Thought you all might be interested in some info posted by a recent SAE World Congress attendee.
SAE World Congress Update: You can probably find some of this info on the web:
First of all some of the exhibits:
GM:
Cadillac STS SAE 100 Technology Integration Vehicle
Supercharged LS2 producing 505hp @ 5600 rpm, 520 ft-lbs @ 3600 rpm
6 speed automatic w/ driver shift control
Dymag 2-piece Carbon Fiber rims with magnesium spokes and fastened titanium bolts 19” front 20” rears
Pirelli P Zero Rosso Asimmetrico tires
255/40 ZR19 front and 275/40ZR20 rears
Brembo Composite Ceramic Discs (15” front 14”) w/6pison calipers front and 4 piston calipers rear
Next gen Onstar
Valeo blind spot detection system
Mobileye lane departure system
Lots more
H2H
Hydrogen powered H2
180 hp
60 mile range
C6 convertible [yellow one at GM and red one at an SAE booth (Corvette won best engineered vehicle for 2005)]
LS7 cutaway
Z06 cutaway
Z06
Dodge:
Viper SRT-10 coupe
Charger SRT-8
Ford:
Mustang GT convertible
Shelby GR-1
Now my notes from the corvette technical sessions:
The LS7 produces 505hp @ 6300 rpm
and 470 lb-ft @ 4800 rpm
400 lb-ft is available from 2000 rpm
This is the first engine tested under SAE standard J 1349 revised
All GM engines will be tested under this standard from now on. This standard basically requires a third party certified SAE representative to certify the horsepower. All other manufacturers will probably use this standard soon as well.
The C6 was the first 400hp car that did not require the gas guzzler tax and they are hoping the C6 Z06 will be the first 500 hp car w/o the ggt. This is not in the bag but preliminary results look promising.
On one presentation by Tadge Jeuchter (assistant vehicle chief engineer) he listed price versus power to weight. The price was between 65 and 70K. The power to weight ratio was better than the Ford GT and the Ferrari 360.
The aluminum frame saved 136 lbs
Mg roof panel saved 6.6 lbs
CF floors and wheel housings saved 7.5 lbs
Mg suspension cradle saved 12 lbs
CF fenders saved 11.7 lbs
The frame was engineered to match steel frame physical and functional interfaces.
First time a frame engineered in steel has been reengineered for aluminum. Their basic goal was to make the production process at Bowling Green no different than with the steel frame.
The reason for CF fenders in stead of hood is mainly the fenders had to be changed anyway to accommodate the wider tires and the hood is a carryover part from the C6. More on that later.
The shared panels between the C6 and Z06:
Hood, Roof Skin, Doors, Hatch, Rear Facia
Unique parts:
Front Fascia, Fenders
The 2005 clutch was designed for the Z06 output so the clutch is the same used on the base C6
The LS7 is actually 11 mm narrower than the LS2.
The intake on the LS7 is 25% less restrictive than the LS2
Same restriction as LS6 but with 23% higher airflow at peak horsepower
Cylinder Heads flow 40 % more than the LS6 on intake 25% more on exhaust
Valve angle went from 15-12 degrees due to racing experience
Rocker ratio went from 1.6 to 1.8
Lift on Cam is 15mm or 591
The titanium valves and con rods are coated for thermal protection
Titanium intake valve (56mm) is 26% lighter than LS2
Sodium filled exhaust valves(41mm) are 18% lighter than LS2
LS7 has 37% lower back pressure than LS2
Crankshaft is 4140 steel w/ undercut and rolled filets
Piston: floating pin with polymer coated skirts
Rods are tapered on piton pin end to reduce mass
Engines are balanced, hot tested, and shipped to Bowling Green
Z06 gear ratios: 2.66, 1.78, 1.3, 1, 0.74, 0.5
C6 Z51 ratios: 2.97, 2.07, 1.43, 1, 0.84, 0.57
Does not reduce Z06 top speed but the Z06 will probably not reach 200 mph. It will top out above 190 though.
Tires were developed by Goodyear and feature Goodyear patented technology developed on the C5-R called DTS.
