Why is my timing so high??

[boostin]

My logs from tonight are f*ucked up. First things first - main mods are big28 turbo, 550's, Walbro 255, still have stock side mount. OK, I kept leaning my car out, because timing kept advancing and when I started out, it was peaking at about 24 deg. However leaning it out didn't improve my mph at all. What it did do was advance my timing sky high- on my last run, timing was at 21 at the start of 3rd gear, steady incline and peaked at 27 deg Unfortunately I don't yet have an EGT. I guess my question is what the hell is going on, my AFC settings were at -45 in the lower rpm up to -37 at 7k. I'm afraid I might be detonating because my settings are so low for 550's, but I'm not getting any knock. Also- why is my car not running any faster?

 

[boostin]

Oh ya- sorry I forgot to mention I was running VP C16.

 

[kpt4321]

-45 is ass rich. I bet you're knocking, but since the ECU is seeing such a tiny airflow signal, you're still getting decent timing.

Go to like -10% and tune from there.

And, use the damn fuel trims!

....Kyle T.
93 TSi AWD "TURBO4"
14b - 12.8 @ 108

 

[boostin]

I did start at about -10. Also, I'm pretty sure it doesn't matter how much you have your car leaned out - if your knocking, your ECU will still cut timing and it never did.

 

[ILOSE]

Originally posted by kpt4321
-45 is ass rich.
Go to like -10% and tune from there.

And, use the damn fuel trims!

....Kyle T.
93 TSi AWD "TURBO4"
14b - 12.8 @ 108

What in the hell are you talking about? Please explain how in the world taking away fuel especially down 47% is ass rich?
Forget fuel trims they are useless for track runs.

Post your slips. One with settings at the start and the last one with the leaned out tsetings. And as much info as possible. There are a lot of thing sto take into consideration. What was the weather like as well?

 

[boostin]

Weather was about 70-75 degrees. Boost was set at about 22-23. The car started out gaining mph. I'll just post to where nothing changed. I don't know for sure what the setting were, but I do remember pretty well what percentage I took out after each run.

Run 1

60' - 2.112
1/8 - 8.669
mph - 84.52
1/4 - 13.334
mph - 106.33

Run 2 - Leaned it out 3% across the board

60' - 1.749
1/8 - 8.089
mph - 85.77
1/4 - 12.706
mph - 106.13

Run 3 - Leaned it out 6% to 5000 rpm and 5% from 5k to 7k

60' - 1.904
1/8 - 8.407
mph - 84.78
1/4 - 13.032
mph - 106.35

Once again, the car never cut timing so I am assuming I am getting no knock. What I don't understand is I leaned it out a total of 8-9% and my mph did not go up at all. A local guy told me C16 really does make that much difference (I am used to Sunoco 116) so I should keep leaning it out as long as there is no knock. Any other opinions? An EGT gauge is in my near future, but it would be nice to know until then.

 

[kpt4321]

Hehe, I meant ass lean. Post edited.

Yes, fuel trims are useless for track runs. However, they are AWESOME for finding what ballpark you need to be in for corrections. I *ALWAYS* tune the lo throttle map to the fuel trims first, that gives you a very good idea of where you need to be.

If his low throttle settings are -43% as well, then his fuel trims will show how lean he is. If the lo throttle settings are quite a bit differnet than the high throttle ones, then he has a problem.

Yes, knock does make the ECU pull timing. However, if you decrease the airflow that the ECU "sees" then you will get more timing advance. With the AFC as lean as you have it, that could account for your timing being high.

...Kyle T.

 

[boostin]

That makes more sense. I meant my settings were that lean in the lower rpm's, not low throttle. I've been doing some research and saw some things about the air flow maps and how they affect timing, but it still doesn't explain why my mph never went up.

 

[Boosted98gsx]

what g/rev's are yall running?