The Official C8 Corvette Thread...

[Gotta-Qik-C7]

If that's the real engine/exhaust sound, that is beyond legit. At 600+ hp N/A, no one is doing V8s like that right now, and even in recent times, no one really did it. The F458 peaked at well less than 600 hp, and the Ford Voodoo barely beat the 15+ year-old LS7. This sounds like it will rival the N/A V10s of Lamborghini and Audi. Will be very interesting.

Two things I REALLY don't - squar-cle steering wheel and exhaust tips. Bugs me to no end. I have a feeling that on the Z06 the latter will be different, but still.

Yeah the Z06 will get round center mounted exhaust! I like the steering wheel in a weird kinda way! LOL!

[Payman]

http://www.youtube.com/watch?v=W3NTAImpNBQ&ab_channel=Chevrolet

[Payman]

sweet ginger galvanized Jesus. 

That candy orange one with the blacked out C pillar. 

[r0tor]

WTF... Everyone knows there is no replacement for displacement.  Why the small girly engine 

[Payman]

WTF... Everyone knows there is no replacement for displacement.  Why the small girly engine 

Sez the guy with the puny Wanker engine. 

[MX793]

This is the sort of engine the C8 always should have had.  The low-revving pushrod SBC just seems out of character in such an exotic body.

That said, without VVL, this thing is going to have the same "problem" as the GT350.  Big power on paper, but peaky. 

[FoMoJo]

This is the sort of engine the C8 always should have had.  The low-revving pushrod SBC just seems out of character in such an exotic body.

That said, without VVL, this thing is going to have the same "problem" as the GT350.  Big power on paper, but peaky. 

Yes, it brings it up to a whole new level.  A true exotic.  Every exotic needs to scream rather than rumble.

[GoCougs]

The GT350 couldn't maximize Voodoo performance because it was heavy with tall, widely spaced gears all with only a ~10% power bump over the Coyote.

The C8 Z06 with 670 hp and 8sp DSG is following in the footsteps of high-revving N/A vehicles such as the 911 GT3, R8 V10, F458 (i.e., lighter weight, more power and many-speed DSG such that there are no material powerband flat spots that need to be mitigated via VVL - i.e., acceleration is huge anywhere in the tach).

[afty]

This thing looks like a beast. A high revving, naturally aspirated, flat-plane crank V8 is just what you want in these days of turbos and EVs.

[FoMoJo]

Good article...How Chevrolet Created the Most Powerful Naturally Aspirated V-8 Ever For the New Z06

[MX793]

The GT350 couldn't maximize Voodoo performance because it was heavy with tall, widely spaced gears all with only a ~10% power bump over the Coyote.

Wow, the only remark you were remotely correct about was that the GT350 was a bit portly.

GT350 did not have widely spaced gears.

1st to 2nd: 1.457:1
2nd to 3rd: 1.385:1
3rd to 4th:  1.298:1
4th to 5th:  1.240:1

For comparison, a Honda S2K (another screamer)

1st to 2nd: 1.532:1
2nd to 3rd: 1.381:1
3rd to 4th:  1.276:1
4th to 5th:  1.232:1

Shorter 1-2 jump and the remainder are pretty much the same.  Unless you want to argue the S2k had "widely spaced gear ratios".

526 hp is a shade more than a 10% bump over the 435 that the Coyote made at the time the Voodoo came out.  And despite having shorter overall gearing and 90 more hp, the 435 hp Mustang GT would walk a GT350 in a top gear roll-on from 40 mph up to well into the triple digits.  Because a screamer FPC motor with no VVL will be peaky.

The C8 Z06 with 670 hp and 8sp DSG is following in the footsteps of high-revving N/A vehicles such as the 911 GT3, R8 V10, F458 (i.e., lighter weight, more power and many-speed DSG such that there are no material powerband flat spots that need to be mitigated via VVL - i.e., acceleration is huge anywhere in the tach).

The regular C8 has a curb weight of nearly 3600 lbs with the go-fast package.  It's no feather weight (only 150 lbs lighter than a GT350).  Don't see the Z06 being appreciably lighter.

Gearboxes don't eliminate dips and deadspots in the powerband.  Assuming GM selects ratios correctly, they can make it so the car stays in the power once it clears first gear, but we'll see how that works out.  The C8 gets walked by heavier and/or less powerful Euro cars like the M4 at speed because despite having an 8 spd DSG, 5 of those ratios are overdrives and widely spaced.  Even with a very short final drive, it hits terminal velocity at the top of 6th gear, leaving 2 gears on the table.  A 911 GT3RS, in contrast, hits its terminal velocity in top gear.

