Hi all,
I have a 2003 Excursion 4x4 with a 7.3. I’ve done a lot to this truck so far but one thing I would like to do is get the EGT’s down. It still has the stock Garrett with a WW2 installed. I went from the Ford AIS to the SB intake which I thought would give me more flow. I believe it did but just not enough. I read Sous’s tale of 2 turbos where he installed the “undersized turbo“ and seems to have worked out. This led me to the KC300x .84 A/R since I need a drop-in option. Anyone have an opinion or alternate idea? Details below.

My experience:
Light towing and/or heavy payload at 65 mph I regularly bump over 1000° on moderate grades and if I don’t shift down they will go 1100 to 1200 or more.
The engine has good power in all situations. It will produce over 25 pounds of boost if I get into it.

Usage:
Travels between 1400 ft. to 6500 ft. elevation. Worse at higher elevation of course.
Light to moderate towing

So far I’ve done:
Adrenaline HPOP
TS6 chip
WW2
Pedestal delete
SB intake
Dieselsite mechanical wastegate controller
411 gears to compensate for 35” tires
35” tires
Boost fooler
Bellowed up-pipes

 

Welcome to the forum. First off, the engine is designed to handle 1250* for extended periods and 1300* for short bursts. Are you seeing temps above those? If so then I'd first look for boost or drive pressure (exhaust) leaks. Those will reduce airflow and thus create higher EGT's.

 

If I don’t downshift it will ramp up pretty quickly to 1200 or more. I’m hoping to stay around 1000° to 1100 when I’m towing or heavy payload for longevity. Plus the 4R100 doesn’t like a lot of downshifting. Maybe this is unrealistic but the EGT’s climb so quickly on a grade.
I installed the bellowed up-pipes on the exhaust side and I can’t see any telltale soot marks so I think it’s sealed pretty good. On the intake side I put all new boots on the CAC and did the leak-down test. Result was good. Plus boost climbs very quickly.
Thanks

 

What tune are you running. What kind of weight are you towing, and what style load~big air catching camper, or a lower profile load?

Sous’s 363 from his thread isnt an undersized turbo, it is an appropriately sized turbo…

your egts are very good numbers that most guys would be elated to have.

 

I found your FTE member name humorous.

A KC 63/68/.84 is a solid turbo and a great option for people like you that are looking for a drop in. I wish that turbo had been an option when I went with a T4 kit in 2018, but it was not. I am more than happy with my Borg Warner turbo and have zero regrets, but it would have been nice to give that turbo a shot. I know of at least 2 of these turbos on personal friends trucks and they are very happy with them. I have nothing bad to say about the KC 63/68/.84 turbo.

Have you seen the turbo matrix crated by FTE'r RacinJasonWV?

Link: Turbo Matrix - MST, KCTurbo, SXE Reviews

That will give you some ideas about turbo sizing when considering injectors, use of vehicle, elevation, etc...

Regarding your EGT measurements, what tune are you running on the TS6 when you are towing and seeing near 1200° or more? What elevation are you at based on your previously stated 1200' - 6500'? Is this EGT observation toward the top of the grade or is it accelerating from a stop?

1200° is not bad although it may not be ideal in your mind.

When you performed the boost leak test and you said the results were good, does that indicate that boost held for a short period, you saw no leaks with soapy water, etc?

EDIT: My apologies for the repeated questions from ESwift, we were typing at the same time and I took too long it seems.

 

I have been torture testing a few turbos to the max the last few days

 

I did not see exhaust mods other than bellowed uppipes - have you removed the stock restrictive muffler yet? That would be next on my list, replacing it with either a straight pipe or Walker BTM.

As others have noted here, I do not see a reason to change your turbo from the MST, based on the data you have presented. If you still want to, the KC balanced assembly would be a good next step with stock injectors.

 

Have you looked around your exhaust manifolds for soot? My up-pipes are fine, but I have about half of my cylinders leaking on the exhaust manifolds. I don't know how much of an effect this has on EGT though I suspect some. On steep grades with my 10K lbs 5th wheel toy hauler I can see 1600+* if I put my foot into it. I have to be careful and I still struggle to keep it under 1400 for some of these pulls. I'm hoping the manifolds help with that though (along with some other mods).

There are people on here who can make 25 to 30 psi boost and still found boost leaks, so psi isn't a good indicator of not having a leak.

What RPM are you at when you see these high EGT's?

 

E-Swift:
Tune; TS-6 50hp when towing or climbing. Higher setting make EGTs hotter.
Weight; varies from GVWR to GCWR occasionally. Typical is 5 to 7k trailer and maybe 1000 in cabin. Low profile mostly or towing a pickup or Jeep.

Sous:
Thank you for attaching that matrix link. It should be very useful I’m going to study it.
Elevation: I live in 2 places. Phoenix 1200 and my ranch 6500. It’s worse driving around at higher elevation.
EGT rise scene: when I roll into a grade at 65mph, 4th gear-lock, temps climb super fast. I usually downshift at 1200 degrees so I’ve never seen how high they would actually go.
Leak down; I used a gauge at 25psi if I remember right. Held pressure for at least 15 min. This was 3 years ago so I hope I’m correct. It seems like a good outcome to me.

