NefMoto

Been trying to figure out best timing for running e85  and read somewhere here that kfzw should be set close to kfzwop for me7.  Problem for me is I don't think I know kfzwop for my m5.92 AEB.


I am thinking I should estimate based upon ME7 files what the equivalent KFZWOP timing values would be for my AEB and tune to approach these values, bad idea?
This is shown below. I don't really know how the ms loads for my maps correspond to the %loads in the me7 maps but I figured they probably represent the same info for scaling purposes.

If anyone has a good kfzw map for 100% e85 on an AEB would very much appreciate seeing the values.  Im all stock except for DV and big injectors.

Thanks for whatever info and advice you can share.

Im running Me7.5 an I started adding around 2 degrees over the entire map.. Then i raised them slowly bit by bit at the same time I measured my EGT´s very very close.. (Also log your inition so that you know that youre on target) I also started off by running very rich around Lambda 0.75 at higher loads and slowly decreased the lambda until EGTs went up. I have never managed to get knock ever on E85. Its a bit scary. (E85 is not so sensitive to run rinch, but check you injector duty cycles so they dont get stuck.). Im not sure if this is the proper method though.. Im still looking for a godd method to tune E85 without a dyno..

Thanks for info,  did you always increase the timing over the entire map?  Did your lambada change much from a 93 tune?

Part I'm really struggling with is how the kfzwop values are so skewed from kfzw base values, not  just more advanced. 

I'm interested in the kfzwop values because I think they represent MBT and something close to what e85 timing should be.  Can someone confirm this for me?

I can start off slowly bumping up timing but I'm gonna struggle knowing if I've added too much without a billion logs of rpm. timing and load.  I'm scouring the inter web to find a dyno tuned kfzw map for e85 I can use as a guide.




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Im running this now in my Me7.5... But today I added 2 degress more over entire map just to se what happens :) Didnt logg or anything.. It ran slightly better i must say.. i could be placebo but. Im going to add some more timgin in low load areas...  I just have to fix my immo problem in the other thread... I have managed to lock my ECUs :(

With E100 you can go next to 9° plus advance in high load/RPM ... in mid range 6°...in low load /RPM areas somethig between 3 and 6° works great...

KFZWOP is optimal for gasoline, Ethanol burn slower and shall have more advance to work good... you can use it as a start point, but at end will notice values greater than KFZWOP work better... something like 3° plus entire range at least.

Dont´forget to raise KFZWOP to not fall at engine torque monitor issues...

KFZWOP you said something there..  I have to take a look att that

When is KFZW and KFZW2 used?  and when do we see when we are close to melting the pistons? E85 dont knock! Are you using an EGT gauge?

Hope i dont steal the thread here :)

Thanks for the info, both of you.  I guess I will start with setting my KFZW a few% lower than my inferred KFZWOP AEB map and try to get my timing close to Jims in the load areas and then begin the logging and tweaking.

KFZWOP is NEVER directly used for actual timing. It is a reference to calculate ignition efficiency.

Thanks for clarify that !

I was assuming based upon what I read that it was good guide for running e85 when not knock limited. I don't really know enough to argue so ill keep reading until I figure it out.  Thanks.

There is no need touching OP at all. You can ad about 3-6 deg on E85 allover the range
One thing here is really importen and it is you do not need to log EGTs or knock. It is pointless n wrong when tuning E85
What you need to do is
Start at oem timing values. Ad 2 deg and LOG!!!
Ad 2 deg again and LOG!!
As long it is making Torque and is faster - ad timing. When it start making less TQ at timing raise - you are done.
Dont get gready here. Take it easy and know your Ethanol content.

thanks for that info Mocke.. But can you log knock? Is there any?

I just came in from a test run and I added now 3 degrees on stock timing in low areas.. I got the feeling that it was a bit more alive. Im look into the 2000 rpm+ range now and se what happens... I dont have the EGT gauge installed but will try to install one..

KFZW and KFZW2 are used cam (VVT) position

E85 will give you much lower temperature than gasoline... and is related more with lambda values (BTS stuff), point is the higher EGT will give you the best torque mantaining lambda at same value.

For example, Up TSi (MED17.5.21) here in Brasil uses E100 and even in BTS never goes down lower than 0,95 lambda (when running E100, witg gasoline it´s something close to 0,75 lambda)...even in high load, RPM and prolongued time as it never reach temperature to mel anything...


Log EGT to achieve best troque values - OR as said by mocke just start raising advance till get best torque values... Keep lambda at a secure point and after found the "best" advance you may want to deal with lambda and see what happens...

KFZWOP is never used to timing as said by nyet, it´s a theorical value for optimal advance (FOR GASOLINE) if not knock limited...   E85 timing will ALLWAYS be higher than this...

which means, of course that the ECU will calculate ignition efficiency wrong, so ideally, you do want to set KFZWOP correctly.

It seems to me there is some confusion here about how E85 works.

E85 (measured 85% ethanol content, to be specific) is extremely knock resistant.  EGT doesn't mean anything when tuning E85, either.  EGT does not indicate how close you are to MBT.

