Hey,

Anyone ever give consideration to using peltier semiconductors to cool the canzoomer/pcm units? I would think that the amount of airflow going through the PCM cover, it should be enough to draw heat away from the semicondoctor device right? The only problem that may occur is condensation?

Anyone have any thoughts/ideas?

 

Interesting thought. And before someone asks, here is info on the Peltier...

 

I dont think that would work to well. I have thought about using them to cool my computers, but the prep work and added danger they introduce as well as rediculuous cost always makes me turn away. You can not air cool a peltier, they have to be water cooled since they put out a tremendous amount of heat off of one side. The cold side does indeed get cold, below freezing, but the hot side gets damn hot, well over 200 degrees. Air cooling for the hot side would do nothing. Also the condensation they produce is tremendous. If you use these inside a home pc you have to basically cover the whole motherboard and processor and other stuff with waterproof dilectric grease so the water doesnt get all over it. They are indeed a cool product, but I dont believe they would work in this application.

 

Good points. I think a small fan would be better.

 

Currently there are alot of peltier products that use air cooling. The neck coolers for that Sharper Image sells, Portable drink coolers, CPU fans, these all use fans to cool the peltier device.

I guess it would depend on the temperature deltas.. We wouldn't need something that went below 0, just 50 degrees F or so? That should be easily dissipated by a combination of fans and natural airflow through that chamber..



I was thinking that the ariflow while the car was moving could be enough to dissapate thier heat.. I can see your point though, as there would be no airflow when idled at a stop light.

Also, someone mentioned that air is drawn through the PCM cover into the air intake.. this will raise the temp of that air.. Would the volume of air that is passed through there significantly raise the temp of the air that passes the MAF?

 

Looks as if, the temp of the cz unit is more than 80F (which I believe it is) and you have high humidity (Fl, 80% +) You can have only a temp differential of 6 degrees or you'd get condensation.. that's not good

 

The peltier plate would have to be half in/half out of the enclosure to get rid of the heat....would be pretty obvious at 'warrantee-time'!

You already have ducted cool air cooling to the enclosure, so if the problem is "no air flow at a stoplight" can anyone in the class suggest an answer? Yes, you at the back? That's right, a FAN, good answer Jones!

You cant have any pudding if you don't eat your meat......
sorry, different flashback.....

S

 

I mentioned a fan in my post too Just brainstorming, not saying it's viable

The peltier device wouldn't have to be half in/half out, you could just attatch it to the metal casing of the pcm and/or canzoomer unit. It will traw heat from the metal and cool the casing, it would cool the inside of units dissipate the hot air into the cavity covered by the plastic housing..

Still would have to overcome condensation issues or you'd have water going into your airbox.. or into the electronics..

THis has the potential to provide more cooling than just a fan..

 

guys,
The temp in the ecm box is well past 80 degrees F. in Ga in summer! I'll bet its around 110-120! The exit for the airflow from the ecm is around the end of the engine intake. I'm not an expert but i guess this would "draw" some air through the box while youre at a red light or stuck in traffic. How much is needed is anyone's guess at this point, From rx8 friend no heat related failures yet. A fan is the only solution that I can think of and would be easily installed,but--- if your dealership raised the hood and saw it they would start asking questions and warrenty problems could arrise! Guy331 ypu are a critical thinker but I dont think "we" can use your idea(carowners that is). Anyone ever felt how hot the battery gets also? As far as the air intake sucking in hot air, I havementioned that before. As seemingly(from all the other posts i have read) as sensitive the MAF is on this car maybe the hotter air does have some affect. I do know that my car does feel a little stronger when it is cooler(the engine that is). I know ,I know air density and all that but never-the-less HEAT and electronics do not mix well.
thoughts all?
ilddragger

 

I guess critical thinker is good, thanks

I know the heat gets higher than 80F.. I was using that as an example while playing devils advocate.. with 80F and 80% humidity, the viable temp delta would be only 6 degrees before condensation happened.. which is NOT good.

