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2009 Chevrolet Corvette ZR1
hondacura4
Member Posts: 6
I just find it hard to beleive that the LS7 is pretty much maxed out according to the GM guy. As we all know it has 7.0 full liters and 505hp. Given the displacement I dont see a reason why this engine couldnt make similar horsepower as the LS9 but of course it wouldnt have the torque output of the boosted 6.2L V8. Maybe it has to do with the pushrod/2 valve design as DOHC/4 valve design is better at making high hp numbers due to its superior combustion efficiency.
If Porsche can reliably/efficiently squeeze 415hp out of a DOHC 3.6 flat 6, Ferrari can squeeze 510hp out of a 4.3 DOHC V8, and Ferrari can squeeze 660hp out of a 6.0L normally spirated V12 why cant GM take the 7.0 LS7 further?
If Porsche can reliably/efficiently squeeze 415hp out of a DOHC 3.6 flat 6, Ferrari can squeeze 510hp out of a 4.3 DOHC V8, and Ferrari can squeeze 660hp out of a 6.0L normally spirated V12 why cant GM take the 7.0 LS7 further?
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7.0L out of that footprint makes for some limitations. We'll know more when they
get around to boosting that platform or maybe others won't try either which will be
fairly telling. As it is, getting 620+HP from 6.2L that is a pushrod, 2v power plant
will be pretty amazing. I'm just convinced that most that drive it will say, 'hey I
feel that power' and the boost needle will be sitting flat. If it does kick in they will
be astounded.
Randy
7.0L out of that footprint makes for some limitations."
Starrow, the blown 6.2L is from the same engine family as the LS7, although heavily revised so that technically makes it a "small block" too, correct? And by "taking the LS7 further" I didnt mean boosting it, just getting MORE from it.
Although the LS7 has proven itself to be a fairly reliable, compact, powerful package I cant say that Im impressed by the overall output as it just seems GM leaves a lot on the table when you compare output to displacement to other manufacturers.
For example. If I compared say .....the Mercedes 6.3 V8 (its actually a 6.2L V8) to the LS7 (7.0L) V8 in the Z06 overall output is similar, as are physical demensions, and I think the weights are closer than one might think. I think Ive read where the two engines are within 11lbs of each other the LS7 being lighter.
The Merc 6.2L makes 518hp @ 6800rpm and 465lbft of torque @ 5200rpm. The LS7 makes 505hp @ 6300 and 470lbft @ 4800. Given the displacement advantage one would think the LS7 would have greater output (hp AND torque) than the Mercs smaller unit but it doesnt. Both are hand assembled low production units so I think its a fair comparison.
Im not dogging the LS series as they are powerful but it just seems that a halo car like the Corvette deserves the best GM has to offer and the technology to back it up. It seems as if GM took the easy way out.
When I read about the technical advancements of engines like the wonderful BMW 5.0L V10, BMW 4.0 V8 (M3), Ferrari 4.3 V8, Ferrari 6.0L V12, Merc 6.2 V8 that put out staggering amounts of power compared to displacement it gives me the feeling that the engineers went the extra mile to reach those outputs. On the contrary it makes me look at the LS7 as just ordinary as I dont see that same challenge for the engineers.
HP but seem to ignore the $ involved. Try putting $'s next to your comparisons
and it might become more understandable why GM isn't getting what the rest are.
The C6 Z is $75-78k with full options and premium color. For a 505hp road race
rocket that I can walk in and buy any day at sticker or below, given the release of
the Blue Devil, how does that compare with the waiting list you have to get on for
a Prancing Pony?
It all gets back to what floats your boat and for me 350hp is plenty on the race
track with street tires. I don't even want to get in a ZR1, note without the dash,
when they show up on track. I've seen enough C5's and C6's into walls without
all the kick of that boost.
Randy
If Porsche can reliably/efficiently squeeze 415hp out of a DOHC 3.6 flat 6, Ferrari can squeeze 510hp out of a 4.3 DOHC V8, and Ferrari can squeeze 660hp out of a 6.0L normally spirated V12 why cant GM take the 7.0 LS7 further?
Bro, it's time for a little education, because there's a reason why Motor Trend says that the LS3 engine is one of the world's finest V8 engines in the world.
First off, we must compare V8's to V8's.
Secondly, we have to find the appropriate engine with which to compare to the Chevrolet engines.
I reject Ferrari's DOHC V8, because the engine generates such little power (347 ft/lbs) and has such an irregular powerband that Motor Trend had to compare it to the LS3 -- not the superior LS7, which has north of 470 ft/lbs.
I will likewise reject any and all DOHC or other V8 engine configurations from any other manufacturer for the same reasons: Poor power output, low fuel efficiency, high particulate output and a substandard, irregular, narrow powerband.
