C7 Z06 vs C6 Z06 performance
12-05-2013, 02:27 PM
#21
Team Owner
May not be. Going off pure speculation of talking out of my ***, since the FI C6 car didn't avoid the guzzler tax, seems worthless to have DOD on a high output FI car that will drink the gas and still incur that tax. BUT if they can manage to rope in 600hp+ on this Vette and avoid the guzzler tax that's quite an achievement, too. That was one of the cool things I always liked about the LS7 Vettes.
Only the ZR1 was hit with the gas guzzler tax. But, the EPA fuel economy ratings are not based on WOT down the Interstate and the low compression ratio used on the ZR1 really hurt the engines efficiency when cruising down the Interstate when not under boost, vs the high compression ratio on the LS3 and LS7. LS7 are well known for running 28-29 MPG on the Interstate with 505 HP. The modern PD supercharger has virtually no parasitic draw when not in boost.
With the DI on the GenV engine I believe that GM will run a high compression ratio and cut back the boost pressure, thus the lower horsepower vs the LS9. With the higher compression ratio, fuel economy should be very little difference than the LT1.
The various supercharged LS3 engines with 10.7 CR and no DI from E-Force, Lingenfelter and Callaway(Maggie) show that retaining the higher compression while using a supercharger(but with less boost than the LS9) works, and lives(I believe Callaway's SC606 they have been driving for years has over 185,000 miles on it's odometer without any problems), and retains the original engine's fuel economy(as long as you keep your foot out of it).
It appears that the C7 LT1 Callaway will have around 610 HP with noting but a blower and I seriously doubt if they are going internal to lower the compression ratio.
I see the C7 Z06 using the same method(high CR and low boost) to up the horsepower without killing the fuel economy ratings and having to pay a gas guzzler tax.
Last edited by JoesC5; 12-05-2013 at 02:29 PM.
12-05-2013, 02:56 PM
#22
Team Owner
Not economically that I can see. I don't think there is such a thing as lightweight rubber suitable for making tires and going to another material other than aluminum for the wheels is expensive. The lightweight magnesium wheels that were an option on the early C5's were a $3000 option.
Last edited by JoesC5; 12-05-2013 at 03:22 PM.
12-05-2013, 04:01 PM
#23
I had those wheels on a c5. Only a couple of lbs lighter than the larger c5z aluminum wheels.
12-05-2013, 04:20 PM
#24
Safety Car
12-05-2013, 04:27 PM
#25
Safety Car
Track capable could mean a litany of things, not just outright speed. GM has not prepared a Corvette to the extent that they had even done the Z28, so even if the performance gap is not that big, the quote could still be true. GM isn't immune to creative advertising.
12-05-2013, 05:03 PM
#27
Melting Slicks
I suspect that the C7 Z06 will gain around a hundred horsepower over the C6 Z06, but the C6 Z06 is approximately 170 pounds lighter than theC7Z51 and then add around 90 pounds on the front end, and larger wheels/tires and that's around another hundred pounds for a total of 270 pounds that the C7 Z06 will be heavier than the C6 Z06.
That hurts a lot of the horsepower gain.
I don't see a lot of areas where they can shed much weight with the C7 Z06 . The C7 already has an aluminum frame so no savings to be gained there. The C7 uses a low density SMC for the fenders and doors, so carbon fiber won't save much weight there. The C6 Z06 used a carbon fiber clad balsa floor pans but the C7 uses a lightweight foam floor pans so not much there to save weight. The C6 Z06 uses a magnesium front engine cradle but the C7 uses a lightweight hollow cradle so no place there to save weight. The C7 already uses lighter weight hollow cast suspension A-arms, so not much there to chop weight with the C7 Z06.
Unless the C7 Z06 drops the AFM and the then uses a super light weight carbon fiber torque tube and prop shaft in place of the C7's heavier components, I don't see much in the way of reducing weight on the C7 Z06.
But, the net result will mean the C7 Z06 will out perform the C6 Z06 just as the C6 ZR1 out performs the C6 Z06.
That hurts a lot of the horsepower gain.
I don't see a lot of areas where they can shed much weight with the C7 Z06 . The C7 already has an aluminum frame so no savings to be gained there. The C7 uses a low density SMC for the fenders and doors, so carbon fiber won't save much weight there. The C6 Z06 used a carbon fiber clad balsa floor pans but the C7 uses a lightweight foam floor pans so not much there to save weight. The C6 Z06 uses a magnesium front engine cradle but the C7 uses a lightweight hollow cradle so no place there to save weight. The C7 already uses lighter weight hollow cast suspension A-arms, so not much there to chop weight with the C7 Z06.
Unless the C7 Z06 drops the AFM and the then uses a super light weight carbon fiber torque tube and prop shaft in place of the C7's heavier components, I don't see much in the way of reducing weight on the C7 Z06.
But, the net result will mean the C7 Z06 will out perform the C6 Z06 just as the C6 ZR1 out performs the C6 Z06.
Last edited by quick04Z06; 12-05-2013 at 05:12 PM.
12-05-2013, 05:05 PM
#28
Drifting
12-05-2013, 05:08 PM
#29
Drifting
The C7 Z06 will certainly be counted in GM's CAFE number. CAFE stands for corporate average fuel economy. The impact of a couple of thousand vehicles over GM's entire fleet will be small, though.
