Why GM should NOT build a DOHC V8

[Guest Wings4Life(BANNED)]

Because it offers little gains.

 

And anytime you want to compare engine smoothness between a coyote, you just step right up.

[El Kabong]

I'd love to discuss the overall conpetitveness of the Coyote engine.

But Ford doesn't advertise it much. Something about a fluffy turbo V6.

Edited August 18, 2015 by El Kabong

[Guest Wings4Life(BANNED)]

And.the main advantage for DI is easier achievable high CR.

5.0 and 5.2L is already there with smarter cam profiles and better volumetric efficiency afforded them through dual cam VCT.

[El Kabong]

Fluff

[Guest Wings4Life(BANNED)]

Another advantage of DOHC btw, in that you don't have to throw every costly trick at it to make power.  

[El Kabong]

Fluffy attempt to justify developmental laziness

[Guest Wings4Life(BANNED)]

"Developmental laziness"  

 

...coming from someone who admires the same basic engine that I could have got the year I was born.

 

 

Comic relief, is what that is 

[El Kabong]

"Developmental laziness"  

 

...coming from someone who admires the same basic engine that I could have got the year I was born.

 

 

Comic relief, is what that is 

I'm sorry that it has taken Ford roughly eight attempts to nail what GM did first time out.

Perhaps I should have rephrased that to read "developmental competence" :D

[Drew Dowdell]

Another advantage of DOHC btw, in that you don't have to throw every costly trick at it to make power.  

 

Compared to OHV, DOHC is the costly trick. 

[El Kabong]

Another advantage of DOHC btw, in that you don't have to throw every costly trick at it to make power.

 

Compared to OHV, DOHC is the costly trick.

Indeed.

[Guest Wings4Life(BANNED)]

 

Another advantage of DOHC btw, in that you don't have to throw every costly trick at it to make power.  

 

Compared to OHV, DOHC is the costly trick. 

 

 

Not in terms of max power.

 

The LS7 uses titanium rods and premium machining and DI to get 505hp out of 7.0L.

It costs far more to make and sell than a 5.2L.

Edited August 18, 2015 by Wings4Life

[El Kabong]

LT4?

[Guest Wings4Life(BANNED)]

2011 800hp Super Snake?

[El Kabong]

Tuner engine?

...sigh. Fluff

[Drew Dowdell]

 

 

Another advantage of DOHC btw, in that you don't have to throw every costly trick at it to make power.  

 

Compared to OHV, DOHC is the costly trick. 

 

 

Not in terms of max power.

 

The LS7 uses titanium rods and premium machining and DI to get 505hp out of 7.0L.

It costs far more to make and sell than a 5.2L.

 

 

I'm not sure how many more times I have to say it.... I'm talking about the every day cars like the Camry and Impala. 

 

Can I make it in big lettering? Will that work?

 

IN NON-SPORTING APPLICATIONS, OHV V6 DELIVERS SUPERIOR DRIVABILITY TO AN EQUIVALENT PEAK OUTPUT DOHC.

[Guest Wings4Life(BANNED)]

And again, drivability is a subjective term to many.

Some want more at highway speeds.

Some want more out of the hole.

 

 

I like both, but prefer a bit more on top end, hence DOHC 

[Drew Dowdell]

And again, drivability is a subjective term to many.

Some want more at highway speeds.

Some want more out of the hole.

 

 

I like both, but prefer a bit more on top end, hence DOHC 

 

At no point on the everyday driving scale will a 300hp DOHC V6 outperform a 300hp OHV V6.  The OHV will be more efficient, have better off the line pull, have more torque throughout the usable RPM range.  The DOHC engine will only see that horsepower at or close to the red-line.  The OHC engine will hit that peak horsepower 20% short of red-line.   In other words, you'll actually get to use all 300 horses in the OHV... in the DOHC engine, the only time you'll see them is when you look at the window sticker. 

[surreal1272]

Tuner engine?

...sigh. Fluff

I'm just going to say this. How many Mustangs are out there with LS swaps and how Vette's are out there with 5.0 swaps? Nuff said (excuse my non-Ivy League educated wording).

[Guest Burnt Valve LS7]

Another advantage of DOHC btw, in that you don't have to throw every costly trick at it to make power.

Compared to OHV, DOHC is the costly trick.

Not in terms of max power.

The LS7 uses titanium rods and premium machining and DI to get 505hp out of 7.0L.

It costs far more to make and sell than a 5.2L.

I'm not sure how many more times I have to say it.... I'm talking about the every day cars like the Camry and Impala.

Can I make it in big lettering? Will that work?

IN NON-SPORTING APPLICATIONS, OHV V6 DELIVERS SUPERIOR DRIVABILITY TO AN EQUIVALENT PEAK OUTPUT DOHC.

What every day car comes with an OHV V-6? None do. Your comparison is pure hypothetical speculation.

They only push rod V-6 even available for every day purchase is the GM truck 4.3L. And even at that size fails to hit 300hp.

[ccap41]

 

Tuner engine?

...sigh. Fluff

I'm just going to say this. How many Mustangs are out there with LS swaps and how Vette's are out there with 5.0 swaps? Nuff said (excuse my non-Ivy League educated wording).

 

While I will completely agree that the super snake and applications like that shouldn't even be brought up.

 

Vette and Mustang engine swaps aren't really comparable. Camaro and Mustang makes waaaaay more sense. Of course there aren't Vette owners wanting a lesser powerful Mustang engine. But Camaro owners..older Camaros wanting the newer 5.0 or Cobra 4.6 DOHC..is a lot more likely. But I will add that I never follow the "swap" crowd. It's never been my thing. I wouldn't put a Chevy V8 in a Ford and vise versa. Now I think it would be cool to have an 80's/90's Camaro/Mustang and swap for the modern 6.2/5.0. That would be cool. I guess the same could be said for the Older -> Newer Corvettes as well.

