Hello tuners from all over the world
Pretty straight forward here how does the flex fuel sensors in the gen 4 platforms react to other fuel like c16....etc I mean let's say I have a car that's I have already tuned on octane 95 and I wanted to upgrade for c16 fuel do I need to tune the flex fuel or it will do everything by itself ? I mean does these sesors work for any kind of fuel or is it specifically for e85?
The alcohol sensor is for measuring alcohol, it won't know if you put 87 octane in it or 116 octane. It's just going to tell you the alcohol content of that fuel.
You would have to create a separate tune file if you wanted to run it on C16, assuming you want it to be far more aggressive than a pump gas tune.
Install a real flex fuel sensor if you plan to run E85 or whatever mix in between.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
Thanks that all I need it to know so I have 2 optionOriginally Posted by 5FDP
1-to have two tune files one of them tuned on 95 octane for daily driving .
The other one tuned on c16 for racing and just reflash every time I need to switch between them.
2-install a flex fuel sensor and it will save me the trouble of having two tunes and reflashing them every now and then between daily driving and racing .
If you plan to run C16 you'd probably still want a different tune file made if you decide to make it really aggressive.
Like I said the flex fuel sensor won't know if you are using 95 octane or 116 octane. You may not want to run the tune on 95 octane if that octane amount isn't going to handle it like 116 octane would.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
OK thanks I got the idea of how the flex fuel works now when it comes to tuning for example if I am going to.use two files like you said one for c16 and one for 95 octane I would tune the file that's already tuned on 95 octane but this time I should be able to have more timing without knock since I am using higher octane fuel my question is do I increase the timing in the base tables high octane for example or is there any other seperate timing tables for fuels like c16?
And whenever tuning flex fuel how do you tune these tables since there are these alcohol multipliers that would increase timing to a specific point but maybe that's not enough for me I want it to add more timing do I increase the base timing table and then log for knock and decrease the base timing table or increase and decrease in the alcohol adder table?
interesting you would ask what was already answered.
"The alcohol sensor is for measuring alcohol"
2012 ZL1 - Maggie Heartbeat, Port & Polish Heads, Custom Cam, Custom rotating assembly, steel sleeved LS9, No NOS and No water meth. 16psi
810rwhp and 820rwtq 91 Octane 6400 rpm
948rwhp and 951rwtq 105 Octane 6400 rpm
999rwhp and 997rwtq on 60% Ethanol 6400 rpm
I run ms109 in a lot of cars and with it solely in the tank with alcohol sensor I typically get around 13.2-13.5 and stoich for this fuel is 13.4....
So there’s that
Email Tunes, [email protected]
96 TA Blown/Stroked, 4L80E/Fab 9
15 C7 A8 H/C 2.3 Blower/PI
14 Gen 5 Viper
Custom Mid Engine chassis, AKA GalBen C
Yeah I got it by now I think to simplify this basically if the flex fuel sensor is already built-in your vehicle you probably don't need to do anything maybe small modification in timing and fueling and you can have best of both worlds when your runing fuel or your usual pump gas .
But I think what was 5FDP referring to is if your trying to make the maximum amount of your alcohol fuel is to have another file for the fuel you want to run that way you can have a more aggressive tune . Now I am curious how do gen3 platforms go about this since they don't have these flex fuel tables I know they can install a flex fuel sensor easily but how do they tune without these flex fuel parameters in hp tuners.
C16 has a stoich of 14.6 or something like that, the flex fuel sensor wont react to the c16, if you want to take advantage of the flex fuel system you should use E85 instead of c16 for racing, both fuels will allow you to go past MBT without knock
Ok so if both fuels will allow me to go past mbt.
can I take the mbt values at wot and just paste it into my base tables and log for knock instead of adding 2 everytime?
u will go way past to the point u will start to loose power and damage your engine if u kept going, when i was on ethanol and one fuel pump failed it went that lean the whole drive line shuttered when i hit boost and i backed off but still didnt see any knock, best to find best torque/hp on a dyno where u can see it increase and drop off in power
My first time tuning on e85 i went so far that the car gained horsepower from me retarding 5 degreesbecause i was waiting fot the knock sensors to tell me when to stop, if NA you wont see more power after 30* of timing
The way your putting.it So what am I supposed to do just put ethanol and hope it's tuned perfect ?I mean there have to be a save way around this
How am I supposed to know where to stop if my knock sensors aren't showing any knock
I don't even know where to start on this thread.
But for this last question- dyno or track is the only way to know. Dyno probably preferable for most.
You can start from where you want.as for dyno vs track a tune like this would be better at a dyno because you can see on the graph just exactly where you start to lose power and stop there but since most of us don't have a dyno we usually tune on the street as you can see the question is mainly about how to know when you start losing power on the street whenever your tuning since the previous comments shared their first time tuning e85 and they said that their knock sensors weren't showing any knock even when they started losing power so in a situation like this you would be adding timing blindly and losing power and not even notice what is going on this thread will be useful for new tuners like me and they wil know what to do then I hope I cleared it out for you thanks for sharing your thoughs on this.
On the dyno, be mindful of the gain you are having, if you add 3 more degrees and see only 2whp increase its time to stop adding timing, if you add 1 degree and get the exact same power its time to stop adding timing.
Yes on the dyno it's perfect but what about the street if my knock sesors isn't showing knock is there an alternative?
The reason your knock sensors didn't show knock is because of your fuel pump failing correct so if you had your fuel pump working your knock sensors would have shown you where to stop right?My first time tuning on e85 i went so far that the car gained horsepower from me retarding 5 degrees
No. E85 doesn't act like 93. If it were me, I'd add timing until it stopped making power on a load bearing dyno then pull 1 or 2 degrees. Then you'd be covered on the street.
Alternatively, run it at the track and add timing until your trap stops climbing.
Alternatively again, run it in Mexico and time some 3rd or 4th gear pulls from 2000 to redline on the exact same piece of road. When your time stops improving in your log file, you're done adding timing.
Last edited by RobZL1; 09-25-2020 at 08:19 AM.
There was no failure, i simply didnt know where to stop and continued adding timing into the 38*, at that time i backed it to 33* and 12.9 afr, the engine was 200k miles and sent a rod thru the block while doing a long 7k rpm burnout two years later, it made 455whp on a TSP vvt1 cam and ran 11.8 full weight on 3000DA and 10.9's on a 150hp nitrous shot.
On that L99 E85 never showed any significant knock track or dyno, on the track it was too easy to add timing and be confused by the results so my advice is to tune timing only on a dyno.
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