"Blue Devil" News: Test Details Roll In
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Rotary Junkie
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It doesn't help Ford that the stroke of the SMALLEST mod motor is slightly longer than that of a Chevrolet 350 or indeed a Ford 351. The bore is .45" smaller than both "old school" small blocks. So the 4.6, while it does have the valvetrain to do high RPM, the bottom-end needed to run the RPM the heads and valvetrain will allow it to do wouldn't be cost-effective. That said, the Cobra rotating assembly can handle some serious power. It's got nothing to do with wanting a low-revving V8 roar.
As to the 6.2 GM DOHC idea: That might work... 'cept it would work better as a 302cid dropped in a Z/28. 4" bore, 3" stroke, just as the original Chevy 302 (NOT 305) as well as the Ford 302. Shorter stroke will allow more revs.
The Corvette shouldn't get overhead cams... Ever. Why?
I think it would be fun to see how far they can beat the world into the ground without them.
GM has their crap together on this front, IMO.
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*ahem*
The Chevrolet 302 was a 327 block with a 283 crank. I'm sure Ford followed a similar formula...
I'm personally under the impression that GM is going to be minimizing the bore a bit on the next generation of V8s, but drastically decreasing the stroke at the same time. I could be wrong, but it just seems as though they'd have more luck with a higher-reving V8 now than they would, say 10 years ago. Particularly if they're playing with direct-injection and some kind of forced induction.
We're likely looking at a return to the 327 (5.3L) or the 350 (5.7L) as standard fare in the small-block world, but I would not be surprised to see the 302 (5.0L) become standard-issue for everything else.
Rotary Junkie
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There's no doubt about the ZR1 being a good car and the engine being very powerful but it has to be said that the Americans indeed seem to follow the "if it isn't broken" line until the end of times. The engine has been praised to be hugely powerful and to have an unbelievable amount of torque but those have been gained by a very cheap approach - displacement. I'll demonstrate.
6.2 litres of displacement, 638 bhp of power, 800+ Nm of torque. Sure, that's a lot of power. But per litre it's "only" 103 bhp and 129 Nm, hardly anything special for a forced induction engine. Even the old R32 GT-R back in 1989 with its first generation RB26DETT had better figures, 280 bhp and 360 Nm out of 2.6 litres, translating to 107 bhp and 138 Nm per litre. And that engine was far from unreliable.
It's already been said many times in this thread that the ZR1 is good but could be much better. Totally agreed. The same power could be pumped out of a smaller engine without sacrificing any fuel economy, and the car would be better balanced as a result. Personally I'm looking forward to GM being forced to make the move to smaller engines, if 302 cubic inch engines were good enough during the muscle car era it should do just well now. The big blocks belong to the classic American road cruisers, now it's time for something different. How about a four litre turbocharged V8 with some 700 bhp? It's possible but is Ameica ready for it? I hope so.
6.2 litres of displacement, 638 bhp of power, 800+ Nm of torque. Sure, that's a lot of power. But per litre it's "only" 103 bhp and 129 Nm, hardly anything special for a forced induction engine. Even the old R32 GT-R back in 1989 with its first generation RB26DETT had better figures, 280 bhp and 360 Nm out of 2.6 litres, translating to 107 bhp and 138 Nm per litre. And that engine was far from unreliable.
It's already been said many times in this thread that the ZR1 is good but could be much better. Totally agreed. The same power could be pumped out of a smaller engine without sacrificing any fuel economy, and the car would be better balanced as a result. Personally I'm looking forward to GM being forced to make the move to smaller engines, if 302 cubic inch engines were good enough during the muscle car era it should do just well now. The big blocks belong to the classic American road cruisers, now it's time for something different. How about a four litre turbocharged V8 with some 700 bhp? It's possible but is Ameica ready for it? I hope so.
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ROAD_DOGG33J
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the Ferrari F40 had that setup. that's supercar territory.
*facepalm*
Seriously, did the argument that HP/Liter actually matters get brought up... AGAIN, just after the post showing how ridiculous it is a page back?
280 Hp from 2.6 Liters is cool, but 620 Hp from 6.2 Liters is still well over twice as much horsepower.
Guess which car is actually faster, the one with the higher hp/liter ratio, or the one with the higher power/weight ratio?
And, just to point this out, because this picture (which I've posted like... 3 or 4 times since it first got posted by someone else here) sums it up so well...
That's the downside of DOHC vs Pushrods, the closer the total mass of the car is to the point on the ground in between all four tire contact patches, the better it handles.
