Poor-sha

I just posted my latest track data comparison. This time I compared Koan's fastest 2:01.6 lap in his C7 GS to my 1:57.5 in the C7 Z06.

Koan is a very good driver and I learned a few things from looking at his data. There were also a few places where I was faster that wasn't just the HP. In the end, the 4s time difference really came down unsurprisingly to the long straights where the Z06 could stretch it's legs.

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topmover

This was very interesting Sean. Thanks for taking the time to post.

Poor-sha

For fun I posted a second video showing the two laps side by side.

BrunoTheMellow

Crazy how different they sound on pdr...

Bad_AX

Poor-sha, thanks for the detailed analysis. Data like this is amazing for understanding lap times.

Any idea/data on the fuel consumption of the two cars?

PeteC7

Very interesting. One thing that caught my eye was the difference in transmission gearing. I always felt like my GS has too big a gap between 3rd and 4th. My 3rd will go up to 105 and the Z06 looks like it runs out to 125 with both 4th gears running out to around 150ish.

The g-force circles seemed to do a similar dance although with the GS lagging in time.

Poor-sha

That's a really interesting question. I know that my Z06 is pretty consistent at 11 gallons in 30 minutes on track. The PDR data does have a fuel level % channel and total fuel capacity is 18.39 gallons. Looking at the session Koan sent me it looks like the GS went through about 5.3 gallons in 12 laps. That roughly works out to just over 6 gallons in 30 minutes. In other words, the Z06 uses about twice as much fuel on track as the GS.

fatbillybob

Those laps the tires were the same on both cars about equally worn too?

Poor-sha

Honestly I'm not sure but both were scrubs.

fatbillybob

Tires make a huge difference but the Z06 is supposed to be faster and on the videos it is. Personally for a racecar I still want naturally aspirated.

Poor-sha

I know you are a very experienced racer and have been doing this a long time, do you run the Pirelli DH slicks much? My experience with them has been that there is a big area in between those first few laps when they are super grippy and the very end when they are completely worn out. In that big middle area I've found the performance to very consistent and both cars were in that big middle area.

I didn't show the G traces in the video but here are the G-sum and lateral G traces from those laps. Z06 in red, GS in blue. You can clearly see some differences but the peaks are about the same and it's more likely due to driver than tire.

Bad_AX

Your estimates are consistent with anecdotal information I have gotten at track events. When the C7 Z06 was introduced and the heat build up issues began to emerge, this metric got almost zero attention. For a given amount of time, the heat energy from all that fuel has to be dealt with. I would love to know if the G.S. with a Katech 7.0 Liter LT1 would still maintain a significant advantage in fuel consumption and if the 7.0 liter GS would close the performance gap vs. the Z06.

fatbillybob

I only ran pirelli DH slicks on Ferrari challenge car. Ping "Olitho", he has raced the pirelli's in transAm pro racing in the C5 vette and will be able to tell you much more than I could.

bullitt4110

I tracked my stock 17 GS for the first time last weekend, I don’t have PDR nor did I keep track of the number of laps but in 3 20min sessions i went through a tank of gas the first day and probably had 1/8 tank after 3 20min session the second day but the second the longer but more technical track. I’m probably considered an intermediate driver. This was at Thunderhill Raceway in Northern CA. Hope this helps.

bigmackloud

Excellent video. Subscribed.

TCorzett

I was on track in the same group/sessions, driving my stock 18 GS (A8) and was getting 5.8mpg the first day (3-mile track, total of 127 miles, ave 47mph) and 6.2mpg the second (5-mile, total of 106 miles, ave 41mph). The first day I had 36 miles (freeway) on the tank before starting and added 10 gallons after the first three 20 min sessions, then needed another 5 gallons after the fourth session just to do the last one (I pulled-in a tad early because the low fuel light came on).

Suns_PSD

The C7GS with a built NA engine would be the ultimate track Corvette. Just sayin'...

bullitt4110

That’s my plan for mine

NemesisC5

Did the GS have the same Aero package as you?

Brakes?

I'm guessing you'll do a similar video comparing your ZO6 data with your ZR1 data?...Or maybe you have already?

Poor-sha

I'm not sure on the GS, maybe Koan will chime in. I *think* he has the AP Racing brakes also and I would suspect the stage 2 aero but would need him to confirm.

Yeah, I will definitely be comparing the Z06 to the ZR1 as soon as I can get it on track.