Car and Driver pulled up some interesting numbers about "low tech" engines.

[Demon-Xanth]

Page 34:

The Z06's pushrod V8 which makes 405HP from 5.7L, compared to the Porche Cayenne S V8 (DOHC 335HP, 4.5L), and the Northstar V8(DOHC 320HP, 4.6L). The Z06 is 6 inches narrower than the Porche, two inches shorter than the Caddy, and about the same length. It's also 44Lbs lighter than the Caddy engine. By only using pushrods they estimate $400 savings and increased reliability.

Pushrods: smaller, lighter, cheaper, more reliable, and more powerful. So what's the down side?

 

[Vette73]

Originally posted by: Demon-Xanth
Page 34:

The Z06's pushrod V8 which makes 405HP from 5.7L, compared to the Porche Cayenne S V8 (DOHC 335HP, 4.5L), and the Northstar V8(DOHC 320HP, 4.6L). The Z06 is 6 inches narrower than the Porche, two inches shorter than the Caddy, and about the same length. It's also 44Lbs lighter than the Caddy engine. By only using pushrods they estimate $400 savings and increased reliability.

Pushrods: smaller, lighter, cheaper, more reliable, and more powerful. So what's the down side?

Does not rev as high, can't do VVT, usually more loud, on paper the OHC motor should get better gas milage(everything equal of course), people want the newwest tech even in their cars, etc....

I have a old Monza that will be getting a 1 peice rear main seal small block chevy, but OHC has advantages and so does pushrod. Juts depends on application.

 

[Demon-Xanth]

I have no problem swapping out an engine that makes 230HP@7000RPM and 180LB/ft@6000RPM with an engine that makes 230HP@4500RPM and 295LB/ft@2500RPM if the weight and size is the same.

As far as variable valve timing goes, consider that the engine in the Dodge Magnum shuts off some of it's cylinders by forcing valves closed instead of letting them open. There's no good reason why variable valve timing can't be done, but there's no really good reason why it needs to be done.

Sure, they don't rev as high. Pushrods can spin to 7000RPM on the street without major work. That's pleanty high for almost every application. Especially going down the freeway at *cough*65*cough* miles per hour.

 

[Savij]

Link to the article from this thread

 

[Eli]

No reason for VVT?

Crack. Pipe. Down. Now.

The ultimate engine will have IVVT, IVVL and IVIT.

 

[Demon-Xanth]

Savij: doh!

Eli: the ultimate engine is easy to work on, cheap, and powerful.
VVT comes with added complexity, cost, and reliability concerns. There's no such thing as a free lunch in engine tech.

 

[OS]

Originally posted by: Demon-Xanth
Eli: the ultimate engine is easy to work on, cheap, and powerful.
VVT comes with added complexity, cost, and reliability concerns. There's no such thing as a free lunch in engine tech.

huh, and yet Toyota puts it on basically every production engine they have.

 

[Demon-Xanth]

OS: and Toyota's "sports car" Celica GTS costs $25k and is slow. With VVT came the cost of making it reliable and mitigating the reliability concerns. I could compare the Celica GTS with the Mustang GT, but that wouldn't be a fair match since the Mustang has a V8.

 

[ThisIsMatt]

Originally posted by: Demon-Xanth
I have no problem swapping out an engine that makes 230HP@7000RPM and 180LB/ft@6000RPM with an engine that makes 230HP@4500RPM and 295LB/ft@2500RPM if the weight and size is the same.

As far as variable valve timing goes, consider that the engine in the Dodge Magnum shuts off some of it's cylinders by forcing valves closed instead of letting them open. There's no good reason why variable valve timing can't be done, but there's no really good reason why it needs to be done.

Sure, they don't rev as high. Pushrods can spin to 7000RPM on the street without major work. That's pleanty high for almost every application. Especially going down the freeway at *cough*65*cough* miles per hour.

It's also harder to build a tranny that can handle higher low end torque than high rpm...

 

[Demon-Xanth]

Low end torque requires larger components or better designed gears, high end power requires better bearings and cooling. But like I said, how fast do you rev on the street? The only vehicles I know of that rev high on a regular basis have two wheels.