Seriously, did the argument that HP/Liter actually matters get brought up... AGAIN, just after the post showing how ridiculous it is a page back?
280 Hp from 2.6 Liters is cool, but 620 Hp from 6.2 Liters is still well over twice as much horsepower.
Guess which car is actually faster, the one with the higher hp/liter ratio, or the one with the higher power/weight ratio?
And, just to point this out, because this picture (which I've posted like... 3 or 4 times since it first got posted by someone else here) sums it up so well...
That's the downside of DOHC vs Pushrods, the closer the total mass of the car is to the point on the ground in between all four tire contact patches, the better it handles.
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huh? i brought up the F40 to show how expensive an engine configuration like that could be
///M-Spec
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It's not about using pushrods this time, it's not about having a better power to weight ratio, it's about making power effectively from a smaller displacement. Something that can be done but that the Americans haven't been bothered to do.
That 620 bhp that is now produced from 6.2 litres could be produced from 5.0 litres. Or even 4.0 litres, still with the same structure but a better super/turbocharger. And I don't think there's anybody denying that a four litre engine with structure X is smaller and lighter than a six litre engine with the same structure X. Now it's time for the US companies to show if their engines really are as good as the ones across the pond. If they aren't, they'll be made better and everyone wins because good engines is what we need.
That 620 bhp that is now produced from 6.2 litres could be produced from 5.0 litres. Or even 4.0 litres, still with the same structure but a better super/turbocharger. And I don't think there's anybody denying that a four litre engine with structure X is smaller and lighter than a six litre engine with the same structure X. Now it's time for the US companies to show if their engines really are as good as the ones across the pond. If they aren't, they'll be made better and everyone wins because good engines is what we need.
Yes. My only point with that comparison was to show that the Corvette engine isn't quite the end-of-all technical masterpiece it's being hyped to be. Its power comes largely from the displacement, not from the innovations in its design. I'd be a lot more impressed if they had a small engine with big amounts of power, now they have a big engine with big amounts of power which is pretty much a given considering they haven't screwed up anywhere. Sure, 103 bhp per litre is a lot but not as ground breaking as it's made to sound like.
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ROAD_DOGG33J
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Leonidae
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not really.. all they would need to do is take an engine from other manufacturer in GM family tree.. say, from a Cadillac's Northstar lineup, and slap two turbochargers on it, with VVT etc etc. no need to invent anything totally new, just putting old innovations into one clever package.
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Did I say it is? No. At the moment we indeed don't know how a small turbocharged American engine fares in comparison to the same class engines from around the world as there isn't one to ba compared. If, and that's really an if, it turns out that they're worse they'll be made better. If they're already on the same line or ahead everything's fine.
Exactly. And my honest opinion is that smaller, lighter, higher revving engines are the way to go in today's world. They can make the same peak power as their bigger brothers but consume less fuel when the power isn't needed.
I understand that a lot of people here know that I'm not particularly a Corvette fan but does it mean everything I, or any other non-fan for that matter, says has to be taken as an immediate bashing? Seriously, the car could be better with a smaller engine. It could also be better if it was lighter. And if the C7 generation incorporates both of these improvements I'll definitely like it more than the current one. Now it's good but built to an old formula that can't be used forever.
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Perhaps the reason Corvette fans get so adamant is that they've been bashed senseless all these years, simply because people don't like it because the car's American.
ROAD_DOGG33J
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Except that Vette engine is pretty economical. Sure gearing helps with that, but it's not like they change the gearing for the magazine tests, etc. If you look at the link M-Spec provided, the Ferrari 360 has a high specific output and drinks fuel like nothing.
I'm not sure many people, mainly Americans, would want a smaller engine. I think that the engine is part of what makes a Corvette, a Corvette. They have come a long way with the engine. Would it really be better off with a smaller engine? I don't think we can say that. There's a reason the phrase "there is no replacement for displacement" exists. What would a smaller engine actually provide? Other than people being able to say that it has a higher specific output.
Leonidae
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There is replacement for displacement and it's been available for everyone since the 70's.. it's called forced induction. And incidentally, ZR-1 HAS forced induction. It pays for it as higher weight and price, but it also gets way better performance. Thing is, that they could still go smaller displacement and improve on other areas, such as variable valve timing.. which is what Dodge already did with Viper, and look what sort of performance gains it got. GM has to stop listening old geezers who want to cling to the glory of the past.
///M-Spec
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Read the thread. It's not about pushrods. It is about the ratio between displacement vs. peak power being an overemphasized and ultimately misleading concept.
