Touch More C8 LT2 Info

[John]

i love to learn even fractions more about Corvette motors. Here, thanks to GM Authority, is some interesting info on the LT2 having a smoother idle and a little more.

Much of the LT2’s additional power can be attributed to how much better it breathes,” Chevy says. That includes the intake manifold, which is bigger and taller compared to the LT1, up to 14.1 liters from the LT1’s 11.1 liters. The intake uses a low-restriction design with identical 210-mm-long intake runners, unlike the unequal-length runners on the LT1. This improves output and increases flow, with three-percent power gains compared to the LT1’s intake manifold. The LT2 also uses an 87-mm throttle body.

On the other side of the combustion chamber, the 2020 Corvette engine comes with a ground-up exhaust redesign specifically tailored for the mid-engine application. This includes high-flow pipes and a four-into-one design with twisted runners that help to ease the stress of thermal expansion. The runners are all roughly 330 mm in length. The end result is a 1-percent power increase compared to the LT1.



The LT2 exhaust also has new catalytic converters, with one split-volume catalyst per cylinder bank. This is a simplification over the two cats used on the LT1, and makes for a more economical design overall. Additionally, the LT2 can activate the new exhaust-scrubbers earlier thanks to new engine tuning, thus lowering emissions by 25 percent.

The 2020 Corvette engine gets a new camshaft profile too, with an extra 1 mm of exhaust lift, now up to 14 mm. This matches the intake side, with increased duration for both profiles to take advantage of the engine’s higher flow. Critically, the LT2 has a very stable idle, even more so than that of the LT1, thanks primarily to a new wide-range air-fuel sensor (WRAF). Finally, Chevy says the LT2 retains variable valve timing, with 62 crank degrees of cam phasing authority.

http://gmauthority.com/blog/2019/11/...-from-the-lt1/

[C8Driving]

An exhaust scrubber? What is that please?

[whl3]

There are an almost infinite number and types of "scrubbers". The term "scrubber" should not be associated with the more common terminology that we would typically use in the household! Scrubbers are most noted for use in industrial applications to clean up exhaust gas emissions. In transportation use, I'd bet they were first used on diesel applications before being used on gasoline fueled internal combustion engines. Most types can either be classified as "wet" or "dry" scrubbers. Below is a general definition from Wikipedia.

"Scrubber systems (e.g. chemical scrubbers, gas scrubbers) are a diverse group of air pollution control devices that can be used to remove some particulates and/or gases from industrial exhaust streams. The first air scrubber was designed to remove carbon dioxide from the air of an early submarine, the Ictineo I, a role for which they continue to be used today.^[1] Traditionally, the term "scrubber" has referred to pollution control devices that use liquid to wash unwanted pollutants from a gas stream. Recently, the term has also been used to describe systems that inject a dry reagent or slurry into a dirty exhaust stream to "wash out" acid gases. Scrubbers are one of the primary devices that control gaseous emissions, especially acid gases. Scrubbers can also be used for heat recovery from hot gases by flue-gas condensation.^[2] They are also used for the high flows in solar, PV, or LED processes.^"

[meyerweb]

Critically, the LT2 has a very stable idle, even more so than that of the LT1

Aw, I like the slightly lumpy idle of the LT1. I hope that's not what they're talking about.

[SheepDog]

The schizoid riddle in the Corvette idle is sacred from way-back. Mourn the passing. Then a reserrection please. The very lumpy is even more primal Corvette.

Did they save it for the Z06 .

[RoketRdr]

An exhaust scrubber? What is that please?

They are referring to the CAT's.

[Boomer]

"The intake uses a low-restriction design with identical 210-mm-long intake runners, unlike the unequal-length runners on the LT1. This improves output and increases flow, with three-percent power gains compared to the LT1’s intake manifold."

Thanks for info. I was glad when I heard the C8 would have the LT1/2. Tried and proven, and now improved more.

[TAdams65]

Aw, I like the slightly lumpy idle of the LT1. I hope that's not what they're talking about.

Yes to this, I liked that I could actually feel the engine running in my Camaro.

[68roadster]

Yes. I think the LT2 is sounding like it will have less snarl or attitude than the LT1. Will be interested to see what the differences are. I am so excited about the design that it will not be a big deal to me as long as I have the NPP.

[Milliwatt Rob]

There was nothing as nice as the lumpy idle on my 1964 C2 with the solid lifter engine, valve clearances set at 030 and 030. Stumbled along with an idle at 750 rpm

[MikeC8]

I had a 13 Boss 302 and the track key would unleash the lumpy cam sound. Really cool and old school. It also had side pipes from the factory that had plates that could be removed. Or change the plates hole size for different sounds. Plates removed was way too loud for street driving but not at the track. Great sounding small block for sure at WOT.

[OldYellow]

The engine sounds like it will be another good step up in the Corvette engines. Has anyone been able to determine where the oil drain plug is? I have seen the oil filter access hole in the cover plate underneath but have yet to determine where the oil drain plug is. If anyone has a picture they can share I would sure appreciate seeing it. I always change my own oil !

[John]

Easily accessible from underneath. At we learned from Josh Holder at the NCM 25th, there is only one drain plug for the LT2. It and the oil filter are easily accessible from underneath. Couple of pictures to help from CorvetteBlogger and TorqueNews respectively.

[MikeyTX]

This bring to mind the eternal question Why ? Every time I read a post by someone wanting to put aftermarket headers on this marvel of engineering I just shake my head in wonder and roll my eyes. Give me an LT2 with exposed surgical stainless factory headers and I'll show the world a classic piece of art.

[Mobius]

Every time I read a post by someone wanting to put aftermarket headers on this marvel of engineering I just shake my head in wonder and roll my eyes. Give me an LT2 with exposed surgical stainless factory headers and I'll show the world a classic piece of art.

I agree, the headers are very sexy, but I was disappointing to find that they are enclosed in heat shielding (for both the Stingray and Z51) to help keep down radiant heat.