Engine/Transmission (1998.5 - 2002) Which Turbo would be Best Value for me?

[PC12Driver]

With a properly sized turbo and fueling tuned to match, my truck with 3. 54s and 31. 5" tires was a towing monster. Sustained 5% grades in 6th with egts below 1200* were the norm with the trailer in tow. The gearing/tire size put me right in the sweet spot of the turbo at highway speeds. When I put a mis-sized turbo on the truck, that's when the egt problems started.



It's not the gears, it's the mis-matched turbo for the application.



In fact, at my normal highway speeds, 4. 10s would put me right in the RPM band that my exhaust drone is most pronounced. Not good at all.



Now, what was this thread about again... ?

 

[Gary - K7GLD]

With a properly sized turbo and fueling tuned to match, my truck with 3. 54s and 31. 5" tires was a towing monster. Sustained 5% grades in 6th with egts below 1200* were the norm with the trailer in tow. The gearing/tire size put me right in the sweet spot of the turbo at highway speeds. When I put a mis-sized turbo on the truck, that's when the egt problems started.



It's not the gears, it's the mis-matched turbo for the application.



In fact, at my normal highway speeds, 4. 10s would put me right in the RPM band that my exhaust drone is most pronounced. Not good at all.



Now, what was this thread about again... ?

Sorry if some of the side issue comments distress you...



This thread is about potential turbos to correct a combination of conditions creating excessive EGT's - and it seems reasonable to consider the WHOLE problem as a total package, rather than try to devise a bandaid large enough to cover a gaping wound...



Not to mention that often these threads are being read by others with similar problems, or well on their way to similar ones - so should contributors totally avoid touching on potentially contributing issues in order to stay on some arbitrary straight line of logic because it might offend someones personal sense of "hijacking"?



IF so, we can instantly shut down about 80% of threads now running on this board...



In this particular case/thread, I don't see any mention of effort or device to increase turbo boost above stock, and with the 1. 6 injectors supplying more fuel, wonder if increasing boost with some sort of boost fooler wouldn't help considerably to reduce EGT's when towing - possibly to the point where there isn't even need of a replacement turbo?



AH, but while my above suggestion MIGHT help the basic EGT condition this replacement turbo thread is about, it is NOT strictly "on topic" - so should I avoid mentioning it lest one of the board's "Hijack police" take issue and haul me off to the Internet pokey?



A little lattitude and common sense can go a long way on relatively informal boards such as this one, nor is it uncommon that some of the peripheral comments offered provide the actual "fix" for the problem under discussion...

 

[GCULP]

I just can not understand why someone would buy a truck with 3. 55 gears when they know they will be towing with it?? It just makes no sense.

the 3:55's were the choice because of 98% of the time the truck is empty, and all of the Cummins Gods, (insert your name here) said these trucks had all the power I would ever need with 3:55's, which 98% of the time it does. If I was retired and was pulling a 5'er all over the country I would have purchased a 1-ton dually with 4:10's, I'm not a complete idiot. So please be careful making comments about someone's senses when I purchased the best truck, engine, gear combination for my use.



Now back on the subject and to re-clarify, I'm not complaining about the temps and power, I'm just looking for the best next step that will be beneficial now and can contiue to be built upon. The ultimate goal is to have a very efficient, reliable daily driver that when I tag on 5000 to 10000 lbs behind it, will perform just as reliable without too much concern.



Another idea I was pondering is, what about switching out the 3:55's for 3:73's, seems to me this would also provide a better mix of gearing. I could pull more hills in 5th gear, and maintain freeway speeds easier in 6th gear. I realize that empy and 70 mph would be around 2100 rpm, but it would be better that winding it up tighter that a $2 watch with 4:10's, anyone done this?

 

[Gary - K7GLD]

the 3:55's were the choice because of 98% of the time the truck is empty, and all of the Cummins Gods, (insert your name here) said these trucks had all the power I would ever need with 3:55's, which 98% of the time it does. ... .



Now back on the subject and to re-clarify, I'm not complaining about the temps and power, I'm just looking for the best next step that will be beneficial now and can continue to be built upon. The ultimate goal is to have a very efficient, reliable daily driver that when I tag on 5000 to 10000 lbs behind it, will perform just as reliable without too much concern.

