LT1 Torque vs LS1 Torque

[Rob]

One thing that may add to the sensation is that supposedly, there is a torque management sub-routine built into the factory programming that momentarily reduces torque in automatics at the shift points to help make the transmission live. I remember reading about that when the LS1 first came out, but haven't heard about it since. Is this fact or urban legend as well?

Torque Management is alive and well in the GTO. Very aggressive in the A4 cars. In fact, getting that tuned out will net you a .5 second ET gain just from that change alone. I know it wasn't as bad in the F-Body but it was still there.

[89RS_dude]

All i have to say is that this started about which "feels" quicker off the line. iIf your talking stock and its only 10-20 lbs difference you really cant"feel that much of a difference. Yeah the ls1 will take off harder but i really doubt it will feel different. just thought id throw in my two cents

[fastTa]

A4 LS1's did indeed have a "Torque Managament" parameter within the PCM factory programming. However, with LS1 Edit, it can easily be "zeroed out" and the "max torque" can be set higher as well.

The overall line pressure within the 4L60E is controlled by a number of other parameters besides TM, but it can also be altered directly with LS1 Edit. There is a dignificant tradeoff though between going to high with line pressure and going to low with line pressure. Going slightly but not near the max (i believe 300) higher will make shifts much firmer and make the clutches live longer. 220 should be all that you ever need on a car under 600 HP.

[LoudLT1]

Ok...i get IT !!!!!
LS1's are faster........

[cbrr_mike]

i dont understand how any of these numbers would come into play outside of city driving.....in a race, your not under 2500 rpms for very long, if at all

[fastTa]

i dont understand how any of these numbers would come into play outside of city driving.....in a race, your not under 2500 rpms for very long, if at all

That's a good point. I think we were just trying to provide some valuable information as to the comparison between the nature of the power curve between the LS1 and LT1.

[cbrr_mike]

i wasnt questioning any of the information, it was all a good read...

it just seems to be a question that comes up a lot.....

[cbrr_mike]

this talk also makes me wonder why "cags" is such a big deal.....if your driving in a way that you dont want it, it 99.99999% of the time wouldnt come on anyway

[RocKin1967]

wouldnt an ls1 rev up faster than an lt1? if so it would get to its peak quicker then the lt1....

[DeWynter]

The change in firing order was made to take advantage of the tuned length intake manifold runners, and the cylinder head design.

The idea that an LS1 has less overall torque delivery down low is pure urban legend. The reason some people comn to this conclusion based on their SOTP dyno is not because of the smooth delivery but just the opposite...the LS1 comes alive in the midrange to upper rpm's and does so very quickly. Put a significant cam in an LS1 and the midrange to upper rpm pull becomes violent. So people might make the mistake of thinking that the LS1 motor doesn't make good overall torque delivery down low.

LS1's make more better power under the curve period. I never really understood why people cared so much about having all of their available torque in the lower RPM's. Granted you need some torque to get your car going, but really....who cares about having a torquey motor down low? If that is all you care about then swap your motor for a dump truck motor. A torque curve in favor of higher RPM's is a good thing.

IMO a person should want the torque where they drive most often. For me I dont need the torque at 5000+ RPM as I dont rev my motor to that anyways I like that fact that my 383 makes 345 ftlbs at 1000 RPM and peaks at 3750 ish with 470 ftlbs as I shift right after that anyways. Its my belife you want your power where you drive. I of course dont quarter mile race very often. just the odd time if I need to lay the smackdown on a fellow friend.

[Jay 02 TA ws6]

wouldnt an ls1 rev up faster than an lt1? if so it would get to its peak quicker then the lt1....

The acceleration with which the engine revs is determined by the torque it is making through the specific rev range as a function of the current gear ratio (and of course things like weight of car, drivetrain, aerodynamics, etc)...

The engine that is going to rev faster through a specific range is going to be the one that is making more torque through that same range.