WILL SHO U
Sooner or later
Thank you, thats all I wanted to know. Appreciate all you guys trying to help.
Anything special to installing new DIS?
- Thread starter WILL SHO U
- Start date
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Buy a TIM and waste your money.
You're not cooling a super computer here
Alldata said:
You're not cooling a super computer here
Rockledge
Pluggin' away
Haven't we all been through this before (with the same lack of a definitive answer)?
http://www.shoforum.com/showthread.php?t=58423
http://www.shoforum.com/showthread.php?t=58423
The manuals say di-electric, and shop source says di-electric, so I have no idea where the idea of heat sink grease comes from. 
Rockledge
Pluggin' away
The idea of heat sink grease also comes from repair manuals. For example, Autozone's "Ford Mustang 1989-1993 Repair Guide", which I believe is based on Chilton's, says this:The manuals say di-electric, and shop source says di-electric, so I have no idea where the idea of heat sink grease comes from.
"Apply a uniform coating of heat-sink grease ESF-M99G123-A or equivalent to the mounting surface of the DIS module. "
https://www.autozone.com/az/cds/en_us/0900823d/80/19/41/0a/0900823d8019410a/repairInfoPages.htm
Hmm... Helms or Chiltons... which one to believe?
Rockledge
Pluggin' away
FWIW, the heat-sink compound referenced in my previous post is a Ford/Motorcraft product:
http://www.fcsdchemicalsandlubrican...icone Heat Transfer Compound&category=Greases
http://www.fcsdchemicalsandlubrican...icone Heat Transfer Compound&category=Greases
Shoaz
Studly dood
Guys, heat sink grease is dielectric.
Not all dielectric grease is made to have good thermal conductivity (which is the idea with heat sink grease), but generally all heat sink grease is also dielectric.
"Dielectric", btw, just means that it doesn't conduct electricity.
As Jason mentioned a while back, generally non-thermal dielectric grease is used to keep connectors clean. Heat sink grease is used when you also need the joint/interface to maintain good thermal conductivity.
Electronics, especially power electronics (like the DIS) can get REALLY, REALLY HOT. And you don't want them to overheat. So Yamaha did a smart thing and gave the DIS a nice, big thermal interface to the end tank, which will generally always be cooler than the block, which has it's own thermal regulation system (i.e., a thermostat, radiator, pump, etc.). That gives a nice means of regulating the temperature of the DIS.
So the thermal interface between the DIS and the end tank serves a good purpose and the point of the heat sink grease is to keep water out of that joint to prevent corrosion and maintain the thermal conductivity of the interface. Grounding is achieved via the screws, so that's a separate issue.
Standing the DIS off from the end tank with a spacer, so that there's an air gap in between, greatly impedes the ability of the DIS to shed heat. Air doesn't conduct heat nearly as well as aluminum (I mean, orders of magnitude difference, aluminum is an excellent thermal conductor, air not so much). I'd expect that a DIS mounted that way will have a much shorter service life than a DIS properly mounted to the end tank.
I don't know that what brand/style/color/nationality/religion of heat sink or thermal compound used matters much, as long as you put something reasonably decent on there.
Not all dielectric grease is made to have good thermal conductivity (which is the idea with heat sink grease), but generally all heat sink grease is also dielectric.
"Dielectric", btw, just means that it doesn't conduct electricity.
As Jason mentioned a while back, generally non-thermal dielectric grease is used to keep connectors clean. Heat sink grease is used when you also need the joint/interface to maintain good thermal conductivity.
Electronics, especially power electronics (like the DIS) can get REALLY, REALLY HOT. And you don't want them to overheat. So Yamaha did a smart thing and gave the DIS a nice, big thermal interface to the end tank, which will generally always be cooler than the block, which has it's own thermal regulation system (i.e., a thermostat, radiator, pump, etc.). That gives a nice means of regulating the temperature of the DIS.
So the thermal interface between the DIS and the end tank serves a good purpose and the point of the heat sink grease is to keep water out of that joint to prevent corrosion and maintain the thermal conductivity of the interface. Grounding is achieved via the screws, so that's a separate issue.
Standing the DIS off from the end tank with a spacer, so that there's an air gap in between, greatly impedes the ability of the DIS to shed heat. Air doesn't conduct heat nearly as well as aluminum (I mean, orders of magnitude difference, aluminum is an excellent thermal conductor, air not so much). I'd expect that a DIS mounted that way will have a much shorter service life than a DIS properly mounted to the end tank.
I don't know that what brand/style/color/nationality/religion of heat sink or thermal compound used matters much, as long as you put something reasonably decent on there.
SASHO91
Zoom Zoom
I have yet to take any temp. readings.. but just from touch, the DIS stays extremly cooler than the X-tube. And this is with the tube being at a very minimum 120*.. Yes, eventually the DIS will get heat soaked (it is connected via metal) but these "spacers" prolong that, while keeping what heat the DIS puts out down as well.
I'll go drive the car around for 30mins or so tomorrow, and get a reading off the tube, and the DIS(metal backplate)....
I'll go drive the car around for 30mins or so tomorrow, and get a reading off the tube, and the DIS(metal backplate)....
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Thanks, SASHO91. I prefer numbers as well.
Shoaz
Studly dood
You need to take the DIS temperature when it's under max electrical load that is generating the greatest heat. I don't know what those conditions might be.
I've shot the DIS with my IR gun before as well, and never noticed much temp diff to the intake. Consider a few things, though:
The DIS package is plastic and will insulate any external temperature monitoring from the electronics temperature, which is what really matters.
Taking the temp of the DIS for this purpose is only really relevant when the DIS is making maximum heat and at peak temperature. If we don't know those conditions and haven't taken its temp in those conditions, we don't have numbers to work with.
