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FSD/PMD "Points to Ponder" How hot does it get

With my fsd on the intake when I would pop the hood most times I could not put my hand on the heat sink. In the bumper it is always cool to the touch.

Leo
 
JMJNet said:
Well, one thing is you cannot measure with the hood close. So, we can only measure a downward trending temp instead of the peak.
Click to expand...

When we did our tests we used a controler that will monitor 5 different thermocouplers. We tried every area in the engine bay even inside the air filter box. All in real time (hood closed). We would run for weeks at a time then change the position of the thermo's. What we found was the coolest spot in the engine bay is on the IP:eek:, but only a few degrees cooler and anywhere else in the engine bay is just to hot.
Long story short, get the PMD out of the engine bay.
 
And it may not be the same on every vehicle. Because my IP is always hotter than anything else in the engine bay. Maybe thats because of the PCM reflash that timing is more advanced, fuel rates are higher.

It may also be different in pre and post 96 when cooling changed. And it could be that my IP is the same temps but my engine itself and the other components just dont get as hot.
 
No refutably conflicting info here, folks: as may be noticed, those tests were performed on an installed-as-new remote-mounted FSD\sink located on the left inner fender wall, far from the offending area, and better, but not good enuff, as that module eventually failed - the original vendor still insists that location is the best - I determined that the later second failure was actually due to filing the heatsink for clearance for the TC probe wires - the aluminum filings eventually shorted the parallel driver transistors to the grounded heatsink, resulting in the only failed drivers that I encountered amongst all the failed modules I tested - my independently-conducted FSD module R&D was unknowingly paralleled by a Swedish engineer, his\my findings posted near simultaneously on "another forum" as failures resulting from contraction\expansion of the epoxy-potted module, along with procedures for recovering some modules if addressed in early failure mode - I ran my original recovered module on the IP for ~5yrs for further R&D (the IP is the coolest spot for the FSD while engine is running, but the heatsoak temps at engine-off can destroy the module), and am still running that original recovered module, subsequently removed from the IP and installed on a remote-mounted heatsink - that's ~9yrs now, on an oem Stanadyne FSD module originally scrapped as failed - also ~7years on a used IP originally scrapped as failed - and that's but a small sampling of the .........rest.......of the story..........................

FYI: the greater the fuel flow thru the IP, the cooler the IP - the hotter the engine coolant and engine oil, the hotter the IP and the higher the heatsoak temps

NOTE: the ~30buck infrared thermometer from harborfreightdotcom is a very handy tool for investigating Diesel stuff.......................
 
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I just don't get it. The proof is in the pudding. Why argue the location? 10+ years have proven out of the engine bay is best. Anyone who wants to keep it there can, but don't come and complain: "my truck just quit, what could it be"?

Leo
 
NVW said:
I just don't get it. The proof is in the pudding. Why argue the location? 10+ years have proven out of the engine bay is best. Anyone who wants to keep it there can, but don't come and complain: "my truck just quit, what could it be"?

Leo
Click to expand...

x2, well said. I think some people are still not convinced and they have to experience it himself. They are sad that they did not find this themselves. NIH. GM has tried it and failed, why should we with just a simple solution. PUT IT OUT OF THE ENGINE BAY.
 
NVW said:
I just don't get it. The proof is in the pudding. Why argue the location? 10+ years have proven out of the engine bay is best. Anyone who wants to keep it there can, but don't come and complain: "my truck just quit, what could it be"?

Leo
Click to expand...

Perhaps they own stock in Standyne and thinking about the longterm?
 
Turbine Doc said:
Which is sort of backed up by redesign/reprogram in 96+ to have dual power to lift via OPS & PCM so both have to be lost for lift to stop, as effort IMO to keep fuel supply constant which is indirect cooling medium for heat xfer for a IP mounted driver.

Also IMO if GM/Stanadyne "fessed up" to this it would open them to much more expensive recall campaign, than the replace upon attrition method the "special policy" 0064 @ 120K/11yr if it survived that long allowed for.

Now that most of those have been through the wringer, what an opportune time to come out with "new & improved" driver for sale to "fix" a problem that GM & Stanadyne for years denied was happening when they were on the hook to replace them.
Click to expand...

If there was no overheating issue then why did Stanadyne/GM come up with the dual power for 96+ lift pumps, and why now a D-Tech, a "new & improved" Stanadyne heat tolerant driver, or the money spent to develop (unsuccessfully) the REMARQ drivers. Out of engine works best, period..........:thumbsup:
 
buddy said:
And it may not be the same on every vehicle. Because my IP is always hotter than anything else in the engine bay. Maybe thats because of the PCM reflash that timing is more advanced, fuel rates are higher.

It may also be different in pre and post 96 when cooling changed. And it could be that my IP is the same temps but my engine itself and the other components just dont get as hot.
Click to expand...