 

[Colt45]

I don't think the 350 will ever die. a hundred years from now, you'll still be able to buy small block chevy's and parts.. unless we run out of oil.

 

[ThisIsMatt]

Originally posted by: Demon-Xanth
Low end torque requires larger components or better designed gears, high end power requires better bearings and cooling. But like I said, how fast do you rev on the street? The only vehicles I know of that rev high on a regular basis have two wheels.

I'm just saying that it's easier for them to build trannys around a high rpm, low low-end torque engine. That way people can jam on the gas and not tear their tranny apart, as opposed to someone jamming on the gas in a high low-end torque engine...

 

[OS]

Originally posted by: Demon-Xanth
OS: and Toyota's "sports car" Celica GTS costs $25k and is slow. With VVT came the cost of making it reliable and mitigating the reliability concerns. I could compare the Celica GTS with the Mustang GT, but that wouldn't be a fair match since the Mustang has a V8.

I don't see what the celica has to do with the discussion at hand. The 2zz engine is good enough that Lotus is using it in the elise. It's not even that slow considering with a familiar driver it runs high 14s bone stock.

The entire automotive industry is putting VVT in cars that can easily take them (OHC). Even GM econoboxes are getting VVT now. It would not surprise me at all if in the coming years the mustang/ford's OHC V6/V8s also got VVT.

The irony, even domestic cars are getting *VTEC*.

 

[Demon-Xanth]

OS: but a crappy driver can get a Mustang GT into mid 14's. A guy at my work who had a heavily modified CRX watched a Firebird pull 15's. He talked to the guy and found out that traction control was on. He agreed to turn it off, and my coworker (who had never driven a RWD car) pulled 13's. First time out. Currently the only cars that I consider fast in the $25k range either feature V8s or feature turbos. If you're calling high 14's fast while others are doing high 13's for the same price, does that make them superfast?

 

[Demon-Xanth]

OS: and the reason why VVT and DOHC are appearing in more and more cars is due to the market's lust for acronyms. People have no CLUE what they mean, but they know that it helps so they MUST have it. Just like LCD monitors, bottled water, sports bars, and 10,000W car stereos.

 

[vi edit]

From real world experience in non-sports cars, DOHC engines have better highway speed passing power than a pushrod of equal stats.

Go hop in a GM 3.4L OHC or the Ford 3.0L OHC get behind a car doing 55 MPH and try puching it to pass them. It's hopeless. In my 30 valve 2.8L Passat or a 3.0L Nissan VQ the results are much different. They get up and run much better than the shortwinded OHC engines.

The DOHC 3.4L in my old Monte Carlo was also better at passing than the 3800 series that's in there right now.

But, the 3800 gets better milage and is indeed cheaper to work on.

Each has it's merits.

 

[OS]

Originally posted by: Demon-Xanth
OS: but a crappy driver can get a Mustang GT into mid 14's. A guy at my work who had a heavily modified CRX watched a Firebird pull 15's. He talked to the guy and found out that traction control was on. He agreed to turn it off, and my coworker (who had never driven a RWD car) pulled 13's. First time out. Currently the only cars that I consider fast in the $25k range either feature V8s or feature turbos. If you're calling high 14's fast while others are doing high 13's for the same price, does that make them superfast?

I'm not interested in your V8 pissing match. Did I ever once say the celica was "fast"? I don't see how you can consider a 14 second car slow, but a 13 second one fast. In fact, I'm not even sure what this has to do with the merits of VVT.

The camaro/firebirds died out because no one wanted to buy them. Being fast in a straight line alone isn't enough to secure a place in the automotive marketplace. The fbodies had horrible build quality and ergonomics, interior pieces were loose even when the car was new, sitting in dealer lots and there were strange bumps on the floorpan.

As for your theory in VVT marketing, it doesn't float because most new cars you don't even know it has VVT unless you dig around under the hood or read all the specs. Do you think people who buy camries and corollas really give a f*ck if it has VVT or not?

 

[Chadder007]

Originally posted by: Demon-Xanth
OS: and the reason why VVT and DOHC are appearing in more and more cars is due to the market's lust for acronyms. People have no CLUE what they mean, but they know that it helps so they MUST have it. Just like LCD monitors, bottled water, sports bars, and 10,000W car stereos.

