C7 Weight Issues
Le Mans Master
Joined: Jul 2000
Posts: 6,559
Likes: 4,501
From: North Dallas 40 TX
I never said, not did I imply, that the LT1 simply dies after 4,000 RPM. What I did say, is that the torque doesn't continue to climb and then I does drop off quite rapidly at the top end compared to the LS7. The LT1 is not designed to move enough air in the upper RPM range to go above approximately 450 HP. Without increasing the amount of air, the engine can't produce more horsepower. Why should the LT1 produce 500 HP at 5,900 RPM when it can't move anymore air then the LS3 with it's 436 HP at 5,900 RPM?
Those are the hints that GM gives us. Why would they produce parts that have this much flow if they did not intent to use it in some part of the production life cycle of the exhaust system?
Last edited by Racer X; Jan 27, 2013 at 09:05 PM.
Melting Slicks
Joined: Aug 2005
Posts: 2,873
Likes: 614
I have a distant family member (cousin) that works for GM and was able to see several C7 mules test at the proving grounds. Once the C7 started matching the times on the track to the C6 Z06 times is when Ed Welburn accepted the "stingray" name plate. My cousin still maintains that the C7 has more hp/tq than the estimated 450 number that is being used. He also said that from the beginning of the project that one of the priority issues was weight reduction. Tadge hammered everyone on the requirement/need to find the best ability to drive the car fast on a track with better precision and steering feel. Obviously weight, balance & suspension was key and this is a significant improvement over the C6.
The C7 is only going to get better. By summer we will all want one.
Cheers, Way to go GM. The C7 looks awesome in Cyber Gray and RED.
The C7 is only going to get better. By summer we will all want one.
Cheers, Way to go GM. The C7 looks awesome in Cyber Gray and RED.
The C7 should be able to take on the C6 and C6 GS with ease by the end of its development. A similar thing happen with the Porsche guys with the 997 GTS and 991S. The 991 with its superior tech and design ended up being a good amount better in every performance metric even though prelim numbers suggested otherwise.
Burning Brakes
Joined: Jul 2004
Posts: 872
Likes: 14
From: Texas
I have a distant family member (cousin) that works for GM and was able to see several C7 mules test at the proving grounds. Once the C7 started matching the times on the track to the C6 Z06 times is when Ed Welburn accepted the "stingray" name plate. My cousin still maintains that the C7 has more hp/tq than the estimated 450 number that is being used. He also said that from the beginning of the project that one of the priority issues was weight reduction. Tadge hammered everyone on the requirement/need to find the best ability to drive the car fast on a track with better precision and steering feel. Obviously weight, balance & suspension was key and this is a significant improvement over the C6.
The C7 is only going to get better. By summer we will all want one.
Cheers, Way to go GM. The C7 looks awesome in Cyber Gray and RED.
The C7 is only going to get better. By summer we will all want one.
Cheers, Way to go GM. The C7 looks awesome in Cyber Gray and RED.
'Distant Family Member' ...try March C&D Magazine
And that's not even what they said. They were talking about the new brakes on the Z51 package as allowing 'some competitive times' at VIR.Had nothing to do with weight reduction - the C7 is heavier.
Had nothing to do with power - the C7 has less that the C6Z06
Had nothing to do with cornering - the C7 is good with just over 1G, but not as good as the C6Z06
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
They wouldn't have said it if they hadn't already done it with the car. 0-60 in under 4 seconds, they tried it and done it. Beat the Grandsport track times at the proving grounds, tried it, done it. There is absolutely no way, they're going to make these claims at the reveal, in front of thousands of viewers, unless they know first hand that it is, indeed, true.
Last edited by lt4obsesses; Jan 29, 2013 at 03:51 AM.
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
Burning Brakes
Joined: May 2005
Posts: 1,091
Likes: 35
From: Coldville
Car seems kinda heavy.
Yes I know all those Air bags and Options.
My C4 86 wieghs in at 3080 with:
Iron Block
Iron Heads
Steal Frame connectors
Way more Sub assemblies
Spare tire & jack
Yeah I no its old Tech but its over 200lbs lighter than C7.
I think they could shed some weight with options.
Delete: 19" 20" wheels
Delete: Electric seats
Delete: thick Insolation
Yes I know all those Air bags and Options.