[Drew Dowdell]

 

 

 

 

Another advantage of DOHC btw, in that you don't have to throw every costly trick at it to make power.

Compared to OHV, DOHC is the costly trick.

Not in terms of max power.

The LS7 uses titanium rods and premium machining and DI to get 505hp out of 7.0L.

It costs far more to make and sell than a 5.2L.

I'm not sure how many more times I have to say it.... I'm talking about the every day cars like the Camry and Impala.

Can I make it in big lettering? Will that work?

IN NON-SPORTING APPLICATIONS, OHV V6 DELIVERS SUPERIOR DRIVABILITY TO AN EQUIVALENT PEAK OUTPUT DOHC.

What every day car comes with an OHV V-6? None do. Your comparison is pure hypothetical speculation.

They only push rod V-6 even available for every day purchase is the GM truck 4.3L. And even at that size fails to hit 300hp.

 

 

Horsepower per litre is a dumb metric because it only tells 1/4 of the story.  It doesn't tell you where you get that horsepower... and in many DOHC V6 cases you will never ever ever see that horsepower because it only exists at an RPM that the transmission doesn't support. If the engine produces 300 horsepower at 6800 rpm, but the transmission forces a shift on you at 6300 rpm, are you getting the advertised horsepower?  My argument is NO you are not.

 

My argument has always been for comparing engines of comparable output.   (I can't believe I have to type all of this out again)

 

Back when GM was making the 3900, the direct competition would have been the 3.0 liter DOHC engines.   The 3900 fit in spaces that the 3.0 liter engines could not. The 3900 produced about the same horsepower as the 3.0 class V6es from Toyota and Honda at the time, but it has much more usable torque. 

 

Back to the 4.3:  

Model/torque/HP

GMC 4.3L V6 305 @ 3,900 285 @ 5,300

Ford 3.7L V6 278 @ 4,000 302 @ 6,500

Ram 3.6L V6 269 @ 4,175 305 @ 6,400

 

The Ford and Ram are going to feel softer off the line than the GMC given equal gearing. 30 lb-ft of torque goes a long way.

 

The GM 4.3 is relatively tiny in packaging... much smaller than the GM 3.6, yet it produces much more torque.  In something heavy like the XTS or Lacrosse, both of which get comments about soft low end torque in review, the PUSHROD 4.3 would actually be an improvement because of the better torque curve even if peak horsepower is lower.  It would improve drivability day-to-day. 

[surreal1272]

 

 

Tuner engine?

...sigh. Fluff

I'm just going to say this. How many Mustangs are out there with LS swaps and how Vette's are out there with 5.0 swaps? Nuff said (excuse my non-Ivy League educated wording).

 

While I will completely agree that the super snake and applications like that shouldn't even be brought up.

 

Vette and Mustang engine swaps aren't really comparable. Camaro and Mustang makes waaaaay more sense. Of course there aren't Vette owners wanting a lesser powerful Mustang engine. But Camaro owners..older Camaros wanting the newer 5.0 or Cobra 4.6 DOHC..is a lot more likely. But I will add that I never follow the "swap" crowd. It's never been my thing. I wouldn't put a Chevy V8 in a Ford and vise versa. Now I think it would be cool to have an 80's/90's Camaro/Mustang and swap for the modern 6.2/5.0. That would be cool. I guess the same could be said for the Older -> Newer Corvettes as well.

 

That Vette owners don't want Stang motors was exactly my point ccap. Stang owners wanted a better motor so they started doing LS swaps. Vette owners have no need to downgrade. As a result, a Camaro owner will go LS long before putting a 4.6 or 5.0L under the hood.

[Frisky Dingo]

 

 

Horsepower per litre is a dumb metric because it only tells 1/4 of the story.  It doesn't tell you where you get that horsepower... and in many DOHC V6 cases you will never ever ever see that horsepower because it only exists at an RPM that the transmission doesn't support. If the engine produces 300 horsepower at 6800 rpm, but the transmission forces a shift on you at 6300 rpm, are you getting the advertised horsepower?  My argument is NO you are not.

 

My argument has always been for comparing engines of comparable output.   (I can't believe I have to type all of this out again)

 

Back when GM was making the 3900, the direct competition would have been the 3.0 liter DOHC engines.   The 3900 fit in spaces that the 3.0 liter engines could not. The 3900 produced about the same horsepower as the 3.0 class V6es from Toyota and Honda at the time, but it has much more usable torque. 

 

Back to the 4.3:  

Model/torque/HP

GMC 4.3L V6 305 @ 3,900 285 @ 5,300

Ford 3.7L V6 278 @ 4,000 302 @ 6,500

Ram 3.6L V6 269 @ 4,175 305 @ 6,400

 

The Ford and Ram are going to feel softer off the line than the GMC given equal gearing. 30 lb-ft of torque goes a long way.

 

The GM 4.3 is relatively tiny in packaging... much smaller than the GM 3.6, yet it produces much more torque.  In something heavy like the XTS or Lacrosse, both of which get comments about soft low end torque in review, the PUSHROD 4.3 would actually be an improvement because of the better torque curve even if peak horsepower is lower.  It would improve drivability day-to-day. 

 

 

 

Sorry to call you out buddy, but your posts are full of misinfo.

 

First off, the GM 3.9 didn't debut until the 2006 MY which was only which was actually 2 years after the Toyota 3.5 came out. And it has a serious power deficit, as well as getting inferior mileage in similar platforms.

 

And actually, the GM High Value series didn't come out at all until the 2004 MY, which is when the 2GR debuted, and a full 7 years after Honda's J Series came out. Which, I might add, made as much power as the GM HV V6 did in it's ultimate form- the 3900. By the time the 3900 came out, the J35 was actually already out, which is also a vastly superior engine.

