S5 TII quick experiment - help needed

[ElTeeFauci]

So I tried this on the "other" forum... didn't turn out so well.

Background:
I've been getting more and more involved with MegaSquirt2. Like most others, I'm using the stock BAC to control idle speed. The operating frequency (think carrier wave) of the BAC has only been speculated on - unlike the FD, the FC's workshop manual makes no mention of this spec.

Progress so far:
Today I tested WankelRevenge's BAC - but he has an N/A. Cant remember s4 or s5.

What I need:
Anyone with and S4 or S5 TII to validate what I found today... or add to the knowledge base.

How to help:
Start the car, allow it to warm up. Disconnect the BAC harness from the valve. Use a multimeter capable of reading frequency... not all of them can, but even some of the cheaper ones can. Insert the (usually red) probe into the harness and allow the reading to settle out - only 1 of the 2 wires in the harness will give you a good number - the other should just be a ground. Report back!

[WankelsRevenge]

Progress so far:
Today I tested WankelRevenge's BAC - but he has an N/A. Cant remember s4 or s5.



Its an S4, the tails are all just for show

[ElTeeFauci]

So my readings have been verified... I have a definite answer for s4 n/a and turbo... just need an s5!

Bueller.... bueller....

[Rotary Evolution]

try 70 hertz

[ElTeeFauci]

Ben... its 120-125 Hz... verified on 2 different cars. Both S4 (1 N/A and 1 Turbo), but I just re-setup my MS2 (and N370 BACV) using this freq, and its perfect. So I'm assuming the S5 (N370) is the same.

Min duty (closed) ~25%
Max duty (fully open) ~98.8%

[ElTeeFauci]

I'm also assuming its Ben from the "other" site... unless you stole his name :)

[Rotary Evolution]

same one, was banned from the 7 club and i don't really regret it.

strange, i saw the 70Hz figure posted a few times but never actually tried verifying it. then again it could have just been a regurgitated figure.

[ElTeeFauci]

same one, was banned from the 7 club and i don't really regret it.

strange, i saw the 70Hz figure posted a few times but never actually tried verifying it. then again it could have just been a regurgitated figure.

Cant say I didn't see it coming :)

They're a bunch of thin-skinned vaginas.

[Rotary Evolution]

Cant say I didn't see it coming :)

They're a bunch of thin-skinned vaginas.

one in particular. i miss when Mark was running the site, he wouldn't let the shit that's going on now fly.

not that i'll miss answering all the redundant questions over and over again, the site is at least chock full of info over the past decade. most stuff i'm working on now i feel like keeping relatively secretive anyways.

[ElTeeFauci]

Honestly, that's how I felt about the info in this thread... due to the fact that nobody would help. *I* don't run a business though, and wouldn't gain from withholding information... I could see why you'd want to - though that may not be your reason. Spite alone is enough.

[Rotary Evolution]

actually this would be one of the few exceptions, in the past people just cranked up the idle because the EMS' out there couldn't handle the BAC until recently so it would be good info to have. but no one has wanted to pay to set it up so, eh.

[RETed]

Honestly, that's how I felt about the info in this thread... due to the fact that nobody would help. *I* don't run a business though, and wouldn't gain from withholding information... I could see why you'd want to - though that may not be your reason. Spite alone is enough.

Anybody who has fucked with the stock BAC valve knows the answer to this question is:
It doesn't matter.

Don't assume that because you didn't get any (useful) info that no one knows what you're talking about.

The "frequency" is limited by the physical limitations of the solenoid valve itself - minimum (effective) frequency, maximum (effective) frequency, dwell.
The number that used to pop up a lot (for us Haltech users) was 33Hz.
I've found that 33Hz was too low a frequency and caused the stock BAC valve to "chatter" on the engine.
Increasing the frequency above 100Hz - 150Hz caused this noise to disappear.
So, thus, I would recommend anything above 100Hz or what your ears can handle.
(As a general rule, don't run maximum duty cycles over 85% - 90% on an electromagnetic mechanical solenoid, or more effectively, 90% - 100% doesn't change much.)

I don't have any experience with that MegaSquirt crap, but if you're talking about a superimposed frequency onto a duty cycle parameter (0% - 100%) - which is sounds like you're trying to do - then it's just a matter of getting the cold start min, warm start min, frequency, and max for each.
Simple.
You can do this on your own by experimentation.
You don't need to be EXACT versus stock #'s.
Using incremends of 10% should get you pretty darned close and running very nicely.


-Ted

[ElTeeFauci]

At first, I was told to run the valve at 244 Hz, which gave almost no change in the status of the BAC when ordered... so I cant agree that it doesn't matter at all. It was working when set at 91 Hz - after we spent a while experimenting... but we wanted the real answer - what was the stock ECU providing; question answered.

Apparently the 244 Hz number came from the 3rd gen.

[RETed]

The 244Hz might be too high, but it should've matter unless it was either locking the BAC valve open or closed.

You can physically check this by placing your hand on the BAC valve and turning it on?


-Ted

[ElTeeFauci]

Locked open... I took it off and checked.