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Discussion Starter · #1 ·
I just got finished with my first late night street tuning session. I've got an 04 evo, 3" TBE + HFC, boost set at 19.5, SAFC and WB.

My first run, safc at all zeros: from 3k to 6.5k A/F went from 12.7 to 10.5, pretty smooth.

My rpm points are: 2.6,2.3.4,3.8,4.2,4.8,5.4,5.8,6.2,6.8,7.2. I never went above 6.8 though.

When I got the WB, I talked to the guys at Roadrace briefly and they said a target of between 10.7 and 11 is good. I confirmed this online that about 11 was ideal.

Anyway, so I've heard "Evos run rich" many times online.. but what I saw, on my first run was lean all the way to 5.4k, then it crossed 11 and went a little rich at the top end.

So after 5 runs and tuning the safc I'm between 10.9 and 11 from 3.4k to 6.8k.

My settings are 6,10,9,6,4,3,1,0,-3,-4,-6,-5.

Can I "feel" any difference. nope. I don't have way of timing my pulls so I compared the time it took to pull from around 3.3k to about 6.3k. I know this is way rough, but my first pull un-tuned covered a higher rpm range than my last pull over the same 6 second period. Yes, all my pulls were along the exact stretch of road, all within the same hour.

So, maybe the bottom line is I don't have enough mods to get any noticable benifit out of the SAFC. I'll be installing the EGT probe and fuel pump soon, then injectors, then perhaps cams.

I just wanted to get some feedback or confirmation that my settings are resonable and my first steps down the tuning path are in line.
 

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I don't think you will find many people saying that a wideband reading of 11 or less is not pretty rich. That said, there is very little to be gained from fuel tuning. So a partly rich fuel setting is good because it is also a means of protecting your motor. You will find people happy with afrs ranging from 11.7 down to 11.1. It is my uneducated guess that anything much less than 10.9 is off the chart fat. Since road race said different, go with them.
My point is the difference in performance between 11 or 11.7 is nominal. The difference two or three degrees of timing make is hugh. So make sure your fuel stays below 11.5 or so, once you are into teens boost, you should be good to go.
 

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Beg, barrow, or steal a logger. It's the best way to make adjustments on the S-AFC. Ya, I know everyone says using narrowband is crude, not accurate, what ever; It works and more importantly, you can derive knock from the timing curve. IMO use a logger first, then clean up after it with a wideband while continuing to monitor for knock.
Having to add fuel is not good with the S-AFC. It's best used with injectors and a pump, so yea you need fuel mods. You then have to then remove so much air the ECU sees that it rewards you with timing, no fuel cut, and you get a lower injector duty cycle.
 

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Discussion Starter · #5 ·
Thanks for the guidance... that's just what I needed to know. Injectors have been on the shopping list but they just moved to the top. I suppose the higher the injector rate the better, so 720cc is what to get. I understand that the first thing I'll have to do is drop my settings across the board by like -30%.

I'm trying to locate information on exactly what the relation is between timing and power. Innovate has a nice set of videos that partially explains it.

http://www.innovatemotorsports.com/resources/lm101.php

They mention something similar to what nothere said, getting the correct A/F provides minimal gains. Getting the timing correct, which acts like a moment arm on the piston and can have a big effect on power.

The timing log is in volts. I'm wondering how that relates to degrees of advance or retard timing? Is 0 volts at TDC? so anything positive is timing advance?

These are probably basic questions. I've read pocketlogger/SAFC tuning guideline posts and the target is .92 - .94 across the rpm range. Easy enough to tune to (with no drops that indicate knock of course). I just want to get the inside scoop as to what is so special about this setting. If is just what experience has taught people over time, then great. If there is some actual theory that lead to this setting, I'm more interested in that.

Forgive me for being picky, I'm an engineer and like to know things work...
 

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Hey Laminarflow,

just give me a call in the middle of next week and I'll assist in Logging. Just have to calibrate it to your car.


Evo8kiko
 

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LaminarFlow said:
The timing log is in volts. I'm wondering how that relates to degrees of advance or retard timing? Is 0 volts at TDC? so anything positive is timing advance?

These are probably basic questions. I've read pocketlogger/SAFC tuning guideline posts and the target is .92 - .94 across the rpm range. Easy enough to tune to (with no drops that indicate knock of course). I just want to get the inside scoop as to what is so special about this setting.
When datalogging, you log; O2 sensor bank 1, ignition timing, and RPM's. The value displayed in voltage is from the stock O2 sensor. The target .92-.94 volts is just a ball park estimate with .91 on the lean side and .95 is rich. Again these are just estimates since the stock sensor is not that acurate. What's so special about them is that I've used .92-.94 volts and then came back with a wideband on several cars to find readings of 11.2-11.4 AFR and very very flat.
When revewing the log the timing is displayed in actual degrees (advanced or retarded). When using a piggyback system, such as the S-AFC, you will see the timing drop as full boost hits, then steadily advance if there is no knock. If there's drops/pulled timing from the ECU, then there is knock that needs to be adressed.
Ideally you use both a pocket logger and wideband. The wideband system does not show timing/knock.
 

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Thanks Turbolarry. We'll be using the Pocketlogger and making sure that it is calibrated to the car. WE'll be logging RPM, timing, O2 bank1. I'll post them up as soon as it is done.
 
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