 

Also, virtually no OHC engines make peak power at redline. To allude to such erroneous information to bolster your position is comical, especially for a moderator. Fact is, all other things being equal, an OHC design engine has far more pros over an OHV one than it does cons. Hence everyone using them. There's a reason why GM ditched the High Value family after all. And if you want proof, compare figures to the LT4 powered Impala SS to the 2012 car which offered the 3.6 OHC LFX has the sole engine. It was just as quick while getting better mileage, despite being down on hp, and significantly down on tq.

 

As for the debate itself, both engines have their advantages, but it's generally accepted that OHC engines offer more than they cede to OHV ones. The GM LSx, and now LTx, fmaily has been an outstanding exception. GM should definitely not drop these great engines just because others have done so, but they can only hold out so long. I have more than a feeling one is coming for use in Cadillacs.

 

Oh, and while I am a GM fan, and like the LSx more than Ford's Mod motors in general, the new Coyote is a hell of an engine, and they sound better than GM V8's, too.

[El Kabong]

FWIW, somewhere back there in this thing I made mention of the basic age of the High-Value V6 design relative to all its contemporaries. The "high value" name itself denotes the true priorities GM had launching the lineup just prior to the events of '08. A clean-sheet OHV design, utilizing the budget and tech wizardry of the LT smallblocks, would doubtless yield similarly giant-killer results.

Nobody is suggesting that OHV engines are without flaws. However, to judge the tech as a whole based on the overall laziness of Detriot from the mid-70s onwards is similarly unfair.

[Drew Dowdell]

Sorry to call you out buddy, but your posts are full of misinfo.

First off, the GM 3.9 didn't debut until the 2006 MY which was only which was actually 2 years after the Toyota 3.5 came out. And it has a serious power deficit, as well as getting inferior mileage in similar platforms.

No no.. it's quite alright.... clearly there is an issue with the forum software that prevents people from reading what I actually type.

As I've said... over and over and over and over and over and over again..... OHV engines are superior DOHC engines OF SIMILAR OUTPUT

 

And actually, the GM High Value series didn't come out at all until the 2004 MY, which is when the 2GR debuted, and a full 7 years after Honda's J Series came out. Which, I might add, made as much power as the GM HV V6 did in it's ultimate form- the 3900. By the time the 3900 came out, the J35 was actually already out, which is also a vastly superior engine.

I cited the 3.0 liter class from the competition for a reason.... the reason I stated above. Because the 3.0 engines are at a similar output. I specifically didn't cite the 3.5 liter DOHC engines because they are in a higher horsepower class and are of larger physical size. In the same physical space as the Toyota 3.5 liter, you can stick the GM 4.3 liter V6, which as the specs show, offer more power in a smaller package. In fact, you can probably even fit a GM 5.3 liter V8 in a spot that would be completely full with a Toyota 3.5. If you're looking to get max horsepower in a specific sized engine bay, DOHC is NOT the way to go. Go with pushrods and throw as much displacement at it that you can fit. If you have 5 cubic feet of box to fill, I guarantee the best way to fill that box with power is to go with a pushrod.

 

Also, virtually no OHC engines make peak power at redline. To allude to such erroneous information to bolster your position is comical, especially for a moderator.

I said at or near red-line.... and it's almost like I haven't already posted a list.... oh wait... I have.

To save you from scrolling up... and I'll even provide links.

GM 3.0 DOHC 255hp @ 6900 RPM - RL 6900 RPM http://www.edmunds.com/car-reviews/track-tests/track-tested-2010-buick-lacrosse-cxl-30.html

GM 3.6 DOHC 312hp @ 6800 RPM - RL 6800 RPM http://gmpowertrain.com/2014_images/charts_lg/lfx_chart_cadillac_ats.jpg

FCA 3.6 DOHC 305hp @ 6400 RPM - RL 6400 RPM http://www.pentastars.com/engines/specifications.php

Toyota 3.5 DOHC 268 @ 6200 RPM - RL 6500 RPM http://www.edmunds.com/toyota/camry/2015/road-test-specs.html

Honda J35Y 3.5 DOHC 278 @ 6200 RPM - RL 6900 RPM http://www.edmunds.com/toyota/camry/2015/road-test-specs.html (arguably, the best spread between peak and RL)

Mercedes 3.5 DOHC 302 @ 6500 RPM - RL 6250 RPM (rated) 6800 RPM (Fuel cut off) http://www.edmunds.com/mercedes-benz/e-class/2015/?tab-id=specs-tab&sub=

What on earth makes you think I wouldn't have actually looked this stuff up before posting it? This ain't my first time at the rodeo.

 

Fact is, all other things being equal, an OHC design engine has far more pros over an OHV one than it does cons. Hence everyone using them. There's a reason why GM ditched the High Value family after all.

The reason is because the automotive media bullied them into it. The GM 3500 in the old boxy Malibu could get equal or better highway mileage to a 4-cylinder Camry even though it had one fewer gear.... but the media was so fixated on comparing the V6 to the V6 and comparing horsepower per liter that they would ignore the superior torque characteristics of the V6 over the 4-cylinder.

 

And if you want proof, compare figures to the LT4 powered Impala SS to the 2012 car which offered the 3.6 OHC LFX has the sole engine. It was just as quick while getting better mileage, despite being down on hp, and significantly down on tq.

Gearing... entirely. The 5.3 only ever had 4 gears to work with and a tall 4th gear. The 3.6 was only mated to the 6-speed auto. Actually they did put the 3.6 in the Rendezvous with a 4-speed and it was pretty crappy.

