I'm the owner of the ZR1 in this video and initially didn't want to be part of this hornet's nest of a thread. I'm mostly coming forward to ask that some of you lay off the driver of the C7Z06. It was a father and son who took turns driving it and the son was driving in this race. I talked to both of them before and after the race and we were all having a great time. In fact, of all the Corvettes, Mustangs, Hellcats, GT-Rs, Porsches, Vipers, BMWs, etc. that were there, I don't know of one instance of anyone arguing or playing the what-if game like a lot of people have done here and we all have the "Corvette" thing in
common. Shouldn't we get along better? Grab a cup of coffee because this is a long post.

This was probably the C7Z06's first time being "raced" and they were still experimenting with things (like manual shifting), and having a good time while doing it. Everyone has to learn sometime. Most owners won't ever race their $100k cars and these guys not only did that, they posted a video of it losing and didn't make any excuses. I was happy to have met them and hope they return to next year's event, hopefully with the Halltech intake I recommended

I guess while I'm here I might as well correct some of the guessing related to my ZR1. I have the Akrapovic catback exhaust, the K&N carbon fiber intake (not cold air since it sucks in engine heat), and a B3 Racing intercooler tank which adds a gallon of water to the system to reduce heat soak. ZR1's don't vent air through the hood like C7's and underhood heat can build up if the car isn't moving. I also went to pure water in the intercooler which pulls more heat than the 60/60 mix it comes with. These are the facts, and my estimations are labeled accordingly. I love both the ZR1 AND the new Z06 and don't want to get into any debates or discussions about looks, interiors, road racing, Tadge said this, or Motor Trend said that, etc. This is about what happened that day, and what's been done to my car. I'll answer any questions related to these things, but will ignore any flaming or what-if arguments since that's already been beaten to death. I appreciate all cars and enjoy like minded people that want to learn and help others with their cars. I'd still like to view this place as somewhere where all Corvette enthusiasts can share and learn and not end up just hanging out in the C6ZR1 area.

Akrapovic exhaust: AKra on their website claims 14HP on a C6Z06. If you look at the dyno curve, it's definitely not from a LS7 so it's not trustworthy, not that I'd believe marketing claims in the first place. The system is the same for the C6Z06 and ZR1, but the stock NPP system is straight through when the baffles are open so it's hard to improve on that. I've seen two ZR1s dynoed with just the Akra system and they were still within the stock HP range for a completely stock ZR1 which is 540-560 on a DynoJet, and 510-520
on a Mustang Dyno. I don't know about the C6Z06 or C7Z06 engines, but Chevy SAE certified the LS9 so it has to be within 2% of rated power (638) so we're looking at about a 13 HP+- variance. Stock ZR1s still don't make over 650 crank even with this system. We do it for the looks and sound (and the 32lbs weight reduction if you spring for the titanium version which is what I have).

UPDATE: Akra revamped their website and I looked it up before posting this. Now they show the peak power gain of 13.5HP at 3450rpm which is believable but nobody cares about since it's out of the RPM range while racing. The gain at 6190rpm is 5.4HP which I can believe, but is negligible. This is still on a C6Z06 and not a ZR1, but it's the same kit replacing the same OEM system so close enough.

