I switched my Camaro over to E85 (71) yesterday (GM sensor with bypass) and made a couple of runs. I was surprised that my ST's and wideband showed rich. I thought since it took more E85, that it might be running a little lean. Idle was especially rich. Any experience? Thanks

 

yes, stoich for e85 is a lot richer... 9.xxx compared to 14.xx for normal gas... the more alcohol content, the richer it will be... that's normal...

 

While STOICH, absolute numerical ratio is indeed heavier FUEL, the LAMBDA value stays the same.
.............Your wideband is still reading oxygen in the exhaust stream.. .

 

OK, For WOT, I am commanding .82 Lambda for 93 octane based on 14.1 Stoich. That gives me a 11.5 AFR----Under Boost.
I am showing 71% for the E85 that I filled the tank with.. I had to do a lot of adjusting of the VE table to get back to .82 after starting on E85, (no maf). I thought that the sensor and alcohol tables compensated for the difference. What I am asking is when filling the Power Enrichment alcohol EQ table, do I use 14.1/1.22 or some other number?
It seems like the sensor is good for changing the timing, but not so much the fuel. I can't just go back to 93 without retuning the VE table. Here is the Alcohol table

 

It says it right there in the help at the bottom, the PE tables are a Fuel/Air multiplier vs Stoich AFR. Really you are targeting the same ratios on E85 as you are with pump gas for the most part. If your fueling is off and it's requiring you to retune your VE table when your ethanol content changes something isn't set right as it should compensate properly assuming your fuel pressure isn't dropping on E85 vs pump gas, but without a tune file posted it's just guessing as to what's wrong.

 

Robert Plant said it best: "The Lambda Remains The Same"

 

I read that. Stoich table goes from 14.2 to 8.7 something. My brain is in a knot.
Here is the tune--no maf, 2 bar SD. There is no fuel pressure drop. I have a gauge in the car. Pressure increases with boost. Fuel Lab brushless pump--- -12 feed to pump, -10 feed to Y, -8 feeds to fuel rails.
Another thing--- I want to be about 12.0 afr WOT with E fuel. So I need to change the alcohol PE table to --???

 

LOL, I guess I can't get that thru my head. If I have commanded PE set to .82 Lambda, and have my VE table tuned to .82 Lambda with 93 octane, VE should not have a big EQ error when I log it running E71---correct? Because the stoich number is now 10.0 instead of 14.1--correct?
I did have to retune VE for E71 after I had already tuned for 93. Eq error was showing rich.

 

Well that's not the OS I expected to see for a 2000 Camaro, guess you swapped in a Gen4 ECM/TCM? What is the entire mod list because I see some really weird stuff with scaling, injection timing, and some other tables.

 

2015 5.3 L83, forged, Bosch 210's (yeah they are genuine) too big though. 2 bar sd, 2012 E38 with 2012 stock harness turned into stand alone. Cam is Cam Motion-- intake lift .631, c/l 111, exhaust lift .629, c/l 120, lsa 115.5, 4.5 advanced. 230/248. Katech cleaned up the heads. 4L80/T42. The Whipple blower case has been converted to port injection.

 

For one thing, your stoichiometric table is wrong. I understand you have doubled it for scaling purposes, but that means you have effectively put 14.1 as your 0% alcohol baseline. Since 14.1 is a general baseline for e10, that will mess up all the stoich calcs. Your 0% baseline needs to start at 14.68. I did not dig any deeper, so there could be something else, but that is a start.

 

Just wondering, are you in a 4th Gen F-Body? Are you running flex fuel or tuned only for E-85? If flex fuel can I get more information as to how you did it?

 

That's easy to change, but the 93 around here is E10. I didn't have a sensor when running 93 so that's why it is 14.1.
So you are saying ---with a sensor---it should start at 14.68 ? thanks!

 

Yes, a 2000 Camaro running Flex. It's a stripped down car with a E38 ecm and 2012 engine wiring harness. It's the car in my sig. I am not familiar with Gen 3 ecm's. If you have HPTuners, you can look and see if you have a Flex fuel tab.

 

.....

 

OK, I fixed the stoich table and fixed the gas and alcohol PE tables along with the boost PE table. This AFR/Lambda/Gas/Alcohol thing had me twisted.
If you see anything else, post it!
Thanks

 

Thanks for the table---it helped get me straight on my setup

 

OK the one thing I'm seeing is the Bosch 210s, those injectors are so affected by heat that their flow rate changes depending on how hot the injector gets and it makes it hard to be consistent at all. Aftermarket standalones can deal with them better because of the closed loop wideband feedback but stock computers don't have that and having an injector with a flow rate that varies with heat is an obvious issue.

Your injection timing is relatively aggressive at idle but looks good up top IMO, just never seen any benefit pushing SOI past 400 deg even with large cams and large injectors. Did you adjust that intentionally because it actually helped? Yes I know ZR1s push it that far but that's strictly emissions related.

Not a fan of running SD on the E38s if you don't have to, their airmass model seems to change quite a bit with intake air temps with default tables. Plus the MAF can read to the moon and is going to be the more accurate measurement.

As for the stoich being at 14.1 vs 14.7, that's less than a 3% change and when you are scaling using the AFR table it really doesn't matter anyways since it's not referencing it correctly to begin with. I really think the majority of your inconsistent fueling is the Bosch 210s and possibly running SD vs MAF on the E38.

 

Injection timing: I changed it to see if it would help. I couldn't tell any change, and forgot about it. I changed it from 510 back to 520 and re did the VE table. Is there a number that you feel I should be shooting for at idle?
I haven't heard that about Sd on the E38's. I may add the maf back at a later date. I made a stand alone harness from a 2012 truck harness and removed the maf plug and wiring. I think I still have it ??? What MAF do you recommend? I think the truck mafs are a little small.
I am with you on the 210's. WOT is about 30%. I have a set of ID 1050X on order which should put me at about 75% at wot and 15# boost. Plus the idle should be a lot better.
Thanks for the help!
I puled up some tunes from other people and looked at the boundary. They are all over the place. Mostly start out in the 500's at idle and the numbers drop from there. A lot were 520 across the board. Some dropped to lower 300's in the higher rpm range. I know there is a scientific way to figure this out, but I don't have enough info.

 

I would use a newer card style MAF that you can just put into an existing intake setup.

On the Gen4 ECMs I'm pretty sure EOI = Boundary - (Normal ECT + Normal RPM). Normally I would be targeting an EOI around 360-380 deg at idle and ramp it up in the higher RPMs but a lot depends on cam timing, injector size, etc. I usually start to increase EOI until I see fueling start to change at idle and then go back down a bit but there are lots of factors and it may not idle as well or might start to increase the smell so a lot depends on the overlap, etc. Targeting the back of a closed hot intake valve to atomize the fuel better vs when it's open and starting to draw in air are two different ways of doing it and obviously overlap plays a big role in that. Either way it's not a huge factor and has minimal effects even with very large injectors from what I've seen.