Interesting DOHC vs. pushrod 500+ motors

[Paul Workman]

Originally Posted by todesengel

The point wasn't missed.

Oh, oh yes it was missed, but it's my fault for being vague though... But, your SC mustang makes a good point too! (I'm just making conversation here - not impugning anyone, OK?)

What I was obliquely pointing out was, how power is made in view of upcoming restrictions (gas mileage) displacement and efficiency are most certainly going to be relevant for production vehicles. And, cubic inch for cubic inch, the DOHC 4-valve configuration with it's independently and dynamically controlled cams and "lifters" breathes soooo much better and has sooooo much more flexibility and output potential than single cam, OHV designs! The DOHC/4-valve approach - is but one example of why in my gut I feel GM is screwing the pooch by chasing single cam OHV technology any further - at least in the long term. (Course, who knows what is going on behind the curtain in GM's engineering shop?) And, when coupled with a 35 mile/gallon (or more?) in the near future, cubic inches to get hp (a la the LS7) may be a thing of the past. Power/displacement, according to my crystal ball, WILL become a relevant factor if output is to remain steady with efficiency a mandate.

To your supercharger point; that is one option that certainly works in the short term. For you or me, or many (most?) ZR-1 drivers on this board, maintenance of such a setup might not be a factor. But, I'm referring to the unwashed masses of Corvette buyers that are needed if the brand is to survive so we car nuts have the luxury of picking and choosing and playing with the picks of the litter, so to speak. Supercharging has been around since WWII, and even Dave Mclellan fooled around with it back in the 70s. Yet, to the casual observers like us, when it came down to "absolute" reliability and performance, even the Callaway approach - that was readily available to GM - was pushed aside in favor of a "better" power plant scheme for the ZR-1.

Well, I'm not a mechanical engineer, so I'm out on a limb here. But, from where I sit, the evolution of the internal combustion engine, as it applies to the Corvette in particular, took a huge leap forward in the form of the LT5. High performance (piston) aircraft engines and motorcycle engines (opposite ends of engine displacement) are often built with 4+ valves per cylinder, and the aircraft example is built with superchargers to boot; where (in both cases) power efficiency IS a factor. So, was the reason GM shelved the DOHC multi-valve concept (in V8s at least) a failure of technology or just expedient?

There was this company that made oaken buckets. Sales started slipping when home builders began to use pipes to carry water to the houses. So, the oaken bucket company decided to combat slumping sales and make the best quality oaken bucket ever. The best oak, topped off with the finest brass rings and handle were produced. And, for a short time, sales did pick up and the company was assured it had made the right decision.

But, eventually, sales plummeted and the company went broke, in spite of making the finest oaken buckets ever produced. They simply failed to realize that people did not want buckets; they wanted water. The bucket was (at the time) the way to do that. But, technology had moved onto a more efficient method of getting water from the well to the sink.

I don't know if the DOHC 4+-valve NA motor is the answer. But, in my gut I feel GM is making the finest "LSx" oaken buckets ever! (was my point).

Pop some popcorn and enjoy the show. The next 5-10 years...are going to be interesting, methinks!!

P.

[Aurora40]

I don't know if you mean shelving the LT5, or shelving the premium V8?

Shelving the LT5, it sounds like that may have been the right move for the base Corvette. It's too bad they didn't at least build the '95 engine and have the C4 go out with a huge bang.

I think shelving the premium V8 is a really poor move. I've no idea what Cadillac expects to sell car-wise besides CTS's in the future. With no premium V8, they really will be at a loss in the large lux car market. At this point, even Hyundai has a DOHC V8, and it makes 430hp to boot.

GM had really neglected the Northstar along the way, so it was probably a huge endeavor to update it. Back in 1992, it made 295hp. By the last redesign, 14 years later, it was only up to 330.

[Pete]

To add a couple of things.

The LT5 is about 30 year old technology and with some of todays technics and tricks we see LT5's potential we get up to 450 whp with stock cams very docile N/A on todays crappy pump gas.
Today they do it with 77 more cubes.
Not too shaby for a 30 year old motor.

HP can be made in all sorts of ways and if raw HP is your game bring some CA$H.