Intake: I just installed the K&N ZR1 carbon fiber kit before this event. Funny part is, I did have the Halltech C6.RS system with the BeeHive on it originally but it doesn't work on a stock tune. I'm not the original owner of this car and the statement from Halltech that says "tuning is required" didn't come out until after the original owner had already bought and installed it after being told by Halltech it didn't require tuning, but was recommended to make sure the A/F was still safe. My first ZR1 was completely stock and made 520HP on a local Mustang Dyno. When I bought the current ZR1 with the Akras and the Halltech intake, it felt really weak during the test drive but still smooth, so I chalked it up to the Winter gas that was still in it. After many tanks and no improvement, I dynoed it at the same shop and it made 490 at the wheels in June, where I was hoping for 550. Now granted it was 8-10 degrees hotter that day, but 10 degrees doesn't account for a 30HP REDUCTION of power vs. a completely stock ZR1. The wide band connected to the tail pipe went off the scale rich (was probably in the 9's) so we knew it was running way richer than it should, hence the power loss. The curve looked good, just low across the board. I pulled that work of art off, and went back to the stock intake and it felt worlds better, but I wanted something more for the
1/2 mile event. An intake is one of the very few things that can be done to an LS9 that doesn't require tuning (if done right, not like the C6.RS on a stock ECU). K&N claims their kit doesn't require a tune and on their private test it made 27HP peak on the same day. Interesting thing is the 1.5 hour break between dyno runs. It took me less than 10 minutes to install the intake so at least half that supposed 27HP gain was from a cooler engine. I'd still like to think it's worth at least 10HP if all temps are the same. The OEM filter is actually pretty good and unique to the ZR1 so an aftermarket intake only slightly straightens out the air path and still pinches down to the same 4" tube and goes through a small throttle body. LS9 throttle bodies are smaller than the LS7 for some reason. Heck, most of the power gain is probably from replacing the accordion thing joining the OEM intake to the throttle body. If I'm ever willing to tune the ECU, I'll throw the Halltech back on when it can get the tuning it so desperately needs.

Intercooler tank: This simply plumbs in line with the OEM system and adds a gallon, almost doubling the total volume. It also has a big port on it so I would pull about 3/4 gallon out after most runs, replace with ice, and top off with the same water I pulled out. I hoped I could chill the whole system and get my IAT2s down to 50 degrees or so to maybe make another 20HP but it didn't work out like I'd hoped. It was a beautiful 70 degree day, so normally if I'm driving on the highway and the car is up to temp, IAT1 would be 71-72 and IAT2
would be around 87-90 degrees while cruising down the highway with no boost heating things up. I was really surprised when I couldn't get my IAT2s below 100 degrees for any run. My hotel was a 20 minute drive so the car was at full temp by the time I got to the track in the morning. I think there's just so much heat in the engine and blower that the few cupfulls of ice couldn't bring the overall system below ambient air temps. Now it did reduce the heat soak time during a run and would never climb more than 10 degrees each time so that was
a benefit. It was also odd that the water I pulled out after a run was cool to the touch but still couldn't get the system below 100-105 degrees at the start of a run. There were no staging lines either so it's not like we were heat soaking while waiting our turn to race. Most guys pulled right up to the line when they found someone to race. Either way, this tank had to have helped a little, but nowhere near as much as I'd hoped. If I did back to back runs I'd gain about 10 degrees per run, and maybe lose 1mph. The big thing is to keep
below 130 degrees so this tank will really help if an event was during the Summer with 90-100 degree air and all cars like the ZR1, new Z06, Hellcats, and GT500s all start heating up their intercooler liquid and pulls timing. I don't think mine will.

So after getting the K&N installed, my butt dyno on the street said the car felt exactly the same as my previous completely stock ZR1. At 600+HP nobody can feel a 20HP swing but if I was at 680-690 I think I'd notice that. I was still worried that it wasn't even making stock power and that something might be wrong, but I'm very happy with the 161 trap speeds so no more worrying. I gave the benefit of the doubt and feel the car is 660-670 at the crank, but that's just a guess. I also have forged wheels and the titanium exhaust so I'm about 50lbs lighter than a stock ZR1, so over 200lbs lighter than a C7Z06. I'm an engineer and a hard numbers guy and ran a lot of simulations and used my reduced weight, a power range of 660-670 crank, the temp and humidity each day, and even the elevation of the track (about 730'), to come up with an estimate/goal of 160mph from a roll, and about 2-3mph higher than what a completely stock ZR1 would do from a roll. I think the DA was around 1800' that weekend. On Saturday with a 14mph head wind I trapped 158-159, and even took my first and only passenger of the day on the last run and hit 159.5 mph. My initial calculations didn't include wind and a storm rolled through on Friday and messed those numbers up. Sunday was the same temp (a few degrees warmer) and had a 0-5mph tail wind. I ran 159-161 all day so a 20mph differential in headwind only shifted trap speeds by 1-2mph. The last run of the day on Sunday (a few hours after the C7Z06 run) was the 3rd in a row and with a passenger and I ran 158.