[loki]

just a comment on the ohv(CIB) vs ohc.... quick calculation based on the 4.3L.... a HP equivilent to my mazda's 2.5 ~185hp would be a 2.8Lv6. That would be interesting to see,

[Drew Dowdell]

just a comment on the ohv(CIB) vs ohc.... quick calculation based on the 4.3L.... a HP equivilent to my mazda's 2.5 ~185hp would be a 2.8Lv6. That would be interesting to see,

 

The fuel economy of the Mazda's 2.5 would be hard to beat with a V6, but if the V6 ran in a Miller Cycle/Atkinson Cycle setup like the the I4, it would have a fighting chance.  It would probably have better low end torque that would allow the cruising gears to be a little taller too.   

 

It wouldn't rev as high as the 2.5 and might not be sporty enough to fit Mazda's image though.

[Frisky Dingo]

 

 

No no.. it's quite alright.... clearly there is an issue with the forum software that prevents people from reading what I actually type.

As I've said... over and over and over and over and over and over again..... OHV engines are superior DOHC engines OF SIMILAR OUTPUT

 

 

I cited the 3.0 liter class from the competition for a reason.... the reason I stated above. Because the 3.0 engines are at a similar output. I specifically didn't cite the 3.5 liter DOHC engines because they are in a higher horsepower class and are of larger physical size. In the same physical space as the Toyota 3.5 liter, you can stick the GM 4.3 liter V6, which as the specs show, offer more power in a smaller package. In fact, you can probably even fit a GM 5.3 liter V8 in a spot that would be completely full with a Toyota 3.5. If you're looking to get max horsepower in a specific sized engine bay, DOHC is NOT the way to go. Go with pushrods and throw as much displacement at it that you can fit. If you have 5 cubic feet of box to fill, I guarantee the best way to fill that box with power is to go with a pushrod.

I said at or near red-line.... and it's almost like I haven't already posted a list.... oh wait... I have.

To save you from scrolling up... and I'll even provide links.

GM 3.0 DOHC 255hp @ 6900 RPM - RL 6900 RPM http://www.edmunds.com/car-reviews/track-tests/track-tested-2010-buick-lacrosse-cxl-30.html

GM 3.6 DOHC 312hp @ 6800 RPM - RL 6800 RPM http://gmpowertrain.com/2014_images/charts_lg/lfx_chart_cadillac_ats.jpg

FCA 3.6 DOHC 305hp @ 6400 RPM - RL 6400 RPM http://www.pentastars.com/engines/specifications.php

Toyota 3.5 DOHC 268 @ 6200 RPM - RL 6500 RPM http://www.edmunds.com/toyota/camry/2015/road-test-specs.html

Honda J35Y 3.5 DOHC 278 @ 6200 RPM - RL 6900 RPM http://www.edmunds.com/toyota/camry/2015/road-test-specs.html (arguably, the best spread between peak and RL)

Mercedes 3.5 DOHC 302 @ 6500 RPM - RL 6250 RPM (rated) 6800 RPM (Fuel cut off) http://www.edmunds.com/mercedes-benz/e-class/2015/?tab-id=specs-tab&sub=

What on earth makes you think I wouldn't have actually looked this stuff up before posting it? This ain't my first time at the rodeo.

 

 

The reason is because the automotive media bullied them into it. The GM 3500 in the old boxy Malibu could get equal or better highway mileage to a 4-cylinder Camry even though it had one fewer gear.... but the media was so fixated on comparing the V6 to the V6 and comparing horsepower per liter that they would ignore the superior torque characteristics of the V6 over the 4-cylinder.

 

 

Gearing... entirely. The 5.3 only ever had 4 gears to work with and a tall 4th gear. The 3.6 was only mated to the 6-speed auto. Actually they did put the 3.6 in the Rendezvous with a 4-speed and it was pretty crappy.

 

 

First off, that's a pointless argument, but that exists virtually nowhere in autodom. That same problem must also apply to you since I explained how Honda was making the same hp out of an engine almost a whole liter smaller 7 years before the 3900. With better mileage and reliability, mind you. You think that 3900 is anywhere near as refined and linear feeling as a J30? Please. Fast forward to when the 3900 was actually out, and there are OHC V6's that are still smaller displacement making significantly more power. Either way, it loses out. And if want a more clear, modern, comparison the LS3 is clearly superior to the Coyote. Oh, wait...

 

Next you post peak power ratings on a handful of engines out of hundreds. Peak power means nothing, it's all about area under the curve, as you mentioned yourself. The fact of the matter is, these aren't peaky engines with poor down-low power like you make them out to be.

 

You can't possibly think OHC is used because of media pressure. That's the dumbest thing I've ever heard. I guess that's why motorsports use OHC engines. Diesels have more torque down low than OHC engines too, and look at how they compare relative to OHC gas engines of similar power. But hey, superior torque characteristics, I guess we need to put diesels in everything.

 

OHV engines serve their purpose, and serve it well. They're not the final word on the ICE that you would have us believe. Technology was long dwindled the gap in the packaging advantages of using an OHV design. Which is their primary benefit.

 

Agree to disagree.

[Frisky Dingo]

Oh, and I missed the comparison to other 3.0~ engines, but the J30 weighed roughly 250lbs. I can't find official weights, but if you think the 3900 was lighter with it's iron block, you're crazy. As for GM's new 4.3, it offers more torque and less power than Toyota's 2GR-FSE. You must know more than the engineers who decided to use the LFX in the Colorado instead of the LV3.

 

They simply don't have the real world advantages you proclaim. They might have an advantage in work applications such as trucks, suv's, but for mass built production cars, they simply don't. Hence practically nobody uses them. 

[El Kabong]

You can't possibly think OHC is used because of media pressure. That's the dumbest thing I've ever heard. I guess that's why motorsports use OHC engines. Diesels have more torque down low than OHC engines too, and look at how they compare relative to OHC gas engines of similar power. But hey, superior torque characteristics, I guess we need to put diesels in everything.

