Here is a fun video driving it around this past Thanksgiving, just showing more of how the trans works with the cuts. I think I’m at the point where I’m going to call it good on setting up the cut time, recovery, and cut % because it’s nice and smooth and about as fast/short of a cut as I dare go.
With the new transmission in the car I was all set for the next half mile event. I had also put in a set of 3.21 rear gears so that I could go 200+ MPH in 5th gear with it’s revised gear ratio and then a couple of weeks before the event I broke it on the street. Literally just twisted the pinion right off the gear so I had to put in my stock rear gears again to make the event. With a 27.5″ tall tire, a .82 5th gear, and the stock 3.55 rear gear ratio that means I would max out at ~194-195 mph going right across the traps even with me raising my rev limiter to 7000 rpms (not a good idea either) so it would be completely worthless to even think about shifting into 6th gear. Looking at the logs I was on the limiter for just over a second on each of these runs but it still ran a new best. Of course this day hit 101 degrees out there so I ran just a couple of times to get a feel for it and next time out I will have a different set of gears in there that allows me to go a bit faster. The goal is still 200 MPH on a stock engine and I really think it has it in it.
I was originally going to send out the trans to just get a billet 5th gear put in it to keep it happy but I ended up opting for a few more upgrades internally. It’s still an H-pattern TR6060 but now it has dog tooth gears in it so I can wide open throttle shift the trans with an engine cut using a strain lever on the shifter. It took a bit of work to setup the cuts for the right duration and cut levels to keep it smooth and safe but testing all went well. Here is a quick dyno video just showing some of the no-lift shifts on the dyno at part throttle when I was doing my initial testing and setup.
Went out to the Gila Bend NoFlyZone half mile event yesterday to see what it could do now with the Motec and better wheels/tires for traction. I have much better control over boost ramps and with a traction control system that works very well I can actually put the power down much better than before. I haven’t turned it up at all, it’s still at the same boost level and making the same power as it was before and on the last outing it went 187.66 on the stock computer with not so great tires. Well this time it delivered with a 192.80 mph and it was so much easier to deal with in the process. I wanted to limit how many runs I made with the stock trans and going into 5th gear since it’s already whining from the last event so once I hit that number I just screwed around for the rest of the day and gave some rides and did some 60-130 rips. I’m going to put a billet .80 5th gear in there to keep it safe and that should also help out a bit in these half mile events to keep the RPMs up and let it pull a bit better in that gear. Made some dragy runs, turns out I shift slow and lose plenty of time in the process. 🙂
A quick recap of Street Car Takeover this past Saturday out at Wildhorse Pass. It was the first time running the Viper after putting the Motec on the car and it ran flawlessly. My biggest concern was that I didn’t want to end up in the unlimited king of the bakery roll class like I did with the C6Z at the Denver event so I just kept it on wastegate the whole time which is right around 900-950 rwhp or so. I had my ass handed to me back in Denver in my C6 Z06 as I qualified against a bunch of 2500 horsepower all wheel drive cars so I wanted to stay somewhere middle of the pack this time to prevent that mistake.
First pass I realized how bad of a spot it is to leave from 40 mph in this car with the stock driveline, 1st gear is worthless as I’ll just annihilate these tires and 2nd gear is only like 2600 rpms or something like that so I don’t have a chance to really build any boost with the very short run up at this track. Antilag can’t save me there! I would be playing catch up the whole race unless I wanted to play the slingshot game and cheat but I don’t have that in me. Then the stock gearing and tire size also screws me as I get to shift into 5th RIGHT before the finish at like 148 mph or so.
Ended up running just over 152 mph but that wasn’t enough to catch Andy’s 1000 rwhp F1X Viper that we did, but at least I lost to a customer. ???? Next time out I will have a decent set of wheels and tires and some valve train that will allow me to run it out in 4th, and maybe a trans that won’t have that issue who knows…
So I put the Motec on and finally had some time to try to dial some things in and this thing just fucking rips. The Motec standard traction control is about as seamless as I’ve ever felt, the only way you know that you are into the traction control is when you hear it because you really can’t feel the cuts. Obviously you still have to setup an appropriate boost ramp so it doesn’t have to work overtime but when it’s done right it’s just plain ridiculous. For comparison the C7 ZR1 traction control is pretty similar when on an actual race track as you can just hear the cuts vs feeling them but the Motec does a better job at higher power levels in a straight line since it’s all adjustable. Just a quick video showing some antilag 2 step action, builds about 10 psi in 2 seconds and 10 psi = 1000 rwhp. 🙂 Now I just need to get some appropriate wheels and tires for this thing so I can the power down.
Took the Viper out to the half mile event this past weekend for it’s first ever runs. We literally just finished it up and haven’t even had much of a chance to drive it other than around the block the night before so this was going to be a true shake down on the new combo. 14 psi of boost is about the most I felt comfortable trying to push with the stock computer, but after running it I feel like I could go a bit further with it. Not a single hiccup or any problems what so ever all weekend, well I guess traction was certainly a problem and I wish I had an aftermarket wheel/tire combo more suited to the event but I just ran out of time. Boost control was fun and the passenger’s job was to click up every time I would shift and throughout the event we were trying different strategies to manage the power. Long story short we did 187.66 mph slipping and sliding all over the place so we fell a bit short of the 190 mph goal with the stock computer. I know it had it in it with just a couple more small tweaks, but we just plain ran out of time.
Twin turbos, yup that was the next mod. Of course this car seems like it was made for a twin turbo setup with how straight forward packaging is with them. My goal was to see if we could make the stock computer play well enough to make 4 digits at the tires and the Viper computer is known to be a real pain in the ass and it is VERY limited. Talking with Joe at Cordes Performance Racing we decided to do a pair of Xona XR 8264S turbos and an A2W cooling setup on a 100% stock engine and see how far we could push it. Everything is custom built at CPR and it all fits like a glove. Now the Motec is already sitting here ready to go after we attempt 190+ in the next half mile race because I’m only willing to push it so far on the stock computer. Then we can really push it with some more safeties in place and a computer that actually has some closed loop control and feedback with advanced traction control. Here are just a few build pics.
Another half mile event and finally got the wife out there to make a few passes. She made huge improvements with every pass and actually had fun with it! Since she had never really raced anything before it was a learning experience and the original tires certainly didn’t help as first gear was worthless and it even started to spin at the top of 2nd gear. The car is still basically stock with just a few things done same as before but I think the next mod will be tires!
Headed out to the Gila Bend half mile to see what this thing is capable of as a baseline before I really dig in and do some big mods. I did tune the car and mix in some good gas just because our 91 oct is terrible but otherwise it’s pretty much stock. It went faster than I expected especially since I’m shifting into 5th right before the traps at the end.
I decided to see what the Viper is all about so I picked up a 2016 Viper GT. With 8.4 liters of engine it’s hard not to make horsepower and the raw nature of this car is visceral to say the least. With the limited production numbers they are certainly rare and unique and completely irrational in almost every metric but so awesome to drive. Eventually it’s going to get a set of twins and a sequential that should make it right at home in the half mile and just general fun on the street.