That leaves only one V8 engine to compete with the Corvette engine, that's Mercedes Benz's 6.3 liter M153 DOHC VVT V8.
As it still stands, the Chevrolet engine still generates more power, weighs substantially less, is more compact, far more efficient, a far more useable, linear powerband and an undisputed and exemplary record in global racing endurance events (such as 24-hours at LeMans).
Here is the powerband for the Mercedes Benz engine -- certainly the finest V8 engine, second to the LSx engine, that powers their AMG coupe:
Notice that the engine doesn't even begin to generate peak power until 3,500 RPM or so, and falls off quickly at or around 6,000 for a pathetically narrow 2,500 RPM powerband.
This is the apex of years and years of research and development in large-displacement, DOHC, VVT engine technology: A very expensive, inordinately complex engine that can't even produce a decent powerband, let alone decent torque or fuel efficiency. How pathetic!
Here's the dynograph for the Chevrolet pushrod engine:
Notice linearity from around 2,500 RPM (not shown but on other dyno's) all the way to the engine's 7,200 RPM and beyond; you will not find a more linear, wider poweband from any engine save BMW's brilliant 6-cylinder (both powerbands equally as linear and broad). Notice tremendous power output commensurate with horsepower (the M156 has higher horsepower in relation to power output, and the very pathetic Ferrari V8 has over 500 horsepower and barely over 300 ft/lbs of power).
Power is 505 hp at 470 ft/lbs of torque. All this in a car that gets roughly the same fuel efficiency as a lowly Honda S2000 (15/26 Chevrolet; 16/25 for the Honda).
Chevrolet could go with DOHC's, VVT technology, addition of doo-dads to compromise power delivery and reliability and poor, thoughtless tuning ("Just throw some cams on the engine, call it VVT or VANOS or whatever, bring horsepower up to like 500 while leaving out the real power then throw it in an ill-concieved chassis and we'll make a million buck$...", or, Chevrolet can stay with the program, continue making the world's finest V8 engine, continue winning endurance race after endurance race and sell passion.
I'd go with alternative #2...
"Horsepower sells cars. Torque wins races."
--Caroll Shelby
Im not dogging the LS series as they are powerful but it just seems that a halo car like the Corvette deserves the best GM has to offer and the technology to back it up. It seems as if GM took the easy way out.
When I read about the technical advancements of engines like the wonderful BMW 5.0L V10, BMW 4.0 V8 (M3), Ferrari 4.3 V8, Ferrari 6.0L V12, Merc 6.2 V8 that put out staggering amounts of power compared to displacement it gives me the feeling that the engineers went the extra mile to reach those outputs. On the contrary it makes me look at the LS7 as just ordinary as I dont see that same challenge for the engineers.
I agree that the Benz 6.3L should be compared to the LS7 (don't compare the 6.3L Mercedes engine with the 6.3L LS3 engine, since the Mercedes engine is a premium engine and the LS3 engine is a base engine designed for luxury/highway use). I disagree with your comment that the other engines are as technologically as advanced as the phonomenal LS7. Sure, the M156 (Benz engine) generates as much hp as the LS7 with slightly less displacement, but let's nopt forget that the LS7 generates more power than the M156, and has a much more useable, broader powerband than the M156 engine.
This is what the larger, 7 liters of displacement in the Chevy engine gets you over the less displacement of the DOHC Mercedes engine: More torque and a far broader powerband.
Try again, Merceds Benz...
HP but seem to ignore the $ involved. Try putting $'s next to your comparisons
and it might become more understandable why GM isn't getting what the rest are.
The C6 Z is $75-78k with full options and premium color. For a 505hp road race
rocket that I can walk in and buy any day at sticker or below, given the release of
the Blue Devil, how does that compare with the waiting list you have to get on for
a Prancing Pony?
Even if the Chevrolet LS7 engine were in the $200,000 Ferrari F430 Challenge Stradale, the Ferrari would still be worth it. In fact, the LS7 engine would probably make the Ferrari a better car.
Pull out the numbers (and convert Kw/Nm to HP/TQ) however, and you see the real picture. Here are the approximate numbers (it is hard to read the M-B chart because of the size) pulled from your charts (I averaged the three Corvette runs):
--------------------Vette (HP/TQ)-----M-B (HP/TQ)
3500 RPM _____260/400_______302/442
4000 RPM _____320/420_______348/457
4500 RPM _____380/440_______389/457
5000 RPM _____420/450_______442/457
_______________________________/465
5500 RPM _____460/440_______483/457
6000 RPM _____480/420_______496/435
______________505
6500 RPM _____480/380_______503/420
____________________________518
7000 RPM _____460/340_______496/370
The first thing you notice is that the Corvette engine never catches the M-B in power output at any RPM (it comes closest at about 4500 RPM).
