The early 5.3 (99) and later 2000- model

[wack]

If the engineers spent so much time in developing a new generation design truck motor.4.8,5.3,6.0.Then why would they, after 1 model year, switch to a different cam design?  Does the newer design have a smoother run up through the rpm range as well as higher hp. and torque rating.It just seems bizarre to me that this would happen.Or was the 5.3 and 4.8 underrated the first year so as not to have a drastic jump in advertised hp from the previous year.Has there ever been a side by side or better yet a dyno test on these 2.I'm pretty sure the earlier motors dynoed rather weak at the rear wheels. I'm just skeptical.

[RyanbabZ71]

add a few horsepower = add a few new customers.

 

Just something to make the truck look better than the previous model yr is my guess

[CMNTMXR81]

If the engineers spent so much time in developing a new generation design truck motor.4.8,5.3,6.0.Then why would they, after 1 model year, switch to a different cam design?  Does the newer design have a smoother run up through the rpm range as well as higher hp. and torque rating.It just seems bizarre to me that this would happen.Or was the 5.3 and 4.8 underrated the first year so as not to have a drastic jump in advertised hp from the previous year.Has there ever been a side by side or better yet a dyno test on these 2.I'm pretty sure the earlier motors dynoed rather weak at the rear wheels. I'm just skeptical.

There are constant changes from model year to model year.  There are constant improvements from year to year.

 

These new generation of LS1 derived Vortec motors are essentially a clean sheet design.  They put it out onto the market and watch what the aftermarket comes up with as well as the owners that modify them.  They then implement this into the next model year from the factory.  It's a never ending cycle for the first few years.  Also they find ways to make things more efficient that can only be found by real world operation.

 

Would you like for me to recount all the improvements and upgrades to the LS1 itself since it first debuted in 1997?

 

It has nothing to do with a "flawed" design upfront but rather a "hey, this works even better, lets add it."

[wack]

I never said the 5.3 was a flawed design. I was curious on opinions as to what the real world differences were.The only external thing I saw was a smoothend air intake tube which has stayed the same since 2000.I put one on my 99 and have noticed a change in engine sound with it at a full throttle.It used to have a wwwrrrrggg sound goin on now it has more of a wwwaaaaaa opened up air intake sound.So there must be some advantage to the newer design.   As a matter of fact my father used my truck this weekend and commented that when he was backing up the #### thing 'felt like an electric vehicle'.Now thats smooth operation.

[CMNTMXR81]

That's good!  

 

Just like I said though, it's a constant learning curve and they add stuff as they feel it improves it.

 

As to the air intake, you said it was smoother, they evidently removed what are called "air silencers" that are supposed to quiet the incoming air charge in order to meet certain noise level requirements.  Since that silencer was removed or made smaller, more air is directly charging into the throttle body instead of circulating around in a silencer, therefore resulting in sharper throttle response and better breathability.  That's part of the concept behind cold air intakes.