they could easily damage the engine.

For what its worth I had a lot of issues in Ohio with fuel quality. Between clogged injectors and other issues I was not comfortable with the accuracy of the inferred values. I will run it only in summer with good known e-85 at summer blend levels.

So that doesn't degrade engine durability then? Sounds like it would be a little rough as the engine is trying to figure out what's going on. Does it end up knocking quite a bit during that 3 or so miles?

 

[nastang87xx]

Definitely sounds like a lot going on but very interesting.

When the ECU sees the refueling event (10%) it turns off trims and quickly adjust the target stoich based on the inferred content.

I'm assuming that event is triggered by the fuel needle essentially being moved up rather than down.

Nguage can track the target ALC percentage in realtime.

How does the nGauge know how to do that? Does the 350 have ethanol sensors onboard that just weren't used by Ford during final development and it taps into that or is it listening specifically to the knock sensors and trimming accordingly?

You are supposed to drive the car very carefully as it learns the fuel.

As in with air of extreme caution or simply drive normally without being a douche nozzle? I'm working on the assumed scenario that I would be switching back and forth quite a bit because I would be getting the tune mainly for racing and on the streets, just use 91/93 since it's just so much more readily available and for range purposes when traveling.

Thanks for answering these questions dudes. I'm really new to E85/flex tuning so I want to absorb as much as I can.

 

[superman07]

Yes, the ecu has a event trigger that determines if the fuel level effectively "goes up" default is 10 percent but it can be adjusted in HP Tuners.

The alcohol percentage is simply a guestimate based on the pulse width commanded in order to reach stoich on the o2 sensors. This is why you cannot have any issues with your fuel, injectors, fuel flow, or leaks that effect o2 readings.

you can just drive and cruise. It gets to a point close to the final percentage quite quickly. Sometimes it feels too quick as the fuel may not have mixed completely. The closer the new percentage is to the last learned percentage the faster it goes.

3k rpm holds move it very quickly. I typically will let it go from e10 to e40 before I leave the station. I have never witnessed any knock whatsoever doing this.

 

[superman07]

My UPR catch can malfunctioned and created a ton of non measured air. The car learned a e percentage 40 percent too high. ran like shit and needed to reset the KAM.

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