Audi Endurance racers used diesels. Corvette C7.R uses pushrods. NASCAR uses pushrods. Pushrod engines won the Indy 500 in Penskes, with Benz logos on the rocker covers. And let's not forget the Vipers that go out on the track.

Say what you will about those cars and series-nobody accuses the cars of being fuel-swilling prunes. And yes, the torque is a big help on the track (except possibly for the Penske/Benzes, where the beef was they were TOO powerful).

Edited August 20, 2015 by El Kabong

[ccap41]

You can't possibly think OHC is used because of media pressure. That's the dumbest thing I've ever heard. I guess that's why motorsports use OHC engines. Diesels have more torque down low than OHC engines too, and look at how they compare relative to OHC gas engines of similar power. But hey, superior torque characteristics, I guess we need to put diesels in everything.

Audi Endurance racers used diesels. Corvette C7.R uses pushrods. NASCAR uses pushrods. Pushrod engines won the Indy 500 in Penskes, with Benz logos on the rocker covers. And let's not forget the Vipers that go out on the track.

Say what you will about those cars and series-nobody accuses the cars of being fuel-swilling prunes. And yes, the torque is a big help on the track (except possibly for the Penske/Benzes, where the beef was they were TOO powerful).

Well.. As a NASCAR fna and a fan of autoracing in general.. NASCAR is waaaaay behind on the times when it comes to engine tech as just 2 or 3 years ago they finally made the switch to fuel injection. Yes, in 201X they still ran carbuerated engines. Which is fine. Kept costs down, made it easier for low budget teams to try and keep up, and it was simpler.

 

Ind only ad two brands in their series.. and if you watched that race it was the car who timed the draft the best who won. Okay, a little exaggeration but honestly..not really.. The aero package was very fan-friendly which made for a lot of good racing and passing. They even talked about how it was mostly an aero race.

 

As for the torque that both of these engines are using at 7000+ in NASCAR(up to about 9200rpm) and 10,000+rpm in the Indy cars..they aren't using torque on oval tracks. NASCAR Sprint Cup cars only actually utilize the entire powerband at tracks like Martinsville, Watkins Glen, and Sears Point(I'm pretty sure it's been renamed but I forgot at this point), maybe Pocono as they do shift but last I watched they still kept them reved over 7000rpm. Even on the restarts starting in 1st you're making peak hp and going through the gears. Torque is for everday guys like ourselves(perfect example is your 3.0). Not so much for racing.

[Frisky Dingo]

You can't possibly think OHC is used because of media pressure. That's the dumbest thing I've ever heard. I guess that's why motorsports use OHC engines. Diesels have more torque down low than OHC engines too, and look at how they compare relative to OHC gas engines of similar power. But hey, superior torque characteristics, I guess we need to put diesels in everything.

Audi Endurance racers used diesels. Corvette C7.R uses pushrods. NASCAR uses pushrods. Pushrod engines won the Indy 500 in Penskes, with Benz logos on the rocker covers. And let's not forget the Vipers that go out on the track.

Say what you will about those cars and series-nobody accuses the cars of being fuel-swilling prunes. And yes, the torque is a big help on the track (except possibly for the Penske/Benzes, where the beef was they were TOO powerful).

 

So you have a handful of examples out of hundreds. Congrats.

[smk4565]

I am a DOHC fan of course, but I will say the GM 4-speed automatic killed the pushrod V6 because the Japanese cars had 5 and 6 speed at the time. A 4-cyldiner dohc and 6 speed combo was able to provide the performance and better fuel economy than a 4 speed and 3500 v6 combo.

[Drew Dowdell]

I have qualified all of my statements and you continue to ignore them.

 

I've said multiple times, I'm not talking motorsports, which generally have a displacement limit rather than an engine bay size limit.

I've said multiple times, I'm not talking motorsports, where engines generally run in the 8,000 - 12,000 RPM range, completely unsuitable for every day driving.

 

I've said.... in every day cars like an Impala or Camry, both of which will rarely see an RPM over 4,000 and almost never get to red-line unless they've been stolen, that OHV engines offer superior driving in those applications when comparing engines of similar output.   Thus, a 240hp OHV V6 will feel to be a more powerful engine than a 240hp DOHC V6.   Why?  Because the 240hp in the OHV engine is at a more accessible RPM level than the 240hp in the DOHC, 4900 rpm rather than 6900 rpm.  

 

If you are going unilaterally to agree to disagree with me, I do wish you'd do me the courtesy of at least reading my posts and the links I include. 

 

Of course the area under the curve matters, but so does the generally usable area under the curve.  If a particular vehicle never reaches an RPM in general driving, then the area under that part of the curve is irrelevant. 

 

Take the GM 4.3 v. the GM 3.6 (GMC Canyon, tuned for better torque) v. the GM 3.6 (Cadillac ATS sedan, tuned for horsepower)

 

At the 4.3's peak power output of 285hp, the engine is turning 5300 rpm.

At 5300 rpm in the Canyon's 3.6, the engine is producing 265 lb-ft of torque or 267.42 hp.

At 5300 rpm in the ATS's 3.6, the engine is producing no more than 277hp. We know this because the peak torque for the 3.6 is 275 lb-ft.  The actual HP number is slightly less, but not significantly so.

 

Score @5300 rpm:

4.3 - 285hp

3.6 Canyon - 267hp

3.6 ATS - 277hp

So at 5300 RPM, the 4.3 has more power than the 3.6.

 

 

But who really drives around at 5300 rpm all the time?  How about a more civilized 3,000 rpm?

At 3000 RPM the 4.3 produces 280 lb-ft of torque - thus it is producing 160 hp.

At 3000 RPM the Canyon's 3.6 produces 252 lb-ft of torque - thus it is producing 143 hp

At 3000 RPM the ATS's 3.6 produces 270 lb-ft of torque - thus it is producing 154 hp.

So at 3,000 RPM, the 4.3 has more power than the 3.6.

