: Re-mounting PCM - Idea?



fubar569
06-28-07, 10:08 AM
I've been toying with how to re-mount the PCM in order to run a different and/or more efficient intake setup...the stock one is very good, but i want to evaluate the difference and see if any power is to be had...

if i mount the PCM in its own enclosure, it gets no airflow
if i put it in a new airbox/etc...that presents a restriction...both the PCM and the "airbox"

well...dur...i'm a computer nut and know all about overdoing cooling...

make a new enclosure, mount PCM in enclosure, add small vents...for airflow, run XYZ size tubing to air source and put a 92mm or 120mm size fan flowing 100+ CFM inline with that tube...should be plenty of airflow to keep the PCM happy. the fan runs off 12v and usually take less than 1 amp draw to run (the particular one i have in mind is 650mA and 6 watts)

this would allow almost total freedom for any sort of revised intake setup should one choose to do it while keeping PCM nice and cool...

thoughts?

Submariner409
06-28-07, 01:00 PM
I like the idea. Especially after discovering (this AM) that the PCM runs hot enough to cause pain if you try to pull it right after a road run. If you really think about it, just how much air flows through the air box at, say, 35 mph? Not much, because the throttle butterfly is barely off-idle and engine vacuum is up around 20". There's 8 or 10" of PCM pigtail to fool with, so there must be a solution.........OR go into the top of the existing box, through the cover held on by the resonator bolt.........

jadcock
06-28-07, 01:14 PM
I surmised in the other thread where submariner409 was asking about temperatures that the next step in automotive PCM cooling is active cooling (with a cooling fan, a la your home PC). I think the best deal would be to build your own PCM enclosure, and install two large muffin fans. They'd have to be pretty high capacity I'm sure, but it would probably provide the best alternative to the passive cooling it gets in the intake tract.

The '97 DeVille box is a bit different than the newer ones (or at least the one in my '01 STS). The air box actually sits "on top" of the PCM and all the air is drawn over the PCM (or at least most of it). In my '01, the PCM sits "in" the air box, and you can easily draw a direct path of air flow that doesn't intersect the PCM. It would seem that the newer design doesn't provide as much PCM cooling, but who knows.

airfuel2001
06-30-07, 12:43 AM
What I did was, I had a 3.5 in mandrel piece of pipe from the mass air 90 to my 4 in K&N where it stuck in the corner and was wedged there. I thought it would feed more reasonably cold air to the motor via a heat shield to block rad heat. I placed the computer between the fuse box and the filter and it wouldnt go anywhere, the problem was it would get HOT and that concerned me, after experimenting with that I now have a modded air box and am surprised it is more "crisp" and didnt feel any loss. I also have the peace of mind that the computer is air cooled.

Submariner409
06-30-07, 03:17 PM
:rolleyes: I may duplicate this up in the Seville forum....anyhow, take a flashlight and look outboard of your Seville airbox, and you'll see a rather large hole in the sheetmetal of the side body panel which opens into the area behind the headlight and above the fender liner and lower air deflector panel. If you accurately cut the side out of the airbox and use some 1" foam weatherstripping to form a gasket, you have now more than doubled the air intake area from outside the engine compartment and increased the flow past the PCM.

lisekpl
07-02-07, 10:36 PM
What I did was, I had a 3.5 in mandrel piece of pipe from the mass air 90 to my 4 in K&N where it stuck in the corner and was wedged there. I thought it would feed more reasonably cold air to the motor via a heat shield to block rad heat. I placed the computer between the fuse box and the filter and it wouldnt go anywhere, the problem was it would get HOT and that concerned me, after experimenting with that I now have a modded air box and am surprised it is more "crisp" and didnt feel any loss. I also have the peace of mind that the computer is air cooled.

Can you upload a picture of this, I'm very interested. Thanks

jadcock
07-03-07, 01:09 PM
:rolleyes: I may duplicate this up in the Seville forum....anyhow, take a flashlight and look outboard of your Seville airbox, and you'll see a rather large hole in the sheetmetal of the side body panel which opens into the area behind the headlight and above the fender liner and lower air deflector panel. If you accurately cut the side out of the airbox and use some 1" foam weatherstripping to form a gasket, you have now more than doubled the air intake area from outside the engine compartment and increased the flow past the PCM.

