The never ending debate

[GoCougs]

ET is a better measure of traction.  Trap speed is a better measure of power.  The GMC cars consistantly post faster trap speeds than the Tundra. 

Anyway the Chevy runs the same part time 4WD system the Tundra does, so it's not like the GM's are getting an AWD launch. 

The gearing difference is a big deal despite what you say, as much as over 10% in some gears (important gears like 3rd).  The 300 pound weight difference is less than a 5% difference.  In the very same tests you posted, it looks like the GM cars are the ones having trouble getting off the line (not the Toyota as you imply), with the GM's posting better passing times and trap speeds once underway.

In the first test (well first article as they really both refer to the same test) you see that the overall 0-60 loaded times are faster for the Toyota, but the GM's are faster from 40-60mph while loaded.

In the next test you'll see while the Tundra has a better elapsed time, both GM trucks post better trap speeds.  Not consistant with your theory of traction issues for the Tundra.

In the end we have one test (yes both your articles actually refer to the event covered by different sources) where the Tundra won in fuel efficiency and another where the GM won.  You could only conclude that gas mileage comparisons are mixed.  Plus that test mentioned one major inconsistency.  The Tundra was the only car fully broken in with 8000 miles on the clock, the rest of the field had only around 1000 miles on the clock.  The Tundra usually isn't such a stand out in fuel economy in other tests.  Loaded performance could only be described as mixed as the Toyota has better ET's but the GM's consistantly pulls better trap speeds.  What isn't mixed is unloaded performance as the GM's trounces the Toyota both on ET and trap speed. Plus the 6.2 only recommends premium for max power and it's fine to run on regular.  Considering the decent margin that the 6.2 destroys the 5.7 at the 1/4 mile trap speed, I wouldn't be surprised if the 6.2 still manages to out perform the 5.7 even on regular.

No - gearing difference not a big deal for those tests, as they reached a max of 60 mph. Again, the details, using a max engine speed of 5800 rpm, speed in gears:

Silverado
1st = 38 mph
2nd = 66 mph

Tundra
1st = 37 mph
2nd = 64 mph

Until I see objective proof to the contrary, I plainly see a truck (Tundra) that has traction issues. Plus, it's a smaller displacement engine that runs on regular fuel. I remained thoroughly unconvinced that the 6.2L is as good or better.

[omicron]

And I've seen a 478 cubic inch Hemi in a Austin Healy Sprite. Let's not talk about what CAN be stuffed where if someone feels like it.

That is so painfully awesome it hurts my head just to think about it. I want it.

[SVT32V]

Its not just the height, it's the width. And it's not just the size, it's the price. Plus what does it matter? The new Vette makes like 450HP from 6 liters and gets good gas mileage. As much as I like to tech-snob, the LSx series of engines works. The 5.4L DOHC in the new Cobra needed a supercharger to make the same power. Within the realm of mass produced V8s you don't have that many making that kind of power. And DOHC heads are definitely bigger than OHV or even SOHC heads- to write that difference off as negligible is negligent IMO.

Last I checked the 6.3 liter vette engine makes 438hp, the 5.4 SC GT500 makes 540 hp.  Seems like a good bit more our of the 5.4SC.

[565]

the 6.3L AMG engine (actually 6.2L in displacement) also weighs in at 439 pounds which is what the LS2/6/7 weighs giver or take a few pounds here and there

i'm sick of the "oh pushrod engines are more powerful, have more torque, are lighter, are smaller, and rule the world" bullshit because given equal displacement engines its pretty easy to prove that they aren't more powerful, don't produce more torque, and aren't lighter.  Size is harder to prove but I wouldn't doubt the mercedes engine is any bigger physically either looking at the applications its packaged in.

You know I used to be a big fan of the 6.2, being as light as that claimed 199kg weight and pulling 507hp in the E63 AMG.  However since then (from similar debates on other forums) two things came to light that don't allow this engine to be compared as favorably to the LS7 in real life as it does on paper.

