OHC people tend to forget that nothing in life is free, and cost, weight, packaging, and relative performance are all trade offs.

I'll stick to low CG and low mass engines for my cars that turn.

 

like ive been saying though i dont neccessarily think OHC is bad its just not to where it needs to be on the technology front and alot of those types of motors are far to expensive to maintain and modify that they just dont work with the kind of money the average person has to spend. i think if it developed a little more and was a bit more of a proven technology it wouldnt be so bad

 

This was probably mentioned somewhere else, but there was a company making OHV 4V heads for the LS series engines which flowed over 400cfm on the intake side, but I'm pretty sure they ran out of money fast while making them, considering they don't sell them anymore.

EDIT: Here's the link, but I don't think they actually still sell them.
http://www.araoengineering.com/LSX.htm

 

The same thing it's been getting for the past 40yrs... MONEY! Those parts aren't free and for every single one sold, the government gets a cut. So they force manufacturers to add parts, growing the governments income with each. The government doesn't have to pay for any of them. They simply reap the rewards. SMOG garbage started in the 1970's and that caused manufacturers to spend more, hire more people, design new parts, etc.

Remove all that crap from a new LS7 and look what happens to the performance... It goes up, including economy, I'm sure.

http://www.chevrolet.com/corvette/coupe/features-specs/

I only looked as far as the Chevy website... But I wasn't looking for cars they USED to produce, only those they make today. If you wanna look back, we had cars making between 29 and 35mpg back in the late 80's. They were all 4 bangers, but look today... They're either even smaller or they're Hybrids. The reason... largely, emissions equipment and other government mandated additions. Thing is, we're not buying new 1988 models anymore...

 

Some very intresting ideas being kick around here. and Very nice to see everyone keeping it civil and no arguments starting, esp as its a touchy subject!

I think if people are after an economical car then they need to be looking at a modern deisel engine. Im sorry but when you look at something like BMWs 335/535 engines you have to sit back and take note of what they are doing! these are briliant engines form the factory and will make stacks of power and torque all day long and still get you 35++ to the gallon. then there is the Audi V8 deisels and probably verious other engines to! If you want pretty good performance AND economy then you need to look towards the deisel fuel.... IMO

as for gas, well its still the fuel type to be had for power!

What are you guys feelings about the likes of Lamborgeni V10 and V12 engines? They are DOHC and the V10 is around 5.0ltr. the one thing that I think is great about them is the RPMs they can turn! 8500rpm is doable with the new V12 i think!!! also what about the Farrarei V8s? they are pretty small but are making MASSIVE power N/A.

Regards,

Chris.

 

well you are right there if economy is your thing then diesel is seeing to be the forefron type of engine that is out there for economy. actually as i remember it there is some VW polo blue motion thing that if i remember is capable of like 74mpg or some rediculous number like that.

yes the jambos can turn some crazy rpm but i think the gallardo is in the neighborhood of 550 somethin horse with is probably 48x awhp and i think the murcielago is like 640 with is 5 something to the tires and if the have a performance v10 or v12 and it isnt making that kind of power then they have someting up. also the rpm they can turn has something to do with them being a relatively small cubic inch engine with short strokes. the short stroke is the key to gnarly rpms like that.

as i remember also the ferrari v8s arent the heavy hitters from ferrari all the big power cars are there v12 engines. the v8s are around 4xx something im sure.

one thing i think you over looked is the maintenance cost of these cars. road cars turning that kind of rpm making that much power take alot of money to keep on the road. you have service stuff like that so much its not even funny you spend an absolutely outrageous amount of money getting the car and them keeping it on the road is a whole new ball park of money your getting yourself into. and forget modifications unless your just one of the absolutely priviledged. cars like that are sold as the "best they are meant to be" thats why they are so expensive. when it comes to those types of vehicles you have to look at everything from crazy modifications to standard keep it on the road type stuff because that adds up in a hurry too.

 

Im not going to get off topic with a huge debate over the government with neither of us having solid proof about anything they truly "get" out of it.
While fuel economy may go up a mpg or two without all the emissions crap on an engine they will however pollute more (not that I personally care, but im just saying).


