DOHC LS7

More gutless than this
https://m.youtube.com/watch?v=mWAYZr8B3Ss

>>13875203
it's about efficiency

>>13875234
how do you know it's more efficient?

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>>13875203
What he said >>13875234
I'm sure it makes for better fuel efficiency if you really need that out of your LS7.

I was reading the Wiki on all the LT and LS engines today and it doesn't seem like the DOHC and 4V does a whole lot for power for those big V8s and their application. Especially because they are such large displacement engines that they aren't really stretched to the limit like a lot of smaller displacement and turbocharged engines.

The C4 ZR-1 had the LT-5 that was designed by Lotus and had DOHC and 32 valves. They wanted to use the DOHC for the C5 Z06 but the engine was too big and would've required basically redesigning the car to use. So they broke out the LS-Juan and LS-6 instead.

Pushrods = Pushgods. Chebby.

>>13875234
probably less efficient due to the larger rotating mass.

>>13875267
I think it's also the reason direct injection is so much more efficient. Better air/fuel mix. Also those extra valves make the air, fuel, and exhaust move in and out if the cylinders smoother. This especially makes a difference higher in the rev range.

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>>13875264
Hey Alphonse, why are you so dumb?

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>>13875284
Get reddy for the memes

>>13875281
idk man, C5R heads flow 400cfm
those are CNC LS7 heads
doesn't get smoother than that.

>>13875281
>Also those extra valves make the air, fuel, and exhaust move in and out if the cylinders smoother. This especially makes a difference higher in the rev range.
You're talking shit. If they were flowing more air and fuel or were flowing "smoother" whatever the hell you mean by that, it would make more power.

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YOU CAN ALL STOP ARGUING NOW

>>13875203
This just in: some dude with a rinky-dink shop doesn't have the same engineering capabilities of a multi-billion dollar company.

More at 11.

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>>13875290
It's when you start getting into higher revs that the smoother flowing air/fuel mix makes a big difference. Fluid mechanics or something.

It's not a Ferd so whatever

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>>13875302
Pls leave John Hennessey out of this

>>13875305
You're also talking shit. Horsepower is nothing more than flow. More flow, more power, more volumetric efficiency, more power. If there was any benefit to those probably very poorly designed heads, they would make more power than the stock ones.

>>13875203
Longer and wider than a V12, probably taller too.

>>13875316
Why would it longer than a V12?
they did not change the bore spacing

>>13875341
look at all that shit hanging off the front.

even without it LS engines are long

>>13875352
um?
LS engines are smaller than most modern V6s
Have you ever seen one?

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>>13875352
>even without it LS engines are long
That's incorrect, though. If there's one thing murrican Vee Ates do well, it's fit a lot of displacement and a lot of power in a small package.

>>13875378
It's not tall. But 27.5 inches is long.

>>13875391
Not really. It's only a little longer than most I4s and is much narrower and nowhere near as tall as most V6s

>>13875403
lol okay kid

>>13875412
you just lost
kek

>>13875412
>can't be right
>resorts making himself look retarded with a smug reply

Just FYI, I measured the length of the engine in my 4 cylinder shitbox, it's 23" from transmission flange to water pump pulley.

Looks like you're just dumb.

>>13875203
more valves through dohc (or complicated pushrod systems) allows for higher airflow.

its not like "add more valves, go faster" its a modification (or design choice) that supports other parts, a DOHC setup would support a higher RPM limit and so long as you didnt have other bottlenecks you would produce more power.

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>>13875426
So 4 inches doesn't matter?
If I find an engine 4 inches bigger I can say it's an insignificant difference like you just did?
I was talking about V12s anyway.

>>13875442
REKT

>>13875442
If you think 4 inches is a lot I feel bad for you, buddy. The I6 that goes in the non shitbox version of my car is 30" long. BTW those measurements are crap, the M70's water pump pulley sticks out about an inch past the crank pulley.

>>13875203

>overhead cam
>timing belt

Duh fuck. I will call it a basterd because doesn't deserve to be called ls.

No jk. But thats is cray. I knew coyote and 4.6 has overhead cams and using a chain to link the other but a belt. Is it reliable?

>>13875465
So? what did I say here >>13875316
we are comparing it to an LSx with a bunch of shit mounted to the front. That it likely over 30" long as well.
So the engine in the OP is AT LEAST 6" wider, 2.5" taller and maybe the same length, give or take half an inch.

But of course to memesters the LS1 is some magic engine that fits a 4.4" bore spacing in a 3" gap.