First something seems a bit off with the 6.2 Merc weight claims of 199kg, while the much smaller displacement BMW V8 weighs 202kg. Now BMW aren't fools at making light engines.  The thing about engine weight claims is that unless you pull it out of the car and stick it on the scale, it's hard to compare apples to apples.  People have different ideas of what exactly fully dressed is, and I haven't actually seen an official claim for "fully dressed" for that 199kg figure, the official claim is "dry weight."  Now whether the 6.2's dry weight is in the exact same state as GM's fully dressed claim, that is up to speculation.

Now the other thing that did become a black mark on the 6.2 is that despite claims of 507 hp for the 6.2 Mercedes and 505 hp the 7.0 LS7, there is actually a power gap between the engines.  On real life Dynos, the 6.2 just plain doesn't put down as much power as the LS7.  When you compare the collection of dyno runs, it just plain doesn't.  And it's not like some tiny difference either, it's a pretty big deal.  Obviously there are some sizable variations for engine output and dyno runs so we have to look at the range.

The Merc 6.2 has been dynoing in about the 380-420 range on Dynojet. 

http://www.mbworld.org/forums/w211-amg/162875-my-e63-dyno-experience.html

http://www.mbworld.org/forums/w211-amg/162541-i-feel-dyno-coming.html

http://www.mbworld.org/forums/cls55-amg-cls63-amg-c219/176245-cls63-dyno-results.html

As you can see, these are Dynojet numbers, which are supposed to be the higher reading ones.






I believe the highest recorded for a stock MB 6.2 was 428rwhp.


Compare those numbers to what the LS7 routinely puts down, in the 440 to 460 range on Dynojet.

http://forums.corvetteforum.com/c6-tech-performance/1236902-c6-z06-dyno-video-and-numbers.html?forum_id=101

http://forums.corvetteforum.com/c6-z06-discussion/1954824-stock-z06-dyno-graph.html

http://forums.corvetteforum.com/c6-tech-performance/1231115-2005-z06-dyno-numbers-working-with-exhaust.html?forum_id=101


The highest I've seen recorded was 488 from one particularly strong Z06.

http://forums.corvetteforum.com/c6-z06-discussion/1337820-just-dynod-the-new-z-480rwhp-stock.html?forum_id=100


Here are 3 superposed Z06 Dyno runs to give you a sense of the range the LS7 can put down.




So looking at the range for the MB 6.2 380-428 (highest recorded)  against the LS7 7.0  440-488 (highest recorded).  We are looking at a huge gap here, around 60 rwhp hp of difference.  Now you could try to claim that it's the manual in the Z06 that being more efficient, but that could really only account for a 20hp gap or so.

Actually here is a good comparison of a dyno from a automatic LS3 engine compared to a manual LS3, and the gap between the cars was 19Hp

http://www.dragtimes.com/blog/2008-chevrolet-corvette-ls3-dyno-results


Auto LS3 (this car had less than 30 miles on the clock, and really had no business being on a dyno in the first place)



Manual LS3



Also note that the 6.2 LS3's will put down around the 370-390 range, which is more comparable to what the 6.2 DOHC merc is putting down than the LS7 (as suggested by looking at paper stats).

[SVT32V]

I mean I'm sure everyone has seen the epic difference between the 5.0L pushrod Ford and the 4.6L OHC? I mean I know the 4.6 isn't the most compact of motors when it comes to OHC engines, but the difference in size is staggering.

The motor on the right with its crappy 1/2" two bolt mains and paper thin walls in holding the cams in will self destuct above 400 hp.  The most the factory ever got out of it was 245 hp.

The motor on the left has 6 bolt cross drilled mains with thick main bearings.  The Al block will easily support 800-900 hp with forged internals. The mustang 4V had a lowest rating of 305 and certainly was capable of at least 100 more hp.

Guess what is the same about both engines in the pic?  Both the 5.0 and the 4.6 4V fully dressed weigh the same (full mid 90s smog equipped).

A 3V mustang engine only comes in at 420 lbs.

Race 5.0s use and FRRP A6 block or something like a dart block, any regular 5.0 block is living on borrowed time over 400 hp.

[GoCougs]

WOW you guys are busy...

The 5.0L vs. 4.6L is as to the 5.0L vs. flat head. The 5.0L is larger than the flat head, yet it is more powerful and more robust (just as the 4.6L is larger yet more powerful and more robust WRT the 5.0).

