Ecodiesel power derating as temps rise?

[AEsco48]

Funny. Exactly what I said this morning. I also wonder if the hood scoops for the Rubicon would help the engine bay temp.

Ideally after opening up the scoops we could design and 3d print some attachment that let them act as chimneys that extracted the warm ar in the engine bay out!

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[CrazyCooter]

I really think the choke point is the small front grill area. If this could have been easily fixed at design, it would have been done? If there was a large belt driven fan....it could probably shed the heat, but then fuel economy, noise, and hp would suffer. No free lunch for sure!

 

[869 KPH]

Anyone considered or tried a swap to a Mojave hood to see if more airflow can be achieved that way? I bet opening the scoop on one could work well.

These temps people are talking about is another reason I will 100% avoid adding my own wiring under the hood. I'll get the aux switch option and be very cautious.

 

[Mr._Bill]

The choke point is the front grille area. The engineers have said, in interviews, that they have done all they can without changing the front end design. They use electric fans as there isn't room for an engine driven fan.

 

[Glad_he_ate]

Yup can only move so much air through there. At least ya get a higher powered fan with the towing package, so I have read. Personally have not looked that far into it however

 

[2TH MVR]

I'm well aware of these heat soak issues with turbos. But all this talk about having to pull over and cool the JTRD is a little disconcerting. We'll see. My ordered JTRD should be here in a month. Hopefully.

 

[rharr]

I experienced this on last Saturday. Ambient temp of 115*, Oil, Coolant and Trans temp all 230 or lower. Unloaded, but have an ARE topper, cargo glide and 37s w/ beadlocks. Made a 1 hr highway trip, parked for ~30 minutes then pulling back onto the highway floored it with no power. Pulled off on the shoulder, turned off engine and restarted. Tried to merge onto highway still with no power, and barely able to get to ~45 mph. Stopped again, had it "un-derate" momentarily then derate again. Finally pulled over under an overpass, let it sit for a few minutes, then had no issues. This also happened the week before, with ambient temps 110*+. Before that, I had it happen once in cooler temps, which I figured I may have accidently put it in manual mode. Note: mileage ~14k

I had this exact same thing happen to me. Similar Temps. Seems like something heat soaks when parked. I am trying to be good about starting and idling for a few minutes after it is restarted from running to give what ever is hot a chance to cool down

 

[CrazyCooter]

On my trip last week, I never shut the truck off once it started in the morning, so I never experienced heat soak. Even though the A/C was on pretty much the whole time, I did note the fsan running full speed at every stop.

 

[Steven_B]

For you that have a Tazer, the recent update includes a cool-down mode while the engine is on. Basically just turns the fans on full blast. A few weeks ago I traveled through death valley (107 degrees) mainly as a heat test and play with the new cool-down feature when we stopped for a few minutes. At first, I thought my fan was running in reverse because all I could feel was air coming out the front of the grill vs being sucked in. But it was flowing correctly, the air just had no real place to escape and was coming out the front. Heat's not a big issue up here in the Seattle-Tacoma area, but I am still thinking about adding vents to the hood (I have a Sport) or aftermarket inner fender liners with vents would make a little difference.

 

[rharr]

For you that have a Tazer, the recent update includes a cool-down mode while the engine is on. Basically just turns the fans on full blast. A few weeks ago I traveled through death valley (107 degrees) mainly as a heat test and play with the new cool-down feature when we stopped for a few minutes. At first, I thought my fan was running in reverse because all I could feel was air coming out the front of the grill vs being sucked in. But it was flowing correctly, the air just had no real place to escape and was coming out the front. Heat's not a big issue up here in the Seattle-Tacoma area, but I am still thinking about adding vents to the hood (I have a Sport) or aftermarket inner fender liners with vents would make a little difference.

my plan is to pop my ruby vents, cut the bottoms out for full vent and then cut a 3x12 slot down the center of the hood insulation. The slot in the center should give the heat a chance to get pull out the vents but also allow any water ingress from the vents to be sheeted off the back of the insulation to the side of the engine.

 

[CrazyCooter]

There is a thread going about trying to add the Mojave hood and plenty of talk about opening the Rubi vents. My concern would be that the low pressure that could be present in the engine compartment while underway could be assisting the cooling components in the grill?

There is a reason why vehicles come with air dams, rubber flaps in the grill area, and flaps in the inner fenders no? Cant just be for looks as that stuff costs money to design, install, and manufacture.

 

[rharr]

Here is my solution over weekend.
I'll report back after a few trips.

 

[stickshifter]

my plan is to pop my ruby vents, cut the bottoms out for full vent and then cut a 3x12 slot down the center of the hood insulation. The slot in the center should give the heat a chance to get pull out the vents but also allow any water ingress from the vents to be sheeted off the back of the insulation to the side of the engine.

A lot of engineering goes into engine bay designs with regard to air flow to maximize cooling. It is my understanding that messing with the design can have unintended consequences, and you might end up reducing air flow. But heck, I'm not an engineer, and you might know exactly what you are doing. Perhaps I should get back to work... Good luck!

 

[CrazyCooter]

A lot of engineering goes into engine bay designs with regard to air flow to maximize cooling. It is my understanding that messing with the design can have unintended consequences, and you might end up reducing air flow. But heck, I'm not an engineer, and you might know exactly what you are doing. Perhaps I should get back to work... Good luck!

I agree with you here just from my experience in the automotive trade.

I did see a video over weekend where the guy did some testing in a wind tunnel with a smoke wand removing his hood and thought of these threads where people want to add venting. You could clearly see the vacuum into the radiator with the hood on, but hood removed it seemed to want to divert air over the grill rather than through. for $495hr, one could maybe see where FCA screwed this up?

Have a look for yourself!

 

[rharr]

A lot of engineering goes into engine bay designs with regard to air flow to maximize cooling. It is my understanding that messing with the design can have unintended consequences, and you might end up reducing air flow. But heck, I'm not an engineer, and you might know exactly what you are doing. Perhaps I should get back to work... Good luck!

Just did a 1000 miles this weekend going from tucson to silverton co (lots of mountains) doing 80, with temps in the high 90's.
Engine and oil temp never crept up and never had a derating after a short stop. I would say it's working for me. Time will tell.

Generally speaking jeepers since time has begun have been cut holes and vents into their hoods. Might be something to the collective wisdom...

Jeep engineers have a lot of factors and variables they have to juggle now a days to meet fleet MPG standards. Sometimes what's good gets cut cause it can negatively effect fleet mpg. Look at buying a JT with a soft top, you have to get a bed cover of some sort. I doubt soft tops with no bed cover reduce mpg that much more then a jt with a hard top and no cover but it must so not softtop with no cover for you....

Same time jeep isn't going to throw on a ruby hood on every diesel jt cause that costs more money and the customer won't pay. When I popped the insulation to remove my vents the underside of the hood sure looks designed to take advantage of leting air move through channels stamped in the hood leading to the vents if they were open. The vents were also molded in a way to sure make it easy to cut them open. Some times engineers sneak things into their designs to allow users to mod on their own and deflect MPG/EPA/penalties on to the users and aftermarket.

If they truly didn't think the hood vents would do anything why go through all the trouble of doing a mold where all the grille holes are open and there is a bottom cover plate? It would have been easier to just stamp a single layer faux grill with no holes no bottom plate.

I will try to remember to stick a meat thermometer into the hood vents holes to see how much heat is coming out.

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