Scored a 7427 BPRK from a 454BBC today.

[WallyCJ7]

You got to love a 1/2 price sale at the junk yard today:rockon:. The 2nd truck I checked already had the glove box removed and I didn't even need any tools to pull it out. I now have the wires to make a pigtail from the $42 to $0D so I can use the $42 as a backup.

I as I started looking up info about the transition from the $42 to the $0D I kept seeing that everyone wants this because of the memcal chip and I'm wondering why? Please enlighten me...

So any tips for anything else I should use from all the $0D info on this board would be greatly appreciated.

Wally

[sturgillbd]

Easiest thing to use is a G1 adapter from Moates.net . No soldering. Put flash chip in adapter and plug memcal in it. Plug whole assembly into PCM . Maybe an HDR1 will help also so you dont have to unplug your flash chip from the adapter to read it or program it. I made a homebrew HDR1 .

[sturgillbd]

As for why I like the memcal type is the PCM dumps data at 8192 baud instead of 160. Data is almost instant when showing the dash and lots more data points when logging.

[WallyCJ7]

I understand PCM baud rate but why the memcal out of a 7.4L over the 5.7L?
I have the G1 with the ZIF socket ordered so I should be good to go...

As for why I like the memcal type is the PCM dumps data at 8192 baud instead of 160. Data is almost instant when showing the dash and lots more data points when logging.

[sturgillbd]

I was referring to the later PCMs (memcal) vs C3 ecms (eprom). Memcal from donor vehicle should have a cylinder bore as closely matched to transplant vehicle as possible but where you have an AMC 401, its bore is 4.165". The 454 engine has a 4.250" bore. The 454 memcal more closely matches the 4.165" bore than a 350 memcal . The 350 engine has a bore of 4.00". The memcal has a knock filter on it which sends a voltage to the ecm to retard timing when the knock sensor hears knock. The knock sensor is basically a microphone. The knock filter is basically an amplifier and a bandpass filter to only listen for spark knock in which the frequency of the sound of knock is dependent on the bore size. Hopefully this makes sense. JeepsandGuns has fought false knock with his 401. He can probably tell you more since he has done a similar conversion except now his is MPFI instead of TBI.

[JeepsAndGuns]

I have tried both 350 and 454 knock filters and had no luck with either. I have come to the conclusion that GM knock filters to not like AMC 401's, or at least mine. On top of trying different knock filters/memcals, I have tried moving the location of the knock sensor, and also installing it in a elbow to try and desensitize it, all with no luck. I gave up on it long ago and just tuned spark by ear. Not the best way but its all I had, and everything seems to be working fine. I just have spark retard disabled.