"Dad" > wrote in message
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>
> "Dad" > wrote in message
> .. .
>>
>> "uncle_vito" > wrote in message
>> .com...
>>>
>>> "Dad" > wrote in message
>>> .. .
>>>>
>>>> GM is reusing the engine designation LT1 for their 2014 Corvette
>>>> engine. Massive head changes along with more tweaking of the piston/rod
>>>> design. Interesting intake runners feeding into large head ports
>>>> between exhaust and intake valves that have traded places.(?) Valves
>>>> were also cocked to make room for those bigger runners and required the
>>>> long lost eyebrows in the piston tops. Not a huge HP/TQ increase maybe
>>>> 450 with a 6,500 RPM red line/fuel-c/o. Like most GM engines it will
>>>> have VVT but I still don't get a clear understanding as to how their
>>>> system works yet.
>>>>
>>>> Never got into the LT5 and only drove it twice and now the base
>>>> Corvette engine makes it rather ho-hum. Plus it hasn't held it's King
>>>> of the Hill position very well with the present push rod engine that
>>>> turns out 22% more HP and this new one will be closing up on that gap
>>>> at 11% in base form.
>>>>
>>>> --
>>>> Dad
>>>> 05 C6 Silver/Red 6spd Z51
>>>> 72 Shark Black/Black/4spd
>>>> 64 Red/red/white top/4spd
>>>
>>> When you find out how the VVT works, let us all know. I am curious if
>>> you get it on both the intake and exhaust.
>>>
>> Sorry about that, I should have said "Like most GM engines it will have
>> VVT but I still don't get a clear understanding as to how well their
>> system works yet." Since it is most like Toyota's they went the simplest
>> way rather than the cam in cam or the more obvious DOHC. I think they
>> spent way to much time building a system that will allow retrofit to the
>> LSX engines but it does get close to 20% HP per cubic inch increase.
>> (correction)
>>
> I did get into some of the design criteria for the GM VVT and find the
> valve timing changes enough to be some of the reason behind the piston
> eyebrows. It's still a solid cam and only changes lobe to piston
> relationship, some of the other designs allow lobe to lobe angle changes.
> I'm sure there will be a number of these designs fall by the wayside as
> their benefits, costs, and durability will dictate their life span.

Thanks for the update.