HMMmm after reading your first post, I had thought your primary concern was the high EGT's when towing:

I'm looking for good dependable Turbo that will help control EGT's while towing our 30' travel trailer, and provide some fun factor for everyday driving.

And again, unless you are using some form of boost fooling and turbo attachment that allows it to spool up more like 32 PSI rather than the OEM 22 PSI or so it came from the factory with, you have lots more power available that will burn the increased fuel your 1. 6 injectors provide, and still keep EGT below the danger point.



I too am running 1. 6's, a 4 inch exhaust and intake mods - I run an Edge comp with the turbo enhancements that put my boost at 32 PSI or so under load, and EGT is below 1200 degrees under those conditions - my turbo is still the OEM HX-35, and we regularly tow a 24 foot 5th wheel for a GCW of nearly 15,000 lbs.



As long as you keep boost in the 32-35 PSI range, your turbo is within it's design range - mine has been in use for RV towing in Sierra grades for over 50K miles with no problems - you might consider that as an alternative to a new and expensive hybrid turbo.



But if you are looking for even higher boost than the OEM is capable of - perhaps above 40 PSI, then you should also plan on the likelihood of needing eventual head/gasket upgrades to properly handle that higher boost level.



It's pretty accurate to say that anything you do to provide better than stock power and reliability for towing situations will undoubtedly also deliver grins empty out on the boulevards - BUT, things that deliver drag racing performance on those streets won't always be what will work best for towing in the hills...



Good luck.

 

[GCULP]

Gary - K7GLD, thanks for the info, you are right on track to what I'm looking for, sorry I get a little defensive when someone questions why a decision was made without all the information, and I then mentioned I would consider changing the gears as well. Also, you nailed it sort of, yes the concerns are EGT's while towing, but the second quote also nails it, I want to control them better, which means I don't expect miracles, but I don't want to have to stare at the guage all the time.



As for the boost elbow, I have been considering it but without some kind of boost fooling device, smarty or edge, I would be setting overboost codes all the time. I was hopeing that a turbo may provide more volume of air without increased pressure, does that make sense. Any way, I think I am leaning toward a Smarty and boost elbow, now knowing what the majority of the responses lean toward more boost pressure without going out of the optimum performance of the turbo.

 

[NoSeeUm]

How did things change for you after you hung the S400 off the bottom? (I'm assuming the new rpm cutoff is less than 2000, but how much?)

Hard to say, I have not hauled my camper and towed my boat yet. I'll let you know how it works.



I had some growing pains tuning my twins, but now I can pull just my boat (2500 lbms) up any about grade starting from about any speed to about any speed in any gear, and my EGT's will stay mostly under 1200F. That is pushing about 40-45 psi of boost. Generally, I set my rate of acceleration with boost, vice EGT. I go over a 1:1 drive pressure ratio around 40 psi. I can make 30 psi of boost easily running empty up a medium grade and EGT's will be 900F - 1000F or so. I hardly ever watch the EGT Stare -o- Meter much anymore. This is with M4's, which really woke up the twins.



Most often, with my camper, I travel 60 mph up hill and down hill mostly just on cruise control and / or using the exhaust brake. That is about 1600 rpm for me these days. I am optimistic, but I have no idea at this point. I am thinking the 285's in 4th at 2100 rpm is going to be the "schpickity ding ding".



The nicest thing about the twins is that they can actually push the EGT's down under low to moderate throttle, where before it was almost always a slow climb with EGT's after the initial fuel surge.



I often think a HX35/S400 might be a more ideal towing set, but I also think the DZ gives me a bit more top end. Which I seem to crave for some dumb reason. :-laf



Jim

 

[Gary - K7GLD]

Gary - K7GLD, thanks for the info, you are right on track to what I'm looking for, sorry I get a little defensive when someone questions why a decision was made without all the information, and I then mentioned I would consider changing the gears as well. Also, you nailed it sort of, yes the concerns are EGT's while towing, but the second quote also nails it, I want to control them better, which means I don't expect miracles, but I don't want to have to stare at the guage all the time.



As for the boost elbow, I have been considering it but without some kind of boost fooling device, smarty or edge, I would be setting overboost codes all the time. I was hopeing that a turbo may provide more volume of air without increased pressure, does that make sense. Any way, I think I am leaning toward a Smarty and boost elbow, now knowing what the majority of the responses lean toward more boost pressure without going out of the optimum performance of the turbo.

