RomRaider

Hi again! So i after alot of research, i have found that the subaru ecus supply a 14hz pwm signal to the ebcs. Is it possible to dissasemble the rom and possibly change this frequency? To say 25hz...

This frequency is directly responsible for the horrible "wastegate flutter" (open closing sound of the wastegate based on the duty cycle provided to it by the ecu.

Most aftermarket ecus have the ability to alter the frequency and duty cycle therefore not exhibiting this horrible sound that most subarus with 3 ports or atmospheric wastegate dumps do.

With the ability to alter the frequency, one could even use a gas type electronic proportional valve in replace of the 3 port solenoid, giving nice smooth boost control similar to the old school hks evc boost controllers that used a stepper motor on a needle valve.

I have found a thread where the frs guys are using ecutek to re purpose their cpc valve and they are using this for boost control and have managed to change the frequency in the rom

as a (slightly) less elegant solution, you could try adding volume to the WGA side of the pneumatic circuit, post EBCS.

this will dull response, the degree to which is commensurate with added volume. basically like adding capacitance to an electrical circuit--the time constant will increase.

i've always used an MBC at WOT.

Are you referring to "hybrid boost control". I understand the idea but surely we can fix the problem where it lies... within the ecu...

for those 16b ecus running carberry rom, it is directly editable--a fact i just learned today.

i know that oren was reaching out to jason regarding whether or not this is a simply editable register in the oem code, or whether jason had to program in adjustability, with the intent of bringing it out for 32b roms.

ken

Ive noticed it in the carberry rom, more for using the ebcs circuit as a alcohol injection solenoid or something, hence it being under the alcohol injection but I guse changing it there still applies it when used as a boost control solenoid? Most solenoids are suggested with a frequency range of around 20-40hz or so. and I thought subarus ran at around 32hz.

I have read in a few places its 14hz, i have not measured this myself. Although hz represents pulses per second. And judging by the sound this sounds about right. Could be even lower. I know that running 20 to 30hz on any other type of ecu with a mac valve does not exhibit this sound. I assume with the restrictor pill its not necessary to run a high frequency on a stock solenoid, also the high duty cycles they run from factory. Maybe its different between 16bit exus and 32 bit.

15.3Hz to be precise. I need to chat to Jason to get an idea where to start looking in the rom - but looks like it is directly editable in the 32 bit roms as well.

Haha! When i posted this, i knew you would have some answers! This would change boost control on the subaru ecu's into something absolutely amazing! Not to sure how far it could be changed, but if it were possible to go as high as 2khz we could directly drive one of these proportional valves!

http://www.clippard.com/part/EV-P-10-2550

All the pid settings could work just the same (adjusted obviously)

This is something that has been eating away at me for a long time.

If 2khz is too far out of range. A simple capacitor and resistor should give a usable 0-12v output.

Regardless of this valve. A common 3 port would make a much cleaner wategate sound. I swear the cars pull nicer with solid wastegate control as apposed to this slow open close affect we are presently dealing with...

I can throw some cash for development! I think everyone with a 3 port should want this!

Any news or further interest in this?

I've spent some time looking for this - no luck as yet. Jason's not going to be able to help, since I assume this is not yet available in the COBB implementation, so his hands are tied. Going to have to put elbow grease in and see if I can track it down. No promises!

No problems! If anyone can do it, its you! Certainly not me... let me know if you run out of motivation i can try and remotivate you!

Bingo:

absolutely unreal!

great stuff oren!

. Carberry Rom? 16bit?