Engine displacement and engine weight/engine external dimensions are necessarily not 1:1. This becomes especially true when you start comparing OHV and OHC designs.
For example, an LS6 from a 2002-04 Corvette Z06 displaces 5.7 liters and produces roughly the same power as the 5.0 liter S62 from a 1999-2003 BMW M5.
However, the LS6 is both lighter and physically smaller than the S62 despite displacing more. It also produces less emissions. Applied in the 3200 lb. C5 Corvette, also gets much better gas mileage than the E39 M5.
Oh, and it costs half as much too.
I would also compare an LS3 from a current C6 to the S65B40 from a current M3 or the 4.2 FSI BNS V8 from the R8 and RS4, but I haven't been able to find reliable specs on the weights/dimensions just yet. Based on past observation, I would expect they are all very similar, with the BMW motor being the largest dimensionally (throttle bodies).
This is an empty statement because it can be applied to any engine from any manufacturer.
But you aren't comparing "structure X" to "structure X". You are comparing engine "ABC" to engine "XYZ". Apples and oranges.
Been there. Done that. Got the t-shirt.
Excuse me, but your entire point was centered on hp/liter and your misconception that an LS series motor MUST be absolutely gigantic because of it's displacement. I've already demonstrated that is not true.
Of course the LS9 is probably a bit taller than an LS3 due to the extra plumbing and the Behr stacked between the heads.
Can you tell me what a fully dressed LS9 motor, ready to run, weighs? What about it's external dimensions? I bet you don't even know.
M
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Well for one, it was historical reasons. The 427 has always been, and for that matter, will always be one of the most-significant engines that GM pushed out in the late 1960s. The Z06 had the LS7 because they could, and to that end, I'd say its a damn-good engine. Considering you can get one in a crate shipped to your house for $15K, turn-key, and it'll run as long as you treat it well... That's an achievement unlike anything else.
The move from the LS1 to the LS2 was again, a move because they could do it. As I recall, the LS2 (and LS3) are both significantly more fuel efficent than the LS1 all while producing an extra 50-80 BHP, all without any added cost to the consumer.
This reduction in engine size, however, is mostly speculation at this point. GM is still otherwise mum on the whole future of the small-block program, but we are due for the next generation engines to debut within two years time. Of course, with the "Ultimate" V8 series being killed off before introduction, its hard to say what technology from that platform will be applied to the next series of engines.
///M-Spec
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Guess what? I happen to own a semi-sporty car with one of those 'smaller, lighter, higher revving' engines.
- The S54B32 in my M Roadster displaces 'only' 3.2 liters.
- It will spin to 8,000 RPM.
- It 'only' has six itty bitty cylinders.
- It makes a 'very modest' 330 horsepower. But that's 103.125 hp/liter, a so-called benchmark number 6 or 7 years ago.
- The Corvette is larger (more passenger and cargo space) but weighs only 50 lbs. more.
- Despite that, the Corvette gets better gas mileage (16/26 vs. 15/22)
- While delivering these numbers, the Corvette also happens to make 100 more horsepower and 156 lb-ft more torque than my M Roady.
Incidentally, my Z will be at the losing end of a drag race. And at most tracks... all else (driver skill) being equal.
Now, I think the Z is more rewarding to drive, to look at and to own, which is why I bought it. But you'll never catch me bragging about my "superior hp per liter" nonsense because I know better.
Fact is hp/liter doesn't amount to squat where it matters... you know, the real world.
Whether we choose to call it bashing or not, don't you react to everyone who says "the GT-R isn't all that impressive" in the same exact way?
M
Leonidae
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well, strictly theoretically speaking, that could cut material costs, and part of GM's Corvette ideology is cheap performance for everyone. saved money could go for better interior (no longer same steeringwheel or dash layout as the rest of GM products), improved quality ( rocker arm failures, roofs blown off at 60mph) etc etc. But this is just my personal speculation.
Leonidae
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*facepalms* since my Internet doesn't work properly, for example google is out of order here, I can't compare MSRP of Viper SRT-10-models before and after adding VVT. but performance gains are obviously greater than increase in price is. from this point of view, VVT would be useful/cheap solution that wouldn't hurt production costs too badly. In addition, it would improve the MPG which seems to be one of the selling points of American performance cars.
The Chevrolet Corvette ZR-1 (that IS official name) will cost $105,500 in the US (up to $117,000 for a full loaded one). It will have 628 hp, 604 lb-ft, go 0-60 mph in about 3.4 sec, and do the quarter mile at 11.3 sec @ 131 mph. Good luck to all the rich (and lucky) to get their hands on this one.