No, the effectiveness of the turbo revolves around PRESSURE - the ability to force added air into the combustion chamber - obviously volume is also involved, but without PSI to push it, the volume won't happen!



Central issue in your case to be aware of is that your OEM turbo is fully capable of boost up to the 35 PSI or so level with the help of a add-on power box with boost fooling and if you choose to go higher with an aftermarket turbo, be sure to factor in the added cost of eventual head/gasket work as part of the expense.



It's quite likely the mere addition of the Smarty or Comp type box, with their added power AND increased available boost with your OEM turbo will be enough - it certainly was for me, though my RV is slightly lighter than yours - my boost and EGT has NEVER been a problem for me, and I have power to spare!



As far as "side issues" are concerned, often what appears to be a simple single-point issue automatically brings with it related points that revolve around it - and to focus purely upon the seemingly SINGLE issue, while ignoring the others as some misguided attempt to maintain "thread purity" might seem proper in regards to board rules regarding "thread hijacking" as complained about earlier - the EXCLUSION of related points can easily rob the central subject of the very information most critical to a final, total solution - I'd FAR rather be supplied with too MUCH info, rather than get too LITTLE in the name of "thread purity"!



This thread is an excellent example - sure, contributors could easily restrain their responses to simply suggesting aftermarket turbos, as you had asked - but fact is, your problem, based upon inspecting your truck setup in closer detail, might easily be cured my reasonable means OTHER THAN the aftermarket turbo you thought was the answer - and without inclusion of those side issue comments you might have spent more money than necessary on hardware that would NOT be as effective as the alternate suggestions provided.



I'm not especially pointing this out for your benefit - but rather for some here who (based more upon ego and personality conflicts than where board operation is concerned!) are far too quick and eager to criticise others for posting material THEY have deemed improper and off-topic to the thread title - when in fact, it may well not be!

 

[NoSeeUm]

I just can not understand why someone would buy a truck with 3. 55 gears when they know they will be towing with it?? It just makes no sense.



The water/ meth might be a solution, but mounting the pump and getting enough water are concerns. I like the Hy breed HX35 option.

I had a feeling where this comment would go.....



I am thinking 285's and 3. 55's in a 6th speed would be a very nice towing / grocery getting rig under the biggest span of truck use. For a strictly work truck, the lower gears would be better.



Jim

 

[NoSeeUm]

With a properly sized turbo and fueling tuned to match, my truck with 3. 54s and 31. 5" tires was a towing monster. Sustained 5% grades in 6th with egts below 1200* were the norm with the trailer in tow. The gearing/tire size put me right in the sweet spot of the turbo at highway speeds. When I put a mis-sized turbo on the truck, that's when the egt problems started.



It's not the gears, it's the mis-matched turbo for the application.



In fact, at my normal highway speeds, 4. 10s would put me right in the RPM band that my exhaust drone is most pronounced. Not good at all.



... .

Harder to do that at 4000 - 5000 feet from my experience.



Jim

 

[Gary - K7GLD]

Harder to do that at 4000 - 5000 feet from my experience.



Jim

Being a natural born skeptic, and an RV tower myself, I find it difficult to accept that 31. 5 tires and 3. 54 gears in 6th gear will satisfactorily tow significant weight over substantial distance up a 5% grade - especially where significant elevation is involved. That would place engine RPM in the 1500-1600 range at legal speeds, which REALLY loads the engine and drivetrain - as well as pushing EGT's to the max.



Not saying it can't be done, just that I'd sure like to see it!



In my case, I went another direction - I went from 265 tires to 285's - our roads here are steep, but lots of 45 MPH curves, so towing in 6th is pretty much out of the question. But dropping to 5th placed the engine RPM too close to the upper edge of the power band at 55 MPH or so to suit me. The move to 285's allowed me to use 5th gear comfortably up steep grades, and I can easily cruise at 55 MPH with adequate useful RPM to spare - plus, the reduced engine RPM out on the flats either towing or empty is a nice plus!



But to use 31. 5's, AND 6th gear up any significant grade is NOT something I would want or work towards as "normal" operation - especially with a NV-5600 that has known weaknesses in 6th gear...

