C7 Weight Issues
01-25-2013, 04:03 PM
#21
Team Owner
They are probably still working on tuning the engine. The numbers posted are only HP/TQ estimates. Once the numbers are released, then we will know.
01-25-2013, 04:03 PM
#22
Melting Slicks
LT1 torque is the same as the LS7 UNDER 4000 RPM. Above 4,000 rpms and the Z06 has more torque(20 lbs-ft but also has 55 horsepower from 4,000 RPM) over the LT1.
In a drag race(which the 0-60 is and the 1/4 mile is), you are only running below 4,000 RPM once, and that's in first gear up to 31 MPH with the Z51. From 31 MPH to 60 MPH, you are above 4,000 RPM and the LS7 will walk all over a LT1. Once you shift into second gear the RPM stays above 4,000 and the superior torque and horsepower will pull away from the LT1, Same for shifting into third gear, and then into fourth gear. I only bring up the Z06 because you did trying to show superiority of the LT1.
But, the LT1 with Z51 should slightly out perform the LS3 GS depending on what the final weight figures are for the Z51. LT1 without Z51; I doubt it will outperform the LS3 GS.
In a drag race(which the 0-60 is and the 1/4 mile is), you are only running below 4,000 RPM once, and that's in first gear up to 31 MPH with the Z51. From 31 MPH to 60 MPH, you are above 4,000 RPM and the LS7 will walk all over a LT1. Once you shift into second gear the RPM stays above 4,000 and the superior torque and horsepower will pull away from the LT1, Same for shifting into third gear, and then into fourth gear. I only bring up the Z06 because you did trying to show superiority of the LT1.
But, the LT1 with Z51 should slightly out perform the LS3 GS depending on what the final weight figures are for the Z51. LT1 without Z51; I doubt it will outperform the LS3 GS.
01-25-2013, 04:03 PM
#23
Le Mans Master
Which C6? Base or GS, which is really the C6 "base" since 2010.
01-25-2013, 04:14 PM
#24
Team Owner
01-25-2013, 04:26 PM
#25
Melting Slicks
LT1 torque is the same as the LS7 UNDER 4000 RPM. Above 4,000 rpms and the Z06 has more torque(20 lbs-ft but also has 55 horsepower from 4,000 RPM) over the LT1.
In a drag race(which the 0-60 is and the 1/4 mile is), you are only running below 4,000 RPM once, and that's in first gear up to 31 MPH with the Z51. From 31 MPH to 60 MPH, you are above 4,000 RPM and the LS7 will walk all over a LT1. Once you shift into second gear the RPM stays above 4,000 and the superior torque and horsepower will pull away from the LT1, Same for shifting into third gear, and then into fourth gear. I only bring up the Z06 because you did trying to show superiority of the LT1.
But, the LT1 with Z51 should slightly out perform the LS3 GS depending on what the final weight figures are for the Z51. LT1 without Z51; I doubt it will outperform the LS3 GS.
In a drag race(which the 0-60 is and the 1/4 mile is), you are only running below 4,000 RPM once, and that's in first gear up to 31 MPH with the Z51. From 31 MPH to 60 MPH, you are above 4,000 RPM and the LS7 will walk all over a LT1. Once you shift into second gear the RPM stays above 4,000 and the superior torque and horsepower will pull away from the LT1, Same for shifting into third gear, and then into fourth gear. I only bring up the Z06 because you did trying to show superiority of the LT1.
But, the LT1 with Z51 should slightly out perform the LS3 GS depending on what the final weight figures are for the Z51. LT1 without Z51; I doubt it will outperform the LS3 GS.
01-25-2013, 04:28 PM
#26
Just heard a rumour from a parts supplier I know. Apparently GM Engineering has been working overtime trying to still take weight out of the C7. That would explain why they are no firm details on weight. It would also explain why they are saying 0-60 in under 4 seconds without fully qualifying that remark. As it stands now it is probably over 4 seconds and they will do everything they can to meet their claims.
01-25-2013, 04:47 PM
#28
Safety Car
No doubt it will kick LS3 C6 A$$. Not hard to figure that out IMO
C7 PROS:
The car has more tq/hp= so it should be faster
The car is lighter= so it should be faster.
The "auto" has a new torque converter= should really kick a$$, 60 ft. & 0-60 mph.
C7 CONS:
Smaller runflats (and lighter) than GS= The "yokel"
behind the wheel will need to know how to drive, so that all the PROS: are not wasted. 
Most drivers will leave all the nannies on to get their "best times" because this car will have more power that needs to be controlled.
The car has more tq/hp= so it should be faster
The car is lighter= so it should be faster.
The "auto" has a new torque converter= should really kick a$$, 60 ft. & 0-60 mph.
C7 CONS:
Smaller runflats (and lighter) than GS= The "yokel"
behind the wheel will need to know how to drive, so that all the PROS: are not wasted. Most drivers will leave all the nannies on to get their "best times" because this car will have more power that needs to be controlled.
Last edited by C7/Z06 Man; 01-25-2013 at 05:57 PM.
01-25-2013, 04:58 PM
#29
Burning Brakes
While not all the claims are baseless, they all are unsubstantiated. Nothing is learned by white washing or denigrating. There are trolls and shills. In the end, the claims still have to be proved.
01-25-2013, 06:39 PM
#30
Team Owner
GM said in one of the vid's they were still working on weight. Doubt it will be much at this point but maybe they are looking at going below a 3100 to 3080 or something like that. Even 20 more pounds at this stage would be huge.