[CaminoRacer]

They just released a 1000 hp big block so when is someone gonna swap that in?

[Gotta-Qik-C7]

sweet ginger galvanized Jesus. 

[GoCougs]

Wow, the only remark you were remotely correct about was that the GT350 was a bit portly.

GT350 did not have widely spaced gears.

1st to 2nd: 1.457:1
2nd to 3rd: 1.385:1
3rd to 4th:  1.298:1
4th to 5th:  1.240:1

For comparison, a Honda S2K (another screamer)

1st to 2nd: 1.532:1
2nd to 3rd: 1.381:1
3rd to 4th:  1.276:1
4th to 5th:  1.232:1

Shorter 1-2 jump and the remainder are pretty much the same.  Unless you want to argue the S2k had "widely spaced gear ratios".

526 hp is a shade more than a 10% bump over the 435 that the Coyote made at the time the Voodoo came out.  And despite having shorter overall gearing and 90 more hp, the 435 hp Mustang GT would walk a GT350 in a top gear roll-on from 40 mph up to well into the triple digits.  Because a screamer FPC motor with no VVL will be peaky.

The regular C8 has a curb weight of nearly 3600 lbs with the go-fast package.  It's no feather weight (only 150 lbs lighter than a GT350).  Don't see the Z06 being appreciably lighter.

Gearboxes don't eliminate dips and deadspots in the powerband.  Assuming GM selects ratios correctly, they can make it so the car stays in the power once it clears first gear, but we'll see how that works out.  The C8 gets walked by heavier and/or less powerful Euro cars like the M4 at speed because despite having an 8 spd DSG, 5 of those ratios are overdrives and widely spaced.  Even with a very short final drive, it hits terminal velocity at the top of 6th gear, leaving 2 gears on the table.  A 911 GT3RS, in contrast, hits its terminal velocity in top gear.

It's not about comparisons but results (here, acceleration). The GT350 underperformed per its (peak) power/weight ratio per the facts I listed; relatively heavy car (resistance to acceleration), wide gear spacing (less average power = less acceleration per gear) and M/T (no legit launch control and big RPM drops between shifts which exacerbates the first two issues). IMO the Voodoo was an exercise rooted mostly in theatrics and GT350 acceleration suffered a bit for it. Of course, address these issues and it's no longer a $60k car...

There are other details to consider. The Voodoo dates back ~30 years and is more or less stuck with the bore, stroke and fundamental head design of a past era; notably the Voodoo has but a 3.70" bore (and 3.66" stroke). The LT6 has a 4.1" bore and 3.15" stroke which speaks to likely (much) larger valves and as a result my bet is a meatier power band. The LT6 also has a 12.5:1 CR, which will also help, which is a byproduct from the LT6 being a modern, clean sheet design.

The C8 Z06 may suffer the from the same maladies (first two - heavy, wide gear spacing) that limited GT350 acceleration expectations but indications per the other vehicles listed are that it probably will not even come close to it.

[GoCougs]

Also of note, the LT6 uses cam fingers followers rather than traditional lifters, which affords shorter cam duration (for low RPM performance) and greater cam lift, less friction and lighter valve train weight (for high RPM performance). News to me, and likely also explains why there is no VVL.

[MX793]

It's not about comparisons but results (here, acceleration). The GT350 underperformed per its (peak) power/weight ratio per the facts I listed; relatively heavy car (resistance to acceleration), wide gear spacing (less average power = less acceleration per gear) and M/T (no legit launch control and big RPM drops between shifts which exacerbates the first two issues). IMO the Voodoo was an exercise rooted mostly in theatrics and GT350 acceleration suffered a bit for it. Of course, address these issues and it's no longer a $60k car...

There are other details to consider. The Voodoo dates back ~30 years and is more or less stuck with the bore, stroke and fundamental head design of a past era; notably the Voodoo has but a 3.70" bore (and 3.66" stroke). The LT6 has a 4.1" bore and 3.15" stroke which speaks to likely (much) larger valves and as a result my bet is a meatier power band. The LT6 also has a 12.5:1 CR, which will also help, which is a byproduct from the LT6 being a modern, clean sheet design.

The C8 Z06 may suffer the from the same maladies (first two - heavy, wide gear spacing) that limited GT350 acceleration expectations but indications per the other vehicles listed are that it probably will not even come close to it.

Big valves tend to hurt low RPM power and breathing.  Honda uses VTEC on the VFR800 sportbike to actually deactivate half the valves at lower RPMs because they get better VE and power production at lower RPMs that way.  At higher RPM they re-engage the valves for better breathing up top.  The result is a fatter overall power band.  Likewise, any motor with VVL will reduce lift, and effective valve area, at lower RPM to foster better VE and power production.  Fixed valve lift on a motor tuned to make peak power at high RPM is going to come at the expense of lower end power.

