They may think, if they made such a car, sales would increase. They'd market the car as if it's nostalgic, or they'd play up the mid-engine... Maybe it will even be a lower cost, although certainly no time soon... Then again, this model would be years away, if it ever happened.

It's not like I can help the fact the OHC is in full swing... Even GM is in the game, and has been for over 2 decades now(longer aside from V8's). Most people don't know an engine type from a hole in the ground. It's the engineers, designers, etc. who make these things "the norm." ... AT the behest of our government, mind you. It's not like the OHV is banned, or anything... But they've placed so many restrictions on them, manufacturers are moving on.

A few yrs ago, M-B designed and built a OHV which it took to INDY and evidently smoked the competition with, and the engine(apparently along with it's design) was promptly BANNED from INDY racing... Why? I have no idea other than it rubbed "the establishment" the wrong way... Prolly because it was cheaper and still made more power and lasted the race, etc. It's been awhile since I read it, so I don't remember the details.

But hey... The newer diesels are doing the same as far as I'm concerned(not in IRL). BIG power and torque, low RPM, long life, efficiency... Not much to not like.

There ya go... which is a small part of why it's here to stay.

By the same token, millions of people feel this way about a well tuned OHC engine, particularly in a sports car. It's not like Ferrari's and so forth aren't popular, even amongst those who will never own them.

Eh... I never cared for the Talon, and while I think the 4G63 was a fine engine, I never wanted one. On the other hand, I like BB's for ALL the wrong reasons!! Those are good examples of give and take though... BB's are never likely to allow for good economy. 4 bangers aren't likely to ever perform as well as BB's. A happy medium is a smaller V8, or a larger V8 "spun from" a smaller V8... Like the LS series.

 

Guys the C7 will just have a makeover, it's the C8 that is rumored to have a major redesign. Over the years I have seen a few automotive rumors regarding new cars that were to be and they never were. If any major changes do take place it will be many years down the road. This world is changing fast so no one knows for absolute sure what will take place in the future.

Right now GM is banking on the Chevy Volt to be a big seller. I hope it does well for GM. GM will also be releasing a couple of small, sporty fuel efficient models soon. The Camaros are selling pretty well for GM. My point being that GM needs bread and butter cars to be competitive, not just specialty cars.

To keep this on topic, GM knows how to build OHC multivalve engines, we all know that, they also know how to build pushrods OHV engines better than anyone, we know that too.



.

 

GM will eventually go 4 valve. even if they only take the (pushrod) 4V heads off the duramax and engineer them to fit the gen III+ blocks and beef up the valvetrain to take 6000+ rpm, they'll sooner or later go 4V. they have to, pretty much. think about it... back in 1997 the LS1 was making 350hp at 346 CID. now we have a 6.3L making 430hp 13 years later. with emissions getting tougher i don't see how GM can stay competitive with 2V V8s. with pushrod 4V heads you can still have have your compact LS engine. just with much more power.

ford's new 6.2L is making, what, 412hp? that's with the 2V heads. knowing ford, they have a 4V version on the drawing board, if not already built and being tested as we speak. do some simple math... the current 5L is making over 400hp... take that same hp/L and stick it to the 6.2L with the new 4V heads and you have over 500hp. from 6.2L and without direct injection! plus with the newer VVT that allows ford to manipulate the intake and exhaust cam timing independently, there's no telling what they can do with this engine. heck, stick a variable intake manifold on it too... they had that for years on the aviator. with all this tech, just tune it right to make power to 7,000rpm or beyond, and they could probably get to 550hp+ all motor and still make emissions. that's beyond the LS7 with 40+ less cubes.

someone said earlier the modulars were crap without boost. that's nonsense... even back in 2004-2005, there were some built 4V 5.4L modulars (still at 330CI) making over 600hp and still very streetable. when you can make power to 8000+ rpm reliably (OHC loves rpm) without a lot of cam, you don't have to make a lot of torque to make horrendous power. that was before the GT heads became the norm too. you can't deny the power 4V heads give. and the modulars are damn strong... quite a few turbo 4.6s with FACTORY heads, block, AND crankshaft have gone 1200hp+. one or two have gone 1500hp+ at over 10,000rpm. they're like V8 versions of those friggin supra engines... just shoot the boost and rpm to it and make unreal power. they're strong.

adios

 

Doubt it, they've done OHC engines in the past, all of which have been over shadowed by the LSx series being smaller, lighter, just as powerful or more so, and cheaper.

