Why do pushrods cause so much butthurt?

But it could have BETTER track records.

>higher COG, heavier engine, worse weight distribution
>better track records

that's not how that works zippy

well essentially you create an egg shaped flume (like they ones used to carry logs), and rig it upside down on the bottom of your car to act as the diffuser. slope it to accelerate the air and cause a pressure difference that would keep your tires on the road. and rig those fins you see in my example to the bottom to spin the fluid (air) horizontally as it moves under the car vertically.

Air is like any other fluid. Like water in a river, it doesn't want to simply flow forward, but it also likes to swirl on itself. a flow is alive, the entire body can spin in the bank. Air behaves the same way. With a poor flow, some fluid will actually move backwards against the flow in eddies.. You don't want this.

I'm thinking with a sculpted enough diffuser, you could rig a rudder on your car and correct understeer- as well as reduce drag and improve topspeed, like a diffuser already does.

in fact, you might as well get rid of the whole panel philosophy when it comes to car and switch to scales and frames that can twist/bend.

a real bare bones skeleton to catch and redirect air. the future of cars is blurring the line between rolling and swimming through fluid.

If one of those breaks you have air pushing back into the ground, thus negating any downward force caused by the low pressure environment.
Since you have to have multiple channels to accomodate for this, the increased channel drag would also be detrimental to overall speeds.

It's a great theory, but I don't think it's viable in racing. There are other issues that I can see.

You could use it Ina tenga thou.
Now THATS science

Scales and bones will not work due to added weight and additional drag created by freemoving (flapping) objects

Because that ancient technology outperforms $100k DOHC engines in $300k "performance/luxury cars" while being smaller, lighter and more reliable and able to be worked on in anybody's garage.

sorry you're retarded.

why would welded metal break? fool

what's the actual benefit of a dohc engine?

serious question because a modern ls makes a fuckton of power and torque really easily, is great on fuel and very compact.

what the fuck is the downside, because i'm not seeing it?

any ls owners want to let me know if there are downsides?

from a benchracing perspective it seems like dohc is fucking meme tier for economy engines (optimising fuel in a civic) and a big displacement pushrod just makes better numbers all over the curve, not just peak.

>and a big displacement pushrod just makes better numbers all over the curve, not just peak.
you should to go tell every single manufacturer other than gm and chrysler about this miraculous unknown fact!

lamborghini and a few others get it too, they have tons of displacement.

i just don't see why cunts are spending money on these elaborate dohc setups when just displacement would suffice (performance setting, not a economy civic).

displacement even makes turbo better!

Lamborghini has big numbers because they are V12

>they have tons of displacement
and high revving ohc engines that place no emphasis on torque or low end power :^)

pushrods are just shit
they dont get good fuel economy, the cars they are placed in with 4 overdrives and crazy tall gearing do
and their power output is mediocre as fuck for their displacement

>gm needs 7 litres to make less horsepower than a naturally aspirated 5.0 dohc engine
lmao

Why hasn't Veeky Forums built its own car yet

Before 100 post long shitpost thread
>revs
>HP/L
>Sound (subjective but a complaint nonetheless)
There's also this, most don't use them and some exotic car makers might shy away from them for the reasons mentioned above and i guess most people just look down on them as outdated tech regardless but then again most didn't use rotaries and even Mazda stopped using them. i doubt people would want a buzz-saw sounding super car over a V12 lambo. it'd be interesting to see if Hybrid technology will allow pushrod performance cars to survive until the end of the Internal Combustion Engine.

>?
You mean black?

Cuz u r a faget

A diffuser is only as effective as the laminar flow that precedes it, that is to say that the entire underbody needs to be treated yet retain cooling for brakes, diff and exhaust.

Turbulence is the enemy, runaway temps are too.

Flow separation will only occur at sufficient flowrates respective to the angle, which is fine since the underbody will be seeing a relatively narrow band of effective flow/velocity.

Pushrod engine will never make the power per cubic inch of a DOHC engine. Never ever ever. The runners on a DOHC engine are straighter than you will ever get on an OHV, they have less valve shroud due to the valve angle, you have more flow surface area running 4 valves per chamber, they will rev higher because the valvetrain weighs less, and you can run higher lifts and longer durations because the lobe profile doesn't need to be as aggressive.
I love pushrod engines, and they are smaller and cheaper for sure. 20 pounds of aluminum in the increased head witch and 15 pounds of chains is negligible in my opinion for weight.
Power curves on modern engines are so fucked up because of the variable cam timing trying to keep up with what the engine wants to do. If you disable the cam phasers the curve will look much more consistent

Here is a good read on a ford 5.4 that John kaase built. Had a lot of work done to it but it made 1.76 hp per cubic inch and 1.63 lb ft per cubic inch at 11.5 : 1 compression on pump gas (which is insane)
www.hotrod.com/articles/jon-kaases-ford-four-valve-mod-motor/

>www.hotrod.com/articles/jon-kaases-ford-four-valve-mod-motor/
Damn, that's a pretty bloody wide and flat powerband.

because only America still uses them ?

Bentley uses them.

Pushrod engines are more from the era where torque, sound and simplicity reigned.
The new tech is for getting to work and back with minimal consumption and maximum output in regards to SFC.

It's two differing techs doing their best to converge but keep their aforementioned strengths, which are IMO counter-intuitive.

>but the reality is that the mod motor, introduced in 1991, has been one of the most successful and innovative series of V-8 engines in production history.
Really? if that's true then Ford should definitely kill themselves for not using the latest evolution of the mod series engines in the latest GT.

blog.caranddriver.com/time-is-running-out-for-bentleys-6-8-liter-v-8-but-not-in-a-hurry/
god dam I thought they were done by now

people confuse complexity with engineering

often the simplest solution is the best

old but a goody

cheersandgears.com/forums/topic/15551-a-case-for-the-pushrod-engine/

gts-r blue pearl i think

Yeah it's the best. Pushrods are the best, god bless based GM, all the other brands have inferior minds. They aren't doing that because pushrods are cheaper and biased Americans will defend American made shit anyway
>GM is working on a DOHC LS engine
That's because they like a challenge and had money to spare on degeloping a worst engine

...

