REVscene Automotive Forum - View Single Post - Dyno testing fuels - Big difference between Shell 91 and Chevron 94

320icar · 10-27-2021, 11:40 PM

alright, so i grabbed some logs. this is going to be a longer post but its necessary to help normal people get a sense of whats going on.

to preface: car is a 2017 focus RS, full bolt ons (intake/FMIC/piping/downpipe/exhaust, plugs, coilpacks, BOV etc). vehicle is set up to run a water/meth injection system and usually does so, but for the sake of this testing it was all turned off. vehicle is tuned by Stratified, has always ran well and been reliable, it is *not* a car-killer tune. they know i track the car and i have asked for a tune to not be on the ragged edge just in case.

vehicle has four tune slots: 91, 91+wmi, 94, 94+wmi. all datalogging for building the tunes have been done with chevron. historically my ecoboost vehicles have not liked Shell, but they have also not liked chevron 94. we find chevron 94 to be too inconsistent to base an entire tune off of it, so we usually settle for 91. although when my water/meth is turned on, i run 94 because any variance in fuel quality is ultimately null and void by the added methanol.

i always fill up Chevron 94. so a few weeks ago i went to the Chevron on 5 and bridgeport in richmond, filled up like normal. after filling up though my Cobb Accessport, i cleared all saved values in the ECU including fuel, ignition, timing, boost targets etc so its starting fresh. i drove around like normal (street, highway, some pulls etc) for 300km and then took two datalogs. all runs were done in 3rd gear, 2500rpm to 6500rpm in similar weather and temperatures.

once that tank was empty, i filled up with Shell 93 (46.5L of my 50L tank) from the station on lansdowne and garden city. once again i reset my ECU, i left it on the same tune slot (94 octane, no wmi). in order to be fully fair, i drove around until that entire tank was empty, and filled up once again on Shell 93 so there was absolutely no chev 94 left.

i upload my logs to www.datazap.me which is a great free website for visualizing and interacting with your tunes. it will open the log files and you can click what perimeters you would like displayed. this works best on desktop, if you try on mobile sometimes it wont work properly. i will include some screen caps you can at least view and get a gist of it on your phone.

Chevron 94 run 1 https://datazap.me/u/320icar/chevron...log=0&data=5-9
Chevron 94 run 2 https://datazap.me/u/320icar/chevron...log=0&data=5-9

Shell 93 run 1 https://datazap.me/u/320icar/shell-9...log=0&data=5-9
Shell 93 run 2 https://datazap.me/u/320icar/shell-9...log=0&data=5-9

here is a quick summary of what perimeters you should be looking at, and what they do

actual AFR - this is the direct wideband air fuel ratio reading from the o2 sensor
boost pressure - feel like this one is self explanatory.
ign timing cyl3 degrees - on the ecoboost motor we watch cylinder 3 (we do so because for some reason its the weakest), this is the overall ignition timing of the motor, with 0 degrees being top dead centre. the higher the number, the better. IIRC my tunes peak at about +15 for no wmi
ign corr. cyl degrees - we watch each cylinder separately here. this value ranged from -6 to +4 degrees, and its a live value of what the ECU is adding or pulling per cylinder compared to its target values. again, higher the number the better, negative values is BAD as it means its pulling timing
knock count cyl. # - we watch each cylinder separately again. some knock is ok, modern motors are designed to keep advancing timing until they see knock then pull back. normally on a WMI datalog run i might see 1 or 2 knocks
oct adj ratio lrn - this is a value ranging from -1 to +1 and its sort of an overall score for your octane rating. negative is actually better here. if you saw a value of +1 then it means it has to adjust to the full amount to compensate for bad fuel. -1 means its actually been able to be more aggressive with the tune overall with good fuel
wgdc actual % - wastegate duty cycle, pretty much shows how much my wastegate is actually being used to reach the target boost numbers.
accel pedal pos % - this car is a fly by wire throttle. this shows how far im pushing the gas pedal
etc angle actual degrees - electric throttle control actual degrees. since it is an e-throttle, the computer can adjust the actual throttle body opening to whatever it wants regardless of my pedal input to control boost spikes etc. in this case 82 degrees is WOT, not 100

alright now that the horribly long winded intro is done, allow me to add some screen caps for those on mobile.

Chevron run 1: lots of knocking, lots of negative timing correction and overtall timing was pretty meh

[img]

Untitled by 320iCar, on Flickr[/img]

Chevron run 2: lots of knocking, lots of negative timing correction and overtall timing was pretty meh

[img]

Untitled by 320iCar, on Flickr[/img]

Shell 93 run 1: virtually no knocking, ignition corrections all positive, slightly more boost and ignition timing matched what i normally get with WMI

[img]

Untitled by 320iCar, on Flickr[/img]

Shell 93 run 2: some timing pulled from cylinder 3 (as mentioned a weakspot on ecoboost) but once again overall very healthy, nothing to be worried about

[img]

Untitled by 320iCar, on Flickr[/img]

i just want to say that this is a very small sample size, only time will tell. you can look in my datazap files and check out old logs, and i will continue to use shell and start trying to datalog some WMI runs and see how it does. Other than my datalogs, I do watch my live info with the cobb accessport every time I drive, and what I see on a daily basis matches the final thoughts.

at this point, i have no doubt in my mind Shell 93 is the superior fuel to Chevron 94

