The colder it is outside the more dense the air is and the more fuel its going to use. If the car is tuned in very cold weather its going to use more fuel then if its warm out. This is why i said the car is going to run very rich in the summer once its warm. This also applys to people(including myself) that have gotten their car tuned on a hot summer day, you have to watch the AFRs when beating on the car on late summer nights when the temps are in the 50’s, car could go lean
right, which is why all the modifiers on most tuning software are important. everything from AIT’s to volt readings need to be carefully adjusted to maintain the AFR when everything else changes.
However i’ve always found that there is no possible way to set every single one of them perfectly especially when it comes to a BIG difference such as a cold wet winter when you were tuned on a dry summer day.
Travis seems to make it sound like the ECU will just take care of itself but I find that hard to believe.
just my 2 cents, I would really like to hear from the experts on this topic.
subaru’s when tuned keep most of the stock info on there correct? Unlike hondata or something where you import as much of the stock data as possible and use that as a starting point?
I ask because I think the real questions are: how much can the ecu adapt after being tuned, and does the tuner have to set them up properly to adapt from the tuners new values to other values which will still hold the AFR at the correct amount.
Weather DOES NOT matter as long as the tuner takes into consideration AID DENSITY and AMOUNT OF FUEL being used. In the OP’s case the tuner would also have to properly dial in BOOST w/ the MBC as the SUBARU ECU can NOT adjust boost once the OEM BCS is removed. IF you keep the OEM BCS (use GrimmSpeed/Perrin/GM 3 port solenoid for better control) then the ECU can also adjust boost depending on outside conditions. The ECU can/will switch maps depending on octane of fuel (knock sensors can detect this, switch ECU from ‘Table A’ to ‘Table B’ to compensate) for several factors such as timing/boost/fuel/limits/etc… Any known/reputable tuner will tell you this and will tune the car in accordance to the weather. Cars will always run more lean in winter (more air density) and more rich in summer (less air density) so the tune needs to be setup inbetween the 2 in a comfortable zone. This AFR will be set in accordance to each vehicle on a case by case basis (despite popular belief, there is no exact number for all Subaru’s…each car will have a zone it prefers to run in depending on motor/mods/how car has been treated/maintained). The tune is only as reliable as the driver behind the wheel who is responsible for setting the MBC to control what the car was tuned for at time of visit.
It makes a world of difference if the car is going to be on an MBC as I stated because the ECU will NOT correct boost pressure based on other ECU parameters. It will ONLY correct if the vehicle is on OEM Boost Control System or upgraded 3 port solenoid. Cold air = more dense = more boost with MBC = driver having to get out and adjust MBC to correct boost pressure car was tuned for. In summer warm air = less dense = less boost with MBC = driver having to get out and adjust MBC to correct boost pressure car was tuned for. AFR should remain close based on boost level (user determined) of MBC.
Like I said previously the ECU can adjust the timing tables depending on what the knock sensor picks up. If OP goes MBC it can’t adjust boost however which is the only concern is the constant upkeep of ensuring the MBC is set to the PSI the car was tuned for.
i would wait untill spring to tune seein as cold air moves better than warm humid air does ,that beein said in the winter your able to push the fuel due to the fact the air is there to run it get it into a warmer climate and your gonna run rich .the additives in the fuel between winter and summer fuel are a big factor also
wow… justin and i are saying the exact same things. the subaru ecu’s use a base map and timing advance multipliers on separate “realtime” maps. the ecu takes into account IAT and MAF readings to select the proper realtime map to run. the only occurrance where the op would need to change or adjust anything would be if he is running an electronic OR manual boost controller. that would be on him to set the boost properly IF AND ONLY IF he has removed the stock boost control solenoid/system. if he is still using the stock BCS, NOTHING NEEDS TO BE CHANGED OR ADJUSTED from season to season as long as his tuner has tuned the vehicle properly. there is NO NEED whatsoever to be retuned from season to season as long as you have a comprehensive tune.
everyone that is suggesting being retuned from season to season has little to no experience with boosted subaru’s and if they do they have ZERO experience with tuning them.
chuck,
justin and i have experience from which we speak… you will have to trust us in this regard.
my SS got tuned last year on one of the coldest days of winter (it was a high of 19*)…well, everyone saw that during the summer on the dyno it was 10.8 AFR across the board…
your SS isnt boosted nor does it run the same type of ecu parameters. and btw… tuned subarus generally run 10.8:1 to 11.5:1 AFR under boost. even if it does lean out slightly you are still 12.2-12.5:1 under full boost which is still “rich” for most of you NA boys, and well within a “safe” zone to operate the vehicle without any problems.
exactly. an intelligent tuner will leave room for variances which will allow the tune to be safe no matter the weather, from 10* to 110*. the base map of a tune should NEVER need to be changed and the “realtime” timing multiplication maps should leave enough room that the car is able to be driven no matter what. if your tune is so aggressive that your shit blows up due to a temperature spike (or drop) then you had a shitty tune.
air is totally different during the winter than in the summer. I dont know the answer but i know simple air density, and air is more dense in cold than it is in warmer climate. Since air/fuel is important i would think that it would have a lasting effect on your tune.