Dig a little deeper and the second thing you notice is that the M-B has the broader torque curve (more space below the curve). The Corvette reaches 90% of peak TQ (405 ft-lbs) at 3600 RPM and stays above 90% until 6200 RPM. The M-B reaches 90% peak of TQ at 2900 RPM and stays above 90% until 6200 RPM. In other words, the M-B is making 90% of peak TQ 700 RPM sooner than the Corvette.
Both the Corvette and M-B reach and maintain 90% of peak HP through the same range (5300RPM - past 7000 RPM).
So to summarize, the M-B makes more horsepower and torque than the Corvette at all RPMs, and the M-B has the flatter torque curve. And Mercedes does it with 0.7 fewer litres of displacement (that's a 10% smaller engine).
I think you need to lay off the Chevrolet cool-aid.
And as we can see, the torque curve of the LS7 is substantially broader (almost by far) than the M/B V8.
370 ft/lbs comes in at near-idle, or 1,800 RPM. 470 tops out at 4,800 RPM, and the return to 370 ft/lbs is at a far-reaching 7,000 RPM's.
With this engine, 500 nm is at both 2,000 RPM and 7,000 RPM's with peak torque (630 nm) occuring in not one but two places: 4,200 and 5,000 RPM's.
Since the LS7 is generating all that power even below 2,000 RPM that extends well beyond 7,000 RPM; and since the M156 doesn't really start generating power 'till 2K RPM with a very sharp drop-off at 7,000 RPM, it's easy to see why Motor Trend is saying the LSx engine is the best V8 engine in the world: The LS7, as I said earlier (you know, before you posted your misleading and deliberately inaccurate "data"), is just flatter, broader and more powerful than the M156 engine.
"The first thing you notice is that the Corvette engine never catches the M-B in power output at any RPM (it comes closest at about 4500 RPM)."
The Corvette engine does in fact generate more power than the Mercedes engine; your facts are from an earlier engine (early 2000's, perhaps? The LS6?), or from an entirely different manufacturer.
Try again, just without the obvious misleading info.
Another LS7 dyno?!?! Just how many are you going to need to try and make your point?
"your facts are from an earlier engine (early 2000's, perhaps? The LS6?), or from an entirely different manufacturer. Try again, just without the obvious misleading info."
Ummm, I used the charts YOU posted. :P
And I'm sure you realize that any dyno charts that you can find for these cars are far from scientific. Tell me, what was the ambient temperature on the day these Corvette and Mercedes dyno runs were made? What was the relative humidity? Density altitude? Did they use a Dynojet or Mustang dyno?
All dyno's measure an engine's output with the engine off the car (at least that's how the manufacturer measures engine output). The tested car that's connected to the dyno is having its RWHP measured, not engine output, thus your questions are mute since engine power and not RWHP is the statistic that's being measured.
Anyway, the second graph I posted was more comprehensive, measuring power output below 2K and above 7K RPM.
Just how many are you going to need to try and make your point?
The point here is is that you did get the point; the point being is that the LS7 has a broader power output and greater torque than the Mercedes engine.
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Ummm, I dunno. If it were priced at or around $250,000, would it be worth it?
Tough call, IMHO...
LS9 is boosted. What racing series uses boosted engines? Not ALMS and to tell
the truth I don't much follow the technical side but seems normal asperation is just
want the race guys want, it lasts. I'm not expecting to see the LS9 on tracks much.
Randy
http://www.youtube.com/watch?v=QLBLWs4agkk&feature=user
I think its exhaust note is one of the finest I've ever heard. It appears to drown out any noise coming from the supercharger. Also, be sure to read some of the comments posted below it. Some of them are hilarious!
Also I think it's fairly obvious the "unnamed driving school" would be Bondurant because well, they just happen to use C6 Vettes, C6 Z06 and probably still have a few C5 up for duty... oh and they're GM's "Official high preformance driving school" (says so on their webpage). Hell, I'd be surprised if some ZR1 mules didn't run there, that place is great for brutal, hot weather testing.
Wow!
http://www.youtube.com/watch?v=ZFqq4jW4JXU
I can't believe you wouldn't be proud to say I drive a Corvette ZR-1. After all, it's not just an ordinary Chevy performance car, like the Impala SS. It's their top shelf car.
The comments on handling are pointed but they don't match what I get from
those driving the car on road courses. For that matter they don't match
what I've gotten from professional instructors at road courses either.
Randy
I guess this would not leave anything for the reviewers to whine about....
We just installed a ZR1 pulley upgrade on a customer's Corvette. While it is not the EASIEST thing to do, it really isn't that hard. I don't think the average weekend mechanic would not be able to do it, but we can do it for them.
We sell a ZR1 Corvette Supercharger Pulley Upgrade Kit online as well.