10-27-2021, 11:40 PM	#206
320icar RS.net, helping ugly ppl have sex since 2001 Join Date: Feb 2011 Location: Richmond Posts: 8,469 Thanked 14,968 Times in 3,904 Posts Failed 471 Times in 216 Posts	alright, so i grabbed some logs. this is going to be a longer post but its necessary to help normal people get a sense of whats going on. to preface: car is a 2017 focus RS, full bolt ons (intake/FMIC/piping/downpipe/exhaust, plugs, coilpacks, BOV etc). vehicle is set up to run a water/meth injection system and usually does so, but for the sake of this testing it was all turned off. vehicle is tuned by Stratified, has always ran well and been reliable, it is not a car-killer tune. they know i track the car and i have asked for a tune to not be on the ragged edge just in case. vehicle has four tune slots: 91, 91+wmi, 94, 94+wmi. all datalogging for building the tunes have been done with chevron. historically my ecoboost vehicles have not liked Shell, but they have also not liked chevron 94. we find chevron 94 to be too inconsistent to base an entire tune off of it, so we usually settle for 91. although when my water/meth is turned on, i run 94 because any variance in fuel quality is ultimately null and void by the added methanol. i always fill up Chevron 94. so a few weeks ago i went to the Chevron on 5 and bridgeport in richmond, filled up like normal. after filling up though my Cobb Accessport, i cleared all saved values in the ECU including fuel, ignition, timing, boost targets etc so its starting fresh. i drove around like normal (street, highway, some pulls etc) for 300km and then took two datalogs. all runs were done in 3rd gear, 2500rpm to 6500rpm in similar weather and temperatures. once that tank was empty, i filled up with Shell 93 (46.5L of my 50L tank) from the station on lansdowne and garden city. once again i reset my ECU, i left it on the same tune slot (94 octane, no wmi). in order to be fully fair, i drove around until that entire tank was empty, and filled up once again on Shell 93 so there was absolutely no chev 94 left. i upload my logs to www.datazap.me which is a great free website for visualizing and interacting with your tunes. it will open the log files and you can click what perimeters you would like displayed. this works best on desktop, if you try on mobile sometimes it wont work properly. i will include some screen caps you can at least view and get a gist of it on your phone. Chevron 94 run 1 https://datazap.me/u/320icar/chevron...log=0&data=5-9 Chevron 94 run 2 https://datazap.me/u/320icar/chevron...log=0&data=5-9 Shell 93 run 1 https://datazap.me/u/320icar/shell-9...log=0&data=5-9 Shell 93 run 2 https://datazap.me/u/320icar/shell-9...log=0&data=5-9 here is a quick summary of what perimeters you should be looking at, and what they do actual AFR - this is the direct wideband air fuel ratio reading from the o2 sensor boost pressure - feel like this one is self explanatory. ign timing cyl3 degrees - on the ecoboost motor we watch cylinder 3 (we do so because for some reason its the weakest), this is the overall ignition timing of the motor, with 0 degrees being top dead centre. the higher the number, the better. IIRC my tunes peak at about +15 for no wmi ign corr. cyl degrees - we watch each cylinder separately here. this value ranged from -6 to +4 degrees, and its a live value of what the ECU is adding or pulling per cylinder compared to its target values. again, higher the number the better, negative values is BAD as it means its pulling timing knock count cyl. # - we watch each cylinder separately again. some knock is ok, modern motors are designed to keep advancing timing until they see knock then pull back. normally on a WMI datalog run i might see 1 or 2 knocks oct adj ratio lrn - this is a value ranging from -1 to +1 and its sort of an overall score for your octane rating. negative is actually better here. if you saw a value of +1 then it means it has to adjust to the full amount to compensate for bad fuel. -1 means its actually been able to be more aggressive with the tune overall with good fuel wgdc actual % - wastegate duty cycle, pretty much shows how much my wastegate is actually being used to reach the target boost numbers. accel pedal pos % - this car is a fly by wire throttle. this shows how far im pushing the gas pedal etc angle actual degrees - electric throttle control actual degrees. since it is an e-throttle, the computer can adjust the actual throttle body opening to whatever it wants regardless of my pedal input to control boost spikes etc. in this case 82 degrees is WOT, not 100 alright now that the horribly long winded intro is done, allow me to add some screen caps for those on mobile. Chevron run 1: lots of knocking, lots of negative timing correction and overtall timing was pretty meh [img]Untitled by 320iCar, on Flickr[/img] Chevron run 2: lots of knocking, lots of negative timing correction and overtall timing was pretty meh [img]Untitled by 320iCar, on Flickr[/img] Shell 93 run 1: virtually no knocking, ignition corrections all positive, slightly more boost and ignition timing matched what i normally get with WMI [img]Untitled by 320iCar, on Flickr[/img] Shell 93 run 2: some timing pulled from cylinder 3 (as mentioned a weakspot on ecoboost) but once again overall very healthy, nothing to be worried about [img]Untitled by 320iCar, on Flickr[/img] i just want to say that this is a very small sample size, only time will tell. you can look in my datazap files and check out old logs, and i will continue to use shell and start trying to datalog some WMI runs and see how it does. Other than my datalogs, I do watch my live info with the cobb accessport every time I drive, and what I see on a daily basis matches the final thoughts. at this point, i have no doubt in my mind Shell 93 is the superior fuel to Chevron 94 __________________ https://i.imgur.com/4PRtABe.gif Last edited by 320icar; 10-27-2021 at 11:57 PM.