Now some of my thoughts, power adders are doing it the easy way it's like "Power for Dummies" book is coming out soon LOL

Also street cars use crappy pump gas, cars that use race gas are just that race cars.
"Show me on 87 octane",i'm from Missouri

Now lets take the turbo/power adders out use crappy pump gas again "show me"

I need to move to Missouri.
My new motto "10's on 87"

Pete

[todesengel]

Easy way? If that were true you wouldn't have imports, and domestics, popping engines with them every hour.

Careful Pete, you are going to be accused of being a bench racer with your claims of "all things being even".

87 is for lawn mowers, c16 and alcohol is for race cars .

The street is run what you brung. When I have your cash in my pocket my wallet doesn't care if i was running 93, 106, 116 or meth injection, it just feels better.

Originally Posted by Pete

To add a couple of things.

The LT5 is about 30 year old technology and with some of todays technics and tricks we see LT5's potential we get up to 450 whp with stock cams very docile N/A on todays crappy pump gas.
Today they do it with 77 more cubes.
Not too shaby for a 30 year old motor.

HP can be made in all sorts of ways and if raw HP is your game bring some CA$H.

Now some of my thoughts, power adders are doing it the easy way it's like "Power for Dummies" book is coming out soon LOL

Also street cars use crappy pump gas, cars that use race gas are just that race cars.
"Show me on 87 octane",i'm from Missouri

Now lets take the turbo/power adders out use crappy pump gas again "show me"

I need to move to Missouri.
My new motto "10's on 87"

Pete

[Jim Nolan]

If I can add my .02 worth. I put a Corsa catback system on my '92 and loved it. Now I have SW headers, no cats and full porting and it now sounds like s##t. The Corsa just doesn't, in my opinion, match up very well on a system with headers and no cats.

[Pete]

No,No,No point missed.
30 year old technology
Compared to todays N/A SBC needs more cubes
Heck,Chevy needed to out do themselfs and they went the easy way slaped a Supercharger in it,i would've prefered N/A 500ci

It's not "run what you brung" it's "bring your wallet and hope you have enough" i.e. if i had Trump money i'd buy the fastest cars from NHRA,now tell me how that run what you brung thing works again.

My new bumber sticker
ZR-1 Landscaping

Pete

Originally Posted by todesengel

Easy way? If that were true you wouldn't have imports, and domestics, popping engines with them every hour.

Careful Pete, you are going to be accused of being a bench racer with your claims of "all things being even".

87 is for lawn mowers, c16 and alcohol is for race cars .

The street is run what you brung. When I have your cash in my pocket my wallet doesn't care if i was running 93, 106, 116 or meth injection, it just feels better.

[todesengel]

Originally Posted by Pete

No,No,No point missed.
30 year old technology
Compared to todays N/A SBC needs more cubes
Heck,Chevy needed to out do themselfs and they went the easy way slaped a Supercharger in it,i would've prefered N/A 500ci

It's not "run what you brung" it's "bring your wallet and hope you have enough" i.e. if i had Trump money i'd buy the fastest cars from NHRA,now tell me how that run what you brung thing works again.

My new bumber sticker
ZR-1 Landscaping

Pete

Lol, yup, completely missed your point, BUT racing is usually about who has the bigger wallet. There are shoestring winners here and there, but building a fast car requires two things, as a rule, thinking outside the box, and money
Cheap, fast, reliable....pick two

[FU]

Originally Posted by DDSLT5

For your listening enjoyment - go to 2:15 or 3:00 for some LT5 fun! )

http://www.youtube.com/watch?v=ZEXXDKyQPVY

THAT SOUNDS UNBELIEVABLE ! No pushrod engine screams like that !

[Paul Workman]

Originally Posted by FU2

THAT SOUNDS UNBELIEVABLE ! No pushrod engine screams like that !

Dittos, Frank! Oooo, yeah! Gives me goose bumps!

It is interesting to see the heads turn and the when one of ours hits that "high note" at a dyno day, or the dismay on some faces when Pete's Green Monster sucks the paint off the door of a C6 Z06 driver...(heh, heh, heh....

Is it spring yet?

P.

[FU]

Originally Posted by Paul Workman

Is it spring yet?

Spring couldn't come soon enough for me.