2009 Corvette ZR1 LS9 Engine

[Kitdy]

Yes but the ton in your power/ton should be the overall weight of the vehicle right? But you could say that where that really is vitally important is in racing, where displacement is regulated aswell as weight. I was saying that when only considering the engine then engine torque to engine weight is not a very important value, as it is torque to the wheels and total vehicle weight that matter. For example does it matter that the Ferrari 430 Scud makes less engine torque per engine weight or the fact that it makes more wheel torque per total vehicle weight than a C6 Z06?

Every little bit of weight counts, even the engine.

When you are comparing engines only, then torque to weight ratio matters.

[culver]

That is only one of many many variables that have been improved over time and you will find that DOHC designs are almost always slightly better at not-knocking then OHV engines. What about increases in VE? or the ability to maintain high VE over a wider range of engine speeds? or how about being able to have a higher redline RPM? you don't think any of those might have contributed to higher specific power and better overall performance?

"always slightly better", I'm sorry you need to provide some backing for that.
VE: Please see my posting in the old OHV vs OHC thread. I specifically address that point. Higher redline only helps HP if I have a fixed displacement limit which is not always the case.
This is a pushrod vs ohc discussion. Please dig up one of the old threads.

weight and complexity yes, size? not really. The overall size of the heads didn't increase significantly to incorperate Valvetronic. The advantages far outweight any disadvantages of that system.

Did they increase in size? Yes. Your previous point was the opposite. From the drawings I’ve seen I would say it was a fair amount as well.

The total weight of the car is what matters. having a slightly heavier engine doesn't necessarily mean you have a heavier car. I never said or claim that OHV engines are bad. I simply claim that DOHC can be and is better, there is a difference.

Engine weight contributes to the weight of the car. All else being equal lighter is better. Your claims that DOHC is better is not well supported. Many of your claims are engine specific for one. That only tells me about the two engines you are comparing. You haven't pulled out enough fundamental information to put together a case that OHV is fundamentally at a disadvantage when you remove issues like displacement limits. We have already seen that Bombardier went with a 2 valve head on their new aero engine despite all the benefits to 4 valve heads. Many of the drawbacks you cite relative to OHV engines are related to the two valve head yet that is what Bombardier chose. You were completely right when you mentioned that a two valve head can work well in the application that Bombardier is trying to fill. However, if it works in that case, perhaps it may not be such a bad idea in other cases? Perhaps when we open up the rules (ie displacement) things change. I haven't seen that sort of fundamental analysis of the issue from you.

Or we can trust that the market already did all that and DOHC must be superior in enough ways to be dominant.

If you read through my old posts you will see that I have addressed that point as well.

I don't flatly refuse to acknowledge anything I simply want to create the proper context. One engine is not better than another because it appears superior when considering one variable. You have to look at the overall picture.

But I haven't seen you do that. You certainly have not done that from a fundamental level.

But all other things won't be kept equal will they? for starters the OHV engine in that arguement would have to have a larger displacement then the DOHC design to make more torque. and what about relative power? what about engine configuration? what about everything else that matters? Thing is we have been comparing street engines that don't necessarily compare fairly. The real advantage that an OHV system might have over a DOHC engine in output per weight is not as big as suggested. If all else is kept equal you end up with a slightly heavier, slightly larger engine that makes significantly more power and torque aswell as a better, flatter torque curve.

You haven't backed this claim very well. As a counter claim (which is flawed as I am only picking two specific engines) I would offer the 5.3L LS family motor used in one of GM's FWD cars. It weighs in at ~460lb and produces an easy 300hp with lots of torque relative to that 300hp (maybe not relative to what you think it's displacement should offer). Now we also have the Nissan VQ motor. In the Maxima sedan it produces ~260hp or so. It has 3.5L of displacement but weighs about the same as the GM motor. It's basically no cheaper to make (that is speculation based on a napkin estimate of the number of parts to machine). In some versions which require premium fuel it just about matches the 5.3L's power. Truth be told I suspect the LS was neutered to avoid hurting the gearbox. The Nissan has nowhere near the torque and really, it's any smaller as installed.
So how are we getting all those slightlys? Mind you the V8 Impala is prices against cars with the VQ motor. I will give you that this is a bit unfair as the VQ is actually quite heavy when compared to other ~3L all alloy motors.


