Effect of SmJr on eng

[Prairie Dog]

I run my SmJr on #2 for towing (9500#) but I wonder if there's anything wrong with using the #3 performance setting.
Assuming I don't use the extra upper RPM power and tow like I always do, is there any harm in towing with #3 like perhaps the timing is different or something else that effects my eng negatively?

Thanks in advance,

Scott

 

[AH64ID]

Since you have gauges you should be good. It will have more timing, and more fuel. 1250° continuous should still be a good number.

Do you have an adjustable boost elbow?

 

[Prairie Dog]

Since you have gauges you should be good. It will have more timing, and more fuel. 1250° continuous should still be a good number.

Do you have an adjustable boost elbow?

Thanks for the response John. I do have a boost elbow that's tweaked for about 36~38 psi. I dont let it sit above 30~32 for any extended time. Ex. temps aren't a problem normally (I do watch it closely on hills).
I know I didn't write my question very clearly. I was just concerned that under the same towing conditions the SmJr may use different timing between the two power levels for a given load.
The only time I would use the extra power is on rare occasions when accelerating onto the freeway or similar.


Thanks again,
Scott

 

[Ozymandias]

What BD told me back then was that it is safe, as long as I upgrade my transmission for it.

Was around 390Hp and 840ft/lbs at the rear wheels with my truck.
I've the printout somewhere in my records.

Oh and a lot of black smoke.

 

[AH64ID]

Thanks for the response John. I do have a boost elbow that's tweaked for about 36~38 psi. I dont let it sit above 30~32 for any extended time. Ex. temps aren't a problem normally (I do watch it closely on hills).
I know I didn't write my question very clearly. I was just concerned that under the same towing conditions the SmJr may use different timing between the two power levels for a given load.
The only time I would use the extra power is on rare occasions when accelerating onto the freeway or similar.


Thanks again,
Scott

It would be more timing, but I still think it’s less timing than I ran on my 05’s tow tune. Combined with the smaller pilot of the 03/04 I don’t think it’s an issue.

 

[Prairie Dog]

Thanks again John.
Is there any indication if running too much timing? Detonation?

S

 

[AH64ID]

Thanks again John.
Is there any indication if running too much timing? Detonation?

S

Not until you start to run way too much timing, but you might see some additional haze and smoke start to develop at mid throttle if the timing is too high.

I never ran my SJR on 3 with the 03/04 pistons, but my Pro tune was more timing and less fuel that what I think the SJR runs.

 

[Prairie Dog]

Great, I'll watch for the haze.

Cheers,
Scott

 

[WalterJ]

Not until you start to run way too much timing, but you might see some additional haze and smoke start to develop at mid throttle if the timing is too high.

I never ran my SJR on 3 with the 03/04 pistons, but my Pro tune was more timing and less fuel that what I think the SJR runs.

Greetings, Can you say a little more re: higher SJr pwr settings w/'03-'04 pistons? I also tow in lvl #2 because on the "flats" I use 'cruise', and lvl #3 feels too aggressive, so have settled on using lvl#2 for towing, and general day-day driving.

Would my 50HP/Bosch Stage #1 injectors be more or less appropriate for use with higher SJr levels? Why? Thanks. Wally

 

[AH64ID]

Since #3 is performance based, and you have larger injectors, it makes sense what you're feeling in 3. The timing of 3 is probably a little better with the injectors, but the duration 1 is best.

If 2 works well then use it, and run the timing on TM2 to maximize it.

With anything bigger than 50's and the primary use is towing I recommend custom tuning, as duration is too much on all the box tuners. My 05 ran duration around 80% of stock, and still dyno'd over 400 rwhp with my Stage 1 BBi's. Any box tune would have been too much fuel and not enough timing for a good tow tune.

 

[Buffalo]

Prairie Dog,
I, also, have an '03, 3500, SRW, NV-5600, 6 speed, 3:73, 4X4 and tow a 25" travel trailer. I live in Phoenix and do most of my towing in the mountainous western U.S. Lots of uphill & downhill. I have the Smarty Jr. and have towed in all three settings. In the Performance Setting, I do notice when going up long, steep hills, that the exhaust gas temps. get a bit warm where as in Setting 2, the Towing Mode, it doesn't seem to matter what hill is in front of me, the exhaust gas temps never get dangerously hot. There is not enough difference between Settings 2 & 3 to make it worth worrying about the exhaust temp everytime I hit a hill. While towing, there seems to be very little difference in engine power and certainly not enough to risk any damage to the engine by running in the Performance Mode, Setting 3. Driving around town without the trailer hooked up, using Setting 3 is no problem. I've never noticed the exhaust overheating like I do with a load and going uphill on the same setting (3).
I like the Towing Mode (2), especially when towing. Works great!!! This has been my experience. Hope it helps. I like the Smarty Jr., also. I've also towed from San Diego to Toronto and Seattle to Charleston, WV. And plenty of towing in the Western States and mountains.

 

[Prairie Dog]

Thanks for your comments Buffalo.
I don't have any EGT issues or, I suppose I might if I hammered it hard enough on the mountain passes but it takes a lot to get it over 1100 degrees - which is what I limit it to. That gets me 55~57 MPH in 5th gear on 6% with a #10K load.
I wonder if the folks who feel 3 is too aggressive have gotten the latest update on their Smarty's. It used to be MUCH more aggressive until the update. I know some did no tlike the change but it removed the sudden onrush on power and made it more linear.
Frankly, I hardly feel a difference between 2 and 3. The difference seems to all be up high in the RPM band (2500+?) and I only spin it like that on rare occasions when on an on-ramp.
So my concerns were more about steady state cruise at moderate throttle settings. The thing I have towatch closely is the boost. It's easy to go well over 35 PSI and for the health of the turbo, I keep it at 34 or less for extended runs. I need a better turbo but can't justify it..

Scott

 

[Buffalo]

Thanks for your comments Buffalo.
I don't have any EGT issues or, I suppose I might if I hammered it hard enough on the mountain passes but it takes a lot to get it over 1100 degrees - which is what I limit it to. That gets me 55~57 MPH in 5th gear on 6% with a #10K load.
I wonder if the folks who feel 3 is too aggressive have gotten the latest update on their Smarty's. It used to be MUCH more aggressive until the update. I know some did no tlike the change but it removed the sudden onrush on power and made it more linear.
Frankly, I hardly feel a difference between 2 and 3. The difference seems to all be up high in the RPM band (2500+?) and I only spin it like that on rare occasions when on an on-ramp.
So my concerns were more about steady state cruise at moderate throttle settings. The thing I have towatch closely is the boost. It's easy to go well over 35 PSI and for the health of the turbo, I keep it at 34 or less for extended runs. I need a better turbo but can't justify it..

Scott

Hi Prairie Dog,
I just noticed that you have an Arctic Silver Fox 32A that you are towing. My trailer is a Nash 25-S (25' with max. weight of 7,000 lbs.) You are towing much more weight than I do. However, I do tow with the fresh water tank (50 gal's.) full and 5, 6 gallon blue water jugs in the bed of the truck along with a 115 gallon auxillary fuel tank that is full much of the time. Even with that, I believe you are heavier than me. I wasn't aware of an update to the Smarty Jr. Level 3. That may be why pulling hills, my EGT's do get to a point where I become uncomfortable. Never had that problem in Level 2. I can go anywhere without worry. And, Level 2 seems to be close to what Level 3 offers. So, for peace of mind, I just use Level 2. I was stationed at McChord AFB between 1966 and 1969 and loved my stay there. Beautiful country and I absolutely loved the mountains.