The never ending debate

[TBR]

I agree. Looking at the results of the LS series of engines, what's the point of this argument? Lots of power in a light package with respectable fuel economy, what's wrong with that?

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[2o6]

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You didn't type that?

[TBR]

You didn't type that?

No, I am trying to get Cougs or r0t0r to answer it.

[GoCougs]

Wow, that's simply too many responses to go tit-for-tat; so for that which comes to mind...

The FEA plot shows exaggerated movement (i.e., not to scale, hence the color code but hard to read the key on the right hand side). Yes, any conventional coil suspension will have "cross talk" but it's through a separate structural member (anti-roll bar). With the transverse leaf it's all the same member, plus it is dynamic, causing gods knows what harmonics.

As to the so-called "infamous" 4.6L vs. 5.0L comparison picture. Would the audience be similarly aghast with a comparison picture betwixt the size difference of a 5.0L and a Ford Flathead? Or how about between a Chrysler M-B 6.2L and 392 Hemi? The broken analogy with the 4.6L vs. 5.0L is that the Ford small block never came rated at more than about 240 hp (net) from the factory and was kind of a fragile engine at that, yet the 4.6L was not only leveraged from the beefier 5.4L that had to do duty in trucks, it had to be designed to eventually take the 390 hp (net) in the previous Cobra.

GM's pushrod engines are cheapo VVT - the do not phase intake relative to exhaust and to do not have variable lift. They simply phase the whole cam relative to the crank. Better than nothing but substantially off the mark. At least Chrysler with the Viper V10 went with a cam-in-cam approach to phase intake relative to exhaust (and both relative to the crank); it like GM's engines however doesn't have variable lift, either.

The reason why GM and Chrysler can mope along with their anachronisms is that there is precious little competition. The only real competition is the Toyota 5.7L, and I dare say that even with the recent GM (6.2L) and Dodge (revised 5.7L) , the Toyota 5.7L still wins the towing, acceleration and MPG categories in most any comparison people care to cite. I suspect however that many are hinging on the Corvette. The 911 with a physically smaller engine, less displacement, and despite being being a bigger, heavier car yet down on peak power is every bit the performer as that of the Corvette. Further,  BMW's 5.0L V10, the 911 GT3's 3.7L F6, and M-B's 6.2L V8, utterly towers over the N/A versions of the LSx. The Corvette gets lucky because it gets to use a truck engine. Nothing new, really. And certainly nothing special.

[565]

The reason why GM and Chrysler can mope along with their anachronisms is that there is precious little competition. The only real competition is the Toyota 5.7L, and I dare say that even with the recent GM (6.2L) and Dodge (revised 5.7L) , the Toyota 5.7L still wins the towing, acceleration and MPG categories in most any comparison people care to cite.

Oh really?  Please find me these comparison tests where the six speed auto 5.7 Toyota beats the six speed auto 6.2 Chevy in towing, acceleration, AND MPG.


Oh wait I found a comparo.

http://www.edmunds.com/insideline/do/Drives/Comparos/articleId=147067

Except omg, they must have not gotten the memo because it appears that 6.2 beat the 5.7 through the 1/4 mile.

6.2 Chevy:  1/4 Mile (sec @ mph): 14.9 @ 94.1 mph
5.7 Toyota: 1/4 Mile (sec @ mph): 15.1 @ 91.7 mph

Well surely the 5.7 must have gotten better MPG from it's godly OHC's right?

Silverado: 14.2 mpg
Tundra: 13.6 mpg

Well so much for that.

So the Tundra only beats the Chevy in towing then and that's because the test Silverado came with the 3.42 gear ratio, compared to the Tundra with a final drive of 4.30.

[sandertheshark]

Excuse me, I can't hear you over the sound of how awesome I am.

[GoCougs]

Yes, I was incorrect in thinking of the times per an engaged transfer case owing to major traction problems (here, last paragraph) to get 0-60 of 6 sec and 14.6 sec 1/4 mile times (more on that later).

