yell03

Post #30 had updated Dragy results

I hit 1500 miles today and temps were a brisk 39 degrees, tire temps never got better than "cool" on the display.

Until I know a car I never go without any nannies, especially on summer rubber in cold temps.

***Except for my previous Nissan GTR with 575whp and my current Porsche 911 Turbo S with 543whp both on All-season radials - AWD is very forgiving in any temperature with all-season radials***

Back to my question...

I wanted to test Launch Control so I went in to Z-mode and programmed the PTM to "SPORT ECS ON" - (next step up would have been "Race 1 ECS OFF" and I am not familiar enough with the car's handling in cold temps to try it on the street)

I had my Launch Control settings at 4000rpm with 10% Slip as a Baseline for the cold unprepped streets.

I did about 4-5 launches today and all except for one got off clean, one bogged, but that one I had set the PTM to "DRY ECS ON" which I think the nannies are too aggressive.

My first 2 launches were PTM "DRY ECS ON" , the first was a smooth surface and it got off well, but the 2nd bogged badly.
The next 2-3 launches were PTM "SPORT ECS ON" and they were nice clean launches.

Do any of you guys Launch in Z-mode with the PTM set to "SPORT ESC ON"?

I wanted to try launching with the car in Sport Mode (instead of Z-mode) and double tapping the TC OFF button putting it in to ESC Competitive Mode, but didn't get a chance today.

Would the car launch differently in Sport Mode ESC Competitive Mode vs Z-mode PTM to ESC SPORT TC ON?

This car launches much differently than my Porsche Turbo S, the Porsche revs to 5500rpms and when you lift off the brake it just rips your head off with a slight chirp of the tires. It is a very violent launch.
The C8 Z06 with 10% slip feels just like slipping the clutch in a manual tranny car and after it finally engages fully it takes off like a bat out of h-ll.

turbotuner20v

If you're pressing z mode twice and the car is going into PTM mode with the 2 yellow lights on, this is the exact same as pressing the T/C button twice and choosing PTM mode using the dial outside of z mode

yell03

Thanks.
I guess my question is if using PTM Sport ESC ON is as good for launching as PTM Race 1 ESC OFF

vegasredz062

10% slip is very annoying. Try 6% its closer to dumping the clutch vs riding the crap out of it.

I have found good success 4000RPMs 5-6% slip

turbotuner20v

There are Drive Modes. And there are PTM Modes. I think you may be blurring between the 2

turbotuner20v

If comparing

This:
- Drive Mode = Sport
- Quickly press TCS Off twice
- ECS Competitive Mode displays

VS

This:
- ZMode set with PTM = Sport/Race1/Race2
- Drive Mode = ZMode (double press)
- Car is now in the TCS/Stability combo of the chosen PTM setting

For straight line launch, I would think Competition Mode with no TCS would be best with Stability as a safety net but presumably not engaging

PTM Race 2 would be the next closest from a TCS OFFish perspective, but Stability is also off


A 3rd option might be to press and hold TCS Off (vs 2 quick presses) to fully disable all TCS and Stability

AzDave47

I have generally had the best results with PTM Race1 4000RPM and 10 to 15% slip. On the surfaces I have run on less slip causes the engine to bog. Road surface, road temps, tire temps and ambient temps all play a part. I have done PTM Sport, Race 1 and Race 2 and not had any problems controlling the car.

There is no one ideal launch setup.

yell03

On a prepped dragstrip yes, on an unprepped surface dumping the clutch is not the fastest launch in my experience.
I am starting at 10% and will adjust slip up or down depending on the results, but I don't plan on beating on the car that often.

WOW, I should have read the manual, but usually the manuals are useless.
This is actually very helpful.
From the looks of it the best would be to put it in Drive Mode Sport and double tap the TC off button to get it in to Competitive Driving Mode, this give you FULL Engine Power, but also retains ESC ON in case the back end comes around too far.
In Drive Mode Z-Mode choosing TCM sport it reduces engine power and leaves ESC ON.
I will still use my Custom Launch of 4000rpms and 10% slip as a starting point. If it bogs I will increase the slip %.
Many thanks!!!

