Engine/Transmission (1998.5 - 2002) High EGT Black Smoke and Running Warmer than Normal

[cerberusiam]

A larger compressor is not the answer in this case. It'll only help egts at high RPMs, and hurt anything else below

Large compressor equal more air across the board and better air at lower boost. More air equals lower EGT's, simple formula.



The stock compressor is not up to the task of added fuel under heavier loads, better compressors with newer technolgy exist that are. Probably will have to swap the complete turbo out to get a chasis that will work correctly but its entirely doable with excellent results.

 

[KBrennan]

Don't sweat those numbers. You're pretty close to where my stock HO was. And if the factory is okay with those level of temps, then you're doing just fine. You're gonna run hot when you're pushing that much air with the 5ver. Remember, you can hold 1250 all day long (assuming your injectors are nice and balanced, and your pyro is accurate).



A larger compressor is not the answer in this case. It'll only help egts at high RPMs, and hurt anything else below. You'll find yourself downshifting earlier and more frequently in the hills. When towing, your "level ground" boost will be lower, and the egts will be higher. In the hills, you might see lower temps after the downshift. I've currently returned to the stock turbo after trying several combinations for this very reason. Towing performance and egt control is much improved. I'll see around 950* on flat ground with the 11k 5ver in tow (stock turbo, 275s, untapped Comp), so you're right in line with my temps.



What are you using for boost fooling?

I see you have a leveling kit. What size tires are you running?

What gear ratio do you have?

I do not have a boost fooler and the rearend is 3. 54 and I run LT265 tires

 

[Beast2B]

The rushing sound you hear sounds a lot like mine under load. Sort of sounds like a huffing sound. A restrictive air filter being sucked inside out (better filtering over better flow for me). Turbo surge?

My head hurts reading all this physics, and I like physics! Hopefully someone can explain the surge better than me.

 

[PC12Driver]

I do not have a boost fooler and the rearend is 3. 54 and I run LT265 tires

It's odd that you can pull 28 psi then. The ECM should be setting a code and rolling back the fueling once you're above the low 20s. Have you thought about a boost fooler, or maybe something like an Edge EZ? The EZ would also reshape your fueling curve a bit and add some timing. The timing would give you a touch better milage and drop EGTs 50-100*. Lotsa good, safe towing power with a stock turbo with that combo.



The reason I was asking about the gears and tires was that big tires and tall gears can cause higher egts, since the engine rpm is running on the bottom side of the turbo's efficiency. Much less than 1500-1600 rpm and the stock turbo isn't getting enough energy in cruise to keep the compressor working hard. Your overall gearing combo is pretty tall and could be why your egts are on the high (but still safe) side of things.

 

[KBrennan]

It's odd that you can pull 28 psi then. The ECM should be setting a code and rolling back the fueling once you're above the low 20s. Have you thought about a boost fooler, or maybe something like an Edge EZ? The EZ would also reshape your fueling curve a bit and add some timing. The timing would give you a touch better milage and drop EGTs 50-100*. Lotsa good, safe towing power with a stock turbo with that combo.



The reason I was asking about the gears and tires was that big tires and tall gears can cause higher egts, since the engine rpm is running on the bottom side of the turbo's efficiency. Much less than 1500-1600 rpm and the stock turbo isn't getting enough energy in cruise to keep the compressor working hard. Your overall gearing combo is pretty tall and could be why your egts are on the high (but still safe) side of things.

How well will the Edge work with my Banks Stinger kit.

 

[PC12Driver]

Large compressor equal more air across the board and better air at lower boost. More air equals lower EGT's, simple formula.



The stock compressor is not up to the task of added fuel under heavier loads, better compressors with newer technolgy exist that are. Probably will have to swap the complete turbo out to get a chasis that will work correctly but its entirely doable with excellent results.

Once again, only part of the equation.



A turbocharger balances energy between the intake and the exhaust. It does not create energy.



To move more air on the compressor side, more energy is required from the exhaust side. Just sticking a bigger fan on one side doesn't create more energy. Like an airplane, just sticking a bigger prop on the front doesn't make it any faster (typically slower, in fact). Basic physics: you cannot do more work and not require more energy.