First, the vehicle(s):

1.) Rear gear ratio is irrelevant, it's the final gear ratio that matters (c'mon, you know this):

The Silverado's gear ratios are:
4.04, 2.36, 1.52, 1.15, .85, .66

W/3.42:1 rear that equates to:
14.0, 8.1, 5.2, 3.9, 2.9, 2.3

The Tundra's gear ratios are:
3.33, 1.96, 1.35, 1.00, .728, .588

w/4.30:1 rear that equates to:
14.3, 8.4, 5.8, 4.3, 3.1, 2.5

As we can see the Tundra has only a slight advantage and not the substantial advantage you implied by simply comparing 3.42:1 vs. 4.30:1. I also remind everyone what we already know that the Tundra is the heavier vehicle (380 lbs per the Edmunds test).

2.) Recommended fuel for GM 6.2L is premium (kindly reference the Edmunds tests). Recommended fuel for the Tundra is regular.

Next, the tests:

1.) In the Edmunds test the Tundra is better at towing and got identical towing MPG.

2.) Tundra a wee bit slower unloaded but faster when pulling plus 10% better MPG:
http://www.trucktrend.com/roadtests/pickup/163_0902_2009_half_ton_truck_comparison/speclfications_and_data.html

3.) Tundra a wee bit slower unloaded, faster when pulling, and about tied on hill climb and again 10% better MPG:
http://special-reports.pickuptrucks.com/2008-light-duty-shoot-out.html

So, a heavier truck pulling more weight gets better MPG and has better acceleration points to traction issues for the Tundra when unloaded, and feeds right back into the very article posted.

[GoCougs]

LOL - so, we've covered push rods, leaf springs and the Tundra; what other hot-button issue pray tell is next...

All this angst and energy. I think it's good for you guys.

[Onslaught]

LOL - so, we've covered push rods, leaf springs and the Tundra; what other hot-button issue pray tell is next...

All this angst and energy. I think it's good for you guys.

Let's see. Is the inferior pushrod engine that's put in the Corvette powering a sports car or not?

[Minpin]

Is Obama working for the 'people'?

[GoCougs]

Let's see. Is the inferior pushrod engine that's put in the Corvette powering a sports car or not?

How dare you: IT'S A GT NOT A SPORTS CAR.

[omicron]

How dare you: IT'S A GT NOT A SPORTS CAR.

Egads! A manual Corvette convertible is certainly a sports car!

[Gotta-Qik-C7]

  This is better than the Ridgeline debates!

[GoCougs]

Yeah, and the Titan, too.

[Laconian]

Yeah, this does feel like the Octagon.

[565]

Yes, I was incorrect in thinking of the times per an engaged transfer case owing to major traction problems (here, last paragraph) to get 0-60 of 6 sec and 14.6 sec 1/4 mile times (more on that later).

First, the vehicle(s):

1.) Rear gear ratio is irrelevant, it's the final gear ratio that matters (c'mon, you know this):

The Silverado's gear ratios are:
4.04, 2.36, 1.52, 1.15, .85, .66

W/3.42:1 rear that equates to:
14.0, 8.1, 5.2, 3.9, 2.9, 2.3

The Tundra's gear ratios are:
3.33, 1.96, 1.35, 1.00, .728, .588

w/4.30:1 rear that equates to:
14.3, 8.4, 5.8, 4.3, 3.1, 2.5

As we can see the Tundra has only a slight advantage and not the substantial advantage you implied by simply comparing 3.42:1 vs. 4.30:1. I also remind everyone what we already know that the Tundra is the heavier vehicle (380 lbs per the Edmunds test).

2.) Recommended fuel for GM 6.2L is premium (kindly reference the Edmunds tests). Recommended fuel for the Tundra is regular.

Next, the tests:

1.) In the Edmunds test the Tundra is better at towing and got identical towing MPG.