I'm talking from anytime, ever.
And clearly you missed the point again, please reread what I was saying:
"Stop, how many performance cars today can get at least 19/27mpg?
Now how many of those (what 3 or so?) have at least 400hp?"
I was using that as a point of how OHC engines are actually not any more "efficient" and a pushrod engine.
The pushrod LS6 gets better gas mileage than any 400hp production engine that I know of (and still better than many 250-300hp engines as well).

 

Very cool engines but ridiculously expensive, and still physically massive thanks to be OHC although pretty lightweight thanks to the use of high tech ($$$) materials.

 

I'll add some perspective about fuel economy when comparing OHC and OHV. One of the reasons car manufacturers utilize OHC is because you can get 'more' power for a smaller displacement than OHV. What I mean is that you can typically rev higher and produce larger peak HP numbers. European manufacturers had historically done this to get power from smaller engines because of taxes imposed by their governments on displacement though I'm not sure if they still do impose those taxes. The downside of that approach is the transmission gearing. If you look at a 6 speed from a BMW M car for example you'll see ridiculously (relative to our cars) lows gears in the trans and the rear. The new M3 V8 is a good example of a V8 car 4.0 litres that gets crap for gas mileage; just 20 mpg highway. To get 420 BHP the engine needs to rev to 8300 rpm. And the gear ratios: 1st: 4.06 / 2.40 / 1.58 / 1.19 / 1.00 / 0.87 with a 3.85:1 rear. There's no cruising at <2000 rpms in a 50% overdriven gearbox for that car.

Obviously a larger engine can get the same power (and loads more torque) at a lower RPM, but it doesn't matter if that larger engine is OHC or OHV. The C4 Zr-1 had a 5.7 DOHC engine that was rated for 25mpg highway back in 1990. And believe me there was no loss of low end torque... I've driven them.

We just see more smaller displacement engines attempting to utilize OHC to make power because, well, they can. If you compared two engines of equal displacement and similar HP/TQ (nothing wild in either engine) in the same vehicle and drivetrain you'll find negligible fuel mileage differences. The problem is trying to find two engines to compare. E.g. A n/a 6.4 litre 630BHP Lamborghini engine is nowhere near comparable to a *stock* n/a 6.2 430BHP LS motor in terms of fuel mileage. Get the LS motor stretched to 6.4 and make 630BHP n/a then compare how much fuel it needs. The LS might still win, but at least then it's a true comparison. Same goes for LSx vs Mod Ford.

$0.02

 

This is something to consider... On two fronts, if memory serves correctly. First, diesel, though not really part of this topic(which is why I've avoided bringing it up) is certainly THE way to go impo. There are serious diesels available and, while they're heavy, they are far more efficient than gasoline engines. AUDI makes a V10 diesel which I think has been used to win(overall) the 24 hr Le Mans 2 or 3 times already. That shows me they not only make great power/torque, but are also still efficient(comparatively) and durable.

Diesel fuel is also easier to create than gasoline, and is cheaper to make as well. Add that to the efficiency of diesels and you have a winner. Maybe that's why European cars are so commonly diesel powered.

As for the "Polo" or whatever it's called... I don't believe that's available in America and I believe that's the car I read about which convinced me, our government DOES NOT CARE what the economy is. They evidently said "NO" to that car BECAUSE it doesn't meet American emissions standards... At 74mpg... I don't care what the emissions is... It HAS to burn less fuel than anything on the road here(cars in class anyway) and therefore, creates less emissions overall, as opposed to PPM. For some reason, our fed won't allow it to be sold in America, yet the very same government insists that ALL manufacturers increase fuel economy in America.

There's really no debate to be had regarding the government gaining money by forcing manufacturers to add parts. Simply stated, they do. They tax everything.

Economy surely rises when emissions crap is removed. I don't care how "dirty" they burn, as I truly believe we cannot hurt the earth's atmosphere even if we try. Remove weight, improve economy... Usually. Remove weight AND allow for better airflow through a given engine, surely economy rises. Many emissions parts hurt flow, particularly in cylinder heads and intake systems, along with the obvious, exhaust. Smog pumps add drag to the engine and that can't help economy either. In a nutshell, emissions parts cause lower economy, no matter how clean an engine burns.

The whole emissions thing is a scam in my view, based on common sense alone, which tells me that making any engine less efficient is also going to cause it to burn more fuel and when it does that, it produces more emissions, whether or not they're "cleaner" in a ppm sense.