My IAT2s were pushing 120 at the start of that one and even at that temp I could have still run a 160 if I didn't have the rider. The ice tank didn't really give me additional power, but it kept me away from the nasty 130+ IAT2 range where the ECU pulls timing. The modded ZR1s with 720-760HP crank all had cooling mods and could hot lap without any drop in trap speed vs. the 1-2mph for me or the C7Z06.

The race itself: So the driver initially said in full auto mode it was having to downshift from 5th to 2nd at the cones. I told him I was trapping 160-161 vs. his 155, so to even the race up a bit I suggested a 50 roll so he'd be right after the A8's natural shift point and I'd watch his car instead of anticipating the cones and would only move after I saw him downshift and move himself. It wasn't until after watching the PDR footage that it shows he tried out manual mode, which explains why he got a very quick half to 3/4 car lead at the hit.
2nd is good to low 90s in a ZR1 and I had already caught up and slightly passed him before hitting 3rd, mostly because the Z06 hit the rev limiter and lost its momentum. Once in 3rd I continued to pull further away in each gear and had 5+ cars by the end. The PDR only shows the forward facing view so it's not true that I only pulled on him after 120. I pulled from the moment I hit the throttle at 50 and continued in each gear.

So we have similar aero, his is a stock C7Z06 with Stage 1 aero. The rear wing looked a little taller than I expected, but it definitely wasn't the Stage 3 and didn't have the center wicker bill. I also have a raised Katech carbon rear spoiler so about the same height as the Z06. No front winglets or even an air splitter on the C7 and it was an A8 auto, not M7 like some had thought. My advantage is weight and maybe 10-20HP because I'm not stock. My disadvantage is the transmission and the crappy Nitto INVOs. I'm soooo putting Michelin Super Sports on when these wear out. The A8 upshifts faster than the Porsche PDK twin-clutch and can use more gear for torque manipulation to help accelerate the car if there's traction. I had to granny shift 3rd and 5th because of a crappy clutch master cylinder which is a common problem with C6's. Oddly enough, I got TSB in the mail last week regarding the master and if the clutch sticks to the floor Chevy will replace it. Mine hasn't stuck to the floor yet, but it gets real soft even after one high rpm shift.

So we talked about my power and weight advantage beforehand and both already knew the expected outcome and were just racing for fun, which we both had. I also ran a couple of guys making 720-770 at the crank and my goal was just to see how close I could hang. I actually won some of those if the other car spun down low more than me and couldn't catch me in time. They may still pull 165mph, but the winner is who gets the finish first.

The organizers started allowing dig racing in the afternoon and I would have loved to do that, but the Z06 was very popular that day and had a line of people waiting to race it. The A8 is awesome from a dig and has an advantage vs. a ZR1 or M7 but this was an unprepped airstrip so everyone on real street tires had traction problems. I had to pedal the gas all the way to 90mph, so the A8 could still easily blow the tires from a dig and drop back if traction wasn't managed as well as a driver of a manual car, yet both would still run the same mph. Whether anyone rolled at 40, 60, or even from a dig with the full 400' head start, trap speeds only varied by maybe 1mph. At 160mph we're covering 235' per second and there just isn't enough runway to really increase the speed, but to pull on a car you need to be able to put the power down to move forward. I even missed 5th once against a modded ZR1 and still trapped 160, but I quickly dropped back around 2 cars while I was fishing for the gate. We were dead even until I missed the gear too. An M7 or ZR1 would just have to be on their
game if running an A8 from a dig, but if a similar car spins or bogs more than the other guy, they just lost the race. If the Z06 comes back next year and has an intake, I'll probably expect to lose by 2-3 cars from a dig, and we'll still both have fun doing it regardless of the outcome. I think it's an awesome car and I'm glad we ran each other despite all the drama in this thread.

I'd also like to mention that the Z06 never had any heating issues and ran consistent all day. It also kept a lot closer to me than a stock 2009 Viper ACR making 600HP crank. The Viper dropped off a lot faster and he even came back and asked for seconds and was still grinning after falling behind me the second time! Nice guy and was happy to run anybody and probably lost to three generations of Corvettes and never took it personally. I lost to a modded GT-R, Porsche 911, and a Lingenfelter ZR1 and was also grinning the whole time. How about we get back to enjoying our cars (Viper included) and helping each other get faster?