The BMW V10, M-B 6.2L V8, Porsche 3.8L F6, et al., are all superior engines.

The correct Northstar/small block analogy should be 1990. In 2009 the Northstar is an ancient throwback, however, almost 20 years ago, it was superior to the 305/350 V8 of the time.

[r0tor]

Also note that the 6.2 LS3's will put down around the 370-390 range, which is more comparable to what the 6.2 DOHC merc is putting down than the LS7 (as suggested by looking at paper stats).

stock S63AMG chassis dyno on a dynopack (not overly optimistic dynojet)... the 6.3 engine at its highest factory potential.  Also keep in mind, mecedes will be more worried about NVH then a corvette engineer would be, therefor the driveline components tend to be beefier and therefore have more inertial losses.  Also, the benz has a torque converter to deal with  .  So in conclusion, its putting down the same numbers as a larger displacement 7.0L LS7 engine.

[GoCougs]

Anytime I see a chassis dyno I tune out. There are inherent issues with getting better than ~5% accuracy, and myriad times I've seen erroneous operation (as in, "a lighter drive shaft gave me 10 hp!"). The only proper comparison is via a stand-alone, water brake style engine dyno.

Further, the M-B 6.2L is luxury engine used in cars, vans and SUVs; the LS7 is a tapped out, very limited production sports car engine.

[565]

stock S63AMG chassis dyno on a dynopack (not overly optimistic dynojet)... the 6.3 engine at its highest factory potential.  Also keep in mind, mecedes will be more worried about NVH then a corvette engineer would be, therefor the driveline components tend to be beefier and therefore have more inertial losses.  Also, the benz has a torque converter to deal with  .  So in conclusion, its putting down the same numbers as a larger displacement 7.0L LS7 engine.

This was that new "dynopack" dyno at DC performance wasn't it?

That Dyno reads notriously high.

http://forums.viperclub.org/srt10-srt10-coupe-discussions/626330-before-after-paxton-dyno.html

"If it was the same type as the new Dyno that DC Performance is now using, then I would not have the same question because Dan Cragin said that the new dyno produces numbers that are higher than a Dynojet. So, if possible, please indicate what kind of dyno was used. Thanks."

In case you are wondering Dan Cragin is the guy who actually owns DC performance, so straight from the horse's mouth.

Here is a realistic S63 AMG Dyno done by the same guys DC performance on their Dyno Jet. (probably the same car too)

http://www.dragtimes.com/2009-Mercedes-Benz-S63-AMG-Dyno-Results-Graphs-16625.html

[ChrisV]

the 6.3L AMG engine (actually 6.2L in displacement) also weighs in at 439 pounds which is what the LS2/6/7 weighs giver or take a few pounds here and there

i'm sick of the "oh pushrod engines are more powerful, have more torque, are lighter, are smaller, and rule the world" bullshit because given equal displacement engines its pretty easy to prove that they aren't more powerful, don't produce more torque, and aren't lighter.  Size is harder to prove but I wouldn't doubt the mercedes engine is any bigger physically either looking at the applications its packaged in.

the mercedes engine, sitting outside the car, is physically bigger. As is teh lecxus engine i have sitting in my garage, and the measurements i took off the 4.4 liter BMW engine in my own car (thinking maybe i could use a version of it in my project instead of the Lexus).

You can call BS all you want, but until you do more than read a magazine and drive your rotary car around, you will continue to be wrong.

Oh, and do you have equal displacement V8s sitting around to determine and gurantee which is lighter? or are you using V6s that in typical domestic form were cast iron engines, rather than aluminum, thus changing the comparison...

[ChrisV]

The motor on the right with its crappy 1/2" two bolt mains and paper thin walls in holding the cams in will self destuct above 400 hp.  The most the factory ever got out of it was 245 hp.

Actually, with Cleveland style heads, the factory rating was 290hp in my '70 BOSS 302. And they were capable of 8000 rpm in streetable form, much like the Chevy DZ302 of the same era.