DTS= dynamically tuned solution
It basically features an asymmetrical trade pattern so tires “lean” into turns
Tires C5 Z06 C6 Z06
Front 265/40ZR17 275/35ZR18
Rear 295/35ZR18 325/30ZR19
Wheels
Front 17x9.5 18x9.5
rear 18x10.5 19x12
Brakes
C5 Z06 2 piston front
1 piston rear
2 pads per caliper
C6 Z06 6 pistons front
4 pistons rear
1 pad per piston (all same part number)
Rotors C5 Z06 C6 Z06
Size weight(lbs) size weight
Front 325x32 8.2 355x32 11.5
Rear 305x26 6.3 340x26 8.9
Exhaust went from 2.5” nominal diameter to 3”
Aerodynamics
Drag coefficient 0.34
Added mass saved
Brakes 27.5 lbs Aluminum Frame 136 lbs
Dry sump oil 17.6 lbs Interior and acoustics 33 lbs
Exhaust 11.7 lbs Mg front cradle 11.9 lbs
Rear battery 8.8lbs CF fenders 11.7 lbs
High capacity Axle 8.8 lbs CF floors and wheel housing 7.5 lbs
EOC and diff cooler 7.7 lbs Fixed roof 6.6 lbs
Wheels and tires 6.2 lbs
88.3 lbs added 206.7 lbs removed
Some power to weight ratios
Enzo 4.53
Saleen S7 5
Carrera GT 5.03
Z06 6.26
Ford GT 6.31
Weight distributions Front Rear
C6 Z06 50.6 49.4
C6 coupe 52.3 47.7
C5 Z06 53.6 46.4
Z06 is capable of 205 in 5th gear although it won’t hit 200 mph due to aerodynamics
60 mph in 1st gear
Power and efficiency
Same chart as in back of the book C6 and in the April issue of Automotive Engineering International so I won’t post everything
Power Fuel Economy Index
Z06 505 hp 20.7 mpg (conservative) 10,500
C6 400 22.6 9040
911 GT2 477 18.2 8681
Viper SRT-10 500 15.5 7750
Reason Ceramics were not used for Rotors –affordability (duh)
Aerodynamics
Nf / N @ 300 kph 0.48 Normal Force Distribution
Ram FEAF 48.9 Cooling flow
Powered FEAF 63 powered cooling flow
300 lb reduction in lift at 186 mph
Side mirrors actually produce downforce
Part reduction in drag
Splitter 202 lbs
Wheel opening leading edge extension 22 lbs
CHMSL 80 lbs
Total 304 lbs
Brake flow @ 80 kph
C5 Z06 C6 Z06
Front 2 cmm 10 cmm
Rear 1 cmm 2 cmm
Dual durometer front air dam is common to XLR, C6, and Z06
Consists of stiff upper section to keep its shape at speed and softer lower section to reduce scraping on curbs.
Still being worked on is a brake duct incorporated into front splitter
They actually brought in a 360 modena to test it’s aerodynamics because Ferrari claims it actually produces downforce. The Corvette guys were not able to duplicate that in the lab but said it is possible that it may produce a little downforce.
AL space frame:
Total weight of frame 285 lbs
Steel frame is 421 lbs
Their goal in developing the AL frame was seamless integration into the assembly process
The aluminum frame increase in effective gage by 1.9 mm
Steel frame gage is 2mm
AL frame gage is 4mm
AL Steel
Bending Stiffness 22.9 Hz 21.5
Torsional Stiffness 28.3 Hz 26.9
As to why they didn’t use magnesium for the rear cradle:
The main goal for the C6 Z06 was weight reduction in the front
Engineering restrictions would have been basically the same as the front
Carbon Fiber
2004 hood was first class A surface CF panel
They plan on building 7000 Z06 a year
Main priority for weight reduction was front parts and high parts to improve weight distribution and center of gravity
Candidates for CF body panels
Hood, Fenders, roof, rear quarters
Structural candidates
Interior and outer wheel house, Tub reinforcement, floor panels, Upper and lower plenum
Rear quarter panels were not chosen even though they had to redesign them anyway because of low priority for weight reduction in the rear. Same for Tub reinforcement.
Hood was a carryover part so cost would have been even more to develop new part out of CF. More later
Wheel house outers accounted for 22 lbs of weight savings with no increased tooling costs.
The floor panels are Balsa wood sandwiched inside CF (Carbon molding compound to be exact). The continuous random glass strand mat on the C6 is 1.25mm thick top and bottom versus 0.9 mm of CF.
Specific gravity is 1.5 vs 1.9 for glass
1.41 kg saved per panel
Carbon Fiber wheel housing
2mm thick versus 2.5 mm for normal part
1.1 specific gravity versus 1.4
0.73 kg saved per part
The Z06 will be the highest production volume of Carbon Fiber parts @ 7000 cars per year
2004 Z06 Carbon Fiber hood was largest previously at 2000 parts in a year
Choice of Fenders over hood:
Tooling costs
Validation complexity because of opening and closing of hood and other reasons
More Quality improvement for the fenders than the hood
No bonding or bond readout problems with fenders because of no need for bonding
Risks with fender
Complex shape
Die locks
RRIM CF
Specific gravity 1.33 gm/cm 1.58
Thickness 3.5 mm 1.2 mm
Natural Frequency 1st mode 32.4 Hz 70.8
$500 k in tooling costs saved in development of Fenders
They are looking at other technologies than glass for rear hatch
Ti exhaust was scrapped pretty much purely for cost reasons but the priority of weight reduction in the front also played a small part.
