Is everyone experiencing inconsistency in AFR per gear? If so, have you been able to figure out a way to compensate for this? For example, at the same RPM point and the same boost level, I've seen AFR off by almost a full point when comparing two different gears (for example, a 2nd-to-3rd gear pull).

I made the LOF and HOF maps identical (stock map for safety) to rule out the possibility of map changes due to knock or noise. I didn't have a chance to log any of the OBD2 stuff (MAS, timing, etc) because the Palm batteries died.

1st gear; 5760 RPM; 233 KPA; 10.80 AFR
2nd gear; 5775 RPM; 236 KPA; 10.47 AFR
3rd gear; 5789 RPM; 234 KPA; 10.00 AFR (max rich)

1st; 5751; 235; 10.78
2nd; 5866; 235; 10.45
3rd; 5807; 236; 10.00 (max rich)

2nd; 5822; 234; 10.71
3rd; 5841; 235; 10.00 (max rich)

 

that is normal...when there is more load on your motor you'll run richer. tune for your target AFR's in 3rd gear.

 

Yes the AFR will vary by gear. I have done 3rd and 4th gear WOT runs and found the following:

3rd gear AFR------4th gear AFR
@ 5700 11.07------10.28
@ 6100 11.15------10.28
@ 6400 11.17------10.48

Some have suggested that this is a good thing since it protects your engine from detonation under heavier loads. That is why a lot of tuners tune in 3rd gear. It makes the car a bit richewr in 4th gear and gives you a safe tune.

BTW, what are you using to log your AFR?

 

Given that the load (boost) is within 3 KPA per gear at the same RPM (+/- 30 RPM in some cases), that shouldn't really hold true, should it? I guess the problem is that we are talking about calculated load based on an unknown formula/logarithm that involves several variables.

It just seems like kind of a hack to run pig rich in 4th so that you can have a good 2nd gear tune for autocross - or a fairly lean 2nd gear tune so that you don't do your turbo diesel impression at the drag strip.

I am using the software that came with my wideband (FJO) for datalogging AFR vs Boost vs RPM and a PocketLogger for everything else.

 

I think there are more factors contributing to load than throttle position, RPM, and boost level, look at the load cells adjacent to the cells you know to apply, its possible you need to adjust those too.

In general, the higher the load, the richer the ECU (The way its mapped) wants to run.. But there are a few additional tables representing load values (Open Loop Load #1 and Open Loop Load #2) that you might also want to look at besides the fuel map itself.

 

remember that VE may change as load increases even for the same boost and RPM level..

 

Yeah, that's the algorithm/formula I referred to. Hopefully, as the code gets disassembled further, someone can figure out exactly what parameters we need to monitor to determine the "ECU load." Obviously, it's not actual boost since there is no proper MAP sensor. I'm also assuming there are other fudge factors like air temp correction involved.

And I have been adjusting load cells "in the area." If I my logged value is 230 KPA at 5800 RPM, I will typically adjust the 220 and 240 load cells at the 5500 and 6000 RPM rows.

 

That works.. I do the same thing.. I think when the logger tool for the OpenPort cable is released, you can more closely monitor relevent values (Air mass value and calculated engine load, I'd bet some cars are hitting a calculated load value of well over 100% which would likely force some sort of interpolation of the map above 260% column

 

I've been curious myself, try unplugging your vehicle speed sensor and see if the same thing happens.

-Martin

 

so would that mean at 3rd gear WOT with 21 psi. that 11.0 is fine?

 

Some more data, FWIW. No PocketLogger info; stock LOF map and modified HOF map. All in format (RPM, KPA, AFR)

3rd gear *only* pull from ~2000 RPM:
2514, 134, 11.71
3017, 179, 11.77
3542, 244, 11.38
3967, 244, 11.40
4528, 236, 11.44
4975, 240, 11.58
5482, 234, 11.40
6000, 237, 11.44
6476, 230, 11.48
6986, 227, 11.21
7065, 223, 11.02

4th gear *only* pull from ~2400 RPM:
2512 126 13.69
2728 157 12.53
3026 207 11.73
3250 234 11.62
3449 245 11.46
3760 237 11.40
3992 245 11.31
4264 242 11.29
4512 233 11.23
4751 240 11.25
5011 239 11.31
5270 237 11.23
5524 237 11.09
5771 235 10.94
5997 234 10.92
6257 232 10.84
6493 225 10.82
6747 226 10.80
[end]

Drag-style pass (including ~6200 RPM "two-step" launch with ~131 KPA boost, LTS 1-2, NLTS 2-3 and 3-4):
1st
5630 232 11.73
6072 229 11.62
6864 217 11.92
7208 211 11.46

2nd
5632 235 10.92
5903 231 10.96
6880 225 11.07
7015 226 11.00

3rd
5671 236 10.73
6087 233 10.88
6839 225 10.94
7163 218 10.94

4th
5624 238 10.65
6000 234 10.71
6501 227 10.84
6821 221 10.84
[End]

 

Here is my data contribution to this thread. It is supports Scrappy Jack's data. Note that the AFR is about one full point lower in 4th gear than it is in 3rd gear at 6K rpm. Also note that peak boost is higher in 4th gear than in 3rd gear.

 

No changes from the last logs. Pulls started around 2000 - 2500 RPM. Left out data below 4000 RPM because of differing load-per-RPM-point.

2nd gear *only*
4033 233 11.75
4534 235 11.62
4961 237 11.79
5607 230 11.92
6043 232 11.88
6513 221 12.27
7068 217 11.55

3rd gear *only*
3987 243 11.40
4549 231 11.64
5036 238 11.64
5518 237 11.42
6031 236 11.69
6476 226 11.56
7009 227 11.19

It seems to me that the difference in AFR between gears is more dramatic during a multiple-gear pass vs two individual single-gear passes.

 

You probably aren't hitting the same load cells in each gear.. So assuming the cells are tuned for those levels, it should be roughly the same (it does tend to shift a little though) the Stock ECUs fuel map is pretty flat in alot of areas and could explain what your seeing.

 

The evo does run richer with greater vehicle speed and the coolant temp enrichment is very excessive.

I am hoping that the creators of the ecu flash will add additional tuning paramaters in comming months which can help us make better tuning maps - I have been unable to find the enrichment maps myself to date although I am still hunting