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Prep/mods for 1/2 mile standing start at NFZ-Arizona
C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Prep/mods for 1/2 mile standing start at NFZ-Arizona
Aiming for a 165 MPH standing start 1/2 mile this coming weekend at No Fly Zone Arizona, after running a 162.99 MPH at the last event while on Hoosier 315/35/17's. Car makes an uncorrected 580 RWHP here in Arizona
I need to keep the nose up pitch under control at speed, which cause drag and lift. I also need to get thru the 1/2 mile traps closer to 7000-7100, instead of 7300-7400 and hitting the limiter
I'll be running a different wheel/tire combo and a few aero mods in an attempt to eke out that last 2-3 MPH.
New NT05R's at 285/40/18 (advertised at 27.09" diameter and 30#'s) on my CCW C14 18x10's.... new Michelin Pilot Sport 205/50/17's (25" diameter and 22#'s) on my Weld RT-S 17x5's. I still need to pull my extended ZR1 rear spoiler and reinstall the factory duck bill spoiler. Pulled my ZR1 front splitter and installed my factory Z06 air dam which has been modified with an additional 3.5" rubber extension. I've got roughly 2.0" of ground clearance at the bottom of the air dam, which hopefully will close down .75" or better once the air pressure builds and pushes the nose down. I want to kill as much air from getting under the car as possible, which will help with front end lift and hopefully decrease the turbulent air that causes aero drag.....in theory
Hope to run 32 psi or higher pressure in the NT05R's to minimize rolling resistance...front's will be at 40+.
Extended air dam static ground clearance
Modified factory C6 Z06 front air dam with 3.5" extended rubber air dam .
Front rake with 205/50/17 front and 285/40/18 rear.
CCW C14 18x10 and Nitto NT05R 285/40/18
Front end rake with nose up attitude with 315/35/17's on the back, 285/30/19 on the front
FYI...with extended ZR1 spoiler on the back, 335/25/20 rear tire (26.5" diameter) and running out to 7400 RPM rev limiter, car hit VBox verified 171.6 MPH.
Calculator says 174 MPH max at 7400 RPM and 27" diameter tire. I'll back it up to the end of the runway to give me an additional 300' of acceleration room to see if I can hit that 170+ number. I hit 166.8 MPH last time on the short 315/35/17 25.5" tire, having to shift into 5th gear.
Vbox data at 7400 RPM and 335/25/20 rear tire
Calculator for 27" rear tire and 7400 RPM rev limiter in 4th gear.
One of the bigger changes to help the nose stay down on my car over 175 mph was adding Trackspec vents in the hood.
Good luck
I've read all of your post and watched your threads on your high speed runs !!!
I have an aftermarket hood which is vented...the ZR Hood from Carbon Creations. I wish I still had my OEM hood, as I would have added those vents to it to provide better venting and reduce the drag that I have with my taller hood bulge on the aftermarket hood. It look great, but increases drag.
Looking forward to your wind tunnel test results
For those who don't know what RecMech does with his car, go check out his post in the Forced Induction threads
I've read all of your post and watched your threads on your high speed runs !!!
I have an aftermarket hood which is vented...the ZR Hood from Carbon Creations. I wish I still had my OEM hood, as I would have added those vents to it to provide better venting and reduce the drag that I have with my taller hood bulge on the aftermarket hood. It look great, but increases drag.
Looking forward to your wind tunnel test results
For those who don't know what RecMech does with his car, go check out his post in the Forced Induction threads
You can trying spacing the rear of the hood up to allow some of that airflow to escape. Should be cheap and show some improvement.
I forgot about your tire test on the skinnies. Very glad you brought it back to light. How are they performing for you? How much difference, in height, between those and the bias plys you were running? I will probably go this route soon.
You can trying spacing the rear of the hood up to allow some of that airflow to escape. Should be cheap and show some improvement.
I forgot about your tire test on the skinnies. Very glad you brought it back to light. How are they performing for you? How much difference, in height, between those and the bias plys you were running? I will probably go this route soon.
The bad thing about the rear hood to windshield interface is that this is an area of high pressure...think of the old cowl induction hoods where cold air is drawn into the intake. If there was a way to extended the rear of the hood to cover the wiper/cowl area and mate up to the windshield, that would cut aero drag down.
THe 205/50/17's are doing great !!! No engine drag or active handling messages. The difference in steering isn't much different that with my full size front tire setup and is MUCH more stable than my bias ply front runner tires. I can take corners at normal speeds that I wouldn't dare do with the bias ply. I picked up roughly 8 lbs per tire going to the radial front tire but I gained a 186+ MPH speed rated tire and better high speed braking
The bad thing about the rear hood to windshield interface is that this is an area of high pressure...think of the old cowl induction hoods where cold air is drawn into the intake. If there was a way to extended the rear of the hood to cover the wiper/cowl area and mate up to the windshield, that would cut aero drag down.
THe 205/50/17's are doing great !!! No engine drag or active handling messages. The difference in steering isn't much different that with my full size front tire setup and is MUCH more stable than my bias ply front runner tires. I can take corners at normal speeds that I wouldn't dare do with the bias ply. I picked up roughly 8 lbs per tire going to the radial front tire but I gained a 186+ MPH speed rated tire and better high speed braking
Oh okay, did not know that about the hood/windshield.
Good to hear. I think I am going to try the Hankook Evo tires. Same speed rating, 2lbs lighter. I have them on my OEM front wheels and they work great.
