jamie furman

No offense man but your way off on the ZR1, the Z06 is a great car but the ZR1 is better and faster and the ZR1 will run consistent high 10's in decent weather with good drivers all day long. I think the worst pass I ever made in mine is 11.10, and I was at the track last year with 5 stock ZR1's and they all made multiple 10 second passes. The ZR1 is a little harder to drive and takes some dedication and seat time to really run the number, but once you get the seat time I think you will agree the ZR1 is a substantially faster car.

Ranger

355Spider.

What make the ZR1 a particular challenge in optimizing the 1320' ET is launching the car with the 2.29 1st gear. For comparison, 1st gear is 2.66 in the Z06.

Interestingly, the applied rear-wheel torque at a 3600 launch is:

C6-ZR1 2.29 x 504 = 1154 very large tire contact patch
C6-Z06 2.66 x 393 = 1045 large tire contact patch
C5-Z06 2.97 x 325 = 965 medium tire contact patch

The three cars produce very similar 60'. But the difference among them is the applied power in the 60'-330' and 330'-1320'. The ZR1 outshines in those incrementals.

About 10 years ago I wrote that it takes 30-50 passes to get the driver component dialed-in in any severely traction-limited car with a manual transmission. That was true then and remains true today.

Kyle is currently the only ZR1 driver I'm aware of who has accumulated the passes for dialed-in status. And his ETs and their general consistency bear that out.

The ZR1 can be successively hot-lapped 2, 3, or 4 passes in cool weather without notable performance degradation, but in warmer weather the intercooler can become heat-soaked after a single pass. That in turn excessively warms the air entering the combustion chamber, even if the engine coolant temp (shown in the DIC) is in the sweet range.

With that as general background, 355Spider I'd suggest loading those slips into a spread sheet and calculating the incrementals. The numbers to compare and contrast are: 60', 330', 60'-330' (includes the 1-2 shift), and 330'-1320'. Focusing on those numbers will help you sort out the (1) impact of the launch and 1-2 shift [60', 330', 60'-330'] and (2) the possible impact of heat soak [330'-1320'].

Also keep in mind that ZR1 ETs are sensitive to (1) the 1-2 shift duration, (2) limiter clips, and (3) shift point correctness. There's more to it than just getting the launch correct.

Good luck at the track.

Ranger

LB

Meth injection will help with that heat soak issue

Trevor @ Texas Speed

Yeah slicks

pcguy2u

Hey Spider, what was your choice on Traction Control?

355Spider

Thanks Ranger. Great info as usual. I was heat soaked bad from the 60 minute, 85mph drive on the way over. Do you shift when you see the shift light?

yeah we discussed that at length. Someday after I get some 10 second stock runs.

1 push. Tc off. Didn't mess with ah until I did the launch control pass. Shifting IS awesome with launch control.

turbolou

I have plans on buying a ZR-1 some day hopefully soon, Is it worth paying the extra money for a 2010 with launch control or an 09 without. It seems that there is very little diff. between both cars other than that feature & I'm still hearing about the wheel hop issue.Which I hoped would of been resolved with the newer cars.

355Spider

I guess it all depends on the size of your wallet.

Trapper Sean

I would think a 60 minute cruise at 85 mph would ensure that everything would be at normal operating temperature.

I thought cars got "heat soaked" from a 1/4 mile all-out blast immediately followed by puttering around in the pits, or sometimes by interminable puttering around in the staging lanes before trying to run.

I hate to think that, if challenged to a race (by a professional driver on a closed course) I should accept only after assurance that I could cool my car to something less than normal operating temperature.



I rarely make it to the track so what do I know? ... but I do have a lot of ancient history trying to run a supercharged, intercooled 5.0 Mustang on the street, battling head gaskets, heat, fuel octane, etc.

OnPoint

Most of the difference, my friend, is in the gearing. The Z and ZR launch quite differently. Until you've spent some seat time in both, you won't be able to appreciate that. A pilot that has mastered the Z, will need to do some more work if he transitions to the ZR due to the gearing and different launch characteristics.

As to the apparent doubt about the power, my ZR puts a 10+ mph delta over stock Z's in the standing mile. That, my friend is real, and is a significant delta. Trap speeds for folks that have dialed the launch in the 1/4 similarly illustrate it.

GForceSS

You are correct. Heat soak takes place after a car has been running then the car experiences little to no circulation of air or coolant(s). From there parts begin to heat up other parts rapidly. His issue was the car had already been cruising at the 200+ temp with good circulation. The moment he stopped or slowed down there no longer was sufficient airflow to keep it at the 200 (or lower). So for a little while the heat was over powering the cooling, that surge of heat gets transferred to the intercooler etc. Then he went for his pass down the track.

Kind of like going for a long run, sure you sweat while you’re running but the air keeps you from feeling your true body temp….until you stop. Then it’s like a radiating heat wave you can feel all over. One of the reasons heat injury prevention rules say to never just stop moving after a long or strenuous run.

OregonC6

I just have my paid for '05. It's still a great car. Getting my ducks in a row and maybe will swing a ZR-1 in the next year or so.

First to comment on this particular topic: A person does not have to own a ZR1 or any other particular car to understand the wisdom in Ranger's GENERAL comment: "In any severely traction limited manual trans car....."

There is a learning curve in any such car. Also, it's been my experience to always expect a performance car to run better , or considerably better, after it is itself "broken in" with at least a few thousand miles on the clock.

Most of us know about what heat does to engine performance. I cannot help but wonder how the ZR1 would do heat soak wise if that plastic monstrosity were removed from the engine vs. leaving it in place.

Second comment to Ranger: Thank you! I've enjoyed, along with probably many many other people, your highly cogent and thoroughly researched conclusions regarding Z06 performance. I've read and enjoyed your posts for years even though I don't own a Z06. I don't own a space shuttle either but have learned a lot about it from others.

So, simply put, thank you.

range96

Should've tossed a bag of ice on the intercooler between runs to see if heatsoak is the real problem. How did you verify the timing being retarded?

Ranger

I ignore the shift light and instead follow the sweep of the tachometer needle. The rate of change is different in each gear. That rhythm is what needs to be internalized.

Ranger

355Spider

That's funny. We took it off to let engine cool down and that was my highest mph of the night.

Bringing one next time. We didn't measure it in any way bu the lower the collant and oil temp I ran at the higher my mph was so we just assumed it was pulling timing.

Cool thanks.

355Spider

Here's a video to illustrate the wheel hop I was talking about. My advice is don't stay in it like I did.
http://www.youtube.com/user/rmsman?f.../0/B93nQYyHQcg

YWZ08

Sounds like you hit the rev limiter on your shifts?

gripforce-c6

Could it be the crappy Invo tires causing less traction than stock PS2s?

355Spider

That's the no lift launch control shifting. You don't lift throttle so the rpms drop very little in between shifts which sounds funny from the outside. Another guy said that when I got back but I didn't. Not that run anyway.

VY ZR1

Another reason to shut off the nannies and drive it!

Thats definately rev-limiter!