Vg30e tuning, rich afr

[tht_z31]

What’s up everyone, I’ve recently put an afr gauge on my car and have been doing some data logging. Ever since the na2t I’ve always noticed power dropping off pretty hard past 5k. After doing some pulls I saw afr going max rich on the gauge at anything plus 5k rpm. Tonight I tried pulling some fuel on the higher rpm/load boxes, I took a considerable amount out but no change in afr or duty cycle. I am hitting the max load and it’s hits the last value on the table, is it possible it’s pulling fuel from a column im not adjusting? Can overshooting the load value cause this? I’m on factory turbo injectors and a tad bigger t3/t4.

https://youtu.be/ceomk9f4A74?si=svqV4NQpFmTEVMhH
Here is a video of the pull, i haven’t connected the aem to the Nistune yet


Thanks in advance:)

[tht_z31]

I did some more logs today, first, I put the max load TP to a value of 255. I did a log and the load went to 173. Then I reduced the k constant by something like 30%/auto-adjusted TIM and got the max load right around the factory 128. I am not 100% sure that's the way to do that, but cruising fuel AFR is the same, and fuel trims are around the same. Still running into the really low AFR up top though.

After looking back at the logs the MAF translations flash red when the AFR goes full rich, Matt previously told me this was a glitch in the program and it does show normal MAF volts if I change vehicle and then come back. So I don’t think that’s the promblem, I’m just throwing ideas around, but is there some type of safety in the Nistune that causes max rich when the MAF translation goes beyond the ECU voltage threshold?

[Matt]

5.1V is the Max of your MAF sensor. The sensor doesn't seem to do over 5.17 volts in the log, so maybe we are pegging (and the warning is correct).

It seems it might be time to upgrade the MAF sensor. What figures are you making? Standard MAF only good upto about 200-220rwkw

2024-07-14 22_08_27.png

(57.94 KiB) Not downloaded yet

[tht_z31]

yeah, I thought that but the translation table was kind of throwing me in a loop. I'm probably right around 200rwkw, I'll throw in a z32 MAF and then tune from there. I appreciate it

[tht_z31]

5.1V is the Max of your MAF sensor. The sensor doesn't seem to do over 5.17 volts in the log, so maybe we are pegging (and the warning is correct).

It seems it might be time to upgrade the MAF sensor. What figures are you making? Standard MAF only good upto about 200-220rwkw



2024-07-14 22_08_27.png

what's up Matt,
I got a hold of a z32 MAF but got told by some z31 guys it's not worth putting in and rescale the z31 MAF. I don't really understand how rescaling the factory MAF will reduce the volts, but I think I should start by putting the K Constant and TIM back to the original values and then rescale my MAF, if that's correct? I can't seem to find a guide for rescaling the factory MAF.

Will increasing or decreasing the MAF translation map lower my MAF voltage?

Edit- I think I need to increase the translation table by whatever percent? Should I only adjust parts of the MAF translation table in Boost or the entire table? Also what changes will I need to make to the k constant and TIM to compensate for changing the MAF translation? i cant seem to wrap my head around some of this stuff.


I really appreciate the help Matt

[Matt]

I got a hold of a z32 MAF but got told by some z31 guys it's not worth putting in and rescale the z31 MAF.

Not something we really recommend. I'm guessing when you have hit the 'pegged' voltage, they are adding more fuel. This may only work to a certain point. Detail is what we need

I don't really understand how rescaling the factory MAF will reduce the volts

It wont

but I think I should start by putting the K Constant and TIM back to the original values and then rescale my MAF, if that's correct? I can't seem to find a guide for rescaling the factory MAF.

I've not done it so cannot advise

Would stick with the Z32 MAF and scale that in instead. Sorry for the delay on this one

[tht_z31]

Ok cool, all good. I appreciate the help Matt
You’re the man

[FlawleZ]

Are you running a blow through MAF? No reason you should see those voltage levels unless you're push a lot more than 200rwkw.