My C4 86 wieghs in at 3080 with:
Iron Block
Iron Heads
Steal Frame connectors
Way more Sub assemblies
Spare tire & jack
Yeah I no its old Tech but its over 200lbs lighter than C7.
I think they could shed some weight with options.
Delete: 19" 20" wheels
Delete: Electric seats
Delete: thick Insolation
Race Director
Joined: May 2005
Posts: 11,992
Likes: 1,331
From: Middletown, DE
Car seems kinda heavy.
Yes I know all those Air bags and Options.
My C4 86 wieghs in at 3080 with:
Iron Block
Iron Heads
Steal Frame connectors
Way more Sub assemblies
Spare tire & jack
Yeah I no its old Tech but its over 200lbs lighter than C7.
I think they could shed some weight with options.
Delete: 19" 20" wheels
Delete: Electric seats
Delete: thick Insolation
Yes I know all those Air bags and Options.
My C4 86 wieghs in at 3080 with:
Iron Block
Iron Heads
Steal Frame connectors
Way more Sub assemblies
Spare tire & jack
Yeah I no its old Tech but its over 200lbs lighter than C7.
I think they could shed some weight with options.
Delete: 19" 20" wheels
Delete: Electric seats
Delete: thick Insolation
The comparison would be very interesting. I hold to the belief that GM could have made a great Vette sticking to a no-compromise "it will be less than 3K lbs" mandate even given the safety and usable space requirements. But, they had their reasons not to...and they are smart people.
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Race Director
Joined: Aug 2004
Posts: 15,300
Likes: 2,262
From: NorCal
Melting Slicks
Joined: Aug 2005
Posts: 2,873
Likes: 614
Car seems kinda heavy.
Yes I know all those Air bags and Options.
My C4 86 wieghs in at 3080 with:
Iron Block
Iron Heads
Steal Frame connectors
Way more Sub assemblies
Spare tire & jack
Yeah I no its old Tech but its over 200lbs lighter than C7.
I think they could shed some weight with options.
Delete: 19" 20" wheels
Delete: Electric seats
Delete: thick Insolation
Yes I know all those Air bags and Options.
My C4 86 wieghs in at 3080 with:
Iron Block
Iron Heads
Steal Frame connectors
Way more Sub assemblies
Spare tire & jack
Yeah I no its old Tech but its over 200lbs lighter than C7.
I think they could shed some weight with options.
Delete: 19" 20" wheels
Delete: Electric seats
Delete: thick Insolation
I'd like to also point out that the C5 chassis was 4 times as stiff as the C4, and the C7 is 50% stiffer than the C6 chassis.
It's really not comparable.
Race Director
Joined: May 2005
Posts: 11,992
Likes: 1,331
From: Middletown, DE
Where, specifically, is the extra weight? And, how much? You don't know, and I don't know. I just don't want to let the C7 team off quite that easy. They could have made a tremendous statement by designing to a 3K limit and sticking to it. But, it seems they chose not to. Not that the C7 will be a Sherman tank or anything, but I can't help but be disappointed.
Race Director
Joined: Aug 2004
Posts: 15,300
Likes: 2,262
From: NorCal
But apparently the C7 chassis is still LIGHTER! Certainly 99 lbs. less than the C6. And, as I remember, the C5 chassis was not materially heavier than the C4 even with all the stiffness.
Where, specifically, is the extra weight? And, how much? You don't know, and I don't know. I just don't want to let the C7 team off quite that easy. They could have made a tremendous statement by designing to a 3K limit and sticking to it. But, it seems they chose not to. Not that the C7 will be a Sherman tank or anything, but I can't help but be disappointed.
Where, specifically, is the extra weight? And, how much? You don't know, and I don't know. I just don't want to let the C7 team off quite that easy. They could have made a tremendous statement by designing to a 3K limit and sticking to it. But, it seems they chose not to. Not that the C7 will be a Sherman tank or anything, but I can't help but be disappointed.
Melting Slicks
Joined: Oct 2012
Posts: 3,424
Likes: 461
From: Long Island New York
Racer
Joined: Jan 2012
Posts: 429
Likes: 42
From: Chicago Il
St. Jude Donor '13-'14
But apparently the C7 chassis is still LIGHTER! Certainly 99 lbs. less than the C6. And, as I remember, the C5 chassis was not materially heavier than the C4 even with all the stiffness.