2.) Tundra a wee bit slower unloaded but faster when pulling plus 10% better MPG:
http://www.trucktrend.com/roadtests/pickup/163_0902_2009_half_ton_truck_comparison/speclfications_and_data.html

3.) Tundra a wee bit slower unloaded, faster when pulling, and about tied on hill climb and again 10% better MPG:
http://special-reports.pickuptrucks.com/2008-light-duty-shoot-out.html

So, a heavier truck pulling more weight gets better MPG and has better acceleration points to traction issues for the Tundra when unloaded, and feeds right back into the very article posted.

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.

[hounddog]

Pushrods just have a hard time making those ultra high REVs that OHC motors are more capable of.

That is not true. 

NASCAR teams are still running them, and turning up to 15,000 rpms.

Top Fuel dragsters are not allowed to run OHC engines, and they are turning out over 5,000 horses and 15,000 rpms.

The stock HEMI engine can turn 6,200 rpms.  While that is not super high, its operating range is over the entire "safe" zone beneath the "redline." 

[SVT666]

That is not true. 

NASCAR teams are still running them, and turning up to 15,000 rpms.

Top Fuel dragsters are not allowed to run OHC engines, and they are turning out over 5,000 horses and 15,000 rpms.

The stock HEMI engine can turn 6,200 rpms.  While that is not super high, its operating range is over the entire "safe" zone beneath the "redline." 

I've seen a new stock internal HEMI engine in Hot Rod magazine post nearly 500 hp with long tube headers, stage 3 camshaft and an engine controller at over 7000 rpm.

[r0tor]

NASCAR teams are still running them, and turning up to 15,000 rpms.

10,000 at the most.... and my street car car hit that

[r0tor]

Or look how CTS's engine bay looks with the V6 compared to the LS6 V8
I found pics of the shock mounts uncovered so it's easier to look at the passenger side shock mount and see where the engine sits.

There is a reason why the SBC is dropped into anything that has 4 wheels... sometimes ones with 2, lol.


Edit: just read your post ChrisV, haha yea if one thing GM did right it was those Pushrod Engines, lol.

a Mercedes C-Class is smaller then the last gen CTS-V and they fit a 6.3L V8 in it without problems and it weighed less and had more power and torque... -yawn-
mercedes also drops a 6.oL V12 with turboz into a car with dimensions almost identical to the corvette -shrug-

[Sigma Projects]

well sure in racing yea. I just meant in general for modders that it's usually a bit harder for pushrod guys to spin the revs than the OHC guys, not that it's undoable. I know the LS7 was designed to rev to 8K RPMs from the factory, but doesn't because of the cam profiles and the intake flow rates.

I also love boosted pushrod motors  


Go Cougs, i don't quite get your point, I'm not that familiar with those other motors. I'm just talking about the huge size difference between the 5.0 and the 4.6, it's a great example of the size difference. And I thought there were plenty of great 5.0 pushrods drag racing and doing well?

Ok, let me ask you something. Which would you take? An "anchor of a motor" pushrod LS7 with 505hp/470tq or a larger, longer, heavier and more complicated DOHC V10 from the m5 that makes 507hp/384tq to be the engine in the Z06? Or what about a LS6 with 405hp/400tq vs the larger heavier V8 in the M3 that makes 414hp/295tq?

I mean the BMW engines are great, they have great appeal. But just as performance figures the LS motors are superior. They're lighter, more compact and produce more power. I mean yea not as smooth or for audiophiles I'm sure they would prefer the higher revving sound of the BMW motors. But just strictly talking performance you surely can see the benefits of GM's pushrods right?

Not saying it's better per say, just that it has its performance advantages.