We can start. I'll design the logo

How bad is your screen user

It's obviously a very dark navy blue

The more control you have over the opening of a valve you have the better. At lower rpms this isn't as big of a factor.
If you are concerned about hp/l you are a moron. Hp/weight, HP/size, and hp/unit of fuel consumed is what is important.
For a while pushrods were at a pretty clear disadvantage, late 70s, 80s. But GM, and to a degree Mopar, stuck with it and technology became available to makes ohv engine compete with ohc.

They will both probably be evenly matched until retired by individual solenoid controlled valves or electric drivetrains.

>gm needs 7 litres to make less horsepower than a naturally aspirated 5.0 dohc engine
everyone ignores this, jej

voodoo is more reliable as well lmao

Pushrods is awesome for a low revving high torque engine, something like a huge Diesel engine in a truck
Not in a high reving sports car, it won't rev or even be reliable if you drive it hard
It's not too hard to imagine the stress of all those parts moving on a ohv in high revs

Lmao, pushrods work for the LS/LT engines. They're simple, they're light, and they work. Why do you hate having 600 HP in an engine you can squat?

The need to rev is completely subjective, if artificial displacement limits are not imposed. All that matters is a good power curve over the RPM range that your gearing uses.

That laminar flow is extremely effective at high speeds. A boat doesn't need much wind to move.

I'm thinking the diffuser is too flat. Needs to be an egg curve as fluid simply doesn't like to fill out corners. That's a fact.

I agree now about the full underbody diffuser. If I built a car, it would be designed around that.

as for DOHC or pushrods? Neither.

because you will have to squat it a lot from the engine bay

>often the simplest solution is the best
true, DOHC is simpler than pushrods, just a simpler design for the same purpose.

Turbo Diesel cars nowadays also have a very good power curve and power outputs, they are even pretty quick in the straights but is it a real sports car?

bomp

The only thing that even slightly passes for an objective definition of what a sports car is is the winning of LeMans crowns the car the best sports car of that year.

So yes, some diesels have been sports cars :D

OHC is just as old OHV, dummy.

An LS is a larger displacement yet is't smaller and lighter than even a DOHC V6 let alone a DOHC V8. What's the point of comparing HP/liter or cubic inch?

I can apreciate diesels for that, but they aren't really sporty, just really good at holding speeds and in a endurance race they have some advantages, but they can't compete in a hot lap

>2 valve heads

Top kek

Wrong

What in the actual fuck am I looking at?

>plotted torque curve, 1mm = 1lbft
Nigga wat

>The Fagmobile

even if it was smaller, it still is inefficient and a unreliable truck engine for a sports car.

The revolver cam engine

youtube.com/watch?v=uJSLDq7MkhQ

It's made to spin a propeller, but I think it could spin a torque converter just as well.

We did once

or twice

I was expecting a rape van

I will have built the cringiest embarrassment of a Veeky Forums car by summers end. Mark my words

I mean I guess we did have the party van

If it's so unreliable why is it used in planes, desert racing trucks and boats? How is 1700 streetable HP in a package smaller and lighter than a V6 inefficient?

B8

Each engine is different, but a pushrod engine won't be a reliable car if driven hard on a track, compared to a DOHC anyway

Both designs have advantages and disadvantages.

Pushrod and rocker arm engines are typically easier to adjust the valves. Simplicity of design and is well suited for the lower operating speeds. The downside is more parts, and less accurate valve control at high RPMs. Long, slender pushrods are susceptible to flexing at high speeds.

Overhead cam engines reduce the number of moving parts, and do a better job of opening and closing the valves at higher engine speeds. The tradeoff is usually more difficulty in making valve adjustments. There is also the issue of how to drive the cams, whether by chain, belt, gear. This increases the size and complexity of the cylinder head castings, but the rewards are more accurate valve timing and way more capable at higher operating speeds.

>but a pushrod engine won't be a reliable car if driven hard on a track
which is why the c6r rapes the competition and nascars run hundreds of miles per race running 5000-9000 rpm

>but a pushrod engine won't be a reliable car if driven hard on a track

Explain how pushrod powered boats run at full throttle all day without a hiccup then...

literally water suspension. superior to springs

oh and for the record I disagree with the statement that led here. I'm just playing devil's advocate.

pushrods are great for a track. the engine is nice and safe there. In fact, when you get to higher RPMs, you might as well opt for pneumatic valves and forego the discussion altogether.

>run hundreds of miles per race running 5000-9000 rpm
>after each race engine rebuild
I mean I get what you mean, they aren't that bad, LS engines are actually really good, but they have the wrong valve design, it would be a better engine has a DOHC

Your on catfucker

Yeah, but you can't really expect it to do 300k miles do you?

Why did you idiots bump this?

Because Americans are stupid and they microwave their shoes after wearing them around in their homes.

bump

>Overhead cam engines reduce the number of moving parts
>4 cams vs 1
Am i missing something or am i just retarded

>Turbulence is the enemy
skin drag is much greater for laminar flow than turbulent flow

because of this image

F1 engines cover more distance per race and undergo a lot more stress throughout that period
Nascar would be running ohc if rules allowed but of course it's a spectator sport and the retarded rednecks won't have any of that

nascars are faster than f1 cars.

...

Comparing NASCAR and F1 is like apples and oranges. NASCAR is a competition of driver skill, F1 is a test of a cars ability.