best smjr tow setting

[S.Morris]

I am heading south in a few days for a little florida sunshine.
Truck in signature with a motorcycle in bed and non areodynamic 30' TT in tow.
Truck will weigh in at approx 9500lb as will TT at approx same .

I have played with jr settings somewhat in past and find throttle to touchy on default setting when towing. I have towed on tow setting only so far and find pwr good as well as egt but fuel mileage is not any improvement or even lower than stock( changing road and wind conditions make real tough to compare apples to apples).

Would running this combined load over I81 terrain develop better fuel mileage on economy setting or? What is consensus for towing mileage with manual trucks with 3. 73 gear.

Steve

 

[Buffalo]

I have an '03, 3500 SRW, NV-5600, 3:73, Magnaflow muffler & an AFE Pro-Guard-7 air filtration system & have a Smarty Jr. My trailer is a Nash 25-S (25' travel trailer) that weighs about 6000lbs. as far as I can tell.



Mostly, I drive around on the Performance Mode (100 HP) with the Jr. & I never have high EGT's. I can tow in the Performance Mode as long as I am not in serious mountains. Pulling long steep mountain grades can bring EGT's to near the 1200* range, which, is higher than I would like to be.



Switching to the Towing Mode (70 HP), I have NEVER seen high EGT's. , no matter what mountainous conditions I have towed in & I have towed in every Western State.



If you expect to encounter any mountain grades, I would just stay in the Tow Mode & then you won't have to worry about overheating anything. You should be more than safe. I, also, don't notice much difference between Tow & Performance Modes.



I'm very happy with my Smarty Jr. It does everything I want it to do.



Hope my experience helps you in your decision.



Regarding fuel mileage, my experience has shown that the slower I drive, the better the towing mileage. Flat land (Hwy. 99 in CA. between Bakersfield & Sacramento) gave me over 15 MPG's, towing, on 3 fill-ups at about 57 mph. Towing in CA only allows 55 mph. speeds & Hwy. 99 is a truck route. Those conditions were perfect for high mpg's. Earlier in the same trip, in AZ. , between I-10, Vicksburg, Parker, Lake Havasu City & I-40, with lots of stop & go driving & hilly conditions, I only got a bit over 10 mpg.



Joe F.

 

[S.Morris]

Thanks for input joe.

I think I will go one way on tow and one on economy to compare. Will try and keep accurate records regarding wind/road /temp conditions. for hand calculated mpg figures.

 

[AH64ID]

Part of the issue with towing with 70hp over stock is that when you use it the truck uses more fuel than stock, so lower economy. I guarantee that if you were to drive beside a stock truck for the entire drive and mimick his speed for the entire trip you would get better economy.



You can get slightly better economy on TM4, but at the cost of shorter oil life (at least in my experiance).



My rule of thumb (not an issue out of the rockies from what I have seen) TM2: Max EGT 1350, max continous 1300*; TM3 Max EGT 1400, max cont 1350; TM4 max EGT 1300, max cont 1250...

 

[CToney]

I have my TM changed to stock. I don't like smoke and my truck was too "touchy" with the throttle too. I believe this is due to my mods. I get more smoke because of the ats manifold. The larger passages cause the turbo to spool a tad slower. I tow on perf but like the extra power when passing ( I only pass when necessary and try to drive slower but I like the confidence to do so).



Buffalo if you want a bit more performance and make full use of your JR try a HE351 turbo off of the newer trucks. It sure woke my truck up.

 

[AH64ID]

I thought ATS sold the manifold as decreasing the time to spool??



I know for me the timing makes the biggest difference on smoke. But I run TMQ3 becuae I like the way it feels with a trailer better than TQ2. I run stock TQ in the winter and can still smoke on command... Why can't MADS figure out the low boost smoke!

 

[S.Morris]

Well, made the trip south and finally got some online time.
Route south , I81 from Canada/US border to I 64 over to I 95 into mid central Florida.
Did not drive in snow, but lots of wet roads and at times VERY high winds(40-60mph) at times. We were being chased by the MAJOR storm that came out of Texas and hit the North east with major snow and lower eastern areas with very high winds. Ambient temps were never less than 30Fand warmed as the miles rolled south.