A pretty big clue that it just might be an issue is that Yamaha designed the thing with a pretty big thermal interface to a part that will generally be well-regulated temperature-wise and generally fairly cool. I can't quite see the logic how defeating that will make it "better" as it seems to be going pretty well out of one's way if it's not needed. It certainly doesn't hurt anything to keep it thermally connected to the tank, as DIS failures in this configuration are not common. As SHO failures go, the DIS is way, way down on the list.
I'll say it again, with 25 years of electrical engineering experience behind it, so take it FWIW, standing the DIS off from the tank and leaving an insulating air barrier between it and the tank will likely reduce the service life of the DIS by a significant amount.
To me it's akin to disconnecting the heat sink fan on your CPU to save power.
I've shot the DIS with my IR gun before as well, and never noticed much temp diff to the intake. Consider a few things, though:
The DIS package is plastic and will insulate any external temperature monitoring from the electronics temperature, which is what really matters.
Taking the temp of the DIS for this purpose is only really relevant when the DIS is making maximum heat and at peak temperature. If we don't know those conditions and haven't taken its temp in those conditions, we don't have numbers to work with.
A pretty big clue that it just might be an issue is that Yamaha designed the thing with a pretty big thermal interface to a part that will generally be well-regulated temperature-wise and generally fairly cool. I can't quite see the logic how defeating that will make it "better" as it seems to be going pretty well out of one's way if it's not needed. It certainly doesn't hurt anything to keep it thermally connected to the tank, as DIS failures in this configuration are not common. As SHO failures go, the DIS is way, way down on the list.
I'll say it again, with 25 years of electrical engineering experience behind it, so take it FWIW, standing the DIS off from the tank and leaving an insulating air barrier between it and the tank will likely reduce the service life of the DIS by a significant amount.
To me it's akin to disconnecting the heat sink fan on your CPU to save power.
For all intents and purposes, going back a page or so, it doesn't really matter which one you use. Is that a good summation?
93rev2sev
SHO Member
DG or Thermal paste or heatsink grease...it all does the same thing in this application.
It fills the itty-bitty air pockets with something that transfers heat better than air.
You could probably use peanut butter.
Edit: I don't recommend chunky
It fills the itty-bitty air pockets with something that transfers heat better than air.
You could probably use peanut butter.
Edit: I don't recommend chunky
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SASHO91
Zoom Zoom
I do agree on most of your points...
However, I have lost 2-3 DIS modules in the last 3yrs. The ONLY varible I can think of is heat.
What about insulating the two 12mm bolts for the tube? That way the DIS is still mounted correctly and the tube does not heat soak near as much. This, of course, is with a remote ground for the DIS.
naval-avi8or
New Member
Why not just use the CORRECT materials. 99% of the members on here are not engineers nor probably anything even close. I'm pretty sure that the engineers that designed the system designed it correctly. Several members with a clue have already tried to steer it in the right direction but for every correct way they have been several who think they neede to re-invent the wheel.
Now for the book says use DG. Then go to FORD and get the correct DG from the dealer and what they sold me years ago was what the electronics industry calls heatsink compound (the white crap) and not the same as the DG you'll get from autozone aka buld grease. They have two different purposes.
My DIS has almost 200K and is the orignal only removed to clean the intake years ago and once again I used the CORRECT compound. Maybe thats why my DIS has almost 200K and still works.
ENOUGH SAID
Or you could rewire it up under the dash and allow the AC unit to keep it cooled, or maybe add a computer CPU water cooling unit to it.
Now for the book says use DG. Then go to FORD and get the correct DG from the dealer and what they sold me years ago was what the electronics industry calls heatsink compound (the white crap) and not the same as the DG you'll get from autozone aka buld grease. They have two different purposes.
My DIS has almost 200K and is the orignal only removed to clean the intake years ago and once again I used the CORRECT compound. Maybe thats why my DIS has almost 200K and still works.
ENOUGH SAID
Or you could rewire it up under the dash and allow the AC unit to keep it cooled, or maybe add a computer CPU water cooling unit to it.
SASHO91
Zoom Zoom
If no one re-invented the wheel.... where would we be today...... And it's not really re-inventing the wheel, just filling it back up with air (if you want to use metaphores)
If you want to run DG or TP, be my guest... Im not stopping you from doing so.
For the record... everytime I have replaced a DIS, I installed it correctly.
If you want to run DG or TP, be my guest... Im not stopping you from doing so.
For the record... everytime I have replaced a DIS, I installed it correctly.
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naval-avi8or
New Member
yep, thats what I did...I have a bit more gap though...
(car's dirty)
It will still transfer heat, but not nearly as much as the full contact area would.
THIS IS NOT CORRECT. It's more than likley the reason you have lost 2-3 DIS modules in the last 3 years. You can keep refilling the wheel with air, I'll just use the correct stuff.
SASHO91
Zoom Zoom
I was not running this setup when I lost those DIS modules. They were mounted the way they were designed to mount.
I'd rather have some-what cool air running through there than it directly mounted to a 200* crossover tube and have it heat soak the crap out of the DIS.
I'd rather have some-what cool air running through there than it directly mounted to a 200* crossover tube and have it heat soak the crap out of the DIS.
St Louis SHO
Rollin' coal
I've never lost a DIS in all the years I've been messing with these cars. I'd almost say your ground is not the best. I'd add some Grease of your choice, put it back on the crossover, and run another ground to it and see what happens.
SASHO91
Zoom Zoom
Grounds are the least of my worries... I lost two DIS' on my 93 and one on the 91... both have/had grounding "kits"...
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