So many people down with the pushrods

[Oversteer]

Ahh, its too bad the ricers of the world can't see past the short hoods of their fart canned civics to realize how the automotive industry was built. They look down on those with pushrod engines as if it is the worlds worst engine design. Now I will be the first to admit that the DOHC's have definetly proved themselves, but look at the recent comparison in Motor Trend and see how much better the DOHC supercharged 5.4 Ford GT compares to the 7.0 pushrod LS7 Z06 Vette. For 100,000 grand more you get little to no performace improvements over the all american sports car and less fuel economy also.

Fuck the ricers and thier bullshit.

The opinions of this post are based on articles read in Sport Compact Car and Motor Trend magazine.

[Shaun41178(2)]

I fail to realize the point of your post.

I will say the ford gt motor can take a lot more then what comes from teh factory. Hell even a stock block 4.6 cobra motor can handle 600 whp with ease. Thts about 700+ crank hp. So its not like it can perform.

The 5.4 can prob do 700 whp with bolt ons. It will be much harder for a stock block Z06 LS7 to do that.

Not really sure where you are coming from though. Maybe you just finished smoking a huge bowl?

[The Dark Side of Will]

People think that valve gear = technology.

They don't stop to think that the Gen III and Gen IV V8's from GM have some of the most advanced FEA and CFD ever used to design a production engine.

They also don't stop to think that a pushrod engine:

is smaller/more compact than corresponding OHC engine

is lighter/simpler than corresponding DOHC engine

has lower CG than corresponding DOHC engine (except for horizontally opposed engines, of course, in which case the difference is a wash)



The classic example would be LS2 vs VVT Northstar. Both have similar design caliber. The N* has higher specific output and broader power band, but is larger and heavier than the LS2 and has less total output due to less displacement.

[Oversteer]

Hahahaha

Actually I did just finish smoking a really huge bowl and down a few glasses of Rye and Coke so I apologize if I was confusing. After and during my intoxification I was reading a couple of magazines. One article was referring to a person who now works on WRX's having a pushrod past. By this they meant he used to work on pushrod motors, owned a Camaro and apparently that is an embarrassment. Now owning a Camaro may be an embarrassment but not cuz its got a pushrod motor.

Then I read an article comparing the Z06 to the SRT 10 to the Ford GT and the Z06 came out smelling like roses as it was comparable or better than the Ford GT (and Viper for that matter) for $100,000.00 less than the GT. So I was just saying that there aint nothing wrong with pushrods, for the money to hp ratio they seem to be much better, but then again that’s just math.

I like pushrods, like the simplicity and so on. Just got offended by the article in the ricer magazine is all.

There is no replacement for displacement.

[Shaun41178(2)]

ok I see what you are saying now.

Yea SCC can be retarded sometimes.

Basically it was like 4 years or so ago when I still subcribed they turned me off. It was an article in the beginning of the mag, I think it was called "slip angle"

Basically they ragged and dogged on V8 motors and how they only have 2 valve tech and how race teams use carbs(Nascar), that V8's can't make high rpm hp and how everything is old school. They took a shot or two at Nascar.

Now we all know that 4 valves can flow more then two but they were just being retarded.

NASCAR engines spin to 9k for 500 miles. They also make 600 hp which is regulated somewhat by nascar too with restrictor plates. they would make a ton more without that. And to top it off, they do it with only 2 valves and old school Carb tech!! I mean WTF SCC!!!

You need turbos and 4 valves to make the same amount of power that a N/A V8 makes so STFU. Also Pro stock cars run 6 second qtr miles with N/A V8 2 valve engines with carbs!!! the import engines of course need FI to do the same thing.

SCC can be so dumb. I was so close to writing them a letter and rip them apart, but it would be pointless, because they wouldnt' publish it, or if they did, they would haev some smart ass comment and not have a good and thoughtfull retort. Not to mention it wouldnt' get them to wake up so it would be a waste of my time. I dont' subscribe to that mag anymore, but I will read it for free if it has some good cars in it. But fuck that Josh Jacquot loser or whatever his name is. SCC wont' get anohter cent of my hard earned money.

