Javelin MegaDork
Oct. 24, 2012 11:10 a.m.

GM released the info on the Gen V small block V8 today, and they called it the LT1. Yeah, that's not confuse people.

Anyway, the changes to ye old LS3 sound very delicious. Read here.

Cliff notes: 450HP/450TQ from 6.2L, 11.5:1 compression, direct injection, and VVT.

singleslammer HalfDork
Oct. 24, 2012 11:15 a.m.

Ranger50 UltraDork
Oct. 24, 2012 11:21 a.m.

Looks like EPAS is coming too, note no PS pump and belt. But it does look like the balancer is fitted for a 8 or 10 rib belt. Hello supercharger?

Intake minus hideous cover:

Complete artist cutaway:

I know I have more, my FB news feed is cluttered up with this nonsense.

Oct. 24, 2012 11:26 a.m.

OH MY YES!!!

Weren't they working on 5.5L GenV?

Javelin MegaDork
Oct. 24, 2012 11:28 a.m.

GM apparently spent some mind-boggling number like 6 million computer hours on just the combustion chamber alone. Those pistons certainly do look odd.

81cpcamaro HalfDork
Oct. 24, 2012 11:28 a.m.

It does look pretty cool, hopefully it performs great.

As for using LT1 (for the third time now), why not, they have reused just about every engine code already.

HappyAndy Dork
Oct. 24, 2012 11:31 a.m.

The odd piston shape probably has something to do with direct injection.

Ranger50 UltraDork
Oct. 24, 2012 11:32 a.m.
Javelin wrote: GM apparently spent some mind-boggling number like 6 *million* computer hours on just the combustion chamber *alone*. Those pistons certainly do look odd.

Seems excessive, but plausible given the CAFE push for everyone to be in TaTa's in a decade or so...

Oct. 24, 2012 11:47 a.m.
Javelin wrote: GM apparently spent some mind-boggling number like 6 *million* computer hours on just the combustion chamber *alone*. Those pistons certainly do look odd.

That is not exactly as big a number as you think.

6,000,000 hours = 250,000 days at say 20K micro instances as it is mainly math = 12.5 Days of crunch.

92CelicaHalfTrac MegaDork
Oct. 24, 2012 12:00 p.m.

It sounds way better to say that GM started development on the combustion chamber of that motor in the year 1327AD.

kreb SuperDork
Oct. 24, 2012 12:04 p.m.

Pushrods FTW!

This from the company who put the LS1 moniker on a 4 cylinder Saturn!

Kidding aside, it looks like a pretty great motor.

Oct. 24, 2012 12:05 p.m.

^^^ so then, about as long ago as push rod engines in general were designed...

look, its cool and all, and i can't back what im about to say with knowledge, cause i don't have any, but it seems to me there are gains to be had with OHC, and GM seems to ignore those possibilities on their big displacement motors (save for ZR1 in 90's).

anyone know why they dont give up the ghost and go OHC? twin cam? quad cam? 4 cams per cylinder? hell, why not eight?

edumacation plz? :D

-J0N

wvumtnbkr Reader
Oct. 24, 2012 12:09 p.m.

For one, it would make the engine larger. Those cams have to go somewhere.

There was actually a pretty good thread about exactly this topic a few weeks ago. If you search for OHC, you will probably find it.

Rob

Javelin MegaDork
Oct. 24, 2012 12:20 p.m.

In reply to jmthunderbirdturbo:

OHC's weigh more, cost more, take up a lot more real estate under the hood, and don't provide any real benefit with the advent of variable valve lift/duration technology (the "cam in cam"). The GM LS family has had the highest specific outputs (HP/L) and actual ouputs of any V8 for the last ~10 or so years for a reason...

Javelin MegaDork
Oct. 24, 2012 12:21 p.m.
Ranger50 wrote:

Anybody else notice they swapped the intake and exhaust valve locations?!!!?!?

Bobzilla UltraDork
Oct. 24, 2012 12:22 p.m.

