Need help with AFR on MAF to PE table transition

[c6dude]

I was Dyno tuning my car with my HP tuners yesterday and cannot get rid of the rich AFR starting at 4300rpm and finally stabilising at 5500rpm .That is where my MAF maxes out and PE table takes over fueling. Is there a way to make a smoother transition ?
Eventually We were able to get 720 RWHP but the rich condition in that RPM range is costing me about 60 RWHP.

Does anybody know how to tune around this ? He wanted to use his LS2 Edit but I did not want my computer locked out so I stuck with my own HP Tuners so I can tweak it myself. The tune is for my 2006 C6 .
Please Help !!

Here's a couple of videos of my car on the dyno .The first one has a good shot of the screen at the end with the table showing my rich AFR problem.Hope the links work: Thanks Guys

http://video.google.com/videoplay?do...38549549&hl=en

http://video.google.com/videoplay?do...53943243&hl=en

[Russ K]

What is your commanded AFR? I would use the maf afr error % to lower the maf tables were the afr is rich. At the rpm were the maf maxes you will have to work on the pe vs rpm table. With that much boost the 2.5 bar sd update would be the way to go.

Should be a fast ride!

Russ Kemp

[redhardsupra]

if you're maxing MAF (and you should do it so easily with big cubes and 15psi) then it's time for you to do 3barSD tune). otherwise, you never really know how much air you're flowing, so you can't get your fueling right.

[c6dude]

if you're maxing MAF (and you should do it so easily with big cubes and 15psi) then it's time for you to do 3barSD tune). otherwise, you never really know how much air you're flowing, so you can't get your fueling right.

heres snap Dyno AFR results:



Commanded AFR is 18.8 during that RPM to try and lean it out.Check out my HTP file below.Any suggestions welcome.

http://files.filefront.com//;5533610;;/



Speed density will eliminate my MAF right ? I then will be running open loop. I need to be emmssion legal.
It's only between 4k and 5k I need to smooth it out. The rest is fine. There has to be a way around this.

[Bill@HPTuners]

dat link dont work 4 shit. try using the manage attachments feature on this forum.

[Bill@HPTuners]

Speed density will eliminate my MAF right ? I then will be running open loop.

btw SD has nothing to do with whether your vehicle is in open or closed loop. you can be in closed loop SD or open loop SD or closed loop maf or open loop maf.

[Russ K]

You need to set up the open loop tables. The commanded AFR in PE will be the richer of either the PE table or the open loop tables. The LS2's open loop tables are all multiplied together. So at operating temps, intake valve and injector tip temps you need to command 14.7 (1.00 eq ratio) at all engine loads (map kpa). Looks like the open loop tables are commanding ~ low 11.0 AFR. This way the PE table will be in control when in PE mode.

Do you have the scan log from the dyno showing the commanded AFR? Once you get the commanded AFR right ~ 11.75-12.0 AFR, then rescale the MAF using the MAF AFR % error histogram. And where the MAF maxes out, richen up the PE table.

Russ Kemp

[c6dude]

I don't have a dyno log. I am going to do a street log when weather gets dry.
Here is my tune file.....Hope this works :

[c6dude]

You need to set up the open loop tables. The commanded AFR in PE will be the richer of either the PE table or the open loop tables. The LS2's open loop tables are all multiplied together. So at operating temps, intake valve and injector tip temps you need to command 14.7 (1.00 eq ratio) at all engine loads (map kpa). Looks like the open loop tables are commanding ~ low 11.0 AFR. This way the PE table will be in control when in PE mode.

Do you have the scan log from the dyno showing the commanded AFR? Once you get the commanded AFR right ~ 11.75-12.0 AFR, then rescale the MAF using the MAF AFR % error histogram. And where the MAF maxes out, richen up the PE table.

Russ Kemp

Is this the table you are referring to ?

[Russ K]

Yes that is one of the tables. Also put the open loop gas (gear & P/N) tables back to stock. I would change the injector temp table to be all 1.00.

Now you need to set the intake valve temp table so that at operating temp, the values are 1.00 at all map kpa. But you will have to find the relationship between engine temp and intake valve temp. I would start by changing the columns from 162*F & hotter to 1.00 at all map kpa.

Keep checking the commanded AFR with the scanner at operating temps with the car in OPEN LOOP until it is at 14.7. If you go to 1.00 when the engine is cold, you will have a hesitation/stall. Now once you get the commanded AFR to be 14.7 at operating temp (not in pe), then the PE table will be in control of the commanded AFR when in PE. Then rescale the MAF to get the actual AFR to match the commanded AFR.

Russ Kemp

[c6dude]

Yes that is one of the tables. Also put the open loop gas (gear & P/N) tables back to stock. I would change the injector temp table to be all 1.00.

Now you need to set the intake valve temp table so that at operating temp, the values are 1.00 at all map kpa. But you will have to find the relationship between engine temp and intake valve temp. I would start by changing the columns from 162*F & hotter to 1.00 at all map kpa.

Keep checking the commanded AFR with the scanner at operating temps with the car in OPEN LOOP until it is at 14.7. If you go to 1.00 when the engine is cold, you will have a hesitation/stall. Now once you get the commanded AFR to be 14.7 at operating temp (not in pe), then the PE table will be in control of the commanded AFR when in PE. Then rescale the MAF to get the actual AFR to match the commanded AFR.

Russ Kemp

Russ
I just finished modifying my all open loop tables . Thank you very very much for the quick and detailed help you have given me.
I am going back on the dyno next week with an extra fuel pump installed . I then will be able to dial her in to 7200rpm with 18-19 psi of boost without running out of fuel. Hopefully also take care of the mid RPM rich condition.
What you said makes a lot of sense now ,I did not know the open loop tables and PE tables work together on an LS2. Thanks again to you sir for your time.
Perry