Towing with 33” tires versus 35” tires

[1998_K1500_Sub]

I fired up JET DST, these seem to be all the PE-related constants and tables it offers…

I didn't show the tables' contents, I only showed their names. If someone wants to see the any complete tables, just ask.

 

[Supercharged111]

I fired up JET DST, these seem to be all the PE-related constants and tables it offers…

I didn't show the tables' contents, I only showed their names. If someone wants to see the any complete tables, just ask.

Is that for a 411?

 

[1998_K1500_Sub]

Is that for a 411?

1998 black box, i.e., my Suburban

 

[Supercharged111]

1998 black box, i.e., my Suburban

Wow, I'm surprised to see the transient fueling unlocked there.

 

[1998_K1500_Sub]

Wow, I'm surprised to see the transient fueling unlocked there.

I might have simply said "the OE ECU" on my Sub.

The values / parameters / etc. shown are the baseline config, as read by DST (by me w/ my laptop) on 5.28.2010, and as interpreted by the latest(?) DST v2.32

 

[1998_K1500_Sub]

If both thresholds must be met, then you'd just set the TPS one down to zero or something really low so all that's waiting to be triggered is the MAP threshold.

I haven’t done this myself, but intuition tells me to leave some TPS threshold values non-zero so as to keep from entering PE under atypically low RPM (1200) low-vacuum (“high” load) situations... these might be more likely to occur with a manual trans than the auto.

Never mind what I say tho, try it yourself and find out what you like better.

I like the TPS threshold as I can hit PE just before a 4-3 downshift.

Agreed… get that last “umph” out of the engine by enabling PE instead of shifting down to 3rd… and thus possibly avoiding the downshift entirely.

Maybe one can tune the same behavior to occur in 3rd as well, instead of downshifting into 2nd.

Etcetera.

 

[L31MaxExpress]

I haven’t done this myself, but intuition tells me to leave some TPS threshold values non-zero so as to keep from entering PE under atypically low RPM (1200) low-vacuum (“high” load) situations... these might be more likely to occur with a manual trans than the auto.

Never mind what I say tho, try it yourself and find out what you like better.



Agreed… get that last “umph” out of the engine by enabling PE instead of shifting down to 3rd… and thus possibly avoiding the downshift entirely.

Maybe one can tune the same behavior to occur in 3rd as well, instead of downshifting into 2nd.

Etcetera.

My opinion on that has changed over the years. I now downshift well before I hit PE. To each their own I guess.

 

[Supercharged111]

My opinion on that has changed over the years. I now downshift well before I hit PE. To each their own I guess.

I can only do this above 65mph or so, so we'll north of 2000RPM. I believe you didn't want to lug the motor and beat on rod bearings is why you changed?

 

[L31MaxExpress]

I can only do this above 65mph or so, so we'll north of 2000RPM. I believe you didn't want to lug the motor and beat on rod bearings is why you changed?

That was one of the reasons.

Second reason being it was worse on fuel always getting into PE.

 

[Supercharged111]

That was one of the reasons.

Second reason being it was worse on fuel always getting into PE.

Ahh, I find when towing that it usually takes PE fuel in 3rd after downshifting so I just decide whether or not I want to hit PE. It's usually a hill that I'm climbing anyway, so short lived. On longer trips though it could be a steady crosswind.