I'm really not arguing your point on economy. I've agreed with it from the start, at least in the case of the LS series. The point I was making is that our government doesn't care how good the economy REALLY is... It only cares how much more difficult it can make life for manufacturers. That nonsense actually led to the LS series imo. The LT1 was well worn, but didn't meet emissions standards without adjustment... GM tuned it to run hotter, so it could burn off more fuel, or at least spent gases. That leads to shorter engine life. The LS is much more efficient and doesn't need to run as hot to meet standards... That's how I see it anyway. Perhaps the aluminum block and heads were the biggest contributors, and they helped in several ways over the LT1.

In the end, companies are creating more and more efficient OHC engines, at a higher cost, to meet emissions standards while attaining at least decent performance... The only reason I think they're going OHC in so many cases is because those engines generally create lower emissions. I remember hearing back in 1991-3 that the 4.6 was so clean it didn't require a smog pump at all. That is a huge help, particularly over time. I'm sure other OHC's are either the same or similar.

 

My 1997 C5 LS1 didn't need a "smog pump" to pass emissions. I don't recall any C5 or C6s with pumps (EGR).

I'd look for the next production Vette engine to be a DGI (Direct Gasoline Injection) LS series engine of about 5.5 L (~336-340 cubes) with better power torque, fuel economy and emissions that the current 6.0 L LS3. My guess would be about 440-450 hp.

4.065 bore (from the 6.2L) and 3.268 stroke (from the 4.8L) would work out fairly close. Why not?

It's no secret that the current year GT2 class C6.R is a production-based 5.5L DGI (or E85R ehtanol race fuel) engine.

My $.02

Jon

 

then trick the government if that is honestly their plan because that whole idea of emissions over economy is 1 step forward and 2 steps back. why would you make a car that uses more of a limited resource to make less emissions that is absolutely retarded and irresponsible

i think hybrid cars are a joke and the prime example is of course the prius. first of all they make decently efficient motor and put it in the bulky nonsense "green" car. honestly look at what it takes to actually make all that hybrid bs in a prius. watch top gear for god sakes lol they went through the run down of everything it took to make a prius and apparently studies have shown that 1 prius does more long term damage to the environment than a land rover discovery. are you joking me? this hybrid nonsense has to stop once and for all IMO.

i think the economy of an OHC engine is pretty good when used in smaller engine type applications such as hondas and the like but in a v8 or bigger plat form such as ford mod motors or lambos (which in reality get absolutely terrible mpg btw) or whatever gets you going, it just isnt a proven platform in the economy department its hard to make an engine that big and bulky have good performance qualities to make it power a decent sized car and still have enough performance to plant you when needed it just cant be done yet. it has the potential to get there but we havent gotten there yet.

if GM decided to go with the northstar platform as a performance engine i think it will be hard for them to get into something other than caddys simply because the LS series is chevys pride and joy, pontiac used it quite alot, and im pretty sure buick did too, Holden uses the hell out of the series too i just dont know unless the LS series was somehow faded out where they would go with it

 

You sure about them not having the pump? I think the C5 did, needed or not... as a requirement from the government. Even if it had no pump, it still has a plethora of emissions control parts, none of which were free and none of which really help economy... or emissions for that matter.

Most engines probably still require the pump, along with several other parts, even if OHC. How much could GM save on any vehicle by not having to put catalytic converters on? Thousands per model? More? Since they have to warranty that part for some 70,000 miles(maybe 80k), each one they have to replace under warranty simply helps drive up the cost of new cars. How much hp does it "cost" to use cats? After all, their main job seems to be restricting airflow(I know, it causes heat to help burn off excess gases)... So we may all burn more fuel just driving. There's also the added weight and cost to customers who no longer have a warranty... The government "earns" money with each sale, yet all they did is encourage the sale by making up a law. They had nothing to do with the work, etc., but they get paid. Then there's the (no doubt) thousands of vehicles which have burned to the ground, thanks to an overheated cat being parked over tall grass... But THOSE "emissions" don't seem to matter, nor do they cost the government anything... They only make that government more money.

My view is, emissions, like the great debacle known as "man made global warming" is all a big fat disastrous HOAX! A money making SCAM!