 

[PC12Driver]

Harder to do that at 4000 - 5000 feet from my experience.



Jim

How's 160 from Walsenburg to Durango? Does that count? I finally started seeing 1200* on some of the sustained grades above 8,000', at which point I had to turn off the cruise and downshift. Other than that it was speed limit +5/-0. The stock HX35/12 doesn't get enough credit. I certainly couldn't pull that off with my DZ/14, and I'm not sure about my current HTB2/12. But you're right; towing at altitude will really highlight any shortcomings in your airflow mods!



Of course, I'm only at about 18k GCVW. I know that's not much compared to some of the other rigs out there.

 

[GCULP]

Gary - K7GLD, thanks again, you're right, the thread started with the search for a turbo, but it has definately provided the information I am needing. I am now leaning toward a Smarty and boost elbow knowing that the stock turbo "should" be able to handle the 30 to 35 p. s. i. I was also concerned about jumping to a bigger turbo or increased pressure and the head gaskets, not sure I want to make that kind of investment yet. I also have 285 tires and would have to say that while towing I have not been overly satisfied, it feels as though they took some of the edge off the performance, at a minimum I will be going back to 265's next round. What do you think about the 3:73 gearing option.

 

[Gary - K7GLD]

Gary - K7GLD, thanks again, you're right, the thread started with the search for a turbo, but it has definately provided the information I am needing. I am now leaning toward a Smarty and boost elbow knowing that the stock turbo "should" be able to handle the 30 to 35 p. s. i. I was also concerned about jumping to a bigger turbo or increased pressure and the head gaskets, not sure I want to make that kind of investment yet. I also have 285 tires and would have to say that while towing I have not been overly satisfied, it feels as though they took some of the edge off the performance, at a minimum I will be going back to 265's next round. What do you think about the 3:73 gearing option.

I think you will be VERY surprised at the performance improvement the Smarty will provide along with the modding of your OEM turbo for increased boost and controlling towing EGT - I am running the 285 tires and 3. 54 differential, and am very satisfied with mine - if yours leaves you wanting still more, there are still other mods on the horizon you may be interested in as well.



Good luck - and get back to us with what you do decide on, as well as how it works for you!

 

[Boondocker]

Are 3. 73 gears an option on your truck? The factory offerings are 3. 55 and 4. 10. I don't think it would be worth the effort and expense to go from 3. 55 to 3. 73. You might want to do some math (you can find gear ratio calculators on the internet). Start with figuring the change in final drive between tire diameters, like 265 to 285. Then fix the tire diameter and change the gear. Without having done the math, what I think you'll find is something like 265 tires and 3. 55 gears are about the same (final drive) as 285 tires and 3. 73 gears. I don't recall ever hearing anybody say they wanted higher gearing. When you add weight or bigger tires, you need lower gearing to compensate. That's one reason that 1-ton duallies come standard with such small tires

 

[GCULP]

Boondocker, you're right, they're pretty close, but they might just put that extra 150 to 200 rpm back in the power band that I'm looking for. before I go to the expense of gears I will definately look at going to 265's maybe even 245's like the truck had on it from the factory, I'm pretty sure that would make a difference.



To all that have replied and all that have been following this thread, even though it got a little heated and a little off target, it has definately yielded some great information and that's really what it's all about.

 

[NoSeeUm]

How's 160 from Walsenburg to Durango? Does that count? I finally started seeing 1200* on some of the sustained grades above 8,000', at which point I had to turn off the cruise and downshift. Other than that it was speed limit +5/-0. The stock HX35/12 doesn't get enough credit. I certainly couldn't pull that off with my DZ/14, and I'm not sure about my current HTB2/12. But you're right; towing at altitude will really highlight any shortcomings in your airflow mods!



Of course, I'm only at about 18k GCVW. I know that's not much compared to some of the other rigs out there.

You are lucky, I'm jealous... .



My truck almost always would creap over 1250F at 60 mph @ 1800 rpm ( with the 265's) at around 15 - 16k with a 5 - 7 percent grade / SW7. I never felt comfortable running that hot that long. A down shift and running at 2200 rpm @ 55 mph was better and not a whole lot slower. Many times a corner will force me to slow down anyways (slide in camper). I believe my 285's are 32. 5 or so, but they also give me 2100 rpm @ 60 mph (1600 rpm @ 60 mph). I never measured the OEM 265's for size.