>>13875465
>the M70's water pump pulley sticks out about an inch past the crank pulley.
no. you mean the radiator fan

>>13875316
>>13875352
>>13875391
>>13875426

Why is /o/ the Capital of shitposters?

An LSx derived engine can fit transversly for FWD, but this guy thinks displacement = physical dimensions!?

Stop drinking the tap water, children..

no shit it makes the same power at the same rpm. it's literally the same engine.

benefit of ohc is that you can rev it higher.

and his heads probably flow worse than the stock ones. that has nothing to do with the valve train.

>all this talk about flow
>completely missing the point of modern ohc engines.


Combustion chamber shape and valves. You can go to a 4 valve cylinder with ease, which allows use of a near hemispherical head with flat top pistons and a smaller combustion chamber. This allows you to maintain high compression without having a god aweful huge dome that obstructs your flame front, all while keeping the valve train smaller and lighter, and flowing similar numbers. So you can gain revs, gain knock resistance, and therefore gain additional timing on the same octane fuel.

>rustled my jimmies

>>13875586
>you cant have hemi heads with pushrods
literally what. theres nothing stopping you from having a hemi 2 valve head. and there's plenty of examples out there.

i cant believe the ls isnt even a hemi, what a piece of shit.
>300hp
>5 liters
lol

>>13875315
There might be a benefit, if it weren't for poor design. You pretty much said it yourself.

>>13875536
>you can rev OHC higher
Depends on the bottom end hombre. See Ford's 5.4l V8 w/Mustang heads (thanks Ford Australia).

>>13875617
Hemi 2 valve heads aren't as hemispherical or good for flow as OHC ones.

>>13875647
hemi 2 valve heads look exactly the same as hemi 4 valve heads.

anyway you realize hemi, wedge, and active heads all use flat top pistons right? only turbo pistons have recesses other than for valves.

>if this guy wasnt a crook pushrods could redeem themselves
https://www.youtube.com/watch?v=oIrRmbykLdY

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>>13875647
>Hemi 2 valve heads aren't as hemispherical or good for flow as OHC ones.

What the fuck are you smoking? Aren't as hemispherical? DOHC 4 valve semi-hemi setups necessitate a dual wedge style chamber (read; semi-hemi) due to the fact that canting the valves in a DOHC setup introduces a lot of fucked up shit to valvetrain geometry and then fucks with intake charge turbulence having to incoming charges coming in at different angles. The standard hemi is almost perfect in an ideal world, providing a good burn environment with the shortest path in and out with the only real drawbacks being the flow characteristics around the valve when it is made too large, and the issue of compression ratio. Though I just re-read your post and realized you might have meant 2 valve OHC hemi heads, in which case you're still stupid because they're the exact bloody same as two valve pushrod ones.

>>13875690
I do, yes. I didn't mention piston shape myself, that was some other dude.

also yes to the former, but there's a difference between valve footprint and quench area.

>>13875709
Reading this,
>>13875712
Just to clarify, I'm this dude.

I'm going to quickly say "wide heads" and "not everything's a V8" for valvetrain geometry, though we're talking V8s here so that's thrown anyway, then get onto the salient point.

Valve size limits rotation speed almost more directly than valvetrain does, and you mentioned the issue with flow characteristics of overlarge valves. And true hemis 4v/OHC exist, racing engines used them, though didn't call them hemis for trademark reasons-- Other developments pushed them out of relevance however later on.

>>13875745
>valve size
Valve area. I blame whiskey.

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>>13875745
I'm not taking issue with anything as far as factual advantage of a 4 valve setup over a 2v setup so much as the blatant inaccuracy of saying that 4 valve setup can be "more hemispherical" than a two valve, it's a simple matter of real-estate and to my knowledge known exist, do show me proof and correct me if you have some- I mean, you know what hemisphere means, yeah? But I'm arguing so much semantics here and I'll put out the notion that hemispherical combustion chambers don't preclude an engine from being able to wrap hard- A large valve might inhibit that (though not entirely stop it as top fuel engines will show, but that's apples to oranges) but it's a simplistic notion that the only way to supply more air is with a bigger valve because an engine wrapping harder needs more air, yeah? It has less to do with "this larger valve flows more air" as striking the right combination of valve size, port size and shape, runner style and length to achieve a good port velocity to pack the chamber for a good RPM range so writing off the hemi setup as a "V8 thing" is rather narrow thinking. Shit, I think some old Alfas ran hemi style heads and they were little zingboxes.

>>13875296
>tfw no snek
;_;