What is WT?????

Edit: on wait....is that V V and not W? As in Variable Valve Tech?

 

[Bulk Beef]

Variable Valve Timing

 

[Zenmervolt]

Originally posted by: Demon-Xanth
Page 34:

The Z06's pushrod V8 which makes 405HP from 5.7L, compared to the Porche Cayenne S V8 (DOHC 335HP, 4.5L), and the Northstar V8(DOHC 320HP, 4.6L). The Z06 is 6 inches narrower than the Porche, two inches shorter than the Caddy, and about the same length. It's also 44Lbs lighter than the Caddy engine. By only using pushrods they estimate $400 savings and increased reliability.

Pushrods: smaller, lighter, cheaper, more reliable, and more powerful. So what's the down side?

A 4-valve head with pushrods would be a nightmare. And heads with more than 2 valves provide big gains in specific output.

ZV

 

[Kilgor]

The camaro/firebirds died out because no one wanted to buy them. Being fast in a straight line alone isn't enough to secure a place in the automotive marketplace. The fbodies had horrible build quality and ergonomics, interior pieces were loose even when the car was new, sitting in dealer lots and there were strange bumps on the floorpan.

Have you ever driven a Camaro? They were more than fast in a straight line I'll grant you from the factory they were not the best cars on a slalom but if you put them on a real race course they could more than hold thier own. They were not the turds that people make them out to be. GM just didn't want to invest the money it would take to keep the name alive and redo the Camaro the way they should have.

BMW Z8 Lap time 2 minutes, 13.30 sec

BMW M Roadster Lap time 2 minutes, 17.28 sec

Chevrolet Camaro SS Lap time 2 minutes, 16.46 sec

Chevrolet Corvette Z06 Lap time 2 minutes, 8.39 sec

Honda S2000 Lap time 2 minutes, 17.66 sec

Acura NSX Lap time 2 minutes, 14.15 sec

Ferrari 360 Modena Lap time 2 minutes, 7.65 sec

Ferrari 550 Maranello Lap time 2 minutes, 9.25 sec

Porsche Boxster S Lap time 2 minutes, 17.46 sec

Porsche 911 Turbo Lap time 2 minutes, 10.73 sec

 

[ElFenix]

Originally posted by: Zenmervolt And heads with more than 2 valves provide big gains in specific output.

ZV

so does less displacement


plus, specific output is pointless when the other engine weighs less and is physically smaller, in addition to making more torque and horsepower.

 

[ElFenix]

Originally posted by: OS

The camaro/firebirds died out because no one wanted to buy them. Being fast in a straight line alone isn't enough to secure a place in the automotive marketplace. The fbodies had horrible build quality and ergonomics, interior pieces were loose even when the car was new, sitting in dealer lots and there were strange bumps on the floorpan.

wtf does that have to do with a discussion of OHC vs pushrod design?

 

[PlatinumGold]

Originally posted by: ElFenix

Originally posted by: OS

The camaro/firebirds died out because no one wanted to buy them. Being fast in a straight line alone isn't enough to secure a place in the automotive marketplace. The fbodies had horrible build quality and ergonomics, interior pieces were loose even when the car was new, sitting in dealer lots and there were strange bumps on the floorpan.

wtf does that have to do with a discussion of OHC vs pushrod design?

nothing at all. i think OS seems to have forgotten what the discussion was about.


just admit the guy in the article had a point.

there is a place for pushrod engines. that was his claim and it was a valid one. this is similar to that disc vs drum brake thread.

sure discs are better, but is there that much of a difference between 4 wheel discs and disc/drum combos?? not really.

 

[Howard]

Originally posted by: Demon-Xanth
OS: and Toyota's "sports car" Celica GTS costs $25k and is slow. With VVT came the cost of making it reliable and mitigating the reliability concerns. I could compare the Celica GTS with the Mustang GT, but that wouldn't be a fair match since the Mustang has a V8.

That's like saying Dell sucks because they use Intel CPUs. Compare apples and oranges, please.