We can compare Sunday. I think my.LG hood does not have too much rise, but each of the vents does have the raised lip that creates some drag, but also negative pressure to vent from under the hood.
I got my MT ET SS balanced today, one was off 1/2 oz. and the other off 1 oz. but they took much less balance weights than before. I doubt that was enough to create the high speed instability at 140 and above that I saw last time. Joe indicated running lower pressure (24-26) in the 325/30-19s should reduce that instability so that will be something I'll have to check out.
Your calcs of 174+@7400 with those tires ties is very close to my calc of about 171 at 7300 with my tires. Maybe I am closer to 169.
I'll check out your front splitter mod as I will look to do that for Mojave if they have it next year. I have two stock front splitters that are a little scrapped up that would be good donors.
Victor, could you e-mail me you E85 dyno data (I presume you will run that)?
We can compare Sunday. I think my.LG hood does not have too much rise, but each of the vents does have the raised lip that creates some drag, but also negative pressure to vent from under the hood.
I got my MT ET SS balanced today, one was off 1/2 oz. and the other off 1 oz. but they took much less balance weights than before. I doubt that was enough to create the high speed instability at 140 and above that I saw last time. Joe indicated running lower pressure (24-26) in the 325/30-19s should reduce that instability so that will be something I'll have to check out.
Your calcs of 174+@7400 with those tires ties is very close to my calc of about 171 at 7300 with my tires. Maybe I am closer to 169.
I'll check out your front splitter mod as I will look to do that for Mojave if they have it next year. I have two stock front splitters that are a little scrapped up that would be good donors.
Victor, could you e-mail me you E85 dyno data (I presume you will run that)?
We should have some fun runs Sunday!
That instability of the S/S is what scared me off, and why I went to the tried and true NT05R.....I want to run as much pressure as I can to minimize rolling resistance while still getting some traction.
Interesting and almost opposite of what I did. I raised my car as much as possible and removed all the air dams.
I'm interested in how opening fog light holes effects aero. Thinking of bringing a roll of duct tape to tape up the fog light holes since I don't need any oil cooling for racing just hot days with ac blasting.
Interesting and almost opposite of what I did. I raised my car as much as possible and removed all the air dams.
I'm interested in how opening fog light holes effects aero. Thinking of bringing a roll of duct tape to tape up the fog light holes since I don't need any oil cooling for racing just hot days with ac blasting.
What was seen is some of the testing I read about is that the fog light openings are located where the radius begins to the side of the car. air accelerates at the corner therefore dropping air pressure in that zone. I would block off any openings in the body that are not required for such a short sprint
I enjoyed meeting more of the chat board guys (Unreal, Nuclear427) as well as the old friends. I was a little disappointing in my trap speed (158-161), but maybe that was due to the heat vs last December's cool weather.
I did a couple of standing 1/2 mile starts against Nacho (crushed me) and as I knew, it will take some time to get the clutch launch technique down. At least I roasted the MT ET SS on the first run. After rebalancing the tires and dropping the pressure on the 325/30-19 DRs to 26 from 30psi, they were more stable over 140 than in December, still moved around a little but much more manageable.
I was down 5-6mph, along with a lot of people. Just goes to show the effect of head wind, and heat. This event was mostly heat. The staging lanes were killing people.
Good meeting you. Was a decent day. Split my intake manifold, but made a bunch of 185-187 passes.
Tried to find Victor and his friend at the end, but couldn't find them. Had to head out since my intake now has a nice crack in it.
I was down 5-6mph, along with a lot of people. Just goes to show the effect of head wind, and heat. This event was mostly heat. The staging lanes were killing people.
Good meeting you. Was a decent day. Split my intake manifold, but made a bunch of 185-187 passes.
Tried to find Victor and his friend at the end, but couldn't find them. Had to head out since my intake now has a nice crack in it.
On my last pass my water temp was 223* just before launch.
Victor had his alternator bite the dust, Nacho headed out around 3PM and Benjamin (Nuclear 427) may have left around then as he had problems over 6500 rpm, only in 4th. Nacho and I gave Victor's brother rides and he was impressed how the cars took off in 1st gear. This was Joel's first trip to a 1/2 mile event and he needs to practice his watching of the tach and shifting.
I was down 5-6mph, along with a lot of people. Just goes to show the effect of head wind, and heat. This event was mostly heat. The staging lanes were killing people.
Good meeting you. Was a decent day. Split my intake manifold, but made a bunch of 185-187 passes.
Tried to find Victor and his friend at the end, but couldn't find them. Had to head out since my intake now has a nice crack in it.
Cracked another one eh? Godamn that thing makes power. When are you going to sell that LG hood and bolt one of these bad boys on?
That is the reason I tried to sell the LG hood, to run that intake since I've known Ron for almost 20 years now, but considering no one wanted the LG hood ever for 50-60% off new, I wasn't going to take that big of a hit. So it is still a toss up between doing that and just hanging the LG hood on the wall as art, or one of the G1Pro intakes. Would have ordered a G1Pro intake already if Joe would get me pricing. Just waiting on that.
I love the shearer intake, proven to make 1600+rwhp, and not kill low end, but the cost of that, + hood brings it into the $4k range. I know Ron is working on a nice billet hood cut out option so I could just hack my stock hood up. That is tempting to just have that pop up through the hood.
This is the 1st intake I've popped. I know Albert popped 2-3. Stock intakes just can't take 25+psi.
10-18-2017, 11:13 AM
Prep/mods for 1/2 mile standing start at NFZ-Arizona