A larger compressor wheel can potentially move more air. But because of its increased diameter and bite, it requires more energy just to turn because of aerodynamic drag. So you'll end up throwing away some drive energy just to turn the bigger wheel and net less energy being passed into the intake. At big horsepower numbers with lots of fueling, this loss is minimalized because of the surplus energy available in the exhaust, and the benefits of the larger compressor are realized. But that's not the case here. Cruising along at 55 mph with the 5ver in tow using around 120hp on flat ground, there is no surplus, so you're netting less air into the engine due to the increased drag from the larger compressor wheel. Simple formula.



Larger diameter compressor = More aerodynamic drag

Same energy (exhaust) available - increased aerodynamic drag = less energy (air) available to the engine



Again, search around the boards. There are lots of folks that put bigger turbos on their trucks and wonder what happened to their towing performance, and now you're suggesting the exact thing to KBrennan. They believed, as I had at one point, and as you apparently do, that "large compressors equal more air across the board. " That statement is completely incorrect. I myself have wasted a bunch of money on turbos blindly following advice such as yours. Several turbo combinations later, I'm back to the stock HX35/12 and the truck hasn't pulled better, with cooler egts under most driving conditions.



This very thing has been covered over and over on here and other diesel truck boards. Do you want to go down this path again?

 

[PC12Driver]

How well will the Edge work with my Banks Stinger kit.

I'm not familiar with the Stinger kit. Is that the one with airflow enhancements only, or is there a fueling box involved?



If it's just the airflow kit (intake/exhaust), then it'll work great. But, you'll be needing a new clutch to hold it together. Something like a SBC Con-O would do just fine and still be totally smooth for pulling the RV.

 

[KBrennan]

Once again, only part of the equation.



A turbocharger balances energy between the intake and the exhaust. It does not create energy.



To move more air on the compressor side, more energy is required from the exhaust side. Just sticking a bigger fan on one side doesn't create more energy. Like an airplane, just sticking a bigger prop on the front doesn't make it any faster (typically slower, in fact). Basic physics: you cannot do more work and not require more energy.



A larger compressor wheel can potentially move more air. But because of its increased diameter and bite, it requires more energy just to turn because of aerodynamic drag. So you'll end up throwing away some drive energy just to turn the bigger wheel and net less energy being passed into the intake. At big horsepower numbers with lots of fueling, this loss is minimalized because of the surplus energy available in the exhaust, and the benefits of the larger compressor are realized. But that's not the case here. Cruising along at 55 mph with the 5ver in tow using around 120hp on flat ground, there is no surplus, so you're netting less air into the engine due to the increased drag from the larger compressor wheel. Simple formula.



Larger diameter compressor = More aerodynamic drag

Same energy (exhaust) available - increased aerodynamic drag = less energy (air) available to the engine



Again, search around the boards. There are lots of folks that put bigger turbos on their trucks and wonder what happened to their towing performance, and now you're suggesting the exact thing to KBrennan. They believed, as I had at one point, and as you apparently do, that "large compressors equal more air across the board. " That statement is completely incorrect. I myself have wasted a bunch of money on turbos blindly following advice such as yours. Several turbo combinations later, I'm back to the stock HX35/12 and the truck hasn't pulled better, with cooler egts under most driving conditions.



This very thing has been covered over and over on here and other diesel truck boards. Do you want to go down this path again?

I don't want to get a rucus going on but I have been told that there are some turbos on the market that are more efficient then the stck such as the ATS Aurora 3000. It is close to stock but has a beter energy transfer then the stock units so it moves a bit more air from the same exhaust flow rate. I have thought about this but I also have the Banks exhaust brake and not sure if the 3000 will mate up to it. Biger Turbos are for speed and off the line power but that is not what I want.

 

[KBrennan]

I'm not familiar with the Stinger kit. Is that the one with airflow enhancements only, or is there a fueling box involved?



If it's just the airflow kit (intake/exhaust), then it'll work great. But, you'll be needing a new clutch to hold it together. Something like a SBC Con-O would do just fine and still be totally smooth for pulling the RV.

The stinger has the tunner box. It is preset so can not change on the fly like the newer types. It does monitor boost and EGTs and will limit fule flow if EGTs get to high and makes fule rate adjustment as needed for max power. It is interfaced with the ECM.