Gas guzzler tax is a different issue. GM did make it a big point to say that none of their Corvettes were subject to this tax, until the C6 ZR1 came out. So precedent has been set.
Gas guzzler tax is a different issue. GM did make it a big point to say that none of their Corvettes were subject to this tax, until the C6 ZR1 came out. So precedent has been set.
12-05-2013, 05:11 PM
#30
Team Owner
I actually think a lot of weight can be saved by deleting lots of the luxury/sound deadening interior bits. Delete the C7s heavy seats, get rids of lots of the motors (like power seat motors), install thinner glass, delete sound deadening materials, etc. Getting rid of the luxury goodies may save 200 pounds or so.
As the C6 Z06 progressed, it got heavier due to adding additional creature comforts, because that is what people were wanting.
Last edited by JoesC5; 12-05-2013 at 05:20 PM.
12-05-2013, 05:13 PM
#31
Team Owner
12-05-2013, 05:14 PM
#32
Drifting
One area that should be interesting on the C7 Z06 will be what is selected for dampers (shocks). Will the magnetic ride control shocks be standard? Will GM use the DSSV technology that is used on the upcoming Z/28? I've heard a lot of neat things about the DSSV technology, but haven't had the chance to experience it.
12-05-2013, 05:16 PM
#33
Drifting
JoesC5 - definitely agree with your perspective, it's unfortunate that the large majority of aftermarket wheels actually weigh more than GM's OEM C5Z or C6Z wheels.
12-05-2013, 05:16 PM
#34
Melting Slicks
True, but that's only what a very few few want. Look at the C6 Z06 and ZR1. Not that many sold in the base form. Most were upgraded to 2LZ and 3LZ with other weight adding options. People want lower weight but are not willing to give up the creature comforts to get. That's why I talked about weight savings that are under the skin that don't take away from the car's cruising comfort on the highway.
As the C6 Z06 progressed, it got heavier due to adding additional creature comforts, because that is what people were wanting.
As the C6 Z06 progressed, it got heavier due to adding additional creature comforts, because that is what people were wanting.
12-05-2013, 05:23 PM
#35
Melting Slicks
GMs official press release states:
"It will be the most track-capable Corvette ever, designed to deliver supercar levels of performance through unique powertrain, chassis and aerodynamic features."
To me, that means it will be faster than the Z06 and ZR1.
How much faster? That will depend on how the individual race track provides access to the features in which it has improved.
"It will be the most track-capable Corvette ever, designed to deliver supercar levels of performance through unique powertrain, chassis and aerodynamic features."
To me, that means it will be faster than the Z06 and ZR1.
How much faster? That will depend on how the individual race track provides access to the features in which it has improved.
Yes, both the Z06 & ZR1
12-05-2013, 05:27 PM
#36
I doubt it will be close on the track. This car should perform better than the C6 Z06/ZR1 in every situation. That improved aero and chassis stiffness is going to help out big time.
12-05-2013, 05:36 PM
#37
Race Director
Going to a non-runflat tire will save at least 5lb per corner. Going to carbon wheels will knock of 10 per corner. Carbon rotors, which I assume will be standard, are worth another 7lb per corner. So there is potentially a whopping 22lb per corner to be saved, which counts 3X what chassis weight does for handling. 12lb of that is within reason cost-wise. The wheel material and cost is the big questionmark. The original Dymag carbon wheels were $3K each, but that was back in the 90s. Carbon components have come down significantly in cost since then. If there is a way to get carbon wheels on the Vette, GM will do it.
Other realistic weight saving areas are non-power seats, lexan hatch / windows, and carbon rear quarters.
As Joe says, if they do FI this time around, that becomes a slipperly slope due to the 100lb it adds to the front end of the car, which is why I'd be surprised if they went this way on the Z06. It will be much tougher to significantly improve performance over a Z06 Z07 with FI, and you also have the heat soak issue no matter how good the FI is. The LS9 charge-cooling is marginal due to space limitations, and I don't see that getting better on C7. A big part of "Track capable" means that you can hammer the car all day at a lap session without degraded performance, and I just don't think that is possible with FI. So my money is on a 7.0L NA DI mill making 575-600HP, with the overall car about 100lb lighter than a Z51 due to the aformentioned items.
Either way, I have no doubt that the C7 Z06 will be a big step up from the Z06 performance-wise. Anything less would be embarrassing.
Other realistic weight saving areas are non-power seats, lexan hatch / windows, and carbon rear quarters.
As Joe says, if they do FI this time around, that becomes a slipperly slope due to the 100lb it adds to the front end of the car, which is why I'd be surprised if they went this way on the Z06. It will be much tougher to significantly improve performance over a Z06 Z07 with FI, and you also have the heat soak issue no matter how good the FI is. The LS9 charge-cooling is marginal due to space limitations, and I don't see that getting better on C7. A big part of "Track capable" means that you can hammer the car all day at a lap session without degraded performance, and I just don't think that is possible with FI. So my money is on a 7.0L NA DI mill making 575-600HP, with the overall car about 100lb lighter than a Z51 due to the aformentioned items.
Either way, I have no doubt that the C7 Z06 will be a big step up from the Z06 performance-wise. Anything less would be embarrassing.
Last edited by TTRotary; 12-05-2013 at 05:45 PM.
12-05-2013, 07:33 PM
#39
Race Director
12-05-2013, 08:38 PM
#40
The only question is will it be NA or FI? I bet a blown 6.2. The NA lovers will not be happy.