Ultimately this has just degenerated into a OHV vs OHC debate. Drag up the old thread. In the old thread I tried to the best of my abilities to argue each point from a fundamental level rather than engine X vs Y. With the info in that thread I can not make the case that OHV really is better than OHC (nor was that my intent). However, I think I can make the case that in context of V block motors the one can be competitive with the other.

Anyway, if you would like to continue this conversation please do it in the old thread.

The ZR1 motor looks like it will be awesome.

[Slicks]

You are joking right? I can't understand the logic behind that question. You say that OHV design has some good advantages in size and weight when used in conjunction with V8 configuration right? So if that was such a great advantage the only reason you can think of as to why other manufacturers don't make OHV V8's is because they base their V8s on their I4s? Are you trying to imply that other manufacturers don't know how to make an OHV V8?

I'm saying they are sticking with what they know/have more experience with.

It is plainly obvious why DOHC designs are dominant... Because they allow a better overall engine. Please I want to know why you think that the majority of V8s and every other engine configuration is dominated by DOHC designs?

Better overall? I think you mean bigger overall
I personally believe the main reason is marketing. People like you are a prime example, "ZOMG BUT DOHC AND HP/L!!@!@!$!!!!111 FTW".
Companies can advertise a "high tech DOHC engine". Hell, GM themselves even admitted to using the Northstar in Cadillacs mainly due to marketing, not because its a "superior design to OHV engines."

"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.""
The Pushrod Engine Finally Gets its Due. - - Car and Driver - May 2004

Umm who says that a 4.6L ford V8 won't fit? Won't fit in what? They are a little wider at the heads and alittle taller... do you think that posses the biggest concern?

Wont fit in the common cars that the LS1's are going into. Hell even Mustang owners are swapping LS1 into their car...

[Slicks]

No they are not in fact if you look at the numbers, OHV engines produce less specific torque then DOHC engines.

And thats all they are, useless numbers...

Just look at the LS7, it is a torque monster only because of its huge displacement. It only scrapes up 67.75lbs-ft. per L displacement. Compare that to what almost everyone thinks is a torque weakling the E90 M3's S65 that makes 73.77lbs-ft. per L displacement. If it was like the LS7 it would only put out 271lbs-ft. of peak torque.... On top of that the S65 has a much better torque curve. All of that goes to show that DOHC has significant performance advantages.

And if the S65 was like the LS7 it would weigh 390lbs and be probably half the going price it is now.
That goes to show manufacturers are NOT trying to get the most torque/power out of a given displacement, or engine.
A perfect example of this is the L76 in the commedore/G8 gained almost 50hp (fly wheel) from a dyno tune. Just a tune, nothing else! Thats unheard of in N/A engines.

[Slicks]

Well first we would have to decide what to put in the list (what makes an engine, a good engine?) Then we would have to decide the relative importance of all those aspects, then finally compare both engines... Or we can trust that the market already did all that and DOHC must be superior in enough ways to be dominant.

you say this ^

I don't flatly refuse to acknowledge anything I simply want to create the proper context. One engine is not better than another because it appears superior when considering one variable. You have to look at the overall picture.

Then say this???
My whole friggen argument was to look at the WHOLE picture, not just peak power, or how many OHC v8s are made vs OHV V8s!
Here is the WHOLE picture:
weight, physical size, torque curve(and amount of torque), and cost.

Would it not be ideal to have an engine that is cheap, physically small, lightweight and has a nice flat torque curve (and a high amount of torque)???
hey wait... thats sounds like... AN LS1! Holy shit!
"bUt zomg dizplacements and hp/l!!!111
No, irrelevant, no one cares.