That is what I am thinking, Drive Mode Sport and then double tap the TC off button, full engine power available with ESC ON in case the back end cpmes around too far.

Until I get used to the car i cold temps I do not want to try Race 1, I want that safety net.

Of course if I were on an airstrip with nothing to hit if it spun I would go Race 2 and no nannies, but for the street, even though I go to places where there is no traffic, there are other dangers such as curbs, poles, etc...
In my AWD Porsche I don't worry about it, but with RWD I do.

Please Chevy, put this engine in an AWD Corvette!!!

turbotuner20v

When the PTM setting mentions 'reduced power', that's also in combination with a steering angle measurement for corner exit on road course tracks. In a straight line power should not be reduced

qwazipsycho

39 degrees and you're launching the car with summer tires. Go take a look at those tires now and see if you chuncked them out. I'm shocked no one else has said anything.

Z0HS1CK

I agree.

I took delivery of my car in fall and i'm waiting for warm weather to come before i start attempting to try out LC.

Not taking any chances.

yell03

That makes sense, good info.

They are fine, I waited until they came up to a half-decent temp and the sun was out warming the street surface.

This is why the car will wear all-seasons after these wear out.

Z0HS1CK

Yeah same with me.

I'm probably going to buy 2 sets of tires with my 5k rewards. 1 set of AS and another set of summers and just sell the summers.

Manners226

I ran an autocross yesterday in 50 degree temps and on cold tires I was launching in PTM Sport with LC set at 3,500 rpm and 12.5% slip.

AzDave47

I did PTM Sport, Race 1 and Race 2 on a back country two lane, unprepped at 6500' elevation and the car was easily controllable. This was a 1-mile trap speed event with the fastest run in Sport at 172.5 MPH and the other two runs were within 0.9 MPH of that. 0-60 was 3.2, 3.1 and 3.5 seconds.

yell03

Thanks, PTM Sport sounds like a good compromise.

turbotuner20v

Yes, 90% of the time people will want ESC on, so:
- Competitive Driving in Sport Mode (TC off / ESC on)
- Zmode or Track Mode + PTM Sport (performance TC on / ESC on)

if you want ESC off:
- Zmode or Track Mode + PTM Race 1 (performance TC on (same level as Sport)/ ESC off)
- Zmode or Track Mode + PTM Race 2 (performance TC on (barely)/ ESC off)
- TC/ESC off completely using long single press

If the surface is good and the tires are warm you may gain performance in Competitive Driving mode driving through a small bit of wheel spin.

PTM Sport's TC is better (less harsh intervention) than the standard TC, but it will still intervene and possibly bog acceleration in an unwanted way. But it might also salvage a run that would otherwise blow the tires off, so in some runs you might want that safety net vs outright power deployment.

yell03

Did some initial shakedown runs today using my Dragy for accuracy (not the in-car PDM which always reads overly optimistic)

It was 54 degrees out
Tire Pressures were up to 36-37lbs (this morning at cold start in 30 degree weather they were at 30-31lbs)

I set it to Z-mode and PTM to Sport ECS ON.

I wasn't expecting great results.

The 0-60s were:
My one valid run was a 3.51 (with rollout)
My other close to valid run was a 1.3% decline and that was a 3.26 (with rollout)
My best 60' was a 2.02.

These were with a 4000rpm launch at 10% slip.
I definitely need to lower the tire pressures down a bit, but I always run my car at whatever they are at after cold pressures are at 30lbs in the morning.

For comparison...

My Porsche runs 0-60 in 2.64 and does a 1.61 60' time on unprepped streets in 37 degree weather.
My C8 Z51 ran 0-60 in 3.19 in 54 degree weather and did a 1.82 60' time in 59 degree weather.

I think I need to wait for warmer 70 degree weather to get some traction and a harder launch with the C8Z, but I don't really want to beat on the car that much.

turbotuner20v

Could you post the Dragy G's vs speed graph? Any runs in Competition Mode? Do you have PDR?

If you really wanted to get scientific you could record in PDR to note the TC intervention moments and compare that to the g-force dips in your Dragy acceleration graph and try to find a setting that minimized both TC intervention and G force dips

yell03

Give me a bit, I will post them.
Quite a difference in Gs between the Porsche and the C8Z