Have you done this on yours?

AlBundy
07-03-07, 03:20 PM
Can you upload a picture of this, I'm very interested. Thanks

:yeah: Very interested.

dkozloski
07-03-07, 03:39 PM
The PCM is a digital device. It either works or it doesn't. As long as it doesn't throw codes or cause random problems it's working just fine. If it ain't broke don't fix it. What I'm trying to say is that the PCM functions just fine in its present environment. It may seem extreme for various human body parts but the PCM seems to tolerate it well. You're focusing on a problem that doesn't exist.

Submariner409
07-04-07, 04:36 PM
:stirpot: dkoz......After some surfing, found out that most PCM's, no matter what mfr., seem to run around 120-130 degrees. Lotsa brainwork there.....(PCM - the big ones, not the chipsets out in the left fender area by the driver's foot......)
Jadcock.......yep, the outboard side of my airbox looks like Swiss cheese. Didn't make a whit of difference anywhere that I can tell with a stopwatch and speedo.....pretty primitive. The PCM still hits 123 degrees measured with an IR thermometer. I'll probably score a used airbox online in case I need to restore things to close-to-stock.

dkozloski
07-04-07, 05:10 PM
:stirpot: dkoz......After some surfing, found out that most PCM's, no matter what mfr., seem to run around 120-130 degrees. Lotsa brainwork there.....(PCM - the big ones, not the chipsets out in the left fender area by the driver's foot......)
Jadcock.......yep, the outboard side of my airbox looks like Swiss cheese. Didn't make a whit of difference anywhere that I can tell with a stopwatch and speedo.....pretty primitive. The PCM still hits 123 degrees measured with an IR thermometer. I'll probably score a used airbox online in case I need to restore things to close-to-stock.
It might be interesting to find out what the worst case design specs are for the PCM. Because the car seems to run fine in desert environments it must be pretty tough.

dkozloski
07-04-07, 05:15 PM
When solid state electronic ignition systems first appeared on factory Detroit automobiles in the 60's they were all plagued with reliability troubles except for the GM DelCo systems that were mounted on the front side of the radiator support. MoPar systems in particular were problematic. Delco used a magnetic pickup and the Mopars were optical. The Delco black box was heavily finned and in a direct airflow path. I never saw one fail.

AJxtcman
07-04-07, 05:34 PM
http://www.amerigon.com/index.php
click on the 1 2 3 4 tabs

dkozloski
07-04-07, 06:28 PM
I prefer Hilsch vortex tubes.
http://www.pdbuchan.com/ranque-hilsch/ranque-hilsch.html

AJxtcman
07-04-07, 07:11 PM
I prefer Hilsch vortex tubes.
http://www.pdbuchan.com/ranque-hilsch/ranque-hilsch.html

I have one.

Submariner409
07-04-07, 09:40 PM
:highfive: dkoz......I ordered my 1965 Chevelle Malibu SS 327/350 with "transistor ignition". Yep, the 3x5 black box was on the front radiator/hood latch support and there was a trigger on the distributor lower plate. That goes back a ways.............I put over 110,000 on it before a nighttime total...........

dkozloski
07-04-07, 11:51 PM
:highfive: dkoz......I ordered my 1965 Chevelle Malibu SS 327/350 with "transistor ignition". Yep, the 3x5 black box was on the front radiator/hood latch support and there was a trigger on the distributor lower plate. That goes back a ways.............I put over 110,000 on it before a nighttime total...........
I had a '66 SS396 El Camino with oval intake ports. After the valve guides went I put in a factory new Z28 302 with export cam kit and AFR heads. Everybody in town swore that it had to have a 427 in it the way it went. It would easily turn 8000RPM. Twelve second quarter mile. The 396 I had left over wound up in the back seat of a '66 Corvair using most of a Crown Corveight kit but by that time it had a gear drive reverse rotation L88 cam and open chamber aluminum heads. It would eat 427 Corvettes alive. I used the Delco ignition with the 302 in the El Camino but I had a Delta Electronics Capacitive discharge kit in the Corvair using the 302 aluminum distributor. The 396 turned an easy 7500RPM and never missed a beat.