But all other things won't be kept equal will they? for starters the OHV engine in that arguement would have to have a larger displacement then the DOHC design to make more torque. and what about relative power? what about engine configuration? what about everything else that matters? Thing is we have been comparing street engines that don't necessarily compare fairly. The real advantage that an OHV system might have over a DOHC engine in output per weight is not as big as suggested. If all else is kept equal you end up with a slightly heavier, slightly larger engine that makes significantly more power and torque aswell as a better, flatter torque curve.

You forgot WAY more expencive.

Yes but the ton in your power/ton should be the overall weight of the vehicle right?

And the engine is the single most heavy part of a vehicle. It contributes much weight to the overall car, and where that weight is.

But you could say that where that really is vitally important is in racing, where displacement is regulated aswell as weight. I was saying that when only considering the engine then engine torque to engine weight is not a very important value, as it is torque to the wheels and total vehicle weight that matter.

And all else equal, lighter engine = lighter car.
More engine torque = more wheel torque.

[hightower99]

I'm saying they are sticking with what they know/have more experience with.

And you really think that is even close to being a good answer and a logical conclusion? You think that the majority of manufacturers out their are ignorant enough to just keep doing what they do even though you say that OHV is better?

I personally believe the main reason is marketing. People like you are a prime example, "ZOMG BUT DOHC AND HP/L!!@!@!$!!!!111 FTW".
Companies can advertise a "high tech DOHC engine". Hell, GM themselves even admitted to using the Northstar in Cadillacs mainly due to marketing, not because its a "superior design to OHV engines."

Again does that really count as anything close to a logical conclusion? The best you can do is say that the only reasons as to why DOHC engine designs completely dominate the market is because the majority of manufacturers are doing what they know and banking on what little marketing can be done with DOHC and specific performance.... I hope you realise that most DOHC engines compete against other DOHC engines and therefore you can't really market DOHC anymore (just like there isn't so much focus on marketing ABS because almost every car has it). Specific power is also rarely a major marketing point.

Wont fit in the common cars that the LS1's are going into. Hell even Mustang owners are swapping LS1 into their car...

again I have explained why someone would swap an LS1 into a mustang... displacement. Do you have any proof that a 4.6L ford engine won't fit? because AFAIK they do fit but they just aren't as good a choice as an LS1.

[hightower99]

And thats all they are, useless numbers...

The question was: Does OHV make more torque than DOHC... The answer is found by looking at specific torque. He didn't ask what allows a bigger engine.

And if the S65 was like the LS7 it would weigh 390lbs and be probably half the going price it is now.
That goes to show manufacturers are NOT trying to get the most torque/power out of a given displacement, or engine.
A perfect example of this is the L76 in the commedore/G8 gained almost 50hp (fly wheel) from a dyno tune. Just a tune, nothing else! Thats unheard of in N/A engines.

So you think that if the S65 was OHV and weighed roughly 400lbs and made 288HP and 271lbs-ft. it would be a better engine for the top of the line M motor sports division 3-series??? I think I would keep the 445lbs 414HP 295lbs-ft DOHC engine thank you. Also there is a simple reason why the L76 can pick up 50HP with a dyno tune and it has to do with meeting Euro III emissions.

[hightower99]

My whole friggen argument was to look at the WHOLE picture, not just peak power, or how many OHC v8s are made vs OHV V8s!
Here is the WHOLE picture:
weight, physical size, torque curve(and amount of torque), and cost.

Would it not be ideal to have an engine that is cheap, physically small, lightweight and has a nice flat torque curve (and a high amount of torque)???
hey wait... thats sounds like... AN LS1! Holy shit!
"bUt zomg dizplacements and hp/l!!!111
No, irrelevant, no one cares.

HAhaha. How is market not the bigger picture? Do you realise all the variables that you mention are included with proper context in the market? Obviously companires want to make as much money as possible... Most are doing so with DOHC engines so a cheap engine that can't be sold for much is not a good thing. Also the LSx series engines don't have a flat torque curve... I have already shown that. They make alot of torque everywhere because they are large displacement but the curve is not flat.

