CaddyXLR-V

Actually Nissan was making was getting 222hp out of their 3L in the 300zx in NA form, so I wouldn't really say they were behind.

2800lbs and 325hp would be fun. The traditionalists wouldn't allow it though.

That's a good point. While initial costs of developing a new DOHC V8 might be higher, it might be cheaper in the long run, since a lot could be shared with their DOHC V6s and I4s. Any new technology they use on the V8, could be used in the rest of their DOHC engines, without having to figure out how to adapt the technology between OHC and OHV.

Because it was supercharged with no intercooler, the effect was much more pronounced.

Maybe for those in the cold weather. In AZ, my L67 was retarding the timing so much that it probably only had 210hp when the temp rose above 80 degrees. After adding a cam, intercooler, and smaller pulley, it cracked a piston.

Other companies managed to fit DOHC V6s in cars similar in size, or smaller, than GM's midsized cars, and many were fairly easy to get to the spark plugs. For some reason I can't attach pictures, but go here and look at the location of the spark plugs. http://www.attarco.com/images/K8.jpg They are on top of the heads. Where are they on GM's OHV engines? On the side. Which do you think would be easier to get to? Heres a picture of a 3.8L http://forums.justcommodores.com.au/attachments/general/59240d1233910612-history-lesson-3800-v6-owners-3800-series-ii-3.8l-v6-l36-_small.jpg

Well GM should have focused development on those engines, and cancelled the 3.8, 3.1, 3.4 OHV engines, and never started development of the 3.5, and 3.9.

Which they cancelled and let the 3.8 live on. I would call that abandoned.

Oh the 285hp 3.4L DOHC that they abandoned? If they followed through on that engine it would have been much better than the 3.8L.

Does a GTO with an LS2 count? Because I have driven that car hard, many times. But my opinion stays the same. If they put the same time and effort into a 4-5L DOHC turbo engine as they do the LS engines, they could get more out of it.

What would interest me more would be if they hooked 2 of those together, and made a 4L V8 turbo. With the same hp/L it could be making 580hp. Or even a 3.0L I6 with 435hp. They would make some nice engines for a CTS.

Here's a quote from dwightlooi on that: The Duramax head is not particularly good for airflow (the intake and exhaust ports run into one valve first then the other since the valves are tandem not side by side). Also, it is also possible only in a diesel because the Diesel engine uses a a completely flat combustion chamber roof and all four valves are parallel. The approach -- using one rocker to push down on two parallel valves connected by a bridge is not feasible for a gasoline engine. And another: The main problem with 3-valve, twin in-block cam designs such as those proposed by GM a few years ago is that the rods themselves compete for space with the intake runners and ports. It is impossible to have straight, unobstructed runners and intake ports. Perhaps the reason these designs did not make it to production is because the intake port issues limits flow improvements to a point where improvements over 2-valve designs become intangible.

Colts especially after last Sunday, Jets, Dolphins, and Giants for football. Yankees for baseball And Lakers for basketball

No, I completely understand it. Do you not understand that Ford design is not a very good design, and is big even by DOHC standards? And I have done work, and rebuilt both DOHC, and OHV engines before. So I know their size.

Correction to the weights of the engines above. The LS2 weighs 448lbs. The AMG engine is 438lbs. The LS9 is somewhere around 550lbs. The 3.6L weighs 370, so a V8 based off that would be about 493lbs. I would say the trade off of 50 extra pounds would be worth it.

That's why I said if designed right. The engine needs to be designed to take advantage of the higher redline, which will mean more power. And a quick search shows that the 6.3L AMG engine weighs about 450lbs, while a 6.0L LS2 weighs 537lbs. Add in a supercharger or turbo and their plumbing to match the power of the DOHC, and the engine gets even heavier.

Higher redline would make more power. It would also need to shift less. Perception is reality, in every segment. Maybe if Buicks engines had more refinement, they could cut down on the sound deadening materials. Don't they also use shock absorbing motor mounts too?

Doesn't seem like much of an advance in ten years time. GM could probably get 600hp out of a 5.7L DOHC if they tried now.

Higher redline, higher top speed, more power if designed right. More percieved refinement. VVT can also be added to DOHC easier. More valves can be added, with twice as many pushrods, and they still need to come up with a design for where to put those pushrods, and still less control over the valves. Who knows how reliable that will be.

And V8 also has more moving parts and internal friction than a V6, but I don't see you advocating that switch. It's really simple. Engines need to breathe to make power. More valves is better than less valves. More control over the valves is better than less control especially in a performance car.

So your favorite engine would be a pushrod flat 4? Less internal friction lower weight, and a lower center of gravity. Why use a V8 when it is heavier and has higher internal friction than a 4cyl or V6?

I don't understand why every other automaker can make a business case for it, but GM can't. GM always takes the cheaper option. According to GM, they couldn't make a business case for Pontiac, or to sell the UTE here, or to put more manuals in cars. It all comes down to cost. Whatever is cheaper, that is what they choose.

GM does a good job with the V8s. But that doesn't mean they couldn't do better. Their V6s suck. 3.5L in the Malibu doesn't sound healthy. And my 99 2.5L Mazda 626 felt more powerful than the 04 3.5L Malibu that I am driving now, and was much smoother and sounded better. GM could make a V8 sharing parts with the 3.6L, and make a 4.8 V8 with about 406hp. That would be a better engine for a Cadillac, and wouldn't be a bad base engine for the Corvette either.

That's the only engine GM has for the job. The Northstar was developed when, 1992? And DOHC is not a measure of technology, it just allows the engine to take in more air, with better control of the valves. For everyone who says 8 cyl is better than 4 or 6, why wouldn't 4 valves be better than 2? Why would less valve float be a bad thing? I just think if GM stopped making OHV engines in the 60s, and switched to OHC engines, and if Honda and Toyota were still making OHV engines, every one here would be arguing how much better OHC is, because GM does it.

I don't understand how it can be argued that more valve mass, less valves and worse breathing, is better for a performance car. The only arguement that makes sense is nostalgia. The Corvette performs because of light weight, and a big engine, not because it is OHC.