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DISCUSSION => Engine + Driveline => Topic started by: dvmotorsports on February 18, 2010, 03:58:53 PM

Title: AFM Bypass
Post by: dvmotorsports on February 18, 2010, 03:58:53 PM

I want to setup my ITB's, but I don't have a stand alone system yet. So, is there anyway to bypass the AFM signal to run ITB's?

Title: AFM Bypass
Post by: DesktopDave on February 18, 2010, 08:46:40 PM

I wish I had your problem...

Can't you just run the ITB's with the AFM installed?  Or do they flow too much air?

Title: AFM Bypass
Post by: deekay on February 18, 2010, 09:54:14 PM

Quote from: DesktopDave;87782

I wish I had your problem...

Can't you just run the ITB's with the AFM installed?  Or do they flow too much air?

you will lose a bit of power over 6000rpm, but it will work. confirmed because this is how i had to set up my dbilas' after i learned my Alpha-N was DOA.

for what it's worth, ditching the convertible trunk anvil (~70lbs) and switching to an electric fan made up the difference up top, as well as adding appreciable gains throughout the powerband (naturally).

what ITB setup are we talking about? if you have dbilas', a bit of tweaking on the air filter housing bracket and the AFM will meet right up with the hose on the plenum. if you are working with TWM or something else you might have a bit more of a task ahead of you, but i can confirm it will work.

edit: i remember now you were talking about a home-grown setup. what are you using for a plenum?

Title: AFM Bypass
Post by: dvmotorsports on February 19, 2010, 11:06:24 AM

Quote from: DesktopDave;87782

I wish I had your problem...

Can't you just run the ITB's with the AFM installed?  Or do they flow too much air?

Do you mean keep it plugged in and set aside?

You too can have my problem. http://m3spares.com/ Got my ITB's for $140 USD shipped.

Quote from: deekay;87792

you will lose a bit of power over 6000rpm, but it will work. confirmed because this is how i had to set up my dbilas' after i learned my Alpha-N was DOA.

for what it's worth, ditching the convertible trunk anvil (~70lbs) and switching to an electric fan made up the difference up top, as well as adding appreciable gains throughout the powerband (naturally).

what ITB setup are we talking about? if you have dbilas', a bit of tweaking on the air filter housing bracket and the AFM will meet right up with the hose on the plenum. if you are working with TWM or something else you might have a bit more of a task ahead of you, but i can confirm it will work.

edit: i remember now you were talking about a home-grown setup. what are you using for a plenum?

S50B32 EVO ITB's. Plenum will be custom, similar to what that Bonje guy did. I just need to figure out runner lengths. Somewhere between 90-100mm.

I just have no idea how to fool the AFM sensor. And i'll need to run an A/F gauge.

Title: AFM Bypass
Post by: deekay on February 19, 2010, 11:49:46 AM

if you need an intermediary step, the ITBs can breathe through the AFM. this is how my car is set up right now, and it's working well enough that i'm not really anxious to go megasquirt yet.

if you are dead-set on getting rid of the AFM, you can try the hardware dbilas uses for this purpose- "alpha-N 2000". piggyback computer that takes TPS/RPM and feeds voltage to the AFM wire based on those. mine was DOA, but i got it used, so you might have better luck. other than that, your good option is... call dynotech and get a PnPMS.

but with the complexity of the task you already have at hand, i honestly would leave the motronic alone (excepting get a MarkD chip if you haven't already) for the moment. get the ITB setup working with that and you'll know it's solid when you want to move on to better management later. doing ITBs and new engine management at once introduces many variables and is going to make troubleshooting and tuning more difficult.

my $.04- good luck.

Title: AFM Bypass
Post by: dvmotorsports on February 19, 2010, 02:23:48 PM

You are wise grasshopper. That damn Alpha/N unit is almost 1G though. I could build a full EMS for that. And then I have tuning capabilities as well. And which dynotech site? I googled and got back 4 million erroneous results.

Title: AFM Bypass
Post by: deekay on February 19, 2010, 04:41:14 PM

yeah, the only reason i got the alpha-N is i picked it up with the ITBs as a package from a guy in northern california for $1200. at that price i was disappointed it was faulty, but didn't really shed too many tears over it.

todd (the guy that runs dynotech) is on this site, he has a turbo m42 car... he has a thread for it in the swaps/turbos/buildups section. username is "tglaze".

Title: AFM Bypass
Post by: dvmotorsports on February 19, 2010, 04:54:46 PM

do they have a website?

NVM. Found it.

Title: AFM Bypass
Post by: dvmotorsports on February 19, 2010, 04:59:22 PM

I did find this little issue though...

http://www.dynotechonline.com/store/index.php?main_page=index&cPath=65_73_84_186

Title: AFM Bypass
Post by: deekay on February 19, 2010, 05:49:24 PM

my suggestion is send a PM when you're ready. even if it's not listed on the website he does make and sell plug-and-play megasquirt for M42s.

Title: AFM Bypass
Post by: dvmotorsports on February 19, 2010, 06:13:54 PM

good to know. thank you. i'll pm him.