Hello,

I would really appreciate an expert opinion regarding whether the ots map I'm currently running on my '10 MR is within safe limits. The car is stock, except for Injen intake and UICP. I noticed that when I'm running the staqe 1 91ACN injen map, in relatively cool weather (around 58-60 degrees), I see boost spiking to 26.6 lbs, with occasional knock sum of 1, before the WGDC Correction signal shows the wastegate opening and releasing pressure, with boost tapering around 16.5-17 by 7000 rpm. The car seems to run great. I don't drive the car too aggressively, as it's my DD, so WOT runs and such are infrequent. Should I flash to the LWG map right away, or should I be paying attention to other ECU signals to get a clearer picture of whether the map is safe to run on my car, and if so, which ones? I would post a datalog of a pull, but the last ones i took exceed the 100K size limit, even after compressing the file.

Thank you very much in advance for your assistance on this.

 

This seems to be relatively common on the 2011+ stage 1 maps. What RPM are you starting the pull. If you start the pull at 4k RPM and go WOT I've seen people hit boost cut on the stage 1 maps. If you start at say 2500-3k RPMS and go WOT then you might be on target or still overboost in the cold. I had to just dramatically reduce the WGDCs for a friend running the stage 1 map to prevent him hitting boost cut on high RPM WOT situations.

 

Thank you for the reply. I normally start the pulls at around 2K RPMS in 3rd gear (SST). What about the 1 knock count i see sometimes during the puuls? Should I be worried about that? Should I flash to the LWG map? I really don't want to "detune" the car if it's safe as is...Too bad i can't post the datalog I have available. It's around 102K compressed, and if i modify it to delete some rows, it takes out the format required to properly parse the columns....

 

1 count of knock is nothing I'd be worried about.

 

Thank you for confirming that. Just wanted to make sure. Would you say that a momentary boost peak around 26-27 lbs should be of concern?

 

Would you happen to know which WGDC you reduced and to which value? The accesstuner software gives sooo many options not sure which one I should be adjusting.

 

I don't recall the exact values, but I believe I left the passive tables the same (which was at 90% all the way through on his) and changed the reactive tables. I'm going from MEMORY here so DO THIS AT YOUR OWN RISK AND BE PREPARED TO ADJUST. If I recall correctly the reactive tables at WOT are at 100% from 2 or 3k RPMS onward originally. I believe I reduced it to 91% at 3k. 92% at 3500, 94% at 4k, 95% AT 4500, 97% AT 5K and 98% at 5500 and 100% onward after that. Keep in mind he was on the 93 octane map, so you'll probably want to further reduce the values I provided if you're on 91 which I believe has lower target boost levels.

If I were you I'd take the numbers I gave you, subtract 7% from each and do a log, then bump them up slowly after doing pulls and looking at your boost.

With his log particularly, he was getting light upper rpm knock (legitimate, not phantom) in the 6k+ range at 200-220 load since the timing was hitting 20 degrees. I pulled a degree of timing which solved that issue.

In his case I adjusted a lot more but I think if you just adjust your reactive tables (downward) you should be good. I don't recommend you just much else without more knowledge about tuning.

 

I would go with the lwg map..I was boosting around 27 with the regular map and I switched to the lwg map and im boosting right at 25.

 

I switched to the LWG this weekend. Although the weather was slightly warmer than the last time a logged a few 3rd gear pulls, this time I couldn't get past 18.5 lbs of boost. I could see on the log that the WGDC Correction indicating a 10% correction, meaning that the ECU was opening up the wastegate to relieve boost. I went back to the regular map. Maybe it's just imaginary, but the car feels noticeably better in all-around driving with the regular map as opposed to the LWG map. I hope that the occasional boosting to 26+ lbs wont cause any damage to the motor.

 

26 psi is on the top end of acceptable on 93 so long as the rest of the tune is okay. just watch out for in cold weather as that number may increase.

 

Thank you. I'm in California, and we can only get 91 octane here. I'm running the Stage 1 91ACN map for injen intakes. No knock on top end to speak of, and other parameters look within range. Unfortunately i don't have a WB to log AFR values. Should i start adding octane booster?

Quick question, if I may: the car has ways to deal with overboosting, throwing a code and setting the car in limp mode. Would that in itself prevent catastrophic damage to the motor in case of an overboost condition?

 

Yes, but this isn't a good thing to let happen. If the car overboots and goes into limp mode it is trying to save itself; however, there have been dozens of cases of people overboosting to 30+psi and throwing rods straight from their blocks. The overboost protection can't always save you.

 

^^^^

Thank you. So, this begs a question: is an occasional spike to 26-27 lbs of boost safe enough on a stock evo X with an intake running stage 1 map, so long as knock count is 0-1? What other parameters should i monitor (besides AFR) to make sure I'm running within safe limits? I'd hate to "detune" the car to the LWG map, as i can tell if doesn't feel as strong, even in moderate driving conditions.

 

Personally, I'm incredibly **** about my car so I wouldn't run a tune knowing it was overboosting, instead I'd get a pro tune (which is exactly when I did when I had a cobb AP and I wasn't happy with some issues I had).

If you start the pull at 2500 and it peaks at 26.6 then I wouldn't stick with the tune. If you started the pull at say 4k and it peaks at 26.6 then I wouldn't be as worried b/c a pull starting at high rpms or after a shift will often overboost briefly and be corrected to where it should be by the ECU, especially on the factory 2 port boost control system.

However, if you start the pull at 2500 and it only hits say 25 psi or less I wouldn't be so worried if knock is in check.

 

Thanks for your input. I went back and looked at the log, and i did in fact start the pull at a higher RPM range than i first thought: by the time i had the car floored ( as seen by the accel. position reading) i was past 4600RPM. The car overboosted to 26.61 for less than .25 second between 4750 and 5000 rpm, and then the boost settled to around 17 psi by 6500-7000 rpms. While at boost levels between 24 - 26.6 psi, i saw knock count of 1 (total duration .32 second). I would be glad to PM you the datalog, if you care to take a quick look-see and provide me with your feedback.