01-25-2013, 06:40 PM
#31
Team Owner
01-25-2013, 06:51 PM
#33
Race Director
They should just put spicer u-joints in place of the rubber couplings............torque is 1 to 1 from motor through the TT. Works great on my 97 C5
Magnesium wheels would help as well
Last edited by Allthrottleandsomebottle; 01-25-2013 at 06:53 PM.
01-25-2013, 06:57 PM
#34
Drifting
According to my mole hidden deep in the recesses of a GM managers neck...the current pig beast version weighing 3350lbs or so is running that sub 4 second 0-60. They are going to make sure they have the tune to make that number and continue to bump it up as needed to get there.
Then...they drop out another 200lbs and...viola, now you've got something. (of course what you don't have is a passenger seat and interior, but who the heck needs that?)
Then...they drop out another 200lbs and...viola, now you've got something. (of course what you don't have is a passenger seat and interior, but who the heck needs that?)
01-25-2013, 07:00 PM
#35
Le Mans Master
01-25-2013, 07:01 PM
#36
Instructor
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Lets get one thing straight, GM didn't fail on this car. Your just disappointed. The world doesn't revolve around your opinion.
01-25-2013, 07:11 PM
#37
Race Director
And, building off what the one poster suggested, 99% of the time the "fun" accelleration, for 90% of Z AND C7 owners, is probably in the 2K to 5K RPM range anyway. Given what we know today (not that much) indications are there is no significant difference in what the engines will produce in that range.
01-25-2013, 07:33 PM
#38
Joe -- the rest of your analysis flows from the part I copied above, which, unfortunately is an oversimplification. While the Z06 gets its 505 HP @ 6300 RPM (and torque peak of 470 @ 4800 RPM) that does not mean the LT1 will be 55 HP (10%) less all the way from 4K to 6.3 K RPM, especially if the LT1 has identical torque @ 4K RPM! The fall off will be gradual -- quite possibly unnoticeable until about 4.8K to 5K RPM or so.
How do you know?
Pretty sure I did a quick math calculation not long ago. By looking at the dyno charts posted there was something like a 50tq delta between the two at 6300rpm. Wish i remembered the post, but it was easy enough to calculate.
01-25-2013, 07:43 PM
#39
Team Owner
Joe -- the rest of your analysis flows from the part I copied above, which, unfortunately is an oversimplification. While the Z06 gets its 505 HP @ 6300 RPM (and torque peak of 470 @ 4800 RPM) that does not mean the LT1 will be 55 HP (10%) less all the way from 4K to 6.3 K RPM, especially if the LT1 has identical torque @ 4K RPM! The fall off will be gradual -- quite possibly unnoticeable until about 4.8K to 5K RPM or so. Depending on the gear ratios, then, you could be essentially tied for the first 2.5 seconds getting to 40, which would put the C7 wheel to wheel. At that point, the Z should begin losing the C7, but possibly only for a portion of the 4K-7K (or whereever the optimum shift points turn out to be).
And, building off what the one poster suggested, 99% of the time the "fun" accelleration, for 90% of Z AND C7 owners, is probably in the 2K to 5K RPM range anyway. Given what we know today (not that much) indications are there is no significant difference in what the engines will produce in that range.
And, building off what the one poster suggested, 99% of the time the "fun" accelleration, for 90% of Z AND C7 owners, is probably in the 2K to 5K RPM range anyway. Given what we know today (not that much) indications are there is no significant difference in what the engines will produce in that range.
They don't lie.
LS7...
LT1...
The LT1's torque does not keep climbing above 4,000 RPM nor does it's horsepower climb above 5900 RPM.
5000RPM...LT1 is 440 lbs-ft and LS7 is 470 lbs-ft
6000RPM...LT1 is 390 lbs-ft and LS7 is 450 lbs-ft
6500RPM...LT1 is 360 lbs-ft and LS7 is 420 lbs-ft.
7000RPm...LT1 is zero lbs-ft and LS7 is 390 lbs-ft
The horsepower curve also shows the superiority of the LS7.
4,000RPM...LT1 is 340HP and LS7 is 300 HP
5,000RPM...LT1 is 420HP and LS7 is 410 HP
6,000RPM...LT1 is 445HP and LS7 is 500 HP (55HP delta)
6,500RPm...LT1 is 365HP and LS7 is 505Hp (140 HP delta)
7,000RPM...LT1 is zeroHP and LS7 is 500HP.(500 HP delta)
These are GM's dyno graphs. Do you not think GM knows how to operate a dyno?
I don't believe you are capable of grasping the concept that some engines are designed for low end torque and some for high end horsepower. The LT1 was designed for excellent low end torque with out giving up too much on the top end. The LS7 was designed for great low end and high end torque to deliver the horsepower. Just because two engines have 450 lbs-ft of torque at 4,000 RPM doesn't mean they will have the same torque at 6500 RPM (and surely not the same horsepower at 6,500 RPM).
Last edited by JoesC5; 01-25-2013 at 08:08 PM.
01-25-2013, 07:59 PM
#40
Racer
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Just heard a rumour from a parts supplier I know. Apparently GM Engineering has been working overtime trying to still take weight out of the C7. That would explain why they are no firm details on weight. It would also explain why they are saying 0-60 in under 4 seconds without fully qualifying that remark. As it stands now it is probably over 4 seconds and they will do everything they can to meet their claims.
Second, your assumption about the 0 - 60 would be the opposite. Why do you think they used a general claim of "under 4 seconds?" It's already under 4 seconds, meaning it's already at least 3.9, but it could 3.8 or lower depending on how much weight the stip off of it, assuming that's what they are even doing at this point, which I doubt this late in the game. They already stated their claim so they don't need to "meet" it.
Third, it's a rumor. But, either way it doesn't matter because you'll at leaset get a 3.9 second car.