Some have split blocks, but I've seen numerous SBFs putting out well over 400 hp reliably in supercharged form at 306 cid, and many stroked to almost 350 cid that are doing it routinely in NA form. and a My own 306 cid carbed version was a reliable daily driver and autocross engine for 5 years at nearly 400 hp. And that was with cast iron block and heads.

Guess what is the same about both engines in the pic?  Both the 5.0 and the 4.6 4V fully dressed weigh the same (full mid 90s smog equipped).

A 3V mustang engine only comes in at 420 lbs.

Race 5.0s use and FRRP A6 block or something like a dart block, any regular 5.0 block is living on borrowed time over 400 hp.

Or you use an older, seasoned block from the late '60s/early 70s.

And my cast iron block and head 306 (true 5.0) weighed in at 400 lbs ready to run. Would have been lighter with the aluminum heads. As it was, it fit in the RX7 with massive room to spare (the 4.6 doesn't).

The listed weights I've seen on the Mustang iron block SOHC 4.6s are well over 500 lbs ready to run. The all aluminum DOHC is still at about 500 lbs in this form, shipped:



A couple people in the V8 RX7 community have attempted to put in 4.6 mod motors in the cars, and they simply wouldn't fit between the strut towers, while my 306 fit like it was meant to be there:

[r0tor]

Here is a realistic S63 AMG Dyno done by the same guys DC performance on their Dyno Jet. (probably the same car too)

http://www.dragtimes.com/2009-Mercedes-Benz-S63-AMG-Dyno-Results-Graphs-16625.html

i call ultimate  on that because the nimrods are overriding the SAE correction factor on a normally aspirated car

[r0tor]

who the F cares about the 4.6L DOHC mustang engine?  I mean really, its like using an elephant hemi motor as the size of a steriotypical pushrod engine

[GoCougs]

Modded motors are broken context - Ford never built a warrantied, smog-friendly 302/351 good for more than about 250 hp (net as already stated - about 300 gross as in the Boss 302). The engine was tapped in power and warrantability WRT to the retail market - just as the flat head eventually reached its peak in each, and was in turn itself replaced by the OHV.

[omicron]

Modded motors are broken context - Ford never built a warrantied, smog-friendly 302/351 good for more than about 250 hp (net as already stated - about 300 gross as in the Boss 302). The engine was tapped in power and warrantability WRT to the retail market - just as the flat head eventually reached its peak in each, and was in turn itself replaced by the OHV.

Of course you are referring to the North American market, but for interest's sake you'll find the 268hp Falcon XR8 Sprint and GT variants of 1992, the 268hp Falcon GT of 1997, the 295hp Falcon TS50s from 1999-2001 and '01-'02 Falcon XR8s, and the 342ci 335hp TS50 and Pursuit variants of 2002.

[565]

i call ultimate  on that because the nimrods are overriding the SAE correction factor on a normally aspirated car

No they aren't, the SAE correction factors are correct.....



http://wahiduddin.net/calc/calc_cf.htm

http://www.silvercote.com/PDF/VaporPressureTempRH.pdf

[ChrisV]

Of course, we've also strayed into the Ford SB territory, where even the latest 5.0 heads can be bolted onto an early '60s 260 and vice versa. Ford didn't continually improve the SB the way GM did (with the exception of changing from a 5 bolt to a 6 bolt early in the 289 production run. The previous 221/260/early289s were 5 bolt bellhousing designs, and transmissions don't interchange). The LS shares precious little with the traditional SBC except layout.

What the Ford illustrates is how compact a larger displacement pushrod V8 can be vs even the smallest DOHC V8. Even in cast iron form, it was thus lighter than even the smallest aluminum mass production V8 in modern cars (I don't count exotic V8s like Ferraris, et al, due to the fact that they are seriously expensive and made in small numbers, and are not known for living reliably for many miles at a time)

[r0tor]

i will conceed to there being am azing combination of weather effects that leads to a 1.00 CF... in any event, it is still putting out more power then any 6.3L OHV engine while weighing the same -shrug-

[Submariner]

Let's not talk about what CAN be stuffed where if someone feels like it.

Hmmmph...I saw a movie on Cinemax last night with that exact same tag line.

