Towing with a Powerstroke 7.3L (expectation/realistic)

Wes Tausend wrote:
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Thanks for some good info guys. I'm a bit surprised at the low exhaust cooling gain by adding an intercooler to the earlier, non-intercooler engines though. Unless the intercooler simply caused a notable more aggressive low rpm charge burn, resulting in a lot more power.

I understand there is a physical ceiling to limiting exhaust temps as a fixed displacement achieves high HP while remaining at mediocre rpm's. The 7.3L is not normally a good free revver. Is that what happens?

Wes
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I would actually like to ride in one of these 7.3's with all these mods screaming up mountain passes towing 12-13K . I have ,and there is no screaming. ETG's will get the 7.3 long before you can utilize any power increase.

I'd like to see a video of a 7.3 with 13K hooked up pulling the last mile or so of either Daniels in Utah, or the hill out of Ashton Idaho up into Island park . I have towed them both several times with a modded 7.3 with a 13K fifth wheel. Both hills second gear 30-35 MPH, ETG's running right at 1200-1250, can't run any higher then that. My point is I am calling BS on all this power of the 7.3 in the mountains. I'm not talking about the guy bragging about a 7500 lb trailer , I would brag too the 7.3 does pretty good with that weight.

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Thanks for some good info guys. I'm a bit surprised at the low exhaust cooling gain by adding an intercooler to the earlier, non-intercooler engines though. Unless the intercooler simply caused a notable more aggressive low rpm charge burn, resulting in a lot more power.

I understand there is a physical ceiling to limiting exhaust temps as a fixed displacement achieves high HP while remaining at mediocre rpm's. The 7.3L is not normally a good free revver. Is that what happens?

Wes
...

rhagfo wrote:


Wow, this make my decision almost five years ago to go Cummins Ram even better!

LOL, even your truck is not without its fair share of performance mods. And if I remember correctly, you're not on the original engine yourself, right (correct me if I'm wrong).
I look at it a little bit differently, though. My OBS 7.3L PSD is 20 years old with 290K miles on it. All the performance mods I've done have been 250K miles or more. There are not many tow vehicles (or regular passenger vehicles) on the road with over 250K miles that haven't had some significant level of repairs or changes along the way. But in my case, as with most 7.3L PSD's, the changes are primarily external, meaning that nobody is tearing into the engine itself. Not that they're bulletproof, though.

marcsbigfoot20b27 wrote:
Like others have said, its all about the upgrades and tune on the 7.3

For $1000 you can get ceramic coated bellowed up pipes, Riffraff or WW2 turbo wheel, and bigger exhaust. That takes care of most EGTs. Now get a good tune that is changeable on the fly like the PHP Hydra or DP Tuner plus the quiet Ford factory AIS airbox for another ~$350 and you are set.

Those are the mods in my sig and I can pull 7500 lbs at safe temps with the 80 hp tune up 8% at 75 mph all day up at 6000 ft or more.

Wow, this make my decision almost five years ago to go Cummins Ram even better!

Like others have said, its all about the upgrades and tune on the 7.3

For $1000 you can get ceramic coated bellowed up pipes, Riffraff or WW2 turbo wheel, and bigger exhaust. That takes care of most EGTs. Now get a good tune that is changeable on the fly like the PHP Hydra or DP Tuner plus the quiet Ford factory AIS airbox for another ~$350 and you are set.

Those are the mods in my sig and I can pull 7500 lbs at safe temps with the 80 hp tune up 8% at 75 mph all day up at 6000 ft or more.

Wes Tausend wrote:
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The odd thing is why would a relatively large displacement such as 7.3L develop excessive EGT's if newer, smaller displacement diesel engines do not also do so under the same heavy load conditions?

It has been my understanding (based on tons of research) that the 7.3L PSD in a stock configuration is incapable of producing EGT's high enough to warrant concern. However, the very minute you install larger injectors, this becomes a problem. More power upgrades from other sources only exacerbates the problem.

There are simpler ways to lower your EGT's without going through the expense of an intercooler. From what I've read, most people are not happy with the EGT decrease after installing an intercooler on their OBS 7.3L, which is one of the reasons I haven't done this. For the work and cost of an intercooler, one would expect more than a 50 degree difference (which is about what most people have reported).

I chose to make other improvements to decrease EGT's, which consequently add more power and efficiency. There are so many things that go into making this engine perform at an adequate level that I have to wonder if those people who report negatively about its towing characteristics don't have their truck running right in the first place.

For example, one of the biggest PITA things to do on these trucks is to replace the up-pipes. However, if your up-pipes are leaking (which is extraordinarily common on the 7.3L PSD), then you will be robbed of power (boost) and fuel efficiency, while unnecessarily running up your EGT's as you pour in more fuel (in an attempt to make more power). Replacing those on my truck made a huge difference. Also, gutting the EBPV and replacing the stock turbo wheel also made a big difference. When you do all that, replace the original boots on the turbo manifold y-pipe. Anything you can do to "contain" and "create" pressure (for boost and power), the better off you are. Put in a larger exhaust and a tymar-style intake, and you're making even more headway.