I don't think people can go out and use this idea as is, but maybe someone reading this can turn it into something worthwhile later

There may have been no heat related ECU failures, and there may never be.. the fans might work.. that doesn't mean "we" (someone) couldn't research an idea that may be beneficial.

I think we are thinking along the same lines as far as practicality of my thoughts. However, hopefully someone, somewhere can use them.

If so, buy me a beer when you make $$$$ ok? :D

 

Well, I was working on Maurice's car today, testing a new unit, and after running the car for 5 min. or so (it was already nice and warm as he just got back) I almost burned my hand on the PCM. Lid was off the box. Stage 1 was just barely warm.

I'd say most of the heat in there is developed by the stock PCM. I doubt our box has a large effect.

 

guy 321
yes critical thinker is a compliment and if you are ever down my way I'll buy the beer. once we sober up we can ride the dragons tale(a road a few hrs from me that has over 300 curves in approx 11-14 miles) ! Of course it is in the mountains!
rx friend -nice to know its not the cz unit. Maybe that discovery makes it even more important to separate the 2 units. At least some spacers or something. Mine came with two toward the front but Im thinking of adding 2 toward the back also. I guess mazda designed the pcm to withstand the heat ifit was that hot. The stock pcm cooling system certainly didnt cool that much.
Thoughts? ANyone that has mazda connections know anything about this?
olddragger

 

Any updates on anyone's efforts to cool the ECU? How hot does it get in there?

 

I am tempted to buy one just to see if I can mod some of my computer CPU coolers to fit, simple concept really increase airflow, or increase surface aread to disprese heat. Thermal grease is cheap, and so is copper... of course with a giant heat sink sticking off the side of your engine it might be pretty obvious to the mazda techs that something is going on .

It looks to me like the top of the PCM/ECU box is already ribbed for more surface area, and from what I have read the CZ until is a very tight fit on top of the PCM, applying thermal grease on top of the PCM and filling in the ribs with copper would better distribute the heat to the CZ unit... which might be a bad thing... unless you also allow more surface area on the CZ unit to be exposed by extending the copper to outside of the BOX, but then you would probably need a new way to secure the CZ unit.

Has anyone attached a thermal Diode to the PCM to see how hot its really getting? probably would have to take a reading on the outside of its shielded box (which will be lower than the actual heat source of course), because really 120+ degree's is not a problem for silicon, when you start pushing 150+ F then you need to look at cooling solutions. For instance the Pentium 4 processor has a max thermal spec of about 72C which is about 160F, it will run stable at this temp for the most part, if you build a system you really dont want your CPU to go over 145F under maximum load just to be safe.

I don't suppose Mazda posts their thermal specs anywhere do they?

 

Lufa,
This is and has been a concern of mine for some time. I measured the outside ecu box temp on a 92 degree day and it was over 138 degrees. It seems that the rx8 pcm is causing the heat and not cz's 1.1. It had to be hotter on the inside. I dont think there is much airflow in the pcm box at regular speeds. For instance i measured the engine air intake temp on that same day at speeds of 45 mph for approx 15 miles and it was around 118. I then took the car on the interstate at 70 mph(or so) and it was 95degrees. So a ram air affect is present at the higher speeds but at city driving speeds not much airflow is going on. Others on this forum that know a lot more than me have said this is ok. I still have my suspicons(sic) and I bet that when a FI unit is tried on this car heat is going to be a BIG factor. I didnt want to power vent my ecu box because i dont want to void my warrenty.
oldddragger

 

Let's say we bought another ECU lid and made modifications to it to allow for a fan. How do I put hook up the power?

 

magic 8
make sure its a 12 volt fan and just find a hot wire that the ignition switch controls. Guess you would want a fuse on it. Some have mentioned some computer fans as a possibilty. Dont forget to guard agaisnt dust accumulation. it would look cool!
olddragger