 

[PC12Driver]

I don't want to get a rucus going on but I have been told that there are some turbos on the market that are more efficient then the stck such as the ATS Aurora 3000. It is close to stock but has a beter energy transfer then the stock units so it moves a bit more air from the same exhaust flow rate. I have thought about this but I also have the Banks exhaust brake and not sure if the 3000 will mate up to it. Biger Turbos are for speed and off the line power but that is not what I want.

That is probably true, to a point. It is probably more efficient than the stocker, but at what RPM range? From what I've found, turbos have an effective range of about 500 RPM, give or take. I had a 62mm Holset that had a very narrow range (400-500 rpm), and a 62mm S300 that was good for 100-200 rpm more than that. Obviously the S300 was more efficient. But neither of those would pull below 1900-2000 rpm. I can accellerate pretty well from 1400 rpm in sixth with the stocker and have minimal smoke. So between the 62mm S300 and the stocker, which one is more efficient? Depends on the RPM.



Don't get caught up with the "efficiency" buzzword. It may be more efficient than the stocker, but at what RPM? If it doesn't wake up until 1700-1800 rpm, how does that work for you? At 55 mph in 5th, you'll probably have to watch your egts on small rolling hills. Trust me, that gets old. The stocker will be wide awake and making good boost at that point, and egts will be under control.



Like I said in the above post, there is no "across the board" with turbos. If someone tries to sell you that, look elsewhere for info.

 

[PC12Driver]

The stinger has the tunner box. It is preset so can not change on the fly like the newer types. It does monitor boost and EGTs and will limit fule flow if EGTs get to high and makes fule rate adjustment as needed for max power. It is interfaced with the ECM.

Gotcha. That box is doing the boost fooling, and that's how you can get the higher boost.



Waitaminute, that kit has a Banks exhaust housing on the turbo as well, doesn't it? If it does, that would be a 14cm housing instead of the stock 12cm. It flows more, but it doesn't drive the compressor as hard as the 12 would, thus less boost for a given rpm. That would be where your higher cruising egts are coming from. High altitude and hot days would also be more affected (lower boost, higher egts). It's a good idea for high rpms, but not the best for towing. Not bad, but a 12cm would do better at lower/cruise rpms.

 

[cerberusiam]

I have been told that there are some turbos on the market that are more efficient then the stck such as the ATS Aurora 3000.

There are and they out perform the stockers of this type across ther board. A simple change to an HE351 proves that. A lot of the custom turbos will outspool and outperform the stocker in ANY range. Don't get caught up in the rhetoric that "I tried a larger compressor and it didn't work" therefore no larger compressor will work. Its a total fabrication to explain their bad choice.



Compressor design has a lot do with what is delivered for air and there are configurations that will deliver more air at lower pressure using the SAME exhaust flow as the stocker. Naturally when you change the turbo parameters there may be some needed tweaks to the fueling curves. What most people forget to do is tune the fueling to the turbo so it performs at the expected level.

 

[PC12Driver]

What most people forget to do is tune the fueling to the turbo so it performs at the expected level.

Ah yes, the old "add more fuel to help the turbo spool better" suggestion. I expected nothing less from you. For foot to the floor acceleration, this is true. For partial throttle cruising, this is a total miss.



So, you're cruising along with trailer in tow, using about 120hp. You hit a hill, maybe something needing 150hp or so. Just a slight roller. Still significantly less fuel than stock. How would adding increased fueling capability help "spool" the turbo when you are still using less fuel than you can deliver stock? It doesn't. The "more fuel" advice is useless. The larger-than-stock turbo will continue to sag, since it still gets the same energy as it did before the fueling mods.



Know why the larger compressor of the HE351 works so well? They shrunk the exhaust housing to 9cm. They run a teeny housing to extract as much energy as possible from the exhaust to drive the larger compressor wheel at lower engine rpms. Put a 12cm housing on that turbo and it'll result in a higher working rpm than a HX35/12, guaranteed. Once again, you're only looking at part of the equation.



My "bad choice" (assuming this comment was direct at me) came from blindly following advice such as yours on the interwebs. The requirements of a towing turbo lightbulb was turned on for me during a conversation with Van Haisley. He has his own shop out here by me and does a little tinkering with Cummins trucks. Heard of him? Who are you again?