[Sigma Projects]

a Mercedes C-Class is smaller then the last gen CTS-V and they fit a 6.3L V8 in it without problems and it weighed less and had more power and torque... -yawn-
mercedes also drops a 6.oL V12 with turboz into a car with dimensions almost identical to the corvette -shrug-

So comparing two overall different cars? Are you talking about the CTS-V that had the LS6? The 5.7 liter? And then compare i'm sure a very much so larger 6.2L engine? I don't know the interior space of the C-class and what could fit nor what they could do to keep the overall weight of the car less than the CTS-V. But just talking about engines.

Edit: I did some reading and it's a very nice motor, weighing around 453lbs, it would be comparable to a LS7 7.0L. The pushrod similar displacement is the L92 or LS3 at 6.2L and that weighs 402lbs and 414lbs. The LS6 is an older motor and weighs a lot more than the newer LS motors and the same goes for the MB motors as the newer 6.2L weight I referenced was after extensive weight reduction.

[r0tor]

Or what about a LS6 with 405hp/400tq vs the larger heavier V8 in the M3 that makes 414hp/295tq?

last i checked, the two engines are within a few pounds of each other

[r0tor]

So comparing two overall different cars? Are you talking about the CTS-V that had the LS6? The 5.7 liter? And then compare i'm sure a very much so larger 6.2L engine? I don't know the interior space of the C-class and what could fit nor what they could do to keep the overall weight of the car less than the CTS-V. But just talking about engines.

you just compared a 6.0L to a 4.0L V8

[Sigma Projects]

oops sorry should have LS3 for the M3 comparsion. The LS3 is almost 50lbs lighter than the LS6.

I put in an edit in my above post.

"Edit: I did some reading and it's a very nice motor, weighing around 453lbs, it would be comparable to a LS7 7.0L. The pushrod similar displacement is the L92 or LS3 at 6.2L and that weighs 402lbs and 414lbs. The LS6 is an older motor and weighs a lot more than the newer LS motors and the same goes for the MB motors as the newer 6.2L weight I referenced was after extensive weight reduction."


edit: Oh and I meant that because you're comparing an older 5.7L to a new 6.2L. Well yea of course it's going to have more power, but it's not fair to compare old with new like that. The 6.2L should be compared more with the LS7 in terms of new tech and weight.

[ChrisV]

a Mercedes C-Class is smaller then the last gen CTS-V and they fit a 6.3L V8 in it without problems and it weighed less and had more power and torque... -yawn-
mercedes also drops a 6.oL V12 with turboz into a car with dimensions almost identical to the corvette -shrug-

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.






The point still stands: the LS engine is physically smaller, lighter, less complex and less expensive, yet puts out more power, reliably.

This is sitting in my garage right now:



Like the DOHC 4.4 liter I have in my 740iL, I know exactly how big it is and where it fits. I have to, becasue I'm trying to put it in a location that the phyically smaller, but larger displacement pushrod V8 already sits.

I don't sit around reading magazines and do mental engineering. I work with these things directly, hands on.

[r0tor]

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.

[Sigma Projects]

Thank you ChrisV, I too am putting in a larger engine with smaller displacement than compared to another guy who put in a LS1 into the same car and fits just as well as my 3.5L and actually fits I think easier than my 3.5L.

edit: here are some dimensions on some GM pushrods http://paceperformance.com/index.asp?PageAction=Custom&ID=586 I believe when I looked at the M3's V8 length it was about an inch longer than the LS1/LS6

[Cobra93]

I was ready to go order a Camaro SS until I found out it's ugly little secret.

Oh, no, I'd definitely recommend that. I think it's one of the best vehicles GM has built in a very, very long time, and best of breed by a long shot.

Maybe, I could swap in one of those "superior" Northstars for the antiquated pushrod motor. That would surely be a vast improvement, no?

[Sigma Projects]

maybe after GM scraps the current northstar and works on a newer design. I think last time I read that the current northstar design is just too ancient and to make more power out of it will cost too much or something like that so they wanted to start from scratch again on the northstar. But that's just what I remember.