SAE World Congress Update: You can probably find some of this info on the web:
First of all some of the exhibits:
GM:
Cadillac STS SAE 100 Technology Integration Vehicle
Supercharged LS2 producing 505hp @ 5600 rpm, 520 ft-lbs @ 3600 rpm
6 speed automatic w/ driver shift control
Dymag 2-piece Carbon Fiber rims with magnesium spokes and fastened titanium bolts 19” front 20” rears
Pirelli P Zero Rosso Asimmetrico tires
255/40 ZR19 front and 275/40ZR20 rears
Brembo Composite Ceramic Discs (15” front 14”) w/6pison calipers front and 4 piston calipers rear
Next gen Onstar
Valeo blind spot detection system
Mobileye lane departure system
Lots more
H2H
Hydrogen powered H2
180 hp
60 mile range
C6 convertible [yellow one at GM and red one at an SAE booth (Corvette won best engineered vehicle for 2005)]
LS7 cutaway
Z06 cutaway
Z06
Dodge:
Viper SRT-10 coupe
Charger SRT-8
Ford:
Mustang GT convertible
Shelby GR-1
Now my notes from the corvette technical sessions:
The LS7 produces 505hp @ 6300 rpm
and 470 lb-ft @ 4800 rpm
400 lb-ft is available from 2000 rpm
This is the first engine tested under SAE standard J 1349 revised
All GM engines will be tested under this standard from now on. This standard basically requires a third party certified SAE representative to certify the horsepower. All other manufacturers will probably use this standard soon as well.
The C6 was the first 400hp car that did not require the gas guzzler tax and they are hoping the C6 Z06 will be the first 500 hp car w/o the ggt. This is not in the bag but preliminary results look promising.
On one presentation by Tadge Jeuchter (assistant vehicle chief engineer) he listed price versus power to weight. The price was between 65 and 70K. The power to weight ratio was better than the Ford GT and the Ferrari 360.
The aluminum frame saved 136 lbs
Mg roof panel saved 6.6 lbs
CF floors and wheel housings saved 7.5 lbs
Mg suspension cradle saved 12 lbs
CF fenders saved 11.7 lbs
The frame was engineered to match steel frame physical and functional interfaces.
First time a frame engineered in steel has been reengineered for aluminum. Their basic goal was to make the production process at Bowling Green no different than with the steel frame.
The reason for CF fenders in stead of hood is mainly the fenders had to be changed anyway to accommodate the wider tires and the hood is a carryover part from the C6. More on that later.
The shared panels between the C6 and Z06:
Hood, Roof Skin, Doors, Hatch, Rear Facia
Unique parts:
Front Fascia, Fenders
The 2005 clutch was designed for the Z06 output so the clutch is the same used on the base C6
The LS7 is actually 11 mm narrower than the LS2.
The intake on the LS7 is 25% less restrictive than the LS2
Same restriction as LS6 but with 23% higher airflow at peak horsepower
Cylinder Heads flow 40 % more than the LS6 on intake 25% more on exhaust
Valve angle went from 15-12 degrees due to racing experience
Rocker ratio went from 1.6 to 1.8
Lift on Cam is 15mm or 591
The titanium valves and con rods are coated for thermal protection
Titanium intake valve (56mm) is 26% lighter than LS2
Sodium filled exhaust valves(41mm) are 18% lighter than LS2
LS7 has 37% lower back pressure than LS2
Crankshaft is 4140 steel w/ undercut and rolled filets
Piston: floating pin with polymer coated skirts
Rods are tapered on piton pin end to reduce mass
Engines are balanced, hot tested, and shipped to Bowling Green
Z06 gear ratios: 2.66, 1.78, 1.3, 1, 0.74, 0.5
C6 Z51 ratios: 2.97, 2.07, 1.43, 1, 0.84, 0.57
Does not reduce Z06 top speed but the Z06 will probably not reach 200 mph. It will top out above 190 though.
Tires were developed by Goodyear and feature Goodyear patented technology developed on the C5-R called DTS.
