2008 Viper Facts

• The VCA has influence - The original goal was 560 hp.

***600 hp was in large part due to SRT listening to VCA members and stepping up to the challenge. A 100 hp increase on an already impressive motor is fantastic. Thank you SRT!

Gen 1 motor = 50 hp per Liter

Gen 4 motor = 71 hp per Liter

• That yielded a massive jump in power:

• This motor is strong low and high- with the high extended several hundred rpm higher. As we saw firsthand on the dynos:
RPM HP TQ
2400 225 495
3700 410 550 (Power is already beyond a standard vette)
4800 524 570 (Power is now beyond a z/o6)
6000 613 535

• Friction takes a lot of power: The dyno turned the crank with the motor off. It required 175 hp to spin it 6,000 rpm. (That's not 100% from friction, but most all of it is)

• There was a stable 10 degree (+/- 1 deg) delta between the incoming coolant temp and the outgoing coolant temp at the higher rpm loads.

• Driveline loss: They measure a lot of things and the answer was between ~12% depending on what gear and what rpm


• One of the dyno test runs is to run the motor at 100% power for 8 hours - with glowing red exhaust

• Big valves with new angles: 52.8mm (2.078") intake and 40.5mm (1.59") exhaust

• Exhaust cam can change up to 40 deg. This will smooth the idle a lot - to much reduce mis fires and meet EPA needs- but allows for more aggressive profile in mid and upper power bands. Variable exhaust on allows increase in upper power band while a variable intake would increase low end tq.

• Massive flow rate increases as demonstrated by:

Gen 1 as a base
Gen 2 +17% over Gen 1
Gen 3 + 6% over Gen 2
Gen 4 +23% over a Gen 3

Add them all up and you see where a lot of the 400 hp to 600 hp is coming from

• Knock Sensors and Octane: There are 2 knock sensors. they back off the timing if needed. the ecu is calibrated for 91 octane. The ecu will only back off timing - it will not just advance it until it detects a ping so 100 octane will not give any power increase

• The piston/rod assembly is the unit from a 6.1 hemi. Floating pin now. Stronger and better than the Gen 3 unit. That is the reason for the 1mm bore increase

• 74mm Throttle Bodies!

• A new oil filter that will also work on all Vipers. Less pressure drop and better filtration. Napa filter was the base but a relief valve was added specific for the Dodge brand unit.

• All metric bolts now

• They have tuned an 8.4 motor to put out 675hp/650tq with some performance parts
 
Some comparison numbers versus the 2008 Viper:
• Engine efficiency:
2008 Viper = 71 hp per liter
Current Z06 = 72 hp per liter
Ferrari 430 = 113 hp per liter

Curb weight:
2008 Viper = 3324 lbs **
Current Z06 = 3132 lbs
Ferrari 430 = 3196 lbs

Power/weight ratios:
2008 Viper = 0.18
Current Z06 = 0.16
Ferrari 430 = 0.15

** Not fact. Viper weight estimated from 2006 weight (3424 lbs) minus some 11gms/lifter and lighter wheels and tires = 100 lbs max.