PRE-Z06

Yeah, that's the reason I don't run 1/8. I can't stand having to make the shift right before the traps, but sure would have liked to join the 6 sec club. Though I know if I had the non-z51 trans like before, so I didn't have to make that shift, it'd be done easily as I lost 3 mph in the 1/8 having to make that shift.

I went 7.09@101 on a 1.54 making two shifts previously and 7.03@98 on a 1.49 making three shifts with z51 trans.

stanger383

Joe you are right about making up et in the first 1/8. My car dyno 445/428 . my best was a 6.82@99 on my 10.78 run I only back half ed 23.5mph. On another not so great run when I spun I ran 97.6 and 124.33(which is my all time best MPH)

GARY2004Z06

Congrats Joe! Great driving. That launched looked perfect.

Joe_G

Thanks Gary! A complement from an experienced and proven master like yourself means a lot.

What is your launch technique? Are you accelerating into the clutch release too? What's your launch RPM?

GARY2004Z06

Thanks Joe. We try to match the launch to the tires and track conditions. What works at one tracsk on a given day may not work at the same track on another day. We have found that different tracks require completely different techniques and adjustments. We have ran a number of different tires this year including DRs which have not been used in over a year. Our current setup prefers a slick but does run well on a DR. We have been very fortunate to be able to cut 1.3s almost at will on the slick when the track is there. The DR is not quite as cooperative but it does have its moments. As you know, different clutches require different technique and you my friend have optimized yours.
Keep the numbers coming.

Joe_G

That's certainly true...I have to say it's not every day the track will hold a 100% throttle 6800 launch.

Based on my experience I don't think I'll ever get a 1.3 with my setup, and frankly I don't feel compelled to try! :lol

In my case I guess it's the hundreds of passes I've got under my belt that dictates how fast to release the clutch given track conditions. Anybody can floor a car so that's not where the magic is when launching a manual. I was trying to describe what I do to Double A Vette who's coming up to MIR tomorrow and I was struggling how to describe it...I told him to listen to it, that's the best way I guess I can describe it.

I'm still amazed my OE clutch will do this for 62000 miles and 466 passes.

I have another 1.44 video I'll post up this weekend. I haven't even watched it yet, I wonder what it'll show.

robz

It's something that's hard to teach in words.
And you do things subconsiously now that you might not even realize in order to compensate for minor varying conditions.
The driver needs to have some seat time using his/her own method proir to implementing this technique because one needs to have a feel for the car and what it's doing and see and feel the difference.

That launch style also varys from clutch to clutch but the theory never changes.
If people are interested I can put together a general theory of what one should be trying to achieve during a manual vette launch and how to work up to an agressive launch style like the way you do it.

JUIC3D

I'd love that personally.

I feel like I have a good grasp of launching/driving my car, but I would love another resource.

Joe_G

I think your efforts would be well appreciated by many.

I always credit you with a significant factor in allowing me to reach 1.5's at will...accelerate into the launch instead of just hold at RPM and release.

That one tip alone made a huge difference.

Joe_G

At the risk of showing my slow shifting to the world here is my scan of that run.

Three things to note:

Note how I was accelerating into the launch, see the RPM rising (red line top graph) before the car moves (green line top graph).

Also note, I was on the way to flooring the throttle before the tires moved (green line 3rd graph) but I actually lifted just a little on the initial bite. I frankly think it might have been the g-forces, as I see no spin off the line. But I often see little blips of the throttle in the launch sequence on the scans that I do not remember. I do it automatically as I feel the tires bite, or not, during the process.

By the way, notice how the RPM's drop in first gear despite the throttle being floored (green line third chart)...that's the clutch hooking up. Did I mention that this is the 466'th time I've done that to this clutch?

The secret to the good launch is that the RPM's never fall below 4800 during the launch sequence. Easy to say, harder to do.

The G-forces of a 1.44 launch feel pretty nice I can attest.



And in the interest of full disclosure. The reason my shifting was so slow is because I hurt my trans in the run before this where I got a 1.44 but missed 3rd. I broke my 3rd gear blocker ring. It happened to me before - when this happens, you cannot get the car into 3rd without jamming it and it'll grind. Even with my hurt tranny, I knew it was my last chance to get some zero DA weather and daytime traction so I wanted my slip. I knew I could shift slowly and get a decent pass...results in sig.

Here's the part I broke last time, and again this time. I wish I had a 6060!

Joe_G

Oh and there's another interesting nugget of information in that scan...let's see if anyone can guess what it is. It's scary information, that's a hint.

JUIC3D

Time for some bigger injectors sir.

Joe_G

Nope. Good guess, I'm comfortable with 95% duty cycle, I can still command and get 12.5.

JUIC3D

I see you log your oil pressure now. It takes a nasty dip on the launch--worried about oil starvation? Time for an accusump or something else to combat that?

Joe_G

And I want to add...I am putting my rear end in significant peril with these launches. Don't come crying to me if you end up with this....



If you want to play at this level you better be willing to pay because you are going to have to at some point.

JUIC3D

Is that your carnage Joe?

Joe_G

Ding Ding Ding. Someone clued me into this when I noticed the LS3's have something in their tune to cut power for oil starvation. I scanned my car and the g-forces surely do have an effect on oil pressure with our wet sump.

I'm not frankly worried about it, it's been doing this since day one and it's fine. YRMV.

Yes that is the result of my 302'nd launch on my OE 2005 rear end.

JUIC3D

Ya, I was thinking about logging that PID myself but it's not like it'll change anything. I'm not putting a dry sump on the car anytime soon(if ever) so it's one of those "I'd rather not know" things I guess.

I had to google "YRMV" as I had no clue what you were saying.

Nice carnage, did you keep it for the memories?

JUIC3D

True.

Do you think being the first year of the C6, you're prone to more problems than others?

Joe_G

The 05 rear is known to be weak.

I was surprised I got 301 launches out of it.