Short stroke and, presumably, long rods are essential for a FPC motor of this displacement not wanting to shake itself apart from the secondary vibration mode inherent to that configuration.  I'll put money on the LT6 being smoother than Voodoo in the NVH department.

[MX793]

Also of note, the LT6 uses cam fingers followers rather than traditional lifters, which affords shorter cam duration (for low RPM performance) and greater cam lift, less friction and lighter valve train weight (for high RPM performance). News to me, and likely also explains why there is no VVL.

Voodoo also used cam finger followers.

[GoCougs]

Big valves tend to hurt low RPM power and breathing.  Honda uses VTEC on the VFR800 sportbike to actually deactivate half the valves at lower RPMs because they get better VE and power production at lower RPMs that way.  At higher RPM they re-engage the valves for better breathing up top.  The result is a fatter overall power band.  Likewise, any motor with VVL will reduce lift, and effective valve area, at lower RPM to foster better VE and power production.  Fixed valve lift on a motor tuned to make peak power at high RPM is going to come at the expense of lower end power.

Short stroke and, presumably, long rods are essential for a FPC motor of this displacement not wanting to shake itself apart from the secondary vibration mode inherent to that configuration.  I'll put money on the LT6 being smoother than Voodoo in the NVH department.

By definition, for the most power at any given RPM one always wants as much flow as possible (so goes flow, so goes VE, and so goes power). However, in practical terms beyond valve size it's also about cam, intake/exhaust port and combustion chamber design to properly support flow at the various RPMs, and that is where all engines are limited for various reasons, and not all mitigations will work equally across all engines. Look to the LS7, probably the power band dyno chart king, and it had no VVT or VVL - just big valves, big cam, big ports and big CR - and had an epic power band to 7,000 RPM.

The dyno charts and road tests will be out soon enough - will the LT6 drive more like the 911 GT3 RS/Audi R8 V10 or the GT350?

Also, GM has already released LT6 specs, and indeed, LT6 (intake) valves are much larger:

LT6: 1.654"/1.378"
Voodoo: 1.504"/1.300"
Gen 3 Coyote: 1.484"/1.300"

[Eye of the Tiger]

With all these gear spacing problems, it sounds like the C8 needs a CVT.

[MX793]

By definition, for the most power at any given RPM one always wants as much flow as possible (so goes flow, so goes VE, and so goes power). However, in practical terms beyond valve size it's also about cam, intake/exhaust port and combustion chamber design to properly support flow at the various RPMs, and that is where all engines are limited for various reasons, and not all mitigations will work equally across all engines. Look to the LS7, probably the power band dyno chart king, and it had no VVT or VVL - just big valves, big cam, big ports and big CR - and had an epic power band to 7,000 RPM.

The dyno charts and road tests will be out soon enough - will the LT6 drive more like the 911 GT3 RS/Audi R8 V10 or the GT350?

Also, GM has already released LT6 specs, and indeed, LT6 (intake) valves are much larger:

LT6: 1.654"/1.378"
Voodoo: 1.504"/1.300"
Gen 3 Coyote: 1.484"/1.300"

LS7 revved to 7 grand, but output peaked at 6300.  It's sibling the LS3 peaked at 6500, also without VVT or other wizardry.  LS3's torque peaked a few hundred RPM earlier than LS7 as well.  So LS7's powerband wasn't any wider than other performance SBC variants of the time.  90% torque band for LS7 was from 3600-6200, or about 40% of usable RPM ("peaky" Voodoo's 90% torque band is also 40% of usable RPMs).  For comparison, a BMW S65 in the M3 of that time makes 90% torque from 3100 to 7900 RPM, or 61.5% of usable RPMs (and without VVL, so it is technically possible to do revs, and flat torque w/out VVL).

And with a specific output of only 72 hp/L, LS7 is not really in the same league as other motors we're talking about.

[MX793]

With all these gear spacing problems, it sounds like the C8 needs a CVT.

A transmission so capable it was banned by F1.

[Payman]

The Z06 looks so much better than the Stingray to me. Something about the designed bugged me, but seems to be fixed on the Z06.

