Hello all. I have 2 exhaust question pretaining to both engines.

Is the reason the LT1 sounds so good stock and modified than the LS1because of the higer compression ratio and firing order?

Is there any meanigfull power gain from just a cat back on a LS1 WS6/SS? I ask cause they have 2.75" popes and I don't see a extra 1/4" making much difference. Thanks for reading.

 

They sound different because the LT1 has a bigger bore and shorter stroke vs. the LS1's smaller bore and longer stroke. Same reason the LT1 has more low end torque and the LS1 has more top end.

The biggest difference in changing the catback is in the muffler. The stock muffler is very restrictive.

 

The main difference in the "sound" is caused by the differences in the firing order. The LSx series of engines are the first Chevy small blocks to depart from the 1-8-4-3-6-5-7-2 order that was used for more than 40 years. The LSx engines are 1-8-7-2-6-5-4-3.

 

I have never heard that before, and I would be surprised to find that that is true.

In addition to firing order, I've also heard people claim that the LS1's aluminum block is responsible for some of the difference, but I don't think that's true. The LQ9 (iron-block truck cousin of the LS2) has the same LS1-like sound.

 

I also don't believe that the LT1 has a lot more low end torque than the LS1. I have a GM authorized manual that shows the HP/torque curves (admittedly in a fairly small format) for the Corvette versions of the L98, LT1 and LS1 and the LS1 and LT1 show virtually identical torque curves up to 2,200rpm, then the LS1 continues to rise, while the LT1 sort of flattens out in comparison.