[SVT32V]

What the Ford illustrates is how compact a larger displacement pushrod V8 can be vs even the smallest DOHC V8. Even in cast iron form, it was thus lighter than even the smallest aluminum mass production V8 in modern cars (I don't count exotic V8s like Ferraris, et al, due to the fact that they are seriously expensive and made in small numbers, and are not known for living reliably for many miles at a time)

The Ford 5.0 fully dressed for smog regulations of the mid 1990s was over 500 lbs. You can't compare your carbed smogless aftermarket modified engine to a factory engine that has to pass smog and have a warranty.  Apples and oranges.

[SVT32V]

Actually, with Cleveland style heads, the factory rating was 290hp in my '70 BOSS 302. And they were capable of 8000 rpm in streetable form, much like the Chevy DZ302 of the same era.

Of course there were wonderful examples of small block fords but we are talking about the ubiquitous 5.0 of the 90s that was in the pictures.
Some have split blocks, but I've seen numerous SBFs putting out well over 400 hp reliably in supercharged form at 306 cid, and many stroked to almost 350 cid that are doing it routinely in NA form. and a My own 306 cid carbed version was a reliable daily driver and autocross engine for 5 years at nearly 400 hp. And that was with cast iron block and heads.

Yup, some get lucky but Ford could never warranty a 390 hp 5.0 like the '03 cobra.

And my cast iron block and head 306 (true 5.0) weighed in at 400 lbs ready to run. Would have been lighter with the aluminum heads. As it was, it fit in the RX7 with massive room to spare (the 4.6 doesn't).

Yeah, good luck smog certifying it as a production smog passing car.

The listed weights I've seen on the Mustang iron block SOHC 4.6s are well over 500 lbs ready to run. The all aluminum DOHC is still at about 500 lbs in this form, shipped:

The aluminum 3V weighs 420lbs fully dressed.


A couple people in the V8 RX7 community have attempted to put in 4.6 mod motors in the cars, and they simply wouldn't fit between the strut towers, while my 306 fit like it was meant to be there:

The 5.0 is much narrower than the 4.6, no argument there.

[GoCougs]

Of course you are referring to the North American market, but for interest's sake you'll find the 268hp Falcon XR8 Sprint and GT variants of 1992, the 268hp Falcon GT of 1997, the 295hp Falcon TS50s from 1999-2001 and '01-'02 Falcon XR8s, and the 342ci 335hp TS50 and Pursuit variants of 2002.

After a wee bit of Googling those Falcons appear to be the product of "Tickford;' some sort of entity contracted by Ford-AU to build these hi-po versions (something I'm sure you know), so with that I don't know if we can call this "Ford."

Just about any yahoo can easily build with ~$2,000 worth of parts from just about any hot rod shop (Summit, Jegs, PAW, etc.) a small-block Ford of 350+hp; that's not hard. What's hard is getting good NVH, good driveability and good durability, amongst other things. As the market dictated more power and better NVH, the small-block Ford simply couldn't keep up.

[sportyaccordy]

1. You guys are dorks

2. You can't compare the Ford 302 to a new motor weight wise unless you are talking an all aluminum 302 which weighs about 100-120# less than an iron one.

3. All these #'s are semantics and internet penis showing... at the end of the day I would rather the LSx motor. Yea the Merc motor might be DOHC but who gives a fuck? LSx parts are dirt cheap + in abundance, you can get one hooked up to a manual Tremec or w/e gearbox for like $4K, their ECUs are already tapped into and ready for tuning and even in their stone-age technology, as efficient as they are they STILL respond better to mods than comparable OHC V8s.

I GUARANTEE even in their increased production #'s DOHC motors cost more to make. On top of that like someone said 4V motors have more valvetrain loss (though their #'s were off). W/all that VVT VVL bullshit OHV motors are much easier to maintain or rebuild if necessary. For a down dirty sports car I don't know why anyone would choose anything BUT an LSx motor. Why complicate things needlessly?

[565]

i will conceed to there being am azing combination of weather effects that leads to a 1.00 CF... in any event, it is still putting out more power then any 6.3L OHV engine while weighing the same -shrug-

So does that mean I get to "call ultimate " you being a "nimrod" ?     