Running the stock HX35 I made about 26 psi of boost during those times. The cam lowers boost quite a bit on the upper end. I agree with you the HX35 tows pretty well.



What type of air intake / filter do you use?



Jim

 

[NoSeeUm]

Boondocker, you're right, they're pretty close, but they might just put that extra 150 to 200 rpm back in the power band that I'm looking for. before I go to the expense of gears I will definately look at going to 265's maybe even 245's like the truck had on it from the factory, I'm pretty sure that would make a difference.



To all that have replied and all that have been following this thread, even though it got a little heated and a little off target, it has definately yielded some great information and that's really what it's all about.

A friend of mine runs 245's, man they look small. They look really small in those big fender wells, like golf cart tires. That alone would stop me. However, he also has a 6 speed and tows some pretty darn heavy stuff for his moonlighting jobs. He does so in some really rugged country mostly below 2500 feet. Narrow, very steep, windy roads (some gravel) are normal around there. The 245's work really well for him.



But... .



I would take a look at following Gary's advice about tire size depending on where you generally tow at. Consider running 285's and pulling grades in 5th gear for freeways and most highways. Plus, 285 E's will haul a whole bunch more weight unless you go to an F series tire (hard to get?). I think your rpm's with the 285's in 5th will be pretty close to 245's in 6th. That way you can still utilize 6th for some flat land towing and when running empty for fuel economy using your 3. 55 gears to an advantage.



PC12's advice is also good, you can mess around with different turbo's at quite a bit of expense and really not be that much better off. Quite a bit of the turbo advice given out around here is for top end Hp, towing is a different animal.



From my own experience, it is the towing rpm compared to the amount of weight / speed that matters the greatest for controlling EGT. From some dumb reason I can't quite understand, I seem to want to go the fastest that I can go and still run the most efficiently.



It is a hobby, nothing more.....



Jim

 

[SnoKing]

Here is the link to Klenger's gear caliculator.

http://www.klenger.net/dodge/general-reference/gear-speed-calculator.xls



285/70-16 tires.

2000 RPMs

3. 55 73 MPH

3. 73 69 MPH

4. 10 63 MPH



To look at it another way.



62 MPH with 3. 55 is 1700 RPM, with 3. 73 is 1800 RPM and with 4. 10 is around 1960 RPM.



I running the auto with 4. 10's and 265 tires. At 2000 RPM I am towing combine 19K and run up and down normal freeway hills in OD at around 62-63 MPH. In third gear I can climb at step hill at 55 MPH at 2500 RPM. It works really good for me.



I will stick with the 265 tires next time also.



If I was going to charge your gears, I would go to 4. 10 and 295 or 305 tires next time. The down side of low gears is bobtailing on the freeway gets busy at 70MPH.



Not sure on the HO, but on the SO the sweet spot for towing is 2000 RPM's, it will hold that RPM on hills for a long way. I am getting 11. 5 to 12. 5 towing a high profile 5th wheel.



SNOKING

 

[PC12Driver]

What type of air intake / filter do you use?

Jim

That was back in my "Less is more" days. I was using the same filter I have now, the AFE Pro Guard 7 Stage 1 kit. That, a 4" exhaust, an EZ, and the elbow. On the big hills, it would just settle in at about 32-34 psi of boost, egt would hit about 1050-1100, and it would just keep pulling. Probably right at about 2k rpm. It was noticibly warmer about the 5000' elevation level, and then over 8000' I had to drive by the pyro on the long pulls. I sure do miss that setup...

 

[DPrew]

I have the Smarty stacked with a Edge Comp and it works great. I use just the Smarty for towing. I have a Borg Warner S300 turbo and usually stay under 1000 F even with out my water injection turned off. I'll be selling my current turbo in a week after I get my new PowerMax stage 3 turbo installed.



Your missing the boat if you don't get some electronic power help. A few times I've had to run my truck with out electronic power assistance and it drives me insane. None of my other power adders work well with the constrictive factory engine management software working. Performance Turbo Motorsports has the best price on the Smarty.