[p8ntman442]

all pushrod motors are better than dohc because they have less rotational mass.


And you will never get that V8 rumble with a 4cyl 4 valve turbo.


we need a "stirring the pot" smiley. :la:

[Aaron]

There is no replacement for displacement.

Actually, there is.

Forced induction and head flow. But assuming these are the same on both engines, then yes, the higher displacement engine will have the power advantage.

But that doesn't relate to pushrod vs DOHC, as the DOHC can have the same displacement and configuration of displacement.

[The Dark Side of Will]

There is no replacement for displacement.

Actually, there is.

Forced induction and head flow. But assuming these are the same on both engines, then yes, the higher displacement engine will have the power advantage.

Which is it?

[crzyone]

Suppose the new Z06 engine was fitted with a set of good flowing dohc heads. Its output just went way up.

I love when people argue HUGE displacement pushrod engines against "detuned" less displacement motors. I prefer a good comparison, like an LT1 Vs LT5. Same generation sbc's, one with dohc heads. LT1 makes 300hp, the LT5 makes 405. The LT5 is capable of huge NA hp, and I have a few vids of 9 and 10 second ZR1 corvettes.


How about Northstar VS. 4.9? The 4.9 has it beat in displacement, but the N* has dohc heads. 300/300 vs 200/275.

A VVT N* vs LS7 is a bad comparison from the start. One motor is in grandpa's caddy, the other is in Chevy's supercar. I know the N* is capable of making the same power output of the stock 7L LS7, but that is not the purpose they have for it. It has a nice smooth poweband and plenty of power for caddy owners. Lets not forget the LS7 has 2.4L more displacement than the N*.

[Kohburn]

People think that valve gear = technology.

They don't stop to think that the Gen III and Gen IV V8's from GM have some of the most advanced FEA and CFD ever used to design a production engine.

They also don't stop to think that a pushrod engine:

is smaller/more compact than corresponding OHC engine

is lighter/simpler than corresponding DOHC engine

has lower CG than corresponding DOHC engine (except for horizontally opposed engines, of course, in which case the difference is a wash)
.

in that thread on Old Europe - i never denied the advantages of pushrod engines
but their entire argument was that pushrod was better than dohc because a pushrod engine with twice the displacement could make more power than a dohc

it was just a stupid comparison - both designs have advantages

I don't think that pushrods are any more simple for an inline engine though.. in those cases OHC is really simple design and shouldn't add any weight just a little height, with fewer parts.

suibaru went from the DOHC 2.5 to sohc 2.5 because it was cheaper and since they didn't do any variable cam timing it was a waste to have the extra cam in there.

in the production car world it usually boils down to cost

people usually get stuck on comparing a specifc engine to another specific engine.. in those cercmstances a pushrod may be better than an ohc.. or the other way around.. but if you look at what makes each engine a little better and combined as much as possible without concern for cost like dohc with variable cam timing and the latest FEA with a new block, not modified leftovers from another engine.. from the ground up

anyways.. pushrods and OHC each have their advantages and disadvantages - engines always advance no matter which valvetrain they choose to utilize.. as is obvious the current pushrods are way superior to just 15 years ago, as is the latest OHC advancements

__________________________
engineers like to make things complicated, designers like to make them simple

[Oversteer]

I just think that people should respect both motors and their abilities. But ricers generally can't see past their OHC engines.

[Kohburn]

I just think that people should respect both motors and their abilities. But ricers generally can't see past their OHC engines.

ricers by definition think whatever they have is "THE SHIT" and is better than what anybody else has

don't take it to heart

[Aaron]

There is no replacement for displacement.

Actually, there is.

Forced induction and head flow. But assuming these are the same on both engines, then yes, the higher displacement engine will have the power advantage.

Which is it?

