Quote from: ajpturbo on October 06, 2015, 02:25:24 PM
14shocar u might want to try to run the fuel that u are supposed to run...i know its a crazy concept but sometimes when the tune is set for pump gas the car will run properly when u run pump gas.
Sometimes the wild speculation on this forum is too much for me to take...u make mention that it could be wastegates opening or pre detonation...those 2 things are vastly different...if u suspect either of those then why not bad tie rods or a bad brake caliper gasket?
Isnt the whole idea of running the E mix to combat the terrible kr that alot of u think u have?...so then why would high E fuel becausing pre det?
U mention that u thought in time the car would learn and adaptives will take over...the tune is only capable of so much and most of the average 3 bar tunes are not touching the fuel scaling other than making sure the map sensor is scaled for the new sensor for normal gas .
More than likely u have random times with large fuel trims and if it cant trim enough quickly then it could be lean or rich temporarily and ur new exhaust doesnt suppress the previous sound spikes.
The slopes and intercepts in the speed density part of the tune are not optimized for higher E fuels...
U guys would be amazed at how simple the changes are in the tune to make a 3 bar tune..2 values thats all...that doesnt get boost up but u can put a 3 bar sensor in the manifold and change 2 values and the cars fueling is properly scaled but everything in the fuel portion is skewed when u run more e ....if u dont make the changes then u are more heavily relying on the primary 02 sensors to make the changes but u will have higher than recommended fuel trim and thats not the proper way to have a tune set up
I get what you are saying but at these levels we are letting the car adapt exactly how its designed to react to different fuels. All of our cars are stoiched at E10 but many times that's not what we're getting. The 2013+are rated for E-15. There was no change in the programming to deal with this because the deductive fuel logic is already there and there was no need. Had there been a change, it would've been listed in the EPA certification. Driving through the US you will see blends ranging from E0-E15 and no tune change is required. The ECM is using the exact same strategy it uses for E15 as it does for E20 and so on. As long as you don't exceed the LTFT and subsequent imposed time limits at those levels you won't see a cel or dtc.
As I've stated a few times there can be some throttle response laziness when changing blends but once the car is driven and has the time to adapt (trim), that disappears and stays gone if you continue at that blend level. Interestingly when going back to a blend I had previously ran, this was no longer an issue.
I'm not sure high blends or straight E-85 are even necessary as the law of diminishing returns is at play here and there is more energy in straight gas. From what I've researched E20 seems to be the sweet spot as far as performance, driveability, and economy goes.
Now as far as a dyno "debunking the myths"....That seems to be a tad dismissive as members including myself have posted up actual time slips documenting ET drop and higher traps doing nothing but adding some corn. Unless you are willing to test with a known fuel composition, drain the tank, add another known fuel composition, drive the car for a while so DFL can do it's job than retest you won't be debunking anything. Now throw in environmental differences (Like different air temps being crammed down the intake at 90MPH) that can't be duplicated on the dyno. The dyno is a tool, not the final say on what actually happens at the track. Another good example is your CAI findings on the controlled dyno vs other members time slips on the uncontrolled track with back to back intake changes/runs. Hell some days I've seen my best times after the 7th or 8th run with much higher IAT2 than when I started. Good luck figuring that out on the dyno.
And I want to clarify something...
E85 doesn't make any extra power!
What it does is create optimal in cylinder conditions through effective octane and cooling for the car to run max settings of whatever tune you happen to be running, whether it's stock or tuned. My 2013 wasn't magically faster with E-85, it just created the condition for the car to run at its max potential
as it came from the factory and the straight 93 in my area could not.
The trick is finding the
lowest amount of E that will create those conditions while keeping rail pressure high.
