Power loss on hot day (x5d)

[smassey321]

Originally Posted by bfeng

Transmission seemed to be operating fine. Car just lacked power. But-o-meter says it was down 50hp. I was wondering if this was a combo of the ambient heat and not big enough intercooler. I’d forgotten my OBD2 WiFi interface so no data monitoring. Even in winter weather the coolant temp creeps up over 90C on this particular drive when I’m pulling the trailer.

A DPF regen can throw off the but o meter. They always seem to happen when I want to pass someone on a 2 lane road. I just moved to Phoenix and I am surprised how 115 degrees does not affect power that much. But I am hauling air and not towing.

[Bob Bates]

Lucky for me and 3500 bucks Canadian I never have to worry about regen or carbon in intake.

[bfeng]

Originally Posted by smassey321

A DPF regen can throw off the but o meter. They always seem to happen when I want to pass someone on a 2 lane road. I just moved to Phoenix and I am surprised how 115 degrees does not affect power that much. But I am hauling air and not towing.

You just need to do more passing ...

[bono]

I tow 7,000-7,200 lbs trailer with X5d (nickname kanar from the other forum). Last week I drove from Yosemite to Shaver Lake. The last part of the road is 12 miles 8% grade in average and partially 11% grade. This was the most challenging tow for the engine so far – Rockies or other parts of Sierra were never that steep.

Ambient temp was 85-90F.

Transmission temp 93-94C (this is always very stable, I believe I saw only once 95C in a stop and go traffic)
Engine temp: up to 110C, at some point of time I turned off air condition to avoid overheating. I know that some folks noticed engine temp around 120C, still without any error code. I could have stopped for a few minutes to cool down the engine, but with air condition off and windows down, it was OK to drive.
Oil temp: up to 125C. I switched recently from Mobil ESP 5w30 to Valvoline 5W40 MST. I am not sure, if this is how it should work, but I believe that with the new Valvoline oil temp is lower than with Mobil. I was getting 125C with Mobile fairly often and I would expect that on this steep uphill I would notice more than 125C with Mobil.

I have not noticed any loss of power. I was only concerned about the engine temp. 35d did great job. Truly amazing tow vehicle.

[bfeng]

Bono

Thanks for the great info. The hills I was on were not more than 7% grade.

So far my only theory is the heat caused the Ecu to reduce powered or DPF regeneration happening multiple times.
I’m going to do another tow next week, but with less weight (lighter race car, about 5000lbs total)


I wonder if my DPF is getting close to full and restricting flow or causing E-temp to rise too much. I suppose I should spring for something like ICarly so I can see e70 specific operating parameters.

Fwiw, 125C oil temp seems really hot for street operation. I’ve never seen more than 210F/100C sustained on my low tech vintage race motor that makes over 1HP per cc (NA) and runs between 6000-8500 rpm. Average speeds are similar (80-85mph), and we only have a teeny tiny Mocal cooler 1/4 the size of the one on the E70.

What kind of speed were you able to maintain ?

[bfeng]

Tempting to upgrade the intercooler and look into a better oil cooler for both engine and transmission. There is still a place for a GMC Denali 2500hd diesel with 910ftlbs of torque. I’d love to have an old one parked out back just for towing duty. If you haven’t tried one then you haven’t experienced towing nirvana.

And no way am I turning off AC when it’s that hot at muggy. 95F in the Rockies is way different than that temp in the muggy east coast.

[bono]

I believe that the oil temp is usually ca. 10C about the engine temp, i.e. in 95-100C range. When towing 7,000 lbs, it is ca. 10C higher, i.e. in 100-110C range. I am not surprised by additional 15C when towing 7,000 lbs uphill.

I read that up to 150C, the oil should be fine.

I am sure that I will never own a truck... unless I will buy a farm, start cleaning or construction business.

[bfeng]

Originally Posted by bono

I am sure that I will never own a truck... unless I will buy a farm, start cleaning or construction business.

I understand. X5’s SO Much better than any pickup,

But If you raced cars it would be different. Between the gas, spare parts, tools, jack & stands, tire sets, Nitrogen bottle, generator, chairs, pop-up canopy, ice chest (cool shirt), racewear, etc, it is easy end up with +1000lbs of extra junk. At that point loading and unloading an open trailer and your DD for every event becomes a real drag. I could pack it all into an X5 but then I’d exceed the GVWR. I have friends who will buy a crappy old Suburban just to have a vehicle that can be left outside, organized/packed and ready to tow. I want a 28ft enclosed some day so I can bring a race car plus a cool vintage car to zip around like a bmw 2002 or GTV . Plus it’s like having an extra 2-car garage for your toys in the winter.

[sunny_j]

Originally Posted by bfeng;1166547[B

]Tempting to upgrade the intercooler[/B] and look into a better oil cooler for both engine and transmission. There is still a place for a GMC Denali 2500hd diesel with 910ftlbs of torque. I’d love to have an old one parked out back just for towing duty. If you haven’t tried one then you haven’t experienced towing nirvana.

And no way am I turning off AC when it’s that hot at muggy. 95F in the Rockies is way different than that temp in the muggy east coast.

This is what came to mind as well. If it only happens on hot days I'm guessing it's the intercooler. Check out ATM intercoolers which would also eliminate any boost leaks

[bfeng]

Thanks for the recommendation. I was just browsing their site yesterday! This looks like a good modification for HD usage, but from others it seems like more oil cooling capacity is also needed.