Where, specifically, is the extra weight? And, how much? You don't know, and I don't know. I just don't want to let the C7 team off quite that easy. They could have made a tremendous statement by designing to a 3K limit and sticking to it. But, it seems they chose not to. Not that the C7 will be a Sherman tank or anything, but I can't help but be disappointed.
Where, specifically, is the extra weight? And, how much? You don't know, and I don't know. I just don't want to let the C7 team off quite that easy. They could have made a tremendous statement by designing to a 3K limit and sticking to it. But, it seems they chose not to. Not that the C7 will be a Sherman tank or anything, but I can't help but be disappointed.
Melting Slicks
Joined: Aug 2005
Posts: 2,873
Likes: 614
But apparently the C7 chassis is still LIGHTER! Certainly 99 lbs. less than the C6. And, as I remember, the C5 chassis was not materially heavier than the C4 even with all the stiffness.
Where, specifically, is the extra weight? And, how much? You don't know, and I don't know. I just don't want to let the C7 team off quite that easy. They could have made a tremendous statement by designing to a 3K limit and sticking to it. But, it seems they chose not to. Not that the C7 will be a Sherman tank or anything, but I can't help but be disappointed.
Where, specifically, is the extra weight? And, how much? You don't know, and I don't know. I just don't want to let the C7 team off quite that easy. They could have made a tremendous statement by designing to a 3K limit and sticking to it. But, it seems they chose not to. Not that the C7 will be a Sherman tank or anything, but I can't help but be disappointed.
You look at the as-tested weights(not curb weights) for most sportscars these days and its rare to see anything under 3300lb. Cars like the 458 are weighing in a 3400lb even with all of the technology Ferrari used on that car.
In a C/D test a few months ago, the C6 Z06/Z07 came in at 3259lb and the 991 Carrera S was at 3265lb. That's about as light as you are going to get for an all-around $50K+ 400+hp sportscar IMO. The C7 should be of a similar weight.
Instructor
Joined: Jan 2013
Posts: 188
Likes: 0
From: Michigan
I thought the C7 was going to be a super light weight car with a smaller engine .
This didn't happen so to have better performance than the C6 , they need more hp which they did .
The High output model , if weighed the same as the ZR1 needs more Hp than 638 .
DO you guys really think GM will exceed 638 hp? We know they can but will they ?
This didn't happen so to have better performance than the C6 , they need more hp which they did .
The High output model , if weighed the same as the ZR1 needs more Hp than 638 .
DO you guys really think GM will exceed 638 hp? We know they can but will they ?
Drifting
Joined: Feb 2005
Posts: 1,330
Likes: 57
3000lb for a base, non-exotic RWD V8 sportscar is ridiculous IMO. Don't know where people were getting that.
You look at the as-tested weights(not curb weights) for most sportscars these days and its rare to see anything under 3300lb. Cars like the 458 are weighing in a 3400lb even with all of the technology Ferrari used on that car.
In a C/D test a few months ago, the C6 Z06/Z07 came in at 3259lb and the 991 Carrera S was at 3265lb. That's about as light as you are going to get for an all-around $50K+ 400+hp sportscar IMO. The C7 should be of a similar weight.
You look at the as-tested weights(not curb weights) for most sportscars these days and its rare to see anything under 3300lb. Cars like the 458 are weighing in a 3400lb even with all of the technology Ferrari used on that car.
In a C/D test a few months ago, the C6 Z06/Z07 came in at 3259lb and the 991 Carrera S was at 3265lb. That's about as light as you are going to get for an all-around $50K+ 400+hp sportscar IMO. The C7 should be of a similar weight.
I see where you are coming from, and it is true that most modern cars have gotten extremely fat. But the 3000 is not ridiculous; the fact that these cars weigh more than that is ridiculous.
that weight is almost ALL modules, wiring, sound deadening, and NVH crap.
a miata passes modern legal requirements at 2100. The iron motor and diff in that car, and spindles, control arms, etc., are all almost as heavy as the vette's higher horsepower stuff. the body and unibody are ALL steel.
a modern corvette should not weigh much more than 2500, if properly executed, and still be every bit as comfortable and useful as vettes have been all their model lives.