 

How about rather common 2,000 rpm?

At 2000 RPM the 4.3 produces 260 lb-ft of torque - thus it is producing 99 hp.

At 2000 RPM the Canyon's 3.6 produces 252 lb-ft of torque 93 hp

At 2000 RPM the ATS's 3.6 produces 265 lb-ft of torque - thus it is producing 101 hp.

 

At 2000 RPM, the 4.3 and both 3.6's have virtually identical HP.

 

Since you pointed out the area under the curve being more important.  In the area under the curve from 2,000rpm to 5,000rpm, where most people spend their time, the 4.3 offers more power. 

 

 

 

You must know more than the engineers who decided to use the LFX in the Colorado instead of the LV3.

 

Why would you think the engineers get to make that decision? Marketing made the decision because they want to be able to advertise the "highest horsepower in it's class".  As I've already shown, the 4.3 would be a more suitable engine for the Colorado. As you pointed out, in trucks torque is almost always more important than horsepower... and the 4.3 has more torque available under the curve at every point on the RPM band than the 3.6 in the Colorado and in the ATS. 

 

In an application like the XTS, which is knocked for being soft on low end torque, a 4.3 would be a better choice.  Even if we accept a 9 lb-ft reduction in torque due to transverse mounting (ATS LFX v. XTS LFX), the 4.3 would still be producing 296 lb-ft at peak v. the 264 the 3.6 produces. 

 

The material used in the 3900 v. the Honda J engine is irrelevant. There is no reason GM couldn't have used aluminum... thus it was simply an OHV advantage n that GM left on the table rather than a disadvantage of OHV engines in general. 

 

 

 

You can't possibly think OHC is used because of media pressure. That's the dumbest thing I've ever heard.

 

Sure I can. The automotive media has notoriously steered or attempted to steer products to their own liking for decades.   It is all in subtle phraseology.... "the Pontiac G6 takes a whole 3.9 liters to produce 240 hp from its old tech pushrod V6 while the Honda Accord's new SOHC V6 produces 240 hp from just 3.0 liters"  while ignoring that the G6 has more torque and both engines were recent designed and use modern (for the time) tech like VVT - Stuff like that... all hand waving, man-behind the curtain twisting of facts to suit their particular bias.

 

You're relatively new to C&G, but we've documented this kind of stuff in the automotive media for years.... probably for as long as our 14 year existence. 

[ccap41]

I am a DOHC fan of course, but I will say the GM 4-speed automatic killed the pushrod V6 because the Japanese cars had 5 and 6 speed at the time. A 4-cyldiner dohc and 6 speed combo was able to provide the performance and better fuel economy than a 4 speed and 3500 v6 combo.

Completely agree. Those 4speeds were all slushy, never felt like you ever had a gear fully engaged. It'll make anything feel like crap, imo.

[ccap41]

Drew,

I'm not countering you but just asking..kind of..lol

 

Those OHV engines don't rev like the OHC engines, correct? Like those in your examples aren't revving near 7k like the OHC engines will be. Wouldn't that mean the OHV engines would be geared taller to get more mph per rpm? My point is, while yes the OHC engines are meant to rev more and higher they rev higher easier so for them to sit at 2500rpm on the interstate don't be as stressful for a OHV engine to sit at 2500rpm.

 

I really liked your comparison with hp/tq/@rpm. To add to that.. I'm even more curious what power each of them are making at 2000rpm at 1/4 throttle(realistic acceleration). Because your example is assuming a wide open throttle being cracked at 2000rpm, correct? THAT is what I'm actually the most curious about, because that is how people actually drive. Which of these designs(that's what we're really talking about) is the most flexible? I would think flexibility would yield the most variation in results(in a good way) from 1/8 throttle to full throttle. Meaning 1/8 throttle can be more finely tuned through full throttle.

[El Kabong]

You can't possibly think OHC is used because of media pressure. That's the dumbest thing I've ever heard. I guess that's why motorsports use OHC engines. Diesels have more torque down low than OHC engines too, and look at how they compare relative to OHC gas engines of similar power. But hey, superior torque characteristics, I guess we need to put diesels in everything.

Audi Endurance racers used diesels. Corvette C7.R uses pushrods. NASCAR uses pushrods. Pushrod engines won the Indy 500 in Penskes, with Benz logos on the rocker covers. And let's not forget the Vipers that go out on the track.

Say what you will about those cars and series-nobody accuses the cars of being fuel-swilling prunes. And yes, the torque is a big help on the track (except possibly for the Penske/Benzes, where the beef was they were TOO powerful).

 So you have a handful of examples out of hundreds. Congrats.

I have used mostly contemporary examples out of tens, which is probably a higher proportion in racing than you can find on the street these days (if you leave aside the V8 engines).

I'm quite comfortable playing that hand. Why wouldn't I be? It basically proves my point: give pushrod engines a little tech love and R&D and they are easily a match for OHC apps, if it's EXTERNAL displacement you're looking at, as opposed to INTERNAL displacement.

[Drew Dowdell]

Drew,

I'm not countering you but just asking..kind of..lol

 

Those OHV engines don't rev like the OHC engines, correct? Like those in your examples aren't revving near 7k like the OHC engines will be. Wouldn't that mean the OHV engines would be geared taller to get more mph per rpm? My point is, while yes the OHC engines are meant to rev more and higher they rev higher easier so for them to sit at 2500rpm on the interstate don't be as stressful for a OHV engine to sit at 2500rpm.

 

I really liked your comparison with hp/tq/@rpm. To add to that.. I'm even more curious what power each of them are making at 2000rpm at 1/4 throttle(realistic acceleration). Because your example is assuming a wide open throttle being cracked at 2000rpm, correct? THAT is what I'm actually the most curious about, because that is how people actually drive. Which of these designs(that's what we're really talking about) is the most flexible? I would think flexibility would yield the most variation in results(in a good way) from 1/8 throttle to full throttle. Meaning 1/8 throttle can be more finely tuned through full throttle.