With E85 your goal is to move your ignition advance towards MBT (maximum brake torque), but not mechanically damage the engine with an ignition event that occurs BEFORE top dead center.   As soon as you advance past MBT, torque output declines because that energy is wasted on slowing a rising piston that has not yet hit top dead center.   The engine fights itself.

That is how you break hard parts with E85 - combustion before the piston reaches top dead center.  The difference between gasoline and E85 is damaging combustion events won't happen on their own with E85 because it simply does not combust on its own.  YOU will cause the damaging ignition event by pushing your timing advance past MBT, causing the ignition event to occur before top dead center.  It won't get too hot, ping, and then turn inside out.

You will not be able to properly tune E85 for maximum power without instrumentation for combustion analysis and measuring cylinder pressures.  Anyone who tells you otherwise does not understand how E85 works.

Personally I feel as if you shouldn't touch KFZWOP unless you are instrumented for cylinder pressure and combustion efficiency.  If somebody is making changes to KFZWOP, I'd like to know where they are getting the data from, aside from pulling it out of their ass.

Definitely don't disagree.

Jason, Always nice to read info on E85 since I now run all my 3 audis on E85 now..  But i have never bothered to look into my ign tables until now.  I will start experimenting on my Me7.5 1.8T. I had a feeling that it works as you described in your post.  "ign detonation will work against it self"..  I have now added 2 -3 degress all over the table and I will add more in some red areas and se what result i get..

One more Q"..  KFZW = High octane?  KFZW2 = Low Octane?

What do you mean by that last sentence?

No cam advance, with cam advance.

I always ask myself the reason of KFZW & KFZW2 (cam timing variation) if DBC engines does not have it. Then really does cam advance controls it?

early 512kb me7 engines do not have VVT either.
4B0906018P for example. kfzw/2 are verbatim though as well.

I make about 5 cars for week in E100, we have this on pump in Brazil since 70´s

talking about E100 ( E85 is not avalible here in pump)

1- you´ll end with more advance than KFZWOP if you want maximum power

2- Agree that you can´tell real KZWOP values without factory instruments, BUT you have to decide:

If you run lower advance than KFZWOP you are not going deep in tuning (there is some load x RPM that KFZWOP are only 1,5° above KZFW)

If you raise KFZW higher than KFZWOP you may have some issues with ignition efficiency calculation

So, the only remaining thing to do is raise KFZWOP... even don´t knowing the "real" value.

what I do is raise KFZWOP, tune KFZW in dinamometer, after it´s done I make KFZWOP about 1,5 to 2° higher than KFZW... don´t know if it´s the rigth thing to do, but it´s the only way I found.

EGT will change with advance modifications, so it can be used to help find KFZW values, but on dinamometer is much more quick to make it... and believe, in some conditions even E85 can melt pistons... just run more than 0,88 lambda some time and it will happen

KFZWOP will definitely need to be changed to make max power.  No doubt about that.  There is a lot of power on the table.

The problem is MBT is a moving target across the load and RPM ranges.

I think it's virtually impossible to hit all of those conditions on a dyno, AND measure the rise and fall of torque as you reach MBT and then pass MBT.  You can probably get close, but it's a balancing act, and I don't think I'd personally rely on that.

You can also hurt the engine or your fuel efficiency by scaling KFZWOP past MBT at lower loads, something that is difficult to measure on a dyno.

On the subject of knock resistance and what you can get away with, I've been doing a lot of E85 research and testing lately on my beater Allroad, (testing before I convert my S4) and I am amazed you can get away with 225+ degree IAT's when you ride the upper limit of KFZWOP.

Thats what i'm saying... There is no easy copy solution, and demand a lot of logging and test...

You can put easily 9° advance with E100 and not bad will happen, except you past mbt and will end with lower torque values...

If I had to make a half assed attempt at guessing at KFZWOP values, I'd start by simply altering the areas where you think you'll make more timing than the stock KFZWOP, and minimally set those to your max expected timing.

my seadoo file actually has OP less than KFZW in parts of the map. never quite understood that one.

Anyway i tested my ign version 4 today.. feels good but im not ready to decide yet.. I Measured 622C EGT directly after turbo.. Shall i add 100 degress on that to get more close? I added most timing in low areas.. dunno if i want to go more in high rpm and load areas.

While we are on the subject of E85, has anyone else noticed that switching to E85 from pumpgas results in crankcase pressure dropping significantly?

Tuning by feeling never works regardless of the fuel. 

IF you don't have access to a dyno, you should be comparing acceleration #'s to confirm if the car is going faster as a quasi "road dyno"

It's very easy to over-advance on Ethanol.  Tuning it using knock sensors is completely pointless.

For posterity

Using quasi FATS, ended up with 2.25 deg added to the whole map.  Tried adding more in the mid to high load ranges but this appeared to slow me down, the more so with the more timing used.  Not too confident in my testing as my MAF readings also went down when I added more timing.  This could of been due to it getting hotter here in TX over my day of logging.  Regardless, going with what I got for now.

who can say how much to correct the ignition timing angles for operation under propane gas ? vr5 2.3L me7.1 engine.