DTS= dynamically tuned solution
It basically features an asymmetrical trade pattern so tires “lean” into turns
Tires C5 Z06 C6 Z06
Front 265/40ZR17 275/35ZR18
Rear 295/35ZR18 325/30ZR19
Wheels
Front 17x9.5 18x9.5
rear 18x10.5 19x12
Brakes
C5 Z06 2 piston front
1 piston rear
2 pads per caliper
C6 Z06 6 pistons front
4 pistons rear
1 pad per piston (all same part number)
Rotors C5 Z06 C6 Z06
Size weight(lbs) size weight
Front 325x32 8.2 355x32 11.5
Rear 305x26 6.3 340x26 8.9
Exhaust went from 2.5” nominal diameter to 3”
Aerodynamics
Drag coefficient 0.34
Added mass saved
Brakes 27.5 lbs Aluminum Frame 136 lbs
Dry sump oil 17.6 lbs Interior and acoustics 33 lbs
Exhaust 11.7 lbs Mg front cradle 11.9 lbs
Rear battery 8.8lbs CF fenders 11.7 lbs
High capacity Axle 8.8 lbs CF floors and wheel housing 7.5 lbs
EOC and diff cooler 7.7 lbs Fixed roof 6.6 lbs
Wheels and tires 6.2 lbs
88.3 lbs added 206.7 lbs removed
Some power to weight ratios
Enzo 4.53
Saleen S7 5
Carrera GT 5.03
Z06 6.26
Ford GT 6.31
Weight distributions Front Rear
C6 Z06 50.6 49.4
C6 coupe 52.3 47.7
C5 Z06 53.6 46.4
Z06 is capable of 205 in 5th gear although it won’t hit 200 mph due to aerodynamics
60 mph in 1st gear
Power and efficiency
Same chart as in back of the book C6 and in the April issue of Automotive Engineering International so I won’t post everything
Power Fuel Economy Index
Z06 505 hp 20.7 mpg (conservative) 10,500
C6 400 22.6 9040
911 GT2 477 18.2 8681
Viper SRT-10 500 15.5 7750
Reason Ceramics were not used for Rotors –affordability (duh)
Aerodynamics
Nf / N @ 300 kph 0.48 Normal Force Distribution
Ram FEAF 48.9 Cooling flow
Powered FEAF 63 powered cooling flow
300 lb reduction in lift at 186 mph
Side mirrors actually produce downforce
Part reduction in drag
Splitter 202 lbs
Wheel opening leading edge extension 22 lbs
CHMSL 80 lbs
Total 304 lbs
Brake flow @ 80 kph
C5 Z06 C6 Z06
Front 2 cmm 10 cmm
Rear 1 cmm 2 cmm
Dual durometer front air dam is common to XLR, C6, and Z06
Consists of stiff upper section to keep its shape at speed and softer lower section to reduce scraping on curbs.
Still being worked on is a brake duct incorporated into front splitter
They actually brought in a 360 modena to test it’s aerodynamics because Ferrari claims it actually produces downforce. The Corvette guys were not able to duplicate that in the lab but said it is possible that it may produce a little downforce.
AL space frame:
Total weight of frame 285 lbs
Steel frame is 421 lbs
Their goal in developing the AL frame was seamless integration into the assembly process
The aluminum frame increase in effective gage by 1.9 mm
Steel frame gage is 2mm
AL frame gage is 4mm
AL Steel
Bending Stiffness 22.9 Hz 21.5
Torsional Stiffness 28.3 Hz 26.9
As to why they didn’t use magnesium for the rear cradle:
The main goal for the C6 Z06 was weight reduction in the front
Engineering restrictions would have been basically the same as the front
Carbon Fiber
2004 hood was first class A surface CF panel
They plan on building 7000 Z06 a year
Main priority for weight reduction was front parts and high parts to improve weight distribution and center of gravity
Candidates for CF body panels
Hood, Fenders, roof, rear quarters
Structural candidates
Interior and outer wheel house, Tub reinforcement, floor panels, Upper and lower plenum
Rear quarter panels were not chosen even though they had to redesign them anyway because of low priority for weight reduction in the rear. Same for Tub reinforcement.
Hood was a carryover part so cost would have been even more to develop new part out of CF. More later
Wheel house outers accounted for 22 lbs of weight savings with no increased tooling costs.
The floor panels are Balsa wood sandwiched inside CF (Carbon molding compound to be exact). The continuous random glass strand mat on the C6 is 1.25mm thick top and bottom versus 0.9 mm of CF.
Specific gravity is 1.5 vs 1.9 for glass
1.41 kg saved per panel
Carbon Fiber wheel housing
2mm thick versus 2.5 mm for normal part
1.1 specific gravity versus 1.4
0.73 kg saved per part
The Z06 will be the highest production volume of Carbon Fiber parts @ 7000 cars per year
2004 Z06 Carbon Fiber hood was largest previously at 2000 parts in a year
Choice of Fenders over hood:
Tooling costs
Validation complexity because of opening and closing of hood and other reasons
More Quality improvement for the fenders than the hood
No bonding or bond readout problems with fenders because of no need for bonding
Risks with fender
Complex shape
Die locks
RRIM CF
Specific gravity 1.33 gm/cm 1.58
Thickness 3.5 mm 1.2 mm
Natural Frequency 1st mode 32.4 Hz 70.8
$500 k in tooling costs saved in development of Fenders
They are looking at other technologies than glass for rear hatch
Ti exhaust was scrapped pretty much purely for cost reasons but the priority of weight reduction in the front also played a small part.