Quick Timing Table Question

[_1466_]

I apologize ahead of time but I couldn't find this after searching. I don't understand how the ECU determines which timing values to use in the table. Along the left is a set of values from -20hg to 23psi. How does the ECU "know" what level boost I am currently running?

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[gofer]

I apologize ahead of time

Apology accepted.

 

[_1466_]

Haha

I accidentally hit enter when my chair freaked-out on me and slid away...

 

[JayRolla]

I believe the ecu will use the low timing map under 10psi. Anything over that and it will be in the high timing map or if at WOT. It determines this off of throttle position and readings off the maf I believe. I will most likely be corrected though.

 

[Ceddy]

It doesn't know what Boost you are running the Load axis is in Load units or grams/rev units.

Load is approximately equal to kPa at 100% VE. So you can get a rough idea what Load column is equivalent to what boost.

1G Load Axis Conversion Chart:

Edit:

The last Load column isn't anywhere near 23 psi like in your map, it is more near 10 psi.
(Unless you are running the Double Load maps)

 

[_1466_]

So basically, if I don't have the Double Load maps, I'm only running a 14* advance up top on 10 psi? [I have a stage III Keydiver chip] That seems extremely conservative and I still see significant counts of random knock.

I was hoping somehow my ECU was "misreading" the boost level and using a more advanced timing value from a lower load/boost column. In turn, causing my knock. Most of the time my "knock-sum" gauge doesn't even rest on the bottom (-7 hg value) like I feel it's supposed to. Something fishy is going on here. I'm running lean as well... even with the correct adjustments for the delphi/rochester 65lb/hr injectors (680cc). Maybe need a fuel pump rewire?

AFRs

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Knock-Sum gauge doesn't rest on bottom notch like I believe it should...

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I guess it's time to bite the bullet and get Link V3 to see exactly what timing values the ECU is using. Any other suggestions?

 

[Lavery]

You can download V3 off the ECM website for free. You wont get all the features of V3 if your chipped for V2. But you can still use it and its much easier to use.

 

[_1466_]

You can download V3 off the ECM website for free. You wont get all the features of V3 if your chipped for V2. But you can still use it and its much easier to use.

I wish, but right now I'm only running Keydiver chips and no DSMlink.

 

[gofer]

I'm only running a 14* advance up top on 10 psi? That seems extremely conservative and I still see significant counts of random knock.

You've got 91oct Elk piss out there in Colorado so 14* of timing advance is NOT conservative at all. Your AFR's at WOT should hover between 10.5~10.8:1 and don't be surprised if you can't get more than 10* of timing advance. I'm telling you those aren't random counts of knock man, its real if your seeing 14* on 91oct and your AFR's are in the mid 11's on any amount of boost you run.
I'm not familiar with the WB log you posted but it looks to me like your spiking lean, have you checked the wiring on your Evo MAF?

 

[_1466_]

...have you checked the wiring on your Evo MAF?

What exactly should I be checking for? I'll give it a good look over. Make sure the honeycombs aren't hacked and everything is solid.

I'll probably have to go more conservative especially since I have 8.5:1 pistons and the head has been milled twice. I'm probably somewhere around 9:1 CR.

 

[toofast82]

I'll probably have to go more conservative especially since I have 8.5:1 pistons and the head has been milled twice. I'm probably somewhere around 9:1 CR.

Don't expect to be able to run much timing at all on 91oct on ~9:1 as said.

 

[gofer]

Just make sure everythings making a solid connection. Your spiking lean like that because of an airflow reading and I'm guessing it could be the wiring on your Evo MAF or the MAF itself.

 

[_1466_]

Just make sure everything's making a solid connection. Your spiking lean like that because of an airflow reading and I'm guessing it could be the wiring on your Evo MAF or the MAF itself.

I appreciate the help. You have the same concern as Jeff from Keydiver. I'm headed out to check it all now. If I cannot find anything, I'll try and borrow someones MAF to check mine.

Don't expect to be able to run much timing at all on 91oct on ~9:1 as said.

I'll have Jeff burn me a more conservative tune than this one. He was unaware of the head milling (forgot to tell him). I'm currently saving for V3, bigger injectors, new pump, and an AFPR right now. Hopefully, once I have those components, I can get closer to the potential of my motor on E85.

FINAL LESSON LEARNED

91 oct. = Elk Piss = ​

 

[JayRolla]

I agree, I could not run more than 15psi on a stock timing map on 91 and still had detonation. You should look into running just a 255lph fuel pump, 1000+cc injectors and have the ecu burned for e85. Then buy an safc to fine tune. It works great for mathewdesigns here in the springs.

 

[gofer]

FINAL LESSON LEARNED

91 oct. = Elk Piss = ​

I'm from Colorado so I know all about Elk piss for fuel...

 

[_1466_]

I agree, I could not run more than 15psi on a stock timing map on 91 and still had detonation. You should look into running just a 255lph fuel pump, 1000+cc injectors and have the ecu burned for e85. Then buy an safc to fine tune. It works great for mathewdesigns here in the springs.

I truly have been contemplating this route. A good number of awesome results from this combo.

I will definitely be in the market for 1000cc+ injectors and a rewired 255 pump. But, unless I get a screaming deal on a SAFC, I'll prob just purchasing a more conservative chip for now. I would like to have access to timing and fuel as I go E85 in the future. In the end, It just seems like everyone is having too much fun with V3!

 

[ziggo0]

With e85, 1000cc, safc and a chip to make up for the injector size/more aggressive timing - you will be having just as much fun as the v3 users