The LS1 was making 345hp back in '97 because the engineers only wanted 345hp. Do you think GM engineers suddenly just figured out with a little bigger cam and better flowing heads the engine would make 405hp (Im referring to the LS6). And once again, they only wanted to make 405hp, not more, and no where near the potential of the engine.

Except hp/l is ricer math, and useless in comparing engines.

Yet, physically MUCH bigger than the LS7, heavier, and probably more expensive. Who cares about "less cubes" that gets you nothing.

Let me ask you (and others) something. Say you want to build a kit car and you have two engines to pick from. For simplicities sake both engine make the same torque/power curve.
A) 4L engine, 520lbs, bigger, bulkier
B) 6L engine, 400lbs, smaller, more compact
Which would you choose?
Do you see why displacement is irrelevant in the real world?

 

You're not going to see a mid engine 'vette (especially with a TT V6) at a lower cost than a base C6. The extra engineering they have to do to get the completely new chassis working right, let alone a new engine and everything to go along with the forced induction is more than enough to put it past the price.
There have been mid engine vette rumors since the 60s. One of the original engineers had always wanted to make the vette mid engined, but it never happened because of the complexity involved to keep it at a reasonable price.

No, its the marketing teams that make things the "norm", using words like "high tech". GM even admits to it:
http://www.caranddriver.com/features...its_due-column
"So if the pushrod design makes such a good V-8, why does GM make a DOHC V-8 Northstar? "I'm not going to touch that one," laughs Winegarden. GM's party line is that some customers want what it calls "high-feature engines." Winegarden does admit there are some refinement benefits to the DOHC layout, but personally, I don't find the Vette's engine to be a bit unruly. "
More reasons GM went with a pushrod V8:
http://www.corvetteactioncenter.com/...t5-engine.html

 

They say a picture is worth a thousand words, couldn't be more accurate here. The interesting thing to me is that the ls engines are being accused by some as being antiquated and old. However, when I look at those pictures I see a modern, compact, efficient package next to a bulky, over-engineered hunk.

Some things just work.

I see most of this argument as just a spin off of how the imports were going to take over the hot rodding world in the 90's and all of us v8 guys had better just enjoy our last few days of relevancy.... good thing that turned out.

 

One of my favorites

Well said and exactly why I swapped my motor out for the LS. I lost 100 lbs and gained 2 liters of displacement. Not to mention an enormous amount of power, efficiency and better mpgs. Hp/L means nothing


On the other hand, there is room for improvement. But I don't think GM will move to a 3-4 valve head with the ls series to find that extra efficiency.

 

sinistered........absolutely everything you posted was dumb

if its all so badass why is there 6.2l and their 5.0l making very close to the same power? yes mod motors are junk without boost the reason being yes having 4v heads allows for alot more airflow BUT the set up of ford motors is that that extra flow cant be taken car of because you cant put alot of cam in a mod motor and not over cam it so boost is needed to take advantage of that flow..

secondly a stock cube 5.4 or and ford mod motor makin 600rwhp n/a and being streetable. those motors just dont make power wihtout some type of forced inductionc or spray. the fastest n/a mustang around here is a mach1 that runs 12.7 and thats only kuz he has badass suspension and gears. short of him in all my racing out on the streets i havent raced a single ford mod motor that was n/a that was even worth a second look

 

Not when you're talking same displacement it isn't. If one 6.2L is making 400hp and the other 500hp, both emissions compliant, hp/l is reality math. It's the reality that technology has the upper hand now-a-days. Just throwing displacement at the problem isn't going to cut it anymore.

Since Ford's 6.2L is matching GM's 6.2L with 2v heads, what do you think is going to happen when the 4V heads are thrown in? It's kinda obvious.

I've never said the LS engines are antiquated, but they are falling behind and GM better get on the ball. Direct injection on the GenV will be a plus, but it won't be a savior... Ford's 6.2L doesn't have it yet either. Having raced motorcycles my whole life, I've never seen a 2V head beat a 4V head on the same engine.

No pissing contest intended here... just excited to see that competition is getting hot again. GM will respond accordingly (or at least we hope so), and it's all of us who benefits.

I'm 100% GM FYI. I am intrigued by Ford's latest offerings though...

 

Dumb... really? I'll leave it to you to prove that "absolutely everything" was dumb.