You forgot WAY more expencive.

Most of the expense you are talking about is to the consumer which in turn is because of percieved market value. Which is only a good thing for the manufacturers that can do that. It won't be way more expensive.

And the engine is the single most heavy part of a vehicle. It contributes much weight to the overall car, and where that weight is.

Yes if you consider the engine and all ancillaries as a single piece... Yes a 400-500lbs engine is a relatively large weight but the difference is not a deal breaker.

And all else equal, lighter engine = lighter car.
More engine torque = more wheel torque.

I will give you the first one but the second statement needs some context. The Ferrari F430 Scud. makes much less engine torque but manages to make more wheel torque then a C6 Z06. So more engine torque does not necessarily mean more wheel torque it depends just as much on the gear ratios.

[harddrivin1le]

The question was: Does OHV make more torque than DOHC...

Here are my questions:

1) How many Euro pee on performance cars produce 436 Certified HP (or more) AND get 16 city/26 highway EPA (or more) while costing $45,000 US (or less).

Answer: NONE!

2) All aluminum block LS engines (1, 2, 3, 6 and 7) weigh 480 pounds (or less) fully dressed and ready to go - including the flywheel and all engine accessories. The least powerful example produced 345 HP, which equates to a power density of roughly .72 HP/LB of engine weight, while the most powerful (currently produced) produces 505 HP, which equates to a power density of roughly 1.05 HP/LB of engine weight.

How many normally aspirated Euro pee on engines offer equal or better power densities (HP/LB of engine weight)?


The fact of the matter is that you are judging something that you have absolutely NO experience with.

[Slicks]

Here are my questions:

1) How many Euro pee on performance cars produce 436 Certified HP (or more) AND get 16 city/26 highway EPA (or more) while costing $45,000 US (or less).

Answer: NONE!

2) All aluminum block LS engines (1, 2, 3, 6 and 7) weigh 480 pounds (or less) fully dressed and ready to go - including the flywheel and all engine accessories. The least powerful example produced 345 HP, which equates to a power density of roughly .72 HP/LB of engine weight, while the most powerful (currently produced) produces 505 HP, which equates to a power density of roughly 1.05 HP/LB of engine weight.

How many normally aspirated Euro pee on engines offer equal or better power densities (HP/LB of engine weight)?


The fact of the matter is that you are judging something that you have absolutely NO experience with.

Don't use too much logic, you're going to confuse hightower99!

[harddrivin1le]

Don't use too much logic, you're going to confuse hightower99!

Hightower99 will probably resort to quoting HP per liter...as though that actually matters on the street where there is no sanctioned limit on engine displacement.

Here's what matters on the street to most enthusiasts with an OPEN mind:

1) The PEAK HP X FUEL ECONOMY product, where a higher number is better (e.g. 436 HP X 26 MPG = 11,336 HP-MPG)
2) Engine (and vehicle) cost
3) Engine Weight

Anyone with any objectivity should be able to readily see that GM LS engines kick ass in all three categories. They're also virtually maintenance-free and have low centers of gravity.

Those facts probably won't matter to him, either.

I don't even own a GM vehicle and haven't in nearly 4 years, so bias is playing no role here whatsoever.

[Slicks]

And you really think that is even close to being a good answer and a logical conclusion? You think that the majority of manufacturers out their are ignorant enough to just keep doing what they do even though you say that OHV is better?

Most definitly.
Its not about what is "superior", its about what sells.
By switching to OHV thats like admitting GM and Chrysler were right all along with their OHV engines.
An example I can think of it Honda making a unibody truck (ridgline), while that is a terrible design for a truck, they still made it.

Again does that really count as anything close to a logical conclusion? The best you can do is say that the only reasons as to why DOHC engine designs completely dominate the market is because the majority of manufacturers are doing what they know and banking on what little marketing can be done with DOHC and specific performance....