BWST:
Installed MBRP T-409 4” turbo back system. Pretty much a straight pipe. I forgot to mention it.

BradyT88:
No soot around EXH MANs.
RPM range is 2 - 2.4k at 65mph when starting up a grade. Also can occur at lower speeds depending on incline and load.

As as far as hitting 1600 I would have a litter of kittens if I saw that. I use the heck out of this Excursion but I also try to keep things as nominal as possible for extreme longevity. I even went so far as adding a bypass oil filter. I’m a bit mental about it I suppose.

 

I pulled my gopro footage from a run at 25,000 gcvw up a 12% grade today with 180/30 in a race tune, EGT hit 1702

 

I get what you mean about the 4R100 4-3 shift, but the second quote is also a huge part of the problem.

The trans is electronically controlled, and impacted drastically by the tuning. The standard TS tuning is known for harsh, unrefined, transmission killing shifts.

With that said, do you have the standard tunes or some custom tuning on the TS? Might be a good time to invest in a Hydra or ship the chip off for a reburn.

The guys have mentioned boost leak testing. If it’s been 3 years then I think it’s time to check again. I had quick boost to a max of 34psi but still found a plenum leak. It was “small” but I believe substantial. Here’s a video of my good test after fixing the plenum leak. Wish I’d have though to take one of the bad condition.
The EGT, where are you reading it? Manifold can run 1250° continuous but downpipe requires lower value. I’ve heard 1000° for a downpipe sensor or so over the years.

I also found hiding manifold leaks which needed corrected. Doing a feel check on a cold startup is helpful. I also checked with a borescope which is how I found secret soot behind the manifold.

It sounds like you prefer to run in a higher gear with lower rpm. Do not install a “big” turbo and expect to be happy in this regard. A larger turbo will require more rpm and you’ll end up needing to run 3rd gear and downshift more often.

As the guys have stated, you sound like a prime candidate for the KC balanced assembly. Possibly the KC stage1 63/68/.84, which is a bit “larger” but redesigned similar to the SXE family in Sous’s thread.

And lastly, don’t be like nutty Eswift. That poor truck. He’ll tell you it’s all for science though

 

Looks like these guys have you pointed in the right direction. I will mention a few things tho. Turn the chip to stock on the hill climbs. I know, it's so addictive to have that little extra above stock, but your temps will drop around 150-200⁰F. That's the "free" fix. You aren't really towing that heavy that you need the extra 50hp on the climb. I've towed much heavier over the Eisenhower pass in stock tune and still passed many Dodges and Chevys with smaller travel trailers than our 5th wheel

The other thing I'll mention that they haven't covered yet is something easily overlooked. Make sure your AC system is operating at 100%

Not just correctly charged, but take a fin comb to your condenser. Or your transmission cooler since you have have an auto. Whichever is in front. Make sure all the fins are straight, and the correctly sized comb will pull out a plenthora of sand pebbles you didn't even know were there. Any big bugs or bird strikes will bend the fins over blocking air flow to the intercooler and radiator behind it as well. Cooler and more airflow thru all the cooling systems layered setup will help a lot more than you'd expect with EGTs. Underhood temps will drop, intake temperatures from the filter will follow suit, which helps give you denser air going into the turbo which helps with Egts as well.

Plus the less that cooling fan is engaged from being heat soaked under the hood the more power you'll be applying to the wheels instead of the fan (approximately 30-35hp), requiring less fuel, and lower Egts. I even picked up a full 1-1.5 MPG when the fan ran significantly less after running a comb over mine for 2 hours

 

I have to say that i had not considered to comb even though everything looks good!

 

Wes444 brings up a good point!

I followed his lead a couple of years ago and bought a set of combs that look like the image below. I spent a good deal of time cleaning the radiator many times before using the comb, and the debris that came out with the comb was quite a bit. I used foaming coil cleaner, degreasers, high pressure sprayer and low pressure hose and the comb was a great idea.

As he said, rocks, bugs, debris and straightening the fins of the A/C condenser was a good idea.

 

RacinJason:
It shifts really good right now even with the TS6. I think it’s because I installed a dieselsite valve body. No more mushy unrefined shifts. That really worked. However I think I do need to upgrade the chip or get the Hydra. They push the Hydra over at the KC site when you spec the turbo.
The EGT probe is installed at the rear of the driver side manifold on the bottom. Not on the up-pipe.
And yes, I do like to run lower RPMs and higher gears. My wife is a bit sensitive to noise and these aren’t the quietest engines on earth. When she first started riding in it she would ask me if there was something wrong with the engine when I shifted down. Cold starts were another one.

Wes444:
I will try the stock tune next time. Can’t believe I never thought of that. It will be interesting to see what happens.
Regarding the AC system. I know it’s charged correctly. And I just replaced the transmission cooler and radiator about eight months ago. So I should be good to go. I cleaned the AC condenser while I had it apart but I didn’t comb it. It blows at 38° from the center vent. Plus I don’t hear the engine fan roaring very often. However that is a great idea about the combs. I’m going to get a set for ongoing maintenance, thanks for that. I’m going to take it apart again and comb the condenser.