I wanted to verify this on stunt2's IV and my VIII. His were at -9 ltft and mine were at -10 ltft. We both reset our trims. Made pulls and no difference in AFR's.

These were both done yesterday. I'm curious about the results of the 9's. I'll be tuning a 9 shortly, but he's all stock, so I wouldn't imagine the trims to be a factor.

 

I just checked the Evo 8 (94170015) engine control code, and the LTFT trim for WOT is definitely there. Its only the mid-LTFT (and unused high-LTFT) that will affect WOT, and if the LTFT Control Ranges have been changed, then that will affect the range of air flow rates where the LTFT plays a role.

 

Boosted Tuning
is there any point for this, if rewired pump will still cause overfueling ?

besides, I have actual afr quite leaner than map afr and bumping the scaling will throw it off even more leaner

is there any point ?

 

As mrfred stated earlier, you don't need to change anything to account for your negative Lo and Mid trims. It's more than likely due to your rewired pump. If you start messing with things, you are just going to affect your WOT AFR and be chasing your tail.

If anything, you can mess with your maf smoothing at the lower airflows to adjust fueling in just those airflow ranges.

 

We're both using the 9653. I put in the closed loop LT Trim control table to check our roms and they are same as the 9417 in the mid to high and high to mid. Mid to low was at 62.50 versus the 9417 at 56.25.

Funny the 9653 rom doesn't have that included.

Anyhow, I do see how the trims can affect WOT up to the max airflow. However, comparing the 2 back to back logs, everything below max airflow is not affected by resetting the trims.

Maybe 9653 doens't use trims for WOT and 9417 does.

 

We're actually lowering his scaling due to running lean at WOT. This may affect his trims even more. I'll adjust his maf smoothing in the idle and cruise ranges. Thanks l2r99gst

 

I just checked, and it does at well. 95% or more of the engine control code is identical across the Evo 8/9 ROMs. I guess its strange that you're not seeing the effect, but the hotwired fuel pump could obscuring it. One thing you can do is try logging MUT50. This is the LTFT that's being used in the fuel calculation. It uses the same scaling as the other LTFTs do in EvoScan. At any rate, the real solution is to unhotwire the pump.

 

I agree. Isn't there a Spoolin Up rewire kit in the works?

I'll log mut 50 and see what's going on. So that will show the fuel trim as it's happening, correct?

Here is a pic of my logs from yesterday:

 

Yep and Yep. The rewire is getting close. Just working out some details that really are only specific to the E85 Walbro.

Is the mid trim the -4 or -10 value in your log?

 

Yes, low is -4 and mid is -10.5.

 

Ok. But I have NEVER seen it in the EVO 8/9s I have tuned.

And the CL/OL tables are tps based and load based and soon as you go over those limits, the car go to 100% open loop n the fuel trims dont affect WOT afr (IMO).

 

Nevermind, didnt know you were on stock injectors. Thought you were trying to scale larger aftermarket injectors.