 

Very good questions. Unfortunately, I only have the data from the power curves that GM provides, and as you say, those are at full throttle.

 

2500 RPM isn't at all a strain for an OHV engine, it just isn't needed.  OHC can get taller top end gears as you say.   When you have great low end torque, you can have a taller top gear. The old LT-1 in the Buick Roadmaster would loaf along effortlessly at 65 mph turning only 1,600 rpm.  The Passat TDi in 6th gear at 65 will turn only 1,800 rpm.   My Honda CR-V runs over 3,000 rpm. 

[surreal1272]

 

 

 

You can't possibly think OHC is used because of media pressure. That's the dumbest thing I've ever heard. I guess that's why motorsports use OHC engines. Diesels have more torque down low than OHC engines too, and look at how they compare relative to OHC gas engines of similar power. But hey, superior torque characteristics, I guess we need to put diesels in everything.

Audi Endurance racers used diesels. Corvette C7.R uses pushrods. NASCAR uses pushrods. Pushrod engines won the Indy 500 in Penskes, with Benz logos on the rocker covers. And let's not forget the Vipers that go out on the track.

Say what you will about those cars and series-nobody accuses the cars of being fuel-swilling prunes. And yes, the torque is a big help on the track (except possibly for the Penske/Benzes, where the beef was they were TOO powerful).

 

So you have a handful of examples out of hundreds. Congrats.

 

Is there any particular reason why you want to dismiss now two sets of examples? Drew laid it out pretty well after you basically insulted his intelligence on the matter and you totally sidestepped that fact after he corrected you. That makes no sense Dingo.

[Drew Dowdell]

 

I said at or near red-line.... and it's almost like I haven't already posted a list.... oh wait... I have.

To save you from scrolling up... and I'll even provide links.

GM 3.0 DOHC 255hp @ 6900 RPM - RL 6900 RPM http://www.edmunds.com/car-reviews/track-tests/track-tested-2010-buick-lacrosse-cxl-30.html

GM 3.6 DOHC 312hp @ 6800 RPM - RL 6800 RPM http://gmpowertrain.com/2014_images/charts_lg/lfx_chart_cadillac_ats.jpg

FCA 3.6 DOHC 305hp @ 6400 RPM - RL 6400 RPM http://www.pentastars.com/engines/specifications.php

Toyota 3.5 DOHC 268 @ 6200 RPM - RL 6500 RPM http://www.edmunds.com/toyota/camry/2015/road-test-specs.html

Honda J35Y 3.5 DOHC 278 @ 6200 RPM - RL 6900 RPM http://www.edmunds.com/toyota/camry/2015/road-test-specs.html (arguably, the best spread between peak and RL)

Mercedes 3.5 DOHC 302 @ 6500 RPM - RL 6250 RPM (rated) 6800 RPM (Fuel cut off) http://www.edmunds.com/mercedes-benz/e-class/2015/?tab-id=specs-tab&sub=

What on earth makes you think I wouldn't have actually looked this stuff up before posting it? This ain't my first time at the rodeo.

 

Next you post peak power ratings on a handful of engines out of hundreds.

 

I posted GM, Chrysler, Toyota, Honda, and Benz. That easily covers the majority of the market, but since that doesn't satisfy you...Very well, I'll get you the rest.

 

Nissan 3.5 VQ (Maxima) - 300hp @ 6400 RPM - RL 6600 RPM

Ford 3.7 (Mustang) - 305hp @ 6500 RPM - RL 6850 RPM (fuel cut off)

BMW N52 - 272hp @ 6650 - RL 7000 RPM (Last non-Turbo 6 I could find) the balance advantage of an I-6 over a V6 are pretty clear here though.

!!!! Volkswagen 3.6 - 280HP @ 6200 RPM - RL 6000 RPM !!!! So VW is advertising a horsepower rating achieved 200 RPM beyond red-line?

Hyundai Lambda 3.8  V6 - 348HP @ 6400 RPM - RL 6750

 

I've now covered V6es from all of the domestics, the big 3 Japanese, the best Hyundai has to offer (I can't find red-line stats on the Hyundai 3.3, but I doubt it's higher than the 3., and the Germans.

 

Do I need to look up Peugeots and obscure Suzukis too or is this sufficient? 

[Frisky Dingo]

Okay, yep, you guys are right and the ENTIRE AUTO INDUSTRY IS WRONG.

 

I concede, happy now?

[surreal1272]

Okay, yep, you guys are right and the ENTIRE AUTO INDUSTRY IS WRONG.

 

I concede, happy now?

So I guess empirical evidence is not enough huh?

 

Oh and obviously the entire auto industry is not right or else they would all be using the SAME THING.

Edited August 20, 2015 by surreal1272

[ccap41]

 

 

 

Next you post peak power ratings on a handful of engines out of hundreds.

 

I posted GM, Chrysler, Toyota, Honda, and Benz. That easily covers the majority of the market, but since that doesn't satisfy you...Very well, I'll get you the rest.

 

Nissan 3.5 VQ (Maxima) - 300hp @ 6400 RPM - RL 6600 RPM

Ford 3.7 (Mustang) - 305hp @ 6500 RPM - RL 6850 RPM (fuel cut off)

BMW N52 - 272hp @ 6650 - RL 7000 RPM (Last non-Turbo 6 I could find) the balance advantage of an I-6 over a V6 are pretty clear here though.

!!!! Volkswagen 3.6 - 280HP @ 6200 RPM - RL 6000 RPM !!!! So VW is advertising a horsepower rating achieved 200 RPM beyond red-line?

Hyundai Lambda 3.8  V6 - 348HP @ 6400 RPM - RL 6750

 

 

 

Why is that even possible/a thing? Post a rating ABOVE what the engine can even rev to?!?!?