Because the 6.2L is using 2V heads while the 5.0 is using 4V heads. That simple. If you've ever seen a 2V 6.2L head, it's painfully obvious a 4V setup is going on there sooner or later.


The saying "keep your friends close, keep your enemies closer" applies here. You may want to inform yourself a little more about the other side. Just because you "haven't seen it" or, more likely, don't understand it, doesn't mean it doesn't exist. It does get expensive with all that valve train, but they can make some serious power NA. It's a lot cheaper to boost them. The average joe out there is going for the cheapest option... how much does it cost for a H/C/I versus boost on a LS engine again?

 

BTW, unlike the old modular's 100mm bore spacing, the bore spacing on the new 6.2L is 4.53" (115mm).

Remember what a LT5 could do with 400+ cubic inches?

 

Ricer math either way because displacement doesn't show what matters, size and weight of the engine.
What if the 400hp 6.2L is 400lbs and the 500hp 6.2L is 600lbs and so wide it wouldn't fit in most cars?
The reality is comparing displacement (or peak hp to displacement) is irrelevant to anything real world.
What you are failing to see is GM has generally larger displaced engines for a better powerband, not more peak power. And if adding displacement to a current engine doesn't effect size or weight, but yields more power at every RPM then what is the disadvantage?

The engine will gain considerable weight and size (already over the hefty weight its currently at) cost, and complexity. These aren't bike engines...
Ill post this picture again, the engine on the left has less displacement...

Or this (Fords 5.4L OHC vs 5.0L OHV) The 5L is very close in dimensions to the LS1.


Again I think what you are failing to see here is these are street production cars, they are NOT trying to get the most power from their engines, not by any means. If that were the case things would be much different, buts it not the case. They only WANT ~420hp from their engine, they start with a power goal FIRST, not with an engine first and get the most out of it. So why not use the smaller, lighter design to reach that goal?

 

God sintered. Not another pissing match. 3 posts in a row really? Just to defend your point? These are technical forums attracting people interested in finding technical (theoretical) conclusions.

I think JD hit the nail on the head. If GM was interested in extracting EVERY little bit of hp they would've built something like SSC did with the Ultimate Aero with 1287 hp and 1112 lb ft of torque...based on the LS....out of a production vehicle. Peak HP means nothing, the ricers managed 2000 hp out of a 2.0 @cura 10 yrs ago. Does this mean it's a better motor. No. 2000 hp peak out of a given displacement is a moot point. It's cool, but nobody but high school kids give a ****. Top fuel has managed to extract 7000 hp from 2 valves...with push rods.
Even with nearly 3000 CFM, the fuel mixture is compressed into nearly-solid form before ignition. Cylinders run on the verge of hydraulic lock. Again with 2 valves and the basic push rod design.

 

first of all these guys are exactly right because peak horsepower doesn tmean a damn thing if it runs like *** until 7k when it starts to make power because who the hell is gonna wanna drive that.

secondly a a n/a 5.4 would be astronomiclly expensive to build to make 600rwhp and if it ever did it would be rediculously undrivable. when you start makin power 2 things should come to mind. money and streetability and a ford mod motor just plainly isnt the platform for either one of those things to work. you would be so upsidedown in that motor tryn to squeeze 600rwhp out of it n/a it would be insane. and again if it ever made that kind of power it would probably grenade the first couple months of normal driving around.

those motors just are way way to picky to do anything with n/a they just need boost

 

The 6.2 is a truck engine(currently) and it's a 2V... Of course the power will only be close to a 5.0L DOHC made for a performance car. Considering the performance advantage seen over a 3V SOHC 4.6, there's little doubt a 4V 6.2L will make serious power, probably well over 500 with the other parts being essentially the same as they are today. It already makes more torque, in 2v form than the 6.2L in the new SS... It won't get less with 4v heads.

When you have 4V per cylinder, you don't also need large cams to move the same amount of air as a 2V with only 1 cam. That's the major advantage of multi-valved heads. They move more air with less lift and duration than 2v OHV heads. That's the main reason for their design/use. It's also why GM is using 4V instead of only 2, in their Northstar.

There's a reason for all that, beyond trying to do their best... They're not allowed to use 4V DOHC heads. They're not allowed to use turbos either.

When we're talking about all out racing, there's hardly anything that will beat a DOHC engine, given the same engine displacement. Engine overall size matters, but weight it's as big a factor as some believe. Even so, DOHC engines fit into most engine bays and most manufacturers design that bay around the intended engine and not the intended engine around an engine bay.

