8 hours ago
What differentiates the LT from everything else? First let's be honest everything we see here is old technology, very old technology. By the end of World War II the internal combustion engine had pretty much reached its pinnacle. Overhead cams, multi valves, direct injection.... its s all been done, probably before most of us were born. Google the Rolls-Royce Cressy engine or even the good old Allison V12 you will be amazed at the technology in those engines, they make our engines look like toys.
The roots of the modern Hemi engine really lie in Chrysler's attempt at an aircraft engine that was fitted to the later iterations of the P-47 Thunderbolt. The engine proved powerful and could push the Thunderbolt over 500 miles an hour, but once the jet engine came onto the scene the internal combustion engines were old news. I always thought Thunderbolt would make a better name for a Challenger or Charger than Hellcat or Demon.
The LT engine runs a structural oil pan which supports a 6 bolt cross bolted main cap. Aluminum heads and block mean lighter weight and better cooling, although this has been true since the early LS from the late 90s.
Potential energy, that's where it's at. An LT1 runs 11.5 to 1 compression in a 6.2 l engine. The modern Hemi, which really isn't a true Hemi any longer due to production costs and other factors has 10.9 to 1 compression.
GM has applied the technology required to allow an 11.5:1 engine to run on pump gas. The combination of direct injection and continuous variable valve timing allows GM to do this; neither the LS or Hemi has CVVT.
What you end up with is an engine that has tremendous power, especially torque at lower RPM; this is the reason the LT 5.3 can run with the larger engines, especially when equipped with the 10-speed transmission. BTW the 10-speed transmission was developed in conjunction with other manufacturers like Ford, Honda and Toyota.
Unlike an LS3 or Hemi the LT idles at very low RPM and has tremendous torque off idle, I like to say it's halfway to a diesel with its higher compression and maximized cylinder pressure. We have run the 6.2 LT's against Hemi's and LS3's with higher horsepower ratings but more often than not the LT wins.
The new inline 6 twin turbo looks very promising but it is really nothing new. I'm a big fan of the inline 6 and it appears Chrysler has taken a look at the BMW 3 l M series engine. That's not a bad thing they tout V8 performance with better economy and emissions. Smaller displacement engines with forced induction have often attempted to replace the good old V8, like the Ford Ecoboost engine.
I drive about a thousand miles a week in Wranglers with engines from the anemic 3.8 all the way up to LT'4's and various Hemi's. Without question the LT's have the best drivability, fuel efficiency and transmissions IMO.
The day will come when the large displacement V8s will be outclassed by the smaller displacement supercharged engines and electric motors. But for now if you have a large heavy vehicle with a lot of drag it's hard to beat the overhead valve American V8 regardless of manufacturer.