Race Director
Joined: May 2005
Posts: 11,992
Likes: 1,331
From: Middletown, DE
3000lb for a base, non-exotic RWD V8 sportscar is ridiculous IMO. Don't know where people were getting that.
You look at the as-tested weights(not curb weights) for most sportscars these days and its rare to see anything under 3300lb. Cars like the 458 are weighing in a 3400lb even with all of the technology Ferrari used on that car.
In a C/D test a few months ago, the C6 Z06/Z07 came in at 3259lb and the 991 Carrera S was at 3265lb. That's about as light as you are going to get for an all-around $50K+ 400+hp sportscar IMO. The C7 should be of a similar weight.
You look at the as-tested weights(not curb weights) for most sportscars these days and its rare to see anything under 3300lb. Cars like the 458 are weighing in a 3400lb even with all of the technology Ferrari used on that car.
In a C/D test a few months ago, the C6 Z06/Z07 came in at 3259lb and the 991 Carrera S was at 3265lb. That's about as light as you are going to get for an all-around $50K+ 400+hp sportscar IMO. The C7 should be of a similar weight.
Water under the bridge, at this point.
This does not mean the C7 will be a bad or uncompetitive car. Actually, it should be pretty awesome. But, perhaps I'm over-influenced by the Steve Jobs bio that I am in the middle of. He defined what he wanted, and basically took no prisoners in making sure Apple delivered. I guess I was hoping for the same single-minded obsession with weight on the C7. IDK what would have been sacrificed to get there, but that's not my problem
Le Mans Master
Joined: Jul 2000
Posts: 6,559
Likes: 4,501
From: North Dallas 40 TX
I see where you are coming from, and it is true that most modern cars have gotten extremely fat. But the 3000 is not ridiculous; the fact that these cars weigh more than that is ridiculous.
that weight is almost ALL modules, wiring, sound deadening, and NVH crap.
a miata passes modern legal requirements at 2100. The iron motor and diff in that car, and spindles, control arms, etc., are all almost as heavy as the vette's higher horsepower stuff. the body and unibody are ALL steel.
a modern corvette should not weigh much more than 2500, if properly executed, and still be every bit as comfortable and useful as vettes have been all their model lives.
that weight is almost ALL modules, wiring, sound deadening, and NVH crap.
a miata passes modern legal requirements at 2100. The iron motor and diff in that car, and spindles, control arms, etc., are all almost as heavy as the vette's higher horsepower stuff. the body and unibody are ALL steel.
a modern corvette should not weigh much more than 2500, if properly executed, and still be every bit as comfortable and useful as vettes have been all their model lives.
The 2005 Lotus Elise had a curb weight or around 1980 pounds on the Sport package. The size difference between an Elise and a Corvette is huge. The level of interior trim was almost non-existent. Sound deadening? what is that? The Lotus did not meet certain crash standards at that time (low speed without damage) and needed exemptions.
The 2013 Evora S has a curb weight of over 3150 pounds.
In order to get a complete roadworthy, and comfortable ( to the majority of potential buyers) is going to take a significantly smaller car to get to 2500 pound curb weight, or even a dry weight.
The Hennessey Venom GT(built off of an Elise chassis with a custom rear subframe) has a curb weight of 2743 pounds. You could probably drop a few pounds by doing without the supercharger. Still you would not have a car as comfortable and the ability to carry stuff like the Corvette.
Now while you and I could live with something like an Elise as a daily driver (I did) most people would not (witness Lotus sales).
I will be stunned if the base C7 Corvette comes out heavier than the C6 as intimated by GM executives so far. Especially with all the weight savings mentioned.
Thread Starter
Le Mans Master
Joined: Oct 2004
Posts: 6,813
Likes: 287
From: Toronto Ontario Canada
They wouldn't have said it if they hadn't already done it with the car. 0-60 in under 4 seconds, they tried it and done it. Beat the Grandsport track times at the proving grounds, tried it, done it. There is absolutely no way, they're going to make these claims at the reveal, in front of thousands of viewers, unless they know first hand that it is, indeed, true.