olympic

Hey everyone. Does anyone know how much timing advance the 3.5 and 3.7 engines can handle without detonation issues? This is assuming premium fuel (91-93). I understand 93 likely to be able to take a bit more than 91. I wasn't sure if factory mapping is conservative on timing or if that's about as good as it gets.

Is there any difference in the timing advance mapping for the 3.5 and 3.7? I understand both have 11.2:1 compression.

One member was kind enough to let me know that he was seeing 15 degrees of actual timing advance at WOT at redline on 93 fuel on his 3.7 with the factory map.

I'm trying to get my arms around what the 3.5 and 3.7 can handle for timing advance and learn if there are any differences between the 3.5 and 3.7 with regards to timing.

If others are monitoring their actual timing advance at WOT near redline I'd also be curious what you are seeing.

Thanks!

619rcr

I have a custom built j35 running 12:1 compression, bc cams 650cc inj on pump 91 wirh AEM standalone. I've done lots of fuel map changes but absolutely no timing changes. Why because i'm not a professional and don't wanna blow up my motor messing with timing. However, I do have a tune scheduled for later this week.
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The question I have for you, is how do you expect to alter timing and what are you hoping to gain?

olympic

Sounds like a good build. I hope your tune goes well. Would be curious to know how much actual timing you end up running on 91 at WOT around 5,000+ rpm. To answer your question, the timing tables can be adjusted in ktuner. Every degree of timing advance is worth some additional hp and torque. Yes there are other things to be factored in and of course you can only go so far before detonation. I was curious if the factory timing maps on the 3.5 and 3.7 are conservative and whether timing advance can be increased, or if people are not even hitting the timing advance max as already defined in the factory ignition tables due to knock control values coming into play.

619rcr

Got it. Yeah, i know what timing advance can do. But, usually timing is adjusted in a tune after afr is optimized. I do have ktuner on a tlx v6, but again haven't adjusted the timing​​.
For reference below is the default j series ign map from AEM EMS:


As for my tune, meant to say later this month. Hoping to make at least 300whp. I do have ported heads, runners, p2r headers, j37 intake and upgraded valvetrain as well. The car feels really strong as is, it just needs some refinement in the tune.

olympic

Thanks for passing that along! That are some nice upgrades! So basically at WOT (0psi if not boosted so I'll use that 0.2 row) I'm seeing in this table 9.7 degrees of timing advance from 3700rpm on. I don't know about the AEM setup but I am guessing there is a knock limitation and knock retard table to retard the timing back further if knock is encountered. Am I reading that correct that maximum timing advance would be 9.7 degrees at 0.2psi at 3700+ rpm?

619rcr

correct.
forgot to mention load are the far left numbers going vertically. My setup is NA, so I cut anything above 1psi to yield more resolution.

olympic

Thanks. I could tell the left side was boost. I'd be curious what boost timing looks like up to about 9psi if it's easy to do a screen grab.

619rcr

AEM didn't change ign map for more boost in the included base tune, likely because the test vehicle was NA. Matter of fact I recall something to that effect in the setup instructions.

olympic

Okay thanks for the follow up. It is interesting that the AEM ignition timing advance is less than what I'm seeing in the ktuner factory base map for timing.