Sm jr on economy, running mostly 65-68 mph,scan guage showing 100% load very often . Ran 5th gear where necessary, to top of longer climbs. ( TM-2, TQ3)

Average for 1500 miles was 10. 2 usmpg. Ran as low as 8. 7 and high as 11. 3. Even running in South Carolina in what seemed like NICE low wind conditions with scan guage load showing 45-55% mileage not impressive. I know mileage would have improved considerably at 60mph... . according to scan guage loading. All traffic running pretty much 65-70 though.

Truck ran well but gave all it had for long periods out of each fillup.
I will make return trip in about 3 weeks and will have jr set on tow. From what I can see... ... a 5th wheel seems to run about 2mpg better than a TT at the back of an 8' box.

Truck has 3. 73, Sm-Jr,MBRP 4" turbo back, otherwise stock

Steve

 

[AH64ID]

Number's don't sound too bad for the conditions.

 

[S.Morris]

Just an update to this thread. Made it back to the cold country with no problems.

I ran the return trip over same roads in reverse with still very windy conditions with smjr set on tow(99%)tm 2,tq3. In the past with this truck not towing and another V8 gas truck not towing the return trip has always given . 5-. 75 lower mpg then trip down.



I got a low of 9. 8 to a high of 11. 5 for an average of 10. 5 US. Truck needed and used the extra power of tow setting , mostly because of the winds but ran 5th gear on some long pulls for sake of not getting transmission too hot.



From what I can see on this 3000mile test run... . towing on economy does not help mileage and driveability is nicer in tow mode.



On one stretch, just for curiosity, I found that truck would hold a hill at 24-2500rpm in 6th that it would not hold in same gear at2000rpm. This was suprising..... egt were still > 1200 and there was definitely some fuel being used.



Majority of miles were not on cruise as fuel consumption rises using cruise if in any rolling or significant hills.



The one tank of fuel burnt in truck running empty, with general running around netted 18. 2 US.



Put about 2700 miles on the bike while there( it runs way cheaper , and fillups cost $25 instead of $125)



For what I use the truck for I think I will just leave it on tow and call it done.



On a side note: Serviced truck on return and have 3880 hrs and 308000km. This one hasnt wasted any time sitting around idling



Steve

 

[SRadke]

Most electronic manufactures do not recommend heavy towing on economy programs. You may want to check into that.

 

[DMorris]

what are the suggestions for a smarty so6 setting while towing ? I pull a 18k fifth, and had mine on 3, then bumped it to 4 (I think thats 70hp no timming) last time I pulled. Milage was the same -terrible (8-9 mpg) but power was better. Never saw egt over 1200 but only had the mini mountains of Tennessee to deal with, no rockies.
03-3500drw-4:10-6speed. Heading west in 3 weeks and hope to pull the big mountains without too much drama.

 

[AH64ID]

SW3 or SW5 get my vote, I prefer timing.

 

[DMorris]

SW3 or SW5 get my vote, I prefer timing.

I guess I dont understand exactly how timing works



But can you tell me why you prefer timing-maybe it will help me understand the settings better.

 

[jeepit]

I have mine set at 5 all the time. Towing or not. Egt's are no problem except on a large hill while towing.

I have heard the same about the fuel saver setting. Don't use it while towing.

 

[DMorris]

I have mine set at 5 all the time. Towing or not. Egt's are no problem except on a large hill while towing.

I have heard the same about the fuel saver setting. Don't use it while towing.

do you have the rail pressure bumped up at all ? I heard 4 and above you should bump rail pressure up one setting ?

 

[AH64ID]

I guess I dont understand exactly how timing works



But can you tell me why you prefer timing-maybe it will help me understand the settings better.

Timing advances when the injectors fire. This give the fuel more time to burn in the cylinder, and create more power. On SW1 (timing only) 04. 5-07 trucks get as much as 50 rwhp from 1600-2400 rpms, that's FREE power, zero added fuel. So the motor's efficiency is improved. Added timing also means lower EGT's, but you can't use the same safe temps as stock timing due to more heat soak in the cylinder.