Thats a good point.

Our test trucks were a 96 pre HO cooler then we updated it to the HO cooling. The next truck was a late model 96 with factory HO cooling.
 
There will always be differences and variation between trucks and suburban even on the same year. At least the study was as consistent as it can. There is also differences where the vehicle were located, TX vs. CA vs. California.

The results is conclusive that it is hot in there and better to be outside. It is shown in TD's study and Leroy did similar study.
 
JMJNet said:
There will always be differences and variation between trucks and suburban even on the same year. At least the study was as consistent as it can. There is also differences where the vehicle were located, TX vs. CA vs. California.

The results is conclusive that it is hot in there and better to be outside. It is shown in TD's study and Leroy did similar study.
Click to expand...

HOw about my study? SSDiesels junk intake mounted lasted 3 months. HEath Diesels i'm going on 2 1/2 years.

Nuff said. Both Stanadyne drivers.

VIN reports that IP/PMD were replaced at 44,000 miles. Forget the year. Changed it out due to failure at 90,000.

I have about 35,000 on my Heath.

So from my study.

So far Heath and Factory spot are tied at #1, heath without failure, Factory spot made it 45,000 miles.

SSDiesels junk spot made it 3 months, probably 3,000 miles.
 
Come, let us reason together: for those with GMTDScan Tech or Autoenginuity or TechI\II or MT2500 or equiv, post up your indicated fuel temperature readings (which will indicate the actual running temperature of your DS4-831-XXXX IP) while driving in traffic in hot weather with ac on vs ac off - do the same at stationary idle, hood closed vs hood open - - for comparison, my published readings can be found on at least three GM 6.5L Diesel forums, available since the early part of this century...............
 
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My IP is always hotter than my intake and the heatsink on the intake. The heatsink is usually hotter than the intake itself.
IP temps: 130-170*F
D-tech FSD on intake heatsink temps: 110-150*F

In all cases IP was at least 10* higher than FSD, sometimes 20* higher. The actual intake never seems to be too hot, 115-130*F, while coolant is always 190*F constant under all conditions.

Measurements with infared sensor while idling right after all types of use.
Ambient is usually 70-80*F
oil pressure is always a constant 43ish PSI even when switching between 15W and 5W.
Gm-4 turbo and Banks exhaust system, like 3.5"
There is no PMD mounted on the IP.

No towing, just long fast steep runs and 100MPH runs, sustained boost of 13-17psi for minute or more, IATs up to 240*F at high boost, pull over shortly after and check temps. Sometimes with bed loaded with stuff to go to dump, moving applicances, or home improvement concrete and lumber stuff, not too much weight. That and the 50 gallon fuel tank in the bed, but its a light duty so already it weighs a little less.

When I recheck later or just wait to check temps later, the temps on the intake heatsink and FSD are always lower than when checking during operation.

I have seen the IP go up in temp after checking jsut before shutdown, and checking it like an hour later. But only like 7*F, and that was only a few of the times it was checked, not always, seemed that way after hard runs, where I was about 160* and later it got to almost 170*. Only seen IP 170* a few times, after hard runs that I didnt give it time to cool down, to where I think the added voltage and throughput heats it more than added fuel flow would cool it.

This also lines up with TD's post of the PMD location on the IP jumping from 153-169* even without using that PMD.

I'll try taping a 2 channel thermistor display I have to the IP and FSD and see if that produces anything different than the infared sensor.
 
Thanks, Buddy!

I was just being nosy and curious what kind of temps you were getting.

Too me it seems everybody is getting different temps. I almost wish I had a PMD/FSD so I could do a test also.

This also tells me just how different all of our trucks can be. I am sure location has a lot to do with temps also.

This is getting good! :popcorn:
 
The fuel temp and IP temp (where the PMD goes) is not the same. The IP is all sorts of different temps, top of it is about same as fuel, but the side with no PMD on it where it is supposed to be is much warmer. Fuel temps are like 105*F riding around town, and 115* on the interstate. That is read at the IP in the OS assembly through GMTDScan. But for the IP get 130* on some parts of it and the side where PMD should be 155*F usually.

I'll hook up the thermistors today while finishing the fuel pressure gauge. tape them to the IP and FSD heatsink with aluminum tape.
 
Next, because precision-calibrated fingertips, seat of pants guessing, and erronious assumption are not viable instrumentation suitable for reliable testing results, using your GMTDScan Tech or Autoenginuity or TechI\II or MT2500 or equiv, post up your indicated IAT temperature readings (which will indicate the actual running temperature of the interior of your intake plenum) while driving in traffic in hot weather with ac on vs ac off, plus (same with the IP fuel temps) the temps indicated at idle, hood closed, then hood open - for those with charge-air coolers, don't be surprised at the disparities....................
 
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