GM's new 7L 500hp 7100rpm pissing competition.

[CussCuss]

CNC machined heads? Wow!! Marketing bullcrap or what??

I wonder how this might be different from how normal heads are manufactured?

Titanium rods? Now that is surprising. Can anyone verify this marketing article with a tech article somewhere?

Titanium valve springs? Again, I am amazed they went to this length.

John

yep, chevy have been flat out lying, they just put these thing in their press release to sound cool.
As said, the only thing autospeed have done is just wrote some stuff around chevys press release.

[John]

Sorry for not assuming everything I read is 100% correct. I'm sure they wouldn't go as far as to actually state an untruth, but there are many ways to present data that says one thing but means something else. The "CNC Machined" comment is a great example of this.

But obviously you're convinced it must be a good thing, so you'll devour every word as absolutely reality.

John

[Morgo systems]

I think that the desing team did best they were asked to:500 hp and performance to match all other supercars.Who cares if you have only 2 valve head if you can outrun others and do it cheaper;just what hot rodding was originally!
Sure they could make more power with 4-valve heads but some consultation from NASCAR and LeMans engineering teams result engine that performs enough thats it!
I like DOCH engines just because they are simpler than those damd pushrod beasts but if average American customer thinks that he likes traditional design and buys it then the GM did it job!
Not that they going to make money with this but they will enjoy when the Corvette beats the competition... Maybe.Probably.Who knows.It's competition;if everybody knows who will win it's not a competition??

[BigMuz]

Not really an interesting read given its source. By that I do not mean that Autospeed has simply published a marketing article from GM (wonder how much they got paid?) but that none of the figures etc are independantly tested or verified in any way.

Please justify accusing them of being paid to print that article- I think it is pretty ordinary to go accusing someone of something with no proof, especially when they are very clear on who paid for what in all their product testing.

Muz

[Zac]

CNC machined to clean up casting marks I suppose!

[Cplus]

Please justify accusing them of being paid to print that article- I think it is pretty ordinary to go accusing someone of something with no proof, especially when they are very clear on who paid for what in all their product testing.

Muz

Muz, you're always really quick to get on the backfoot and defend Autospeed - may I ask why?

are you related to JE or something?

[BigMuz]

All heads are cnc machined and have been for years- all the flat surfaces, threads, guides and seat insert pockets are machined on nc equipment. They are probably referring to the porting being machined to spec by cnc- that is certainly not common in the oem world. Not sure how much they do though, as it is a really slow process. Might just be port matching by cnc?

Muz

[BigMuz]

I am JE.

Muz

(C'mon mate, it was a cheap shot and I thought it shouldn't go unmentioned.)

[BigMuz]

Having finally had a proper look at the article, the ports are in fact cnc machined with a ball end mill- that is pretty serious.

Thanks to Autospeed for the pic. I'm sure GM won't mind :D

Muz

[rj-astra]

An S2000 engine is one of the worst things I could think of in a road car. You simply have to work it far too hard to make it go. If honda were cleverer they would have used say 3 or 3.5 litres, & it would be a better car for it.

They did "fix" it... by increasing the capacity and reducing the redline on the US market S2000. 2 -> 2.2L and a 1000 rpm reduction in redline. Much better car supposedly

The point is, where does it end? 8L, 9L, 10L? You can see how absurd this argument really is. The whole point is that the auto manufacturers are being lazy by taking the easy way out via a displacement increase.

Get off your high horse. The M5 has grown from a 3.2L I6 to a 5L V10 over the years.
AMG will move from a 5.4L V8 to a 6.3L V8.
Ferrari just increased the V8 in the F430 from 3.6L (F360) to 4.3L and reduced the number of valves per cylinder.

Capacity increases seem to be all the fashion for increasing power.

[edo]

I've often wonderd if when the popular engines went from side-valves to overhead valves did people debate like we are here?
And again did said people with NFI what they're talking about keep adding their $0.02 because they don't understand engines but think they do?

Bill, I think youre barking up the wrong tree. No one has said that a pushrod V8 is superior in efficiency (or any other way except packaging) to a quad cam 4 valve engine.
Likewise Im sure that arguement didnt arise with the death of the flat head ford. Back then though, they ran the same capacity flat head against the same capacity OHV...& the superiority was obvious.
Now you cant really run comparable DOHC V8s against similar capacity & achieve the same result. At the risk of pissing off everyone the LS1 5.7 is similar money & not a lot bigger than Fords 5.4, yet the gen3 is the better performing engine...
If you had a 4.5 litre pushrod V8 (no a 253 doesnt count cause it hasnt been made for 20 years, & I know its 4.2 but thats close enough) to compare to a VH45 then Im sure youre arguement would get up...but compare it to a 7l pushrod & it doesnt.

[Peter...]

Would it be wrong of me to suggest that perhaps a 7 Litre V8 'vette might have a lot more nostalgia based marketing potential than say, a 5 Litre DOHC V8? The yanks are a sentimental bunch, don't forget.

[The Pupat]

Apart from engineers and marketers, who gives a toss about hp/litre?
Its an old argument, its a dead argument - move on already.

Don't drag gingerbeers in this. the ginger beers role is to create a package the is fit for purpose, in this case an LS7 is perfect. Makes an easy relliable 500bhp, It's light, and it is relatively small to fit in the space left by the industrial designers, and its cheap to make and cheap to the neccessary changes to the design and production plant.

Bill, don't kid yourself the amount of money to re-engineer everything required to run a DOHC motor would have been astronomical.

[walkie]

What is the aim though, of a modern automotive engineer? Is it to produce the most possible power from a small displacement, with a devil-may-care attitude to size, weight and cost? Or is it to produce a respectable power output, while minimising size, weight and cost?

The M5 V10 is certainly a piece of art, and I can't criticise it at all. However, I think that it's much more stressed making its 373kW than the LS7, despite its modern technology. I don't think there are many things on there that would be as easily upgradeable as the Corvette. Have a look at the M5's extractors for example, and tell me that you'd bother trying to come up with something better...

[blimpyboy]

The New AMG 6.3 Liter V8.

At 199kg, it's 1kg lighter then the corvette engine, at 510hp it has 10 more horsepower.
Looking at the pictures, it also seems to be quite compact - designed to fit in all of MB's existing range with minimal modifications.
And look at that torque curve! Not bad.

Mind you, the LS7 is still a good engine and i still want a Z06