[Raza]

So have we come to a conclusion yet?  Because I can't tell the difference.  I like Corvette motors.  Especially in GTOs.

[TBR]

All the OHC boys seems to be forgetting one of the most important variables: cost.

[ChrisV]

The Ford 5.0 fully dressed for smog regulations of the mid 1990s was over 500 lbs. You can't compare your carbed smogless aftermarket modified engine to a factory engine that has to pass smog and have a warranty.  Apples and oranges.

I compare it in ready to run form, or to basic engine minus electronics. What it took to make it run in my car. And I can certainly compare the length, height, and width of it in that form. the weights i use are based on what engine swappers have to work with for each engine, not the auxiliary stuff that's neede in their factory application. The 4.6 is still heavier, longer, wider, and taller. Even the basic engine, stripped of all it's crap, does not physically fit where teh 289/302/5.0 fits.

It still had cast iron block and heads. It's only concession to weight savings was aluminum intake manifold (similar to the high po one Ford had available for the small block during it's production run).

Considering I am currently comparing the SBF to the Lexus DOHC in the form that each need to be in to run in my car now, and emissions controls in the newer engine are not a factor (in fact, I was looking into using the Australian Holley carb intake manifold setup for the Lexus engine in street rods and circle track racers down under), and the engine becomes even MORE comparable.

Simply put, the "newer" DOHC engine is physically larger, heavier, and more complex for the same power output.

[Raza]

That is so painfully awesome it hurts my head just to think about it. I want it.

Yes, it is.  I need to lie down now.

[ChrisV]

Of course there were wonderful examples of small block fords but we are talking about the ubiquitous 5.0 of the 90s that was in the picture.

Is there some size difference between the '90s 302, and the '60s 302 that I'm not aware of? We're discussing pushrod engines in general, and SBFs and SBCs in particular. Now you're trying to say that the flaws of a particular '90s version of the SBF is the entire reason to discount pushrods?

Yup, some get lucky but Ford could never warranty a 390 hp 5.0 like the '03 cobra.

Ford never tried to warranty one like mine, but mine lasted a long time in modded form, so it was apparenlty capable of considerably more than teh factory state of tune. Do not fall into the trap of thinking that the factory warrantied state of tune was it's ultimate reliable ability. I mean, I built a Fox mustang with a 466 cid 460 based engine that had over 700 lb ft of torque, over 500 hp, and was a reliable daily driver/track car for over a decade for it's new owner. And I didn't use exotic parts (most of the parts were out of the Ford catalog). What the factory decided was adequte for sale, and what the engines were capable of with only minor tweaks are often considerably different.

Yeah, good luck smog certifying it as a production smog passing car.

We're not talking about smog legal. We're talking about physical size. I could have made it smog legal with very little effort.

And again, since this was a general pushrods vs OHC, what Ford did is different than what GM did. GM was apparently able to make power reliably from a smog legal N/A engine, in about the same physical space, at the same weight. Similar tweaks to the Ford engine can generate good power, reliably, too.

The aluminum 3V weighs 420lbs fully dressed.

You said that already. Source? All the guys putting them into other cars (or trying to) are finding they are much heavier in actuality.

The 5.0 is much narrower than the 4.6, no argument there.

And we come back to the basic point: physical packaging for the same displacement is much more compact for the pushrod engine, as well as being simpler and lower cost for similar outputs.

[GoCougs]

Yes sporty, sure they cost more; so do disc brakes vs. drum, EFI vs. carb, independent suspension vs. rigid axle, unibody vs. BoF, etc., and OHC vs. push rod fits exactly within this list (i.e., costs more but is superior technology).

4V motors do not have more valve train loss; the valve springs on push rod valve trains are massive owing to all that mass (lifter + pushrod + rocker arm) that must be kept in check; at best it's a wash and I would not be surprised if the OHC valve train has less losses.

I'm simply amazed every time this "issue" comes up. There is no debate save for the issue raised about modding. Automakers do not build cars to be modded, they build them to perform and otherwise meet the needs of the market; and simply put, OHC owns push rod in this regard.