Possible to change frequency of pwm feeding ebcs?????

td-d · **Posted:** Mon Jan 29, 2018 7:15 am

h82lose91 wrote:

Address for AE5T110V
Thanks

0xC009E

pyro6314 · **Joined:** Sun Dec 01, 2013 8:17 pm **Posts:** 47

Seeing that some of the MerpMod and variant builds of code use the WGDC as a hook to run portions of code, would changing the frequency that this function is called also affect the frequency that those portions of code run? Is the PWM done separately or am I misunderstanding how it works?

Thanks.

terryjr · **Posted:** Wed May 23, 2018 5:56 pm

In the Carberry ROM, there are a handful of solenoid duty related tables in the alcohol injection table. Would any of those have any effects on the wastegate duty cycle? I changed my PWM Frequency to 20% last year, and while flutter is gone, it just doenst seem right. Im hitting 30 psi in 80 degrees at only 10% duty cycle

terryjr · **Posted:** Mon Jun 04, 2018 3:19 pm

anyone still playing with this? i dont care for 10% to get 30psi

bludgod · **Posted:** Tue Jun 05, 2018 9:26 am

yes i've tinkered this a little on a few cars but normally 20% whilst being great to kill the flutter does mean your duty cycle max table is all single digits. Turbo dynamics also needs a serious reduction to keep things in line as well as the ECU's ability to ramp duty cycle is initially gonna be waaaaaaay out of proportion.

Are you running one of the perrin/mac bullet valve solenoids - the design seems to help things as well.

terryjr · **Posted:** Tue Jun 05, 2018 11:23 am

bludgod wrote:

yes i've tinkered this a little on a few cars but normally 20% whilst being great to kill the flutter does mean your duty cycle max table is all single digits. Turbo dynamics also needs a serious reduction to keep things in line as well as the ECU's ability to ramp duty cycle is initially gonna be waaaaaaay out of proportion.

Are you running one of the perrin/mac bullet valve solenoids - the design seems to help things as well.

its a cork sport housing with a new mac bullet valve in it. I was thinking of trying a bleed style setup on it. Run a line from compressor to wastegate, Tee in the NC port. Valve fails it just runs wastegate. Last fall i had some trouble dialing it in for weather change before the tear down.

kenjiurban · **Joined:** Thu Nov 23, 2017 2:42 pm **Posts:** 24

This looks interesting.... could this be used on the stock oem boost solenoid to get rid of the 3000-4000rpm wastegate flutter at part throttle?
- 2011 wrx stg 2 19psi

x05 · **Joined:** Sun Sep 23, 2018 4:33 am **Posts:** 37

td-d wrote:

Glad to hear it's confirmed as working, I'm looking forward to implementing this myself.

Post up the CAL id's you want defined, and I'll start digging out the addresses. I'll also add the map definition to the EcuFlash 32bitbase on my github branch, but in the meantime, here's the EcuFlash def xml code:

Code:

<scaling name="wastegate_solenoid" units="Hz" toexpr="250000/x" frexpr="250000/x" format="%.2f" min="0" max="255" inc="1" storagetype="uint16" endian="big"/>
   <table name="Wastegate Solenoid Pulse Frequency" category="Alpha - Wastegate" type="1D" level="1" scaling="wastegate_solenoid"/>

And this to CAL xml:

Code:

Since this is going to get into the wild fairly quickly, what the hell

Address for AZ1G101M, AZ1G101N and AZ1G202G is 0xc009a. Try it - seems to be the location for quite a couple of roms. In the older roms, C026A crops up quite often (e.g. for Merp's original rom - A8DH202X).

Otherwise - post up your cal, and I'll pull it for you.

throttlehappy wrote:

Hex Editor search for 3FF761A8 is the key to finding the value

Found the address for A2WC410D: c008a

Thanks so much to you both for the info. Time to start testing (Cobb 3-port) on a 2005 FXT. OCD hates the flutter.

trez0r · **Posted:** Fri Oct 05, 2018 8:57 am

Adding a restrictor pill to 3-port solenoid vent port also greatly reduces flutter. I use 1.2mm diameter pill and at 15hz pwm (which is the same as Subaru stock roms AFAIK) I get no audible flutter and the WGDC required is in region of 40%.

terryjr · **Posted:** Fri Oct 05, 2018 10:55 am

im still not 100% convinced the def is changing the duty cycle correctly. At 0% my car runs wastegate pressure like it should, at 9% its at 30psi. I just feel like theres a multiplier or something off somewhere.

Ive tried so many differnet methods and two ebcs' and the only way to keep it under control is with bleed method but it kills my spool

x05 · **Joined:** Sun Sep 23, 2018 4:33 am **Posts:** 37

Sambo88 wrote:

Frequency vs Duty cycle

Using this chart (thanks, by the way) I tested 25Hz first (Cobb 3-port) until reaching my target (19 PSI) on a VF48. Just a hint of flutter but much better.

Tried 31Hz and it was rock solid (almost sounds like a screamer pipe) until I extended the target to 19.6 PSI, then the slight flutter returned. It seems it doesn’t like anything above 19 PSI, on the VF48 anyway.

Going to try 40Hz but perhaps before doing so, might try a value somewhere between 31-40Hz.

{EDIT} 35Hz and reaching just under 19 reliably with minimal flutter. Acceptable for now. On to DBW tweaking.

x05 · **Joined:** Sun Sep 23, 2018 4:33 am **Posts:** 37

I went back to 31 Hz for the Cobb EBCS and am consistently in the 17-18 PSI range using no more than 40% WGDC. Tiny bit of flutter is still there and adding a Perrin/Omnipower 4-bar MAP sensor helped reduce it a bit more, but it's still there.

After more research, I think I will try the new version of the Perrin EBCS Pro, which is purportedly twice as fast as the common MAC-based EBCSes. The operating temperature range is also superior. Perrin's documentation suggests a range of 20-30 Hz, but no corresponding values relative to min/max WGDC % values.

x05 · **Joined:** Sun Sep 23, 2018 4:33 am **Posts:** 37

Perrin EBCS Pro ordered and inbound.

terryjr · **Posted:** Fri Oct 26, 2018 11:01 am

x05 wrote:

Perrin EBCS Pro ordered and inbound.

nice, ill be following your updates. My corksport thingy is very similar with the mac bullet valve. But i wont be dabbling back into wastegate tuning until spring when im back on e85. I just run wastegate pressure 18-19psi on pump gas and my cars pretty weather dependant

x05 · **Joined:** Sun Sep 23, 2018 4:33 am **Posts:** 37

EBCS Pro arrived. Perrin has a coupon code for almost 15 bucks off (~$134 after): AUTUMN18

Rainy weather & chilly at the moment, so it’ll go on sometime over the weekend.

RomRaider

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