Now... give me that engine in the 4.8L displacement with the short stroke/big bore combo, shove it into the new Caprice and give it 3 pedals with 6 forward gears, and LSD and I'll be the first motherberkeleyer in line to buy it.

tuna55 UberDork
Oct. 24, 2012 12:23 p.m.
wvumtnbkr wrote: For one, it would make the engine larger. Those cams have to go somewhere. There was actually a pretty good thread about exactly this topic a few weeks ago. If you search for OHC, you will probably find it. Rob

the ZR1 C4 was exactly that experiment. The pushrodded motor could manage a much larger displacement for the same engine size, so no net sacrifice of power per pound, power per dimension, power per fuel. In other words, to manage the same hp figure, the OHC cam engine GM would hypothetically design would be heavier, bigger but have less cubic inches of displacement.

tuna55 UberDork
Oct. 24, 2012 12:23 p.m.
Javelin wrote:
Ranger50 wrote:

Anybody else notice they swapped the intake and exhaust valve locations?!!!?!?

Yes I did. I also noted the twisted wedge theory on ehads, which I thought was nonsense when I saw Twisted Wedge do it.

Gearheadotaku SuperDork
Oct. 24, 2012 12:24 p.m.

By continuously refining the pushrod V8, GM has produced engines with the same HP, fuel economy, and emissions as "hi tech" engines at a lower cost, better reliability and easier/less maintenance.

Reusing the LT1 name is purely marketing. I don't like it, there are plenty of other letters/numbers out there to come up with a new name.

tuna55 UberDork
Oct. 24, 2012 12:24 p.m.
Bobzilla wrote: Now... give me that engine in the 4.8L displacement with the short stroke/big bore combo, shove it into the new Caprice and give it 3 pedals with 6 forward gears, and LSD and I'll be the first motherberkeleyer in line to buy it.

Why would you want less displacement?

Bobzilla UltraDork
Oct. 24, 2012 12:25 p.m.

i'M Not kidding GM. Put that into a new caprice with a manual trans you stupid asshats..... Do it or just go bankrupt and I will no longer care.

Bobzilla UltraDork
Oct. 24, 2012 12:26 p.m.
tuna55 wrote:
Bobzilla wrote: Now... give me that engine in the 4.8L displacement with the short stroke/big bore combo, shove it into the new Caprice and give it 3 pedals with 6 forward gears, and LSD and I'll be the first motherberkeleyer in line to buy it.

Why would you want less displacement?

even with the smaller displacement it would still be 350hp, but less cubes to feed would be more highway economy.

That and the 4.8 loves to rev.

92CelicaHalfTrac MegaDork
Oct. 24, 2012 12:27 p.m.
Javelin wrote: In reply to jmthunderbirdturbo: OHC's weigh more, cost more, take up a *lot* more real estate under the hood, and don't provide any real benefit with the advent of variable valve lift/duration technology (the "cam in cam"). The GM LS family has had the highest specific outputs (HP/L) and actual ouputs of any V8 for the last ~10 or so years for a reason...

Not necessarily doubting this one, as i really don't know...

But even over some of the nutso German V8s? I could have sworn the Audi 4.2 is beyond the GM LS family, at least in terms of hp/L. (Which who cares... it's ricer math... just curious. )

dculberson SuperDork
Oct. 24, 2012 12:30 p.m.

I would have thought that direct injection and all the other fanciness would be good for more than 20hp. (the LS3 is 430hp, the LT1 is 450hp, same displacement.)

Still, sweet motor and proof this is a great time to be a gearhead.

yamaha Dork
Oct. 24, 2012 12:31 p.m.
tuna55 wrote:
wvumtnbkr wrote: For one, it would make the engine larger. Those cams have to go somewhere. There was actually a pretty good thread about exactly this topic a few weeks ago. If you search for OHC, you will probably find it. Rob

the ZR1 C4 was exactly that experiment. The pushrodded motor could manage a much larger displacement for the same engine size, so no net sacrifice of power per pound, power per dimension, power per fuel. In other words, to manage the same hp figure, the OHC cam engine GM would hypothetically design would be heavier, bigger but have less cubic inches of displacement.

However, those ZR1's woke up much faster than the comparable tpi once lingenfelter got ahold of them. The LT5 was honestly better than the lt-1. I like the lt5 cars......I really do. I like the lsx cars as well, the experiment produced a great engine that should have been continued.

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