 

i cant lie to you mr. ford lover i actually agree with ya there lol
man made global warming is complete stupidity and its amazing people are buyin into it

 

Whatever I said that made you think I'm a Ford lover... Sorry, just calling it like I see it. I'm hardly the only one. I do like Fords just fine and I think they've done far more "right" over the past 30yrs than has GM... But so what. Honestly, I can't see "loving" a brand. I've probably owned more Fords than GM over the yrs, but much of that is because the only pickup I'll buy is a Ford. On that note, I may soon change my tune. I REALLY like the latest GM's.

The whole thing is about GM making 4V engines. I've spent more time actually talking about GM making 4V engines than anyone else in the thread, from memory. We had Ford brought up for the obvious reason... They build a "performance" OHC V8 and aside from Cadillac, they're "it" in America. However, it isn't like I brought it up, the OP did. My "argument" hasn't been about how the OHC is better either, just that it's here to stay and can be used for performance as well as any engine type.

 

Reading through this thread makes me glad about the existence of various LS motors.

The pictures in this thread comparing the compactness of the LS1 to various dual overhead cam motors made my day. Simplicity, compactness and bang-for-the-buck are bliss.

Enjoy it while you can because thing change ... For better or worse ?
http://www.motorauthority.com/blog/1...-6-c8-corvette



.

 

The smog pump being on any ls engines would be news to me.

 

LS engines came with electric smog pumps e.g. on 4th gen F bodies and I believe C5's as well. EGR on the LS1 manifold but not on the LS6 manifold.

My 02 has no EGR, but definitely has AIR (smog pump) otherwise there is no reason for those hoses running into the exhaust manifold. Not sure about some of the newer cars or the C6 vettes.

 

There is hardly any info on the C7 yet, so this is nothing more that ignorant speculation as far as I'm concerned.
It will not happen, I can tell you that. GM knows that the number of buyers they will lose as opposed to the ones they will gain from this is severely unbalanced. They would lose (m)or(b)illions in the overall scheme.

I just want to say that I have no ill feelings and this is one of the best intelligent conversations on Tech in quite some time. I completely respect your point of view, but your point in bold hardly needed to be made. It's the exact mindset of practically all of America.

I have no real problems with OHC, but I don't see it as better than OHV. I just wish the overall ignorance of the public concerning OHV could be changed. Hell even automotive magazines view OHV as dinosaur technology. They mutter those exact words probably 12 times with each Corvette review, yet the overall tone of their article goes a little something like "wee! torque! boner! bad interior "

I'm willing to bet most OHC nutswingers haven't ridden or driven a decent performing OHV car either ever or in a very long time. The powerband and delivery is intoxicating and is the reason we love these cars.

Much in the same way old school BBC guys look at us weird for loving our little 346 small blocks, I struggle to see what is so great about OHC. I've owned a Talon TSi AWD with a few mods and SOTP it was slower than my old L67 Bonneville despite being close to 2 seconds faster in the 1/4.

 

on the note of the C7 if the ever went to a v6 platform or a mid engine or AWD setup i believe there would be a rush on GM headquearters. if they did any of those things i would view it as blasphemy and gear up for war

secondly i heard a long time ago (of course this was in our "depression") that a restyling of the corvette into the C7 would be post poned until 2014 at the soonest if it wasnt put on hold indefinately. which in my mind given the way the economy is now idk why they would keep that up but they are in charge and i think if they stuck with that plan they are asking for their performance poster child to get stale and unattractive.

honestly i believe it is a bit nonsense how reviewers look at OHV as archaic or ancient and see OHC as a godsend. the reality of it is one CAN be made better than the other its just a personal preference of how the power is delivered in my mind that draws certain people to certain cars. hell thats how the ls series was born.

they took 2 vettes debadged them and did not let the testers which happend to be GM ceo's or something, open the hoods. one had a lt4 pushrod engine and the other had a lt5 DOHC. both cars were tested by the big guns of gm and they ultimately chose the pushrod style simply on power delivery and thats why the ls series ended up as pushrod instead of DOHC despite the lt5 having more power and the like.

people need to look at the facts and what not of an engine before they try to cut it apart and in the very end its personal preference of power delivery and thats all there is to it.

p.s. yea BBC owners need to get there nose out of the air because last time i checked when you build a 500rwhp BBC and a 500rwhp ls motor or SBC and put them in comparative cars who do you think is gonna drag who 1320ft?

yea get wrecked bad kids

owned haha