For drag racing, all that matters is getting to the other end 1st, while following the rules. DOHC's have proved to be capable, end of story.

They don't HAVE to be N/A ya know... Anyway, there are already such engines built and they seem to be doing okay.

Then why are people using DOHC Fords so successfully in racing? It's NOT all about N/A power for a racer, unless he/she is class specific. There have been 600+rwhp Fords on the streets for years already. If all we're talking about is making power, forced induction is the best way(in a car) and it doesn't matter what kind of engine.

Anyway, this isn't about the Ford mod motor, it's about GM going the same basic route, which they're doing, just not in Chevrolet's performance vehicles. Ford's engine simply happens to be a good starting point to see what can be done, since they've been doing it so long with their performance cars.

There are already race built 550hp 5.0L DOHC's and they're winning races... road races... I don't think the odds are high they'll just grenade. One thing about the DOHC modular is, it is extremely durable. Those engines have been known to hold together with basically stock internal parts well over 700hp in street drivers and over 1,000hp in race applications. There was a 5.4L version in a ...gasp... Mustang... running low 7's in 2001... How much power does that require? The factory block held together, along with it's factory crank and factory heads. I think they even used the factory cams.

Matching 6.2L power with a 5.0L doesn't match up to this comment in the least. We've already seen 10's in N/A form. I don't know how much power it has, or how much the car weighed, but I don't care either. The point is, they're doing it and they've only been in street cars for a couple months.

It is what it is... Hating it won't help your plight. I'm not telling you to embrace it, just that talking badly about it won't change the facts.

 

Has anyone here ever built a mod motor? I say screw the DOHC. It costs a billion times more to work on.

for example cams for an 03/04 cobra ~2000 dollars

 

Way back when the 4.6 mod motors first came out I was browsing through the trusty Motorsports catalog and happened to look at the dimensions of the engines. The DOHC 4.6 is nearly exactly the same length as the giant 460...and the 460 without carb turns out to be shorter and narrower.

It amazed me how large the 4.6 DOHC really is. Harder to stuff that big of an engine lower and farther back in the chassis.

 

I worked on some back in the late 90's and early 00's... They get expensive in a hurry and tear down and rebuild was a real pain and time killer, but people who want to build them do it anyway. The cams for an 03/4 Cobra argument isn't worthy... With factory cams, that engine can be monstrous in the power and torque department. There are guys spending less than $1,000 and making 500hp. Well, I don't even remember anymore, but I know some are up in the 600+rwhp and I'm told the cams are stock. Replacing cams and more, some are well over 700rwhp and fully capable of being daily drivers. If I need to spend 4K or even 6K beyond original cost to get that kind of power, and that's what I wanna do... Not a big deal. It's the same basic bill to build a 700+rwhp LS1.

To match that output even with a 6.2L, you'll need a power adder and/or a complete engine overhaul with all new internals. Do you think you may go over $2,000? Over 4? You bet you will. It all costs money. I just looked at a random website offering Crower and Comp Cams sticks for the 03/04 Cobra... $1,080.50 for all 4 cams in any stage, 1, 2, or 3. That's expensive, but not nearly 2K. The cylinder heads are far and away more expensive, at about $1,500 each.

 

your name explains it all. Keep hoping ford will make something that'll run with an ls1( a motor not even in production anymore). Amazing how ford seems to be about 10 years behind on everything. You probably dont know this but 5.4 heads used to blow plugs out alittle fyi

 

You're absolutely right, no turbos. Just the biggest most badass blowers ever put on an automotive application. From now on you are required to wikipedia all of your comments before pushing the "submit reply" button.

Complexity does not mean a more efficient motor, the bottom line is efficiency. Not the amount of valves. K.I.S.S. is a well earned abbreviation. Many manufacturers (including GM) abide by this religiously to retain big power and big reliability.

You do have a good point using smaller dur cams (with DOHC 4v) and optimizing the head to use the dur and lifts, but this can also be done with a 2 valve design the same way, just like GM did, which is what this discussion is about.

End of story? Who are you? end of story that's funny. Again we're here to discuss. you sound 16 and a HALF


Yeah and the Northstar has been superseded by the LS motors...Ya know the non DOHC ones. Fact. end of story

Facts? Did your mom confirm these "facts" or was this another Ford thing?