I cannot even keep track of how many commercials that have used the terms "high tech VVT", "high tech DOHC" "high output DOHC" that I have seen in the past few years. When my dad went to trade in our van for our caddy we have now, I specifically remember the salesmen using the pitch "high tech DOHC engine".

again I have explained why someone would swap an LS1 into a mustang... displacement. Do you have any proof that a 4.6L ford engine won't fit? because AFAIK they do fit but they just aren't as good a choice as an LS1.

If DOHC was so superior why not bore/stroke the mustang engine? I can go out to atleast 5.4L. Why not add FI? A kit would probably be cheaper, and you get to keep the "high tech DOHC engine".
Show me that the 4.6L mustang engine would fit in a small car without cutting the whole thing up. Practically a drop in, like the LS1 swaps.

[Matra et Alpine]

Hightower99 will probably resort to quoting HP per liter...as though that actually matters on the street where there is no sanctioned limit on engine displacement.

So why did GM mention it in the recent ZR-1 annoucnement ??
ZING!

Here's what matters on the street to most enthusiasts with an OPEN mind:

Same your's closed before you got to handling

bias is playing no role here whatsoever.

:choke: .... :splutter: ..... :rofl:



Good engine, but the "it's the best at everything" is plainly erroneous.
'cause why woudl a manufacturer make ANY other engine

[Slicks]

The question was: Does OHV make more torque than DOHC... The answer is found by looking at specific torque. He didn't ask what allows a bigger engine.

Good god child...
Lets review again:
Manufacturers ARE NOT TRYING TO GET THE MOST OUT OF AN ENGINE.
Can you read that? Do you understand that?
Therefore comparing two street engines to each other based on peak numbers, then claiming a certain engine design is superior based on these two engines because of its peak numbers is ridiculous.
Thats like comparing an old RWD buick to a FWD Elan and saying FWD is superior for handling because the RWD buick cannot handle.
The Buick was not made for handling, while the Elan was, apples to oranges.

So you think that if the S65 was OHV and weighed roughly 400lbs and made 288HP and 271lbs-ft. it would be a better engine for the top of the line M motor sports division 3-series??? I think I would keep the 445lbs 414HP 295lbs-ft DOHC engine thank you.

I love how you can just calculate those numbers based on the valvetrain layout

Also there is a simple reason why the L76 can pick up 50HP with a dyno tune and it has to do with meeting Euro III emissions.

Wrong again.
GM tuned the L76 to make its full power on 87 octane. Next they didn't want the new G8 to make more power than the previous LS2 GTO (dealers still need to sell those).

[Slicks]

HAhaha. How is market not the bigger picture?

Because you can wrap a turd in gold foil, tell people its magic, and they will buy it.
That is why we use factual figures, not "I like this, so it is good".

Do you realise all the variables that you mention are included with proper context in the market? Obviously companires want to make as much money as possible... Most are doing so with DOHC engines so a cheap engine that can't be sold for much is not a good thing. Also the LSx series engines don't have a flat torque curve... I have already shown that. They make alot of torque everywhere because they are large displacement but the curve is not flat.

You have yet to show anything about an LSx engine.
As far as the torque curve, how is this not flat?
http://www.ericohlsen.com/FBODY/CamaroDyno.jpg

Most of the expense you are talking about is to the consumer which in turn is because of percieved market value. Which is only a good thing for the manufacturers that can do that. It won't be way more expensive.

Then why are there no cheap, powerful (350+hp) OHC engines out there?

Yes if you consider the engine and all ancillaries as a single piece... Yes a 400-500lbs engine is a relatively large weight but the difference is not a deal breaker.

Tell that to all the supercar makers.

I will give you the first one but the second statement needs some context. The Ferrari F430 Scud. makes much less engine torque but manages to make more wheel torque then a C6 Z06. So more engine torque does not necessarily mean more wheel torque it depends just as much on the gear ratios.

The second statement is still going by "all else equal."