Engine/Transmission (1998.5 - 2002) Not Happy With Towing EGT's

[Cummins724]

Some folks typically confuse operating conditions when empty on the street vs loaded in the hills - yeah, rapid low RPM in fast acceleration from a stoplite is a plus for drag racers - but not really an issue for those towing up grades, where acceleration is slower and smoother, and usually from a much higher beginning RPM - few of us are starting up steep grades from a dead stop with our RV's! :-laf:-laf



In my case, the Smarty combined with my upgraded injectors provides added fueling that makes it pretty much useless in the hills, plus lacks the on-the-fly adjustability of the Comp - which leaves me choosing the Comp hands down over the Smarty for heavier loads in the hills.



Besides, contrary to popular opinion, the Comp DOES fuel substantially lower in the RPM range than a stock truck, especially as you get into the higher available settings!



Sure, more boost than my stock HX-35 provides would likely overcome the over fueling with the Smarty - but would also require more expense in head work, studs and O-rings than I feel necessary for my particular towing expectations.



As I've been saying - what is needed and works best empty out in the drag races in short bursts is NOT always what works best when towing longer distances in the hills!

I understand your opinion, but believe me the larger turbos like a SPS62 or SS62 need to come in faster to beat the heat. Tuners like Smarty make it possible because they get the turbo spinning sooner & moving the hot gases out of the engine before they become hotter gases. It is like holding a torch on metal heats up faster than if you apply heat on/off to the metal. The housings hold this heat unless you are cooling it... which doesn't happen without the turbo spooling. I am just saying that you must beat the heat.

 

[PC12Driver]

The trick to towing with a large turbo is to beat the heat by getting the turbo to spool before the heat takes over. Smarty fuels hard right off idle which spools the turbo faster. The Edge fuels harder after 1800rpm... . too late!

Sure, you could stab the throttle and get the wheel turning and get your boost up and egts down, but that means you also have to accelerate. If you just want to maintain speed with the cruise on and you encounter a slight or gradually increasing grade, then the extra fueling isn't gonna do much for you.



As far as the Comp coming in at 1,800 rpm, that's not quite the case. The Comp adds fueling based on boost pressure. It just so happens that most mid-sized aftermarket turbos don't wake up until 1,800-2,000 rpm. Run a high sub-level and get max fueling as low as 3psi. That's plenty of fuel to get a turbo lit down low. Run a low number and the Comp will de-fuel below as much as 20 psi. So there's the irony: if you step on the pedal to build boost with a low sub-level set, the Comp won't add fuel until there's enough boost. Kind of a catch-22. So if you're running a low S. L. to keep smoke down, you may not have enough juice to get "on top" of the charger.



On the other hand, the Smarty program doesn't care how much boost you're making before it adds fuel, so you can stab the pedal at any time for instant gratification. But, just like the Comp on high S. L. s, you'll make smoke. And with either one, you still have to accelerate to get the extra fueling to get enough exhaust volume to light off the turbo. That's fine if you don't mind working a bit, but some of us still like the idea of set-it-and-forget-it cruise. And that's done by keeping the size of the charger and housing close to stock.

 

[SMoules]

so back to my question, would stepping down to a phat shaft 62/12 help my egts towing with the set up i have?

 

[SnoKing]

Sure, you could stab the throttle and get the wheel turning and get your boost up and egts down, but that means you also have to accelerate. If you just want to maintain speed with the cruise on and you encounter a slight or gradually increasing grade, then the extra fueling isn't gonna do much for you.



As far as the Comp coming in at 1,800 rpm, that's not quite the case. The Comp adds fueling based on boost pressure. It just so happens that most mid-sized aftermarket turbos don't wake up until 1,800-2,000 rpm. Run a high sub-level and get max fueling as low as 3psi. That's plenty of fuel to get a turbo lit down low. Run a low number and the Comp will de-fuel below as much as 20 psi. So there's the irony: if you step on the pedal to build boost with a low sub-level set, the Comp won't add fuel until there's enough boost. Kind of a catch-22. So if you're running a low S. L. to keep smoke down, you may not have enough juice to get "on top" of the charger.



On the other hand, the Smarty program doesn't care how much boost you're making before it adds fuel, so you can stab the pedal at any time for instant gratification. But, just like the Comp on high S. L. s, you'll make smoke. And with either one, you still have to accelerate to get the extra fueling to get enough exhaust volume to light off the turbo. That's fine if you don't mind working a bit, but some of us still like the idea of set-it-and-forget-it cruise. And that's done by keeping the size of the charger and housing close to stock.

Regarding the Comp, that is why I do not understand why people set them to 1x1 for towing. I leave mine on 1x3 all the time. SL 3 is close to stock fueling regarding boost level. SNOKING

 

[Cummins724]

so back to my question, would stepping down to a phat shaft 62/12 help my egts towing with the set up i have?

Call Industrial Injection & ask Brady what he thinks. I'll bet that he agrees with me.

 

[Gary - K7GLD]

Regarding the Comp, that is why I do not understand why people set them to 1x1 for towing. I leave mine on 1x3 all the time. SL 3 is close to stock fueling regarding boost level. SNOKING

With larger injectors, even stock fueling results in excess fuel for some driving situations, such as around town empty - sure, when towing the higher settings are used - and that's that nice thing with the Comp - you CAN change settings on the fly...

 

[DerekW]

you could run a lock-out switch for the converter..... un lock it when you hit the hills and get a little more RPM's and cooler EGT's



you will need to keep an eye on the trans temp gage

having been around transbuilders so many years i personally like the idea of unlocking converter when you hit the long grades to run more rpms to cool egts and a few rpms would be easy pulling heavy is easy than changing gears. just run a good trans cooler post the factory cooler (depending on year some years might get ride of factory cooler altogether cuz lines have a fiititng with OEM restriction so i been told by mike in salisbury, NC whos a builder). just try not to lock and unlock the converter all the time.



You might try a SP stage 3 water injection kit with 8 gallon reservoir so you can drill, tap, route lines, plug in, fill up and not worry so much unless temp rise again.

 

[AMink]

Just a thought, are you sure your intercooler fins are as clean as possible? I went from a 12v to a HPCR, but remember reading that on some years of the 24v models there is a hose or something that provides lots of goo making oil into your fins. Guys got great heat relief by cleaning them thoroughly. Again, just a thought from someone who never owned a 24v. :-laf

 

[rweis]

Why unlock the transmission converter, just run 2nd gear locked (DTT with Smart Controller).



There is a drain back valve in the line going to the transmission water heat exchanger. If you take it out you have to wait 20 seconds after engine start before engaging the transmission to be sure the converter is full of fluid. As I understand the drain back valve it limits 50% of transmission fluid flow.



I took mine out years ago, and I crank 'er up, then put on my seatbealt, then check the mirrors and 20 seconds have elapsed and the converter is ready to go.