When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
First, you have no boosted rows in your afr table. Make them the same as your ignition and fuel table. This will require some differences since some are 16x16, afr is 12x12. Initial drop in timing for boost is ok, but then it starts to not drop enough. I like to drop a degree/psi, starting at ~28 degrees at 100kpa, which would put you at 10-12 degrees at 18psi, you’re at 15. Even if you’re not planning one running that high, it’s good to be safe up there. Even at the 8 psi you’re running, I’d say it’s ~2 degrees too advanced. AFRs should be in the mid to high 11s by 8 psi, but again you don’t have any rows up there.
What max boost do you plan to run?
Where do you have boost cut set?
How high have you gone so far?
I like to have a row of advance above where I plan to max, at where I have boost cut, as an additional safety. In other words, if I hit boost cut, I have already lowered torque by retarding timing. My top row of timing is about 4* retarded for this safeguard.
I'm not sure if anyone else does this, and I admit it is a bit theoretical, as I've not been to a dyno. But I'll tell you, that a TD04 can get away from you really easily and try to run 20+ psi.
That’s going to be really hard to judge, but it doesn’t look like it’ll be correct. If peak demand is at 5500, I’d expect it to taper off more by 7200. Log a full throttle pull from 1500 to redline in whatever gear possible, and I can give you a better answer.
Here's a little megalog viewer education. Go to "calculated fields", "field min and max editor", and select AFR and AFR target. turn off auto scale, and set them both to the same. These settings are 10 min, 18 max. Since they're now the same, AFR should over lap AFR target. As you can see, AFR is lean from ~4500-6000rpm, but stays around 12.9 instead of the 12.5 target to redline. For the 6000-7000 range, 12.5(afr target) divided by 12.9(actual afr)=.96, multiply by 100 for percentage, and you're short 4% fuel. If injectors are setup correctly, that should fix that area. In the mid range where you're dangerously lean, you're short about 15% fuel.
This is also where I should tell you that you also really should be logging fuel pressure with a high quality sensor. If your fuel pressure is dropping, you'll be tuning forever trying to fix this issue. Your duty cycle is dangerously high for such low boost and lean AFRs. Either your FP is tanking or your injectors are too small. Or both.
Curly has the magic, he is the reason I feel confident driving my freshly built msm. If you do exactly what he says your car and wallet will thank you.
I wanted to pile on. Curly has always provided excellent advice.
I've been meaning to ask... this is one of several tunes I have seen recently where the AFR Table is set up to go rich very early. My table is much more like the one for the '99-00 tune on Trubokitty. I don't start going richer than 14.7 until 90 kPa, but my boosted rows look about the same as the OP. Is there a new philosophy about when to start going rich?
OEM computers will keep naturally aspirated engines at 14.7 until ~3500 or more, even at full throttle/100kpa. I typically like 14.7 in cruise, 12.5-13.0 at WOT, and where to blend those two is entirely arbitrary. You could argue for keeping it lean to 90kpa, or richer starting at 70kpa, but you'd be tearing down and carefully inspecting perfectly good engines for years before you settled that argument. Higher boost levels are where damage really occurs, and even then it's still a combination of being too lean and too high of ignition timing that does the damage.
10-08-2023, 03:58 AM
Help with AFR and Spark Table 1992 NA6 1.6L Miata 8psi turbo
0