What do you mean? If everything on 2 motors is the same besides displacement, theoretically the larger displacement engine will have a higher power limit.

However, I would rahter have 100cfm than 1.0l of displacement. And I'd rather have 10psi than 1.0l of displacement. Head flow and FI replace displacement, they get more air into the cylinder, tricking it to perform as a higher displacement engine with small displacement.

[Shaun41178(2)]

ricers by definition think whatever they have is "THE SHIT" and is better than what anybody else has

t

Fiero owners are the exact same way. The FIERO CAN NEVA LOSE!!! fiero owners in general I think are ricers. I mean hell look at all the ghey shit that those loser in OE glue to their cars.

[The Dark Side of Will]

Suppose the new Z06 engine was fitted with a set of good flowing dohc heads. Its output just went way up.

How about Northstar VS. Peice of shit? The Peice of shit has it beat in displacement, but the N* has dohc heads. 300/300 vs 200/275.

A VVT N* vs LS7 is a bad comparison from the start.

New ZO6 already HAS outstanding cylinder heads. 360+ CFM on the intake ports, CNC ported from the factory, etc. And it spins to 7K... with pushrods.

N* vs 4p9 is a bad comparo because the engines are not comparable from the design standpoint. The N* design is of immensely higher calibre than that of the 4p9.

Which is why I chose the LS2 (NOT the LS7) as a basis for comparison. It is of similar design calibre and technology level to the VVT N*. Another good one might be the flat tappet N* to the LS1.

[The Dark Side of Will]

There is no replacement for displacement.

Actually, there is.

Forced induction and head flow. But assuming these are the same on both engines, then yes, the higher displacement engine will have the power advantage.

Which is it?

What do you mean?

You said that there IS a replacement for displacement, but then you said the bigger engine wins. Which is it?

[Aaron]

Will do you have the flowcharts for the new LS7 heads?

If not, well, quite honestly I doubt 360cfm. If so, I'd really like to see them!

Post them here please.

[Aaron]

You said that there IS a replacement for displacement, but then you said the bigger engine wins. Which is it?

There is a replacement for displacement, as often times it is physically impossible to get the heads to flow what the DOHC heads might. Let's take a 3400 vs a 3.4 DOHC. In this manner, you will never get 3400 heads to flow what 3.4 heads CAN after port reshaping/porting/polishing. Therefore, even if the 3400 displaced more, the 3.4 DOHC has more potential as it can acheive higher dynamic compression ratios as a result of the better flowing heads.

But, if you go all out, and make the pushrod 2 valve heads flow and combust equal to that of the DOHC, then yes, the displacement becomes the deciding factor.

I think you know what I mean, you're just being nit picky on my words. No problem with that though.

[Shaun41178(2)]

Will do you have the flowcharts for the new LS7 heads?

If not, well, quite honestly I doubt 360cfm. If so, I'd really like to see them!

Post them here please.

[The Dark Side of Will]

You said that there IS a replacement for displacement, but then you said the bigger engine wins. Which is it?

There is a replacement for displacement, as often times it is physically impossible to get the heads to flow what the DOHC heads might. Let's take a 3400 vs a 3.4 DOHC. In this manner, you will never get 3400 heads to flow what 3.4 heads CAN after port reshaping/porting/polishing. Therefore, even if the 3400 displaced more, the 3.4 DOHC has more potential as it can acheive higher dynamic compression ratios as a result of the better flowing heads.

But, if you go all out, and make the pushrod 2 valve heads flow and combust equal to that of the DOHC, then yes, the displacement becomes the deciding factor.

I think you know what I mean, you're just being nit picky on my words. No problem with that though.

No, I'm trying to get you to be consistent.

Head flow isn't everything.

You can get 600+ HP on 250 cfm in a V8, if you run a HUGE cam with a very narrow LSA. A bigger V8 with the same heads/cam will make more power because the larger cylinders pull "harder" on the ports than the smaller ones. No replacement for displacement.