[GoCougs]

LS7 revved to 7 grand, but output peaked at 6300.  It's sibling the LS3 peaked at 6500, also without VVT or other wizardry.  LS3's torque peaked a few hundred RPM earlier than LS7 as well.  So LS7's powerband wasn't any wider than other performance SBC variants of the time.  90% torque band for LS7 was from 3600-6200, or about 40% of usable RPM ("peaky" Voodoo's 90% torque band is also 40% of usable RPMs).  For comparison, a BMW S65 in the M3 of that time makes 90% torque from 3100 to 7900 RPM, or 61.5% of usable RPMs (and without VVL, so it is technically possible to do revs, and flat torque w/out VVL).

And with a specific output of only 72 hp/L, LS7 is not really in the same league as other motors we're talking about.

The LS7 is leagues beyond the LS3 - simply look at the area under the curves from 4000 - 6500 rpm. The LT1 hangs in there better but the LS7 walks after 5000 rpm:



Here's engine dyno comparison of the LS7 and Voodoo, and the differences are even more stark - the LS7 makes more power and torque virtually everywhere, especially 4000-6500 rpm, with an average of 40-50 hp:



The LS7's advantage, beyond performance, was size, weight, simplicity and cost. To get a materially better, albeit not hugely so (~50-60 hp bump) performing N/A V8, one had to bump up ginormously $$$ to the AMG 6.2L or Ferrari 4.5L (with of course also a huge bump up in size, weight and complexity):



Even 15 years later, the LT2, Voodoo and 6.4L Hemi all fall short of the LS7, and TBH, the aforementioned AMG and Ferrari V8s are marginal in their advantages - so, really, it took the LT6 and 17 years to materially best the LS7. Not too shabby.

[MX793]

The LS7 is leagues beyond the LS3 - simply look at the area under the curves from 4000 - 6500 rpm. The LT1 hangs in there better but the LS7 walks after 5000 rpm:



Here's engine dyno comparison of the LS7 and Voodoo, and the differences are even more stark - the LS7 makes more power and torque virtually everywhere, especially 4000-6500 rpm, with an average of 40-50 hp:



The LS7's advantage, beyond performance, was size, weight, simplicity and cost. To get a materially better, albeit not hugely so (~50-60 hp bump) performing N/A V8, one had to bump up ginormously $$$ to the AMG 6.2L or Ferrari 4.5L (with of course also a huge bump up in size, weight and complexity):



Even 15 years later, the LT2, Voodoo and 6.4L Hemi all fall short of the LS7, and TBH, the aforementioned AMG and Ferrari V8s are marginal in their advantages - so, really, it took the LT6 and 17 years to materially best the LS7. Not too shabby.

Breadth of powerband is the flatness of the curve against itself (e.g. % of usable revs the engine is making at least 90% peak torque), not the comparative area under curves of 2 different engines.  "Peakiness" is the relative lack thereof.  An engine can both be "peakier" than another and present far more area under the torque curve.

[r0tor]

I'll need popcorn for Cougs story when dyno plots are released for the LT6 since it has only 20ftlbs more torque than the voodoo but comes much later... Meaning it would also be inferior to the LS7

[Eye of the Tiger]

A transmission so capable it was banned by F1.

As long as you don't let Jatco build it, sure.

[SJ_GTI]

Sounds impressive, but since I don't race for a living I'd rather have a pooprod and a manual.

[GoCougs]

I'll need popcorn for Cougs story when dyno plots are released for the LT6 since it has only 20ftlbs more torque than the voodoo but comes much later... Meaning it would also be inferior to the LS7

lol wut - 670 hp tells you the LT6 will be vastly superior to either the LS7 or Voodoo at anything you ask it to do.

Beyond that the MathSPIN is easy, actually: peak torque of 460 lb-ft at 6300 rpm and 420 lb-ft at 8400 rpm (peak power rpm). That is flatter than both the Voodoo and LS7 (that is, relatively speaking; between peak torque and peak power rpms).

[MX793]

lol wut - 670 hp tells you the LT6 will be vastly superior to either the LS7 or Voodoo at anything you ask it to do.

Beyond that the MathSPIN is easy, actually: peak torque of 460 lb-ft at 6300 rpm and 420 lb-ft at 8400 rpm (peak power rpm). That is flatter than both the Voodoo and LS7 (that is, relatively speaking; between peak torque and peak power rpms).

Slightly flatter than Voodoo between peaks.  Voodoo makes 90.4% peak torque at peak power RPM.  LT6 is 91.3%.  On Voodoo there's a bigger RPM spread between peak torque and peak power (2750 vs 2100).  But peak numbers don't tell the whole picture.  LT6 may be very flat leading up to peak torque.

[Gotta-Qik-C7]

The Z06 looks so much better than the Stingray to me. Something about the designed bugged me, but seems to be fixed on the Z06.

The smaller rear vents below the lights and center exhaust fix the rear for me!