Though I've upgraded my TV for towing my 5er, back when I used my 7.3L PSD for this purpose, it was more than adequate for the OP's purpose. I can maintain 4th (OD) at 65 MPH on generally flat or moderately hilly terrain and was never disappointed to back down to 55 MPH in 3rd gear when in the mountains. Keep in mind that I tow a lot of big trailers for my business and since business is good I could easily justify the upgrade. Otherwise, I'd still be using my OBS 7.3L PSD for RV tow duties.

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The odd thing is why would a relatively large displacement such as 7.3L develop excessive EGT's if newer, smaller displacement diesel engines do not also do so under the same heavy load conditions?

The answer must lie in choosing the appropriate "tuning", intercooler and turbo setup. So if one is determined to beat newer diesels to the top, it must just be a matter of more precise 7.3L tuning and some well thought-out parts that are still going to cost a lot less than a new truck with a puny engine displacement.

Quality parts and advice like Banks and some others come to mind. As an example, for 7.3L towing, Banks is almost certain to recommend a larger intercooler, or at least intake fluid injection (propane, methanol etc). This seems like the first place to start from an engine that is expected to perform more than the usual over-fueled stop-light-to-stoplight show-boating... an engine that is expected to perform at heavy uphill towing.

My parts choices, if I ever modified a 7.3L, would also possibly only include a larger turbo down-tube, saving plumbing bucks from muffler on back simply because the exhaust needs less and less volume as it cools downstream anyway. And on the other end, a better intercooler reduces the need for a downstream larger intake simply because the better cooled charge is denser, more compact.

For me, sound control is also a major issue after the first few minutes, which is the reason I would not prefer a silty K&N and noisy new airbox. I got more than my fill of extended over-the-road loud diesel thrumming at work.

And finally, just like our locomotives, transmission heat is a major concern and something to consider upgrading as a package. Banks usually recommends this too.

Granted, the old 7.3L runs dirtier nox-wise, but that is an EPA problem only. Admittedly, new smaller engines get better economy too, at light empty load that is. And some newer engines have somewhat more durable internals for extreme competition levels. But there is still no replacement for displacement when pulling. And at sane rpm levels, stock crank and rods are not a problem for the 7.3L.

Wes
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For the OP, if he is still watching. Don't do it. 12k behind your (same as mine) truck is too much for our passes. Blewett pass is tough with even 7500# trailer.

Mine is 7.3, 2000, Ford AIS intake, 4" exhaust, tuner, trans cooler etc. I overtemp on EGT before I run out of "power" meaning I have to back off to 50 mph instead of 60 to keep it from melting down with only a tall TT.

BigToe wrote:
Thank you Glen (SoCal) for your informatively detailed insights on living with your new to you medium duty truck.

And thank you Wes, for connecting the dots on a good take away lesson... which amounts to checking the heater plenums to extract all of the leaf debris, in the cases where the vehicle's HVAC fan resistors are exposed to such debris.

Ugh. Not a job I look forward to.

BigToe,

The job isn't necessarily as bad as it could be. On my Mazda/Ranger, I believe I cleaned the plenum by simply removing a few screws holding the heater motor in place on the firewall and vacuuming debris out through the gaping mounting hole. A quick peek reveals that my Excursion (same as F-250) heater motor is mounted the same way. If I remember, the Impala was a lot more difficult, requiring me to remove a failed heater motor from under the crowded dash. That was Ugh.

A field mouse entered my dear wife's Prius heater plenum by sneaking in through the recirculation vent (I assume). The outside intake grills are fairly critter-tight, but not seed-tight without actual foam (think RV A/C cabin intake, same). During an oil change, the Toyota dealer found the nest when he checked the cabin filter which was chewed into a nice fleecy fuzz suitable for babies.

OTOH, one fall a tree squirrel built a nest under my Excursions hood judging from the size of sticks used. Unfortunately he also chewed a hole midway in the side of my brand new battery (ick), and several vacuum lines. I only found the nest after a couple of short trips and it suddenly didn't start at all... dead, leaky battery. They wouldn't warranty the still-new battery but they did smile. I suppose I could have tarred it up like the old days and refilled the acid. :)

Wes
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Marty,

The truck was ordered new, to be built as a fire truck. I got the original order/build sheet with it, detailing all the options.

They stripped most of the firefighting stuff from the truck before it went to auction. It carried a skid mounted fire apparatus that had the pumps, hoses, tank, generator, storage boxes, etc. There was a large electronics console between the front seats, which they removed, as well as all the emergency lights on the roof and fenders.

I don't see a spark arrestor on the exhaust. If it was there, they took it off.

I have some pics of the truck from before I got it. They're stuck in my old phone now. One of the pics was from when it was a working fire truck, which I found on the internet. Most were pics taken for the auction website, after they stripped it.