[El Kabong]

Okay, yep, you guys are right and the ENTIRE AUTO INDUSTRY IS WRONG.

 

I concede, happy now?

So I guess empirical evidence is not enough huh?

 

Oh and obviously the entire auto industry is not right or else they would all be using the SAME THING.

True on both counts. Lookit, we all have biases and whatnot. The trick is to realize they're biases. The automotive press is no less biased than Fox or CNN. They'll tell you otherwise, at least until recently, when some outlets have begun to open up about past screwups.

As I've said: pushrods are probably done and gone as far as engines of less than eight cylinders go. But the reason they're gone isn't the tech itself, but the sloppiness of execution that too often went into them. Laziness will make any engine layout into a turnip eventually. Either that or none of us are giving the 32-valvers in the Tundra/Titan their appropriate dues?

[G. David Felt]

I give the Titan / Tundra their props, the engine at least moves their metal on the road. Other than that, I am not impressed with ether truck.

[Drew Dowdell]

Okay, yep, you guys are right and the ENTIRE AUTO INDUSTRY IS WRONG.

I concede, happy now?

The entire auto industry is a MARKETING industry that builds cars on the side. They've spent the last 7 decades selling horsepower and dogginniut they're going to keep doing just that... Even it if takes fleecing the customer to do it.

[Drew Dowdell]

Okay, yep, you guys are right and the ENTIRE AUTO INDUSTRY IS WRONG.

 

I concede, happy now?

 

And it's not like vast swaths of the auto industry hasn't been wrong before.  The domestics were wrong about the imports.  The domestics were wrong about the oil crisis.  The japanese and germans were wrong about the Koreans  (I'd say the domestics recognized the threat, but were unable to react rather than unwilling). The whole industry was wrong on the paint process. The japanese were wrong on rust proofing.   The entire industry has been wrong about turbos multiple times and has only recently figured it out.

 

 

BTW... about those turbos. The reason for their popularity today is precisely because of the lack of low end grunt from most engines.   In 4-cylinder, it is usually expected, but when you buy a V6, you want some go power when you take off.  Turbos + DI have given back what the switch to DOHC taketh away. 

[Drew Dowdell]

 

 

 

 

Next you post peak power ratings on a handful of engines out of hundreds.

 

I posted GM, Chrysler, Toyota, Honda, and Benz. That easily covers the majority of the market, but since that doesn't satisfy you...Very well, I'll get you the rest.

 

Nissan 3.5 VQ (Maxima) - 300hp @ 6400 RPM - RL 6600 RPM

Ford 3.7 (Mustang) - 305hp @ 6500 RPM - RL 6850 RPM (fuel cut off)

BMW N52 - 272hp @ 6650 - RL 7000 RPM (Last non-Turbo 6 I could find) the balance advantage of an I-6 over a V6 are pretty clear here though.

!!!! Volkswagen 3.6 - 280HP @ 6200 RPM - RL 6000 RPM !!!! So VW is advertising a horsepower rating achieved 200 RPM beyond red-line?

Hyundai Lambda 3.8  V6 - 348HP @ 6400 RPM - RL 6750

 

 

 

Why is that even possible/a thing? Post a rating ABOVE what the engine can even rev to?!?!?

 

 

I"m sure the engine won't grenade exactly at 6001 rpm, but that's what the engine is rated to.   Keep in mind that this is a VR engine with a 15 degree cylinder bank rather than a V engine with a 54, 60, or 90 degree cylinder bank. So even though it is a 24 valve engine, it is technically SOHC rather than DOHC if you think of it as a V engine, but it is a DOHC rather than SOHC if you think of it as an inline engine.  It is kinda both and neither..... but that may be the cause of the relatively low red-line rating.   It's a very interesting design from a packaging standpoint. 

[oldshurst442]

 

Turbos + DI have given back what the switch to DOHC taketh away.

 

 

Ill like that sentence a lot. I decided to frame it in my post with nice colours. 

Edited August 20, 2015 by oldshurst442

[oldshurst442]

 

 

 

 

 

Next you post peak power ratings on a handful of engines out of hundreds.

 

I posted GM, Chrysler, Toyota, Honda, and Benz. That easily covers the majority of the market, but since that doesn't satisfy you...Very well, I'll get you the rest.

 

Nissan 3.5 VQ (Maxima) - 300hp @ 6400 RPM - RL 6600 RPM

Ford 3.7 (Mustang) - 305hp @ 6500 RPM - RL 6850 RPM (fuel cut off)

BMW N52 - 272hp @ 6650 - RL 7000 RPM (Last non-Turbo 6 I could find) the balance advantage of an I-6 over a V6 are pretty clear here though.

!!!! Volkswagen 3.6 - 280HP @ 6200 RPM - RL 6000 RPM !!!! So VW is advertising a horsepower rating achieved 200 RPM beyond red-line?

Hyundai Lambda 3.8  V6 - 348HP @ 6400 RPM - RL 6750

 

 

 

Why is that even possible/a thing? Post a rating ABOVE what the engine can even rev to?!?!?

 

 

I"m sure the engine won't grenade exactly at 6001 rpm, but that's what the engine is rated to.   Keep in mind that this is a VR engine with a 15 degree cylinder bank rather than a V engine with a 54, 60, or 90 degree cylinder bank. So even though it is a 24 valve engine, it is technically SOHC rather than DOHC if you think of it as a V engine, but it is a DOHC rather than SOHC if you think of it as an inline engine.  It is kinda both and neither..... but that may be the cause of the relatively low red-line rating.   It's a very interesting design from a packaging standpoint. 

 

And this post just gave me a wonderful warm feeling inside.

 

Memories.

Good 'ol wonderful memories.

Edited August 20, 2015 by oldshurst442