Nine Ball
Enthusiast
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I finally had an opportunity to take the new Viper to the drag strip, Royal Purple Raceway in Houston. I had read a few posts/feedback from others like JackB, who have taken their Gen 5 Vipers to the track, where it was mentioned that the clutch didn't like slipping off the line, and that burnouts could cause the car to go into reduced power mode. I experienced both, for myself.
My first pass was the best pass. I made 2 other clean passes later, but in reduced power mode. The car never felt fast the entire night, indicated by the lower than normal trap speeds. It just felt slow, all the way down the track. I've made a lot of hits in this car, out on the streets, and I can tell the difference right away if things feel off.
Details:
2013 SRT Viper w/ Track Pack
ESC and TCS off
5000 rpm launch (clutch roasted on this)
3505 lbs raceweight (driver 180 lbs)
DA = +650'
1.82 60'
7.44 @ 96.47 mph 1/8-mile
11.43 @ 124.34 mph 1/4-mile
http://youtu.be/J-fTB_krD_8
The other two passes, the car only trapped 122 and 120. As DA got better, the car ran slower. It was clear that something was holding back the power after that first burnout I made. It didn't seem to clear up until I was about 20 minutes into driving home, after some highway miles.
Some notes to share about the car, even though I only have 3 runs of experience with it.
-The clutch isn't ideal for drag racing. It reminds me of the stock Corvette Z06 clutch, light pedal pressure and does not like any sort of heat. Once the clutch gets hot, from trying to launch it, it will not disengage properly, and it will slip on the 2-3 shift. It also has the same heat related issues with the hydraulic system, causing the pedal to get spongy. Clamping force feels okay, but not the friction material. I may have someone upgrade my clutch disks to a ceramic/bronze puck arrangement, sort of like the Bad Boyz Garage clutch. Those clutches laugh at heat, and almost grab better when they are hot.
-First gear in this transmission is too tall. It is cool for magazine racers that they can get 0-60 in one gear, but it isn't good for drag racing. You need a lot of rpm to get this car off the line, assuming you have the tire traction. I tried dumping at 4600 rpm and the car bogged hard enough for me to abort one pass. The 5000 rpm dump worked, but my drag radials held better than the clutch did. That was with 31 psi in the tires! I was on 345/30-19 Nitto drag radials, so a similar to stock height tire. Running on stock tires would have been easier on the clutch, but also a trade-off in traction.
-We really need to figure out why these Gen 5 cars lose power after doing 1 dyno run, and apparently after doing burnouts. I had the ESC and TCS turned off each time, yet it still went into reduced power mode. This is unacceptable. I can't jump out of the car after doing a burnout and pull ECM wire harnesses, like SRT showed in their dyno video. What the hell is that all about?
-The car didn't like doing 2nd gear burnouts, even in the wet portion of the box. Brakes were too good, haha. It wouldn't put down enough torque to keep from stalling out. 1st gear burnouts worked like a charm, however.
-The car did show wheel-hop on the later two passes, but that is likely due to the track prep going away as the night went on. It was just a normal test & tune night. I lift when wheel-hop is felt, as that can cause damage to the rear. I blame that one on track prep though. Stock tires would have been worse, in that situation.
So, I learned a lot in 3 runs. Good for mental notes. I plan on trying it again during a track rental day on Nov 3, where I'll be able to get many more passes. I may opt to run on my street tires that day. It will take perfect weather, good track, and, and figuring out why the car goes into reduced power mode, before we see 10s out of these cars.
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As seen in the photos, there were two brand new 2014 Corvettes at the track. Although we never raced side by side, we did get some back to back runs. The automatic trans C7's are no joke at the dragstrip. The red C7 (Edit: has a custom dyno tune) ran an 11.73 @ 118 (1.74 60') right behind me. He later went 11.67, and then after a very long cool-down and pushing it into the water box, it clicked off an 11.47 @ 121, once the DA hit +250 around 11pm. That is a new record for C7s. I know the owner, the car is stock other than a tune, and is a non-Z51 base model automatic. There is something really cool about how they launch, the almost seem to have a higher stall converter on the initial bite, then once the car moves out a few feet, the converter locks up and the tires haze a tiny bit. It consistently cut 1.7 times on the stock tires, regardless of how the track prep went downhill. They are also geared perfectly for the 1/4-mile, hitting the top of 3rd gear at the finish line. The blue C7 (no custom tune) went 12.52 @ 118, spinning off the line. It later went 11.8 from what I was told. It appears GM did their homework with the automatic C7's. They are solid 11 second cars.
Tony
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