redSLed

Short end of the long is that after discovering two days ago that my rom's 2b to 1b load factor was 1.4 and my Evoscan formula was 1.9, I made the correction to match them at 1.9. Of course, my logged loads made much more sense, as did my logged timing. Well, that is the only change I made to the rom. Today I made it out to log and as stated above, load and timing made more sense, BUT I am now logging nearly 1.5+ psi LESS boost from my Omni 4 bar. My question: is there a correlation between logged boost and mismatched vs. correct load factors? I know load is a direct factor in creating boost...but how are the equations for logging psig from my Omni and logging 1b load tied together? This is an SD Evo 8 with the V7 94171715 rom btw. It makes perfect sense to me that if you log lower load, you'll see lower boost. An interesting thing to note is that a month ago right off the dyno (Dynojet), I was logging nearly 2 psi HIGHER than what it was tuned at (26-27.5 psi). This was of course with mismatched load factors, weeks prior to discovering the issue. I was seeing between 27.5 and nearly 30 psi at only 55% wgdc in 3rd gear with a Blouch 1.0XTR BB. After lowering WGDC 6 or 7% I was finally logging values that were in line with the dyno session. Two days later after correcting load factors, I'm now DOWN that magic 1.5-2 psi mark. This is SAME roads, 3 days apart and ambient temps within 10 degrees of each other. I also made sure to be logging 0 psig with the ignition on to compensate for atmospheric fluctuations. What do ya'll think? Thanks so much in advance.

redSLed

Saturday morning bump:

Is it possible to log a false boost value (4 bar map, sd car with 94171715 V7) if the 1b load factors mismatch between the rom and what is logged in Evoscan?

My rom was at 1.4 and Evoscan was 1.9. My logged load was off the charts from where my fuel, timing, etc maps were scaled and boost seemed to be 1.5 psi or so high from where it was tuned at.

After matching factors at 1.4 and logging again, boost seems to have dropped 1.5 or so psi from where it was, as well as logging lower load values.

So, would logging higher load values lead to skewed boost values as well. Higher load=higher boost?

CDrinkH2O

iTrader: (7)

Yes it is possible. It depends on how you have set boost to be controlled. If you are using LOAD to control boost then matching your factors will change the boost values you hit.

redSLed

I was wondering how load-based boost control could effect my values but...my ecu is set up for psi based control with no boost error corrections or wgdc corrections.

I'm still curious as to why my logged boost seems to have changed on average by nearly 1.5-2 psi at points after correctly matching my load factors. That's the only thing that was changed in the rom. I used the same roads for logging and nearly identical weather conditions.

There are small inconsistencies in the rpm at which I started pulls but not my more than a few hundred or so. The turbo seems to spool very quickly and as a result boost seems to be higher when rowing through gears as opposed to a pull from 2-2.5k rpm. For example: changing from 2nd-3rd gear at 7500 rpm produces a higher initial boost spike once 3rd gear is engaged around 5800 rpm.

I'll have to make a small adjustment upward (maybe 3-4%) of my wgdc map and re-log when I hopefully get decent weather here soon, and see what the values look like during a 3rd gear pull.

CDrinkH2O

iTrader: (7)

If you are not using error correction, a 1.5 - 2 psi difference in your boost profile could easily be accounted for by changes in ambient temperatures or baro readings, i.e. air density.

redSLed

I do understand how that could be the case, but could that happen even if ambient temperatures were within about 5 degrees from one day to the next? I always adjust my boost logging equation to read zero with the ignition 'on' to account for fluctuations in pressure. I'll have to experiment a little here. Thanks!

CDrinkH2O

iTrader: (7)

Yep. With no error correction this will happen. Why don't you just turn on error correction to keep your boost levels constant?

redSLed

Thanks man, I didn't realize it could swing that much day to day even in very similar weather conditions? I'm just going to have to bite the bullet and set up psi corrections then. It doesn't look very difficult, what with plenty of how-tos on here!