RomRaider

Anyone ever here of half scaling a rom to add boost to a Subaru NA ecu. Example my brother has a 08 Impreza 2.5i. He finally blew up his 2.5 in it after 60k boosted miles, so he swapped in a ej203. I had him install a wrx 2.5bar map sensor while he was at it so we can log it and make adjustments to his protuned (if thats the term) rom. I knw the guys that tuned it originally and theyre pretty creative.

So i pulled the rom off the ecu, deleted the AVLS codes need to make it run and then rescaled the map sensor to the 2.5bar. Started car, went to back out the driveway and it died. Open the log and it was at -18psi. Well that aint right. Here the entire rom has been pretty much scaled in half. My brother told me he did that to get under a load limit. But his load limit is 4g/rev so i dont get it. I'd liek to be able to make our own rom for it that i can tune and get opinions on in here but not sure if its worth it. The car seems to be running fine, just super rich at wot, has some higher than i like fuel learning and timing is in the negatives.

by scaled in half i mean map sensor scale values are half normal, maf scaling table goes to like 150g/sec at 4.5 volts, injector scaler is 210 even though it has 440's in it etc...

are you sure the MAP scaling has been halved and it's not the MAF scaling that's been halved? MAF hack would be standard enough for people looking to allow higher load limits or higher MAF g/s values than would previously have been allowed.

Only thing I can think of for smooshing the MAP value would be they were trying to boost on a standard (non boost reading) map sensor and figured it may be a way around it throwing an error. -18psi is possible sometimes if you've done away with parts of the secondary air pump (maybe the part that has the atmospheric pressure sensor in it?). What's your atmo reading with ignition on / engine off?

Hi Terry,
This is "05Outback" from RS2.5 forums.

I had this issue but some help here, I found the RPM load limit on my ROM which is different and much lower than the overall load limit (set to 4). The RPM load limit maxes out at 1.3 at 5600 RPM so you definitely need to raise this. I just made all of mine "4".

If you send me the ROM , I can find it for you, OR you can look in the rom for either this string, or partial of this string:

"44160000442F00004448000044610000447A00004496000044AF000044C8000044E1000044FA000045160000452F00004548000045610000457A0000458980004596000045A2800045AF00"

From that string which are the RPM values they look for in the table, I figured (with help of others who had already discovered this...) out the locations of the load vs RPM table.

I have what I found in my Rom here and then had to add a definition to the XML file to point out the table location:
viewtopic.php?f=8&t=10634&p=128913#p128913

So if you did all this, then you'd want to go figure out what has been halved, and double it all to get back to normal values. Then things start to look more normal.

Thanks for the help, i added that table but i think im a address or two off. the rpm/load values are off

I went back and added that table to the 05 Legacy 2.5i def and opened the rom and the table shows up correctly, So the adress must have changed in the 08 forester/impreza rom

oh cool, I was just going to look at it.... but you're all set then?

You should see something like this in stock form. Yeah I would expect them to be in different locations on different years.

its worked on the 05 def i tried, its not working on the 08 rom. i just downloaded hexedit, going to search that string you found and try and find a new address but im very not good at hex or understanding it. like trying to order lunch in a language i dont know here

This is what I came up with for your EZ1GB00H rom:



It went into this file (or at least, that was the XML it loads for your ROM on my local version of EcuFlash):

C:\Program Files (x86)\OpenECU\EcuFlash\rommetadata\subaru\Forester 2.5\EZ1GB00H 2008 USDM Impreza 2.5i AT.xml


Here is the table itself:

found it, now how do i know what address that is lol

to me that address you post looks like it matches this

check above, i think we are posting at the same time.

BINGO, updated that address and it is working, Load capped at 1.50, now to raise that and get this part started

Thanks!

So i'm wondering about this... if your max load defined is 1.0 and everything is halved, the "real" max defined load is like 2.0...

wouldn't you hit more like 2.5 (or 1.25 with everything halved) with your 230whp? I wonder if that was part of the problem with the failure.

I guess some of it would depend on the maf scaling and mine is a little wonky because I have an air straightener (honeycomb) , but I know I hit loads around 2.0 with 180whp. Did he ever log a WOT run to see how high the load hit?

anyway thanks for letting me look at the rom. I'm still trying to get the guts to try out this 10-11 psi supercharger pulley on mine!

the stock rom fuel and timing is scaled to 1.3 g/rev, im pretty sure they reduced the scale and then half'd the maf scale and injector flow to get around the load limits. This should fix it. g/rev normally peak at peak torque so comparing it to horsepower can be off a lot. I think romraider will still log in normal values but i think they are skewed, he claims to see 300 g/sec air flow but i highly doubt that.

I dont know what my car runs, it stops logging at 399.99 g/sec. Ive made 405wtq/427whp at 3.8ish g/rev but ive logged higher g/rev before. I think i was only hitting about 26psi on the dyno, had a hiccup with the ebcs on the way there. cold temp comps were off and i was spiking over the safety and had to just throw a reduced number at it to run, and then forgot to log it.

new update. load and g/sec defeat done. but now we cant log map sensor properly. We put a 2.5bar in, changed scale but it only logs to around 1.7psi and doesnt seem like its reading vacuum correct either. the factory sensor multiplier and offset was 0.019/0.012?