Recap of my first weekend out in the new TTA Z06 (Panoz comparison too)

[Cobra4B]

A little history about me. I've been running HPDEs since 2002 and started doing TT in 2009. I started tracking my old 2001 Z06. In fall 2007 my father purchased a Panoz GTRA from Whirewheel which we prepared around TTS/ST2 rules. I have been driving that car until this past weekend.

For those interested in the build there is a seperate thread in this forum. Basically I scooped up a higher mileage (119,xxx) 2001 Z06 a couple of months ago and set about turning it into a TTA car with intentions to cage it this winter to make it PTA/ST2 legal. I ran VIR full course with Mazdadrivers this past weekend to shakedown the car.

Basically I turned this...




Into this...





The car weighed in at 2840 lbs with a 1/2 tank of fuel and heavier street wheels/tires on the car. It made 361 rwhp after being dynotuned at Virginia Speed. I am running front 2001 OEM Z06 wheels all around. They are 17x9.5 forged aluminum units manufactured by Alcoa. A little Corvette trivia... the 2002-2004 Z06 wheels are spuncast and manufactured by Speedline. They are 1lb lighter per wheel than the forged Alcoas, but are not as strong. For tires I'm running a 275/40/17 Hoosier R6 all around.

The car is running slight toe-out in the front with approximately 2.5 degrees of negative camber and slight toe-in and around 1.5 degrees of negative camber in the rear. The cross-weights came in at 50.3% with 215lbs of ballast in the driver's seat without any extra adjustment.

My graphics came in a bit late, but they showed up Thursday the 26th so I was able to get the car finished up that evening and ready to go to the track on Friday. All loaded up and ready to roll...


Got to VIR Friday evening a little after 6pm without issue. Got the car teched and unloaded. Here's some paddock area shots. My buddy Ryan was there to test his new aero on his ST2 C5. It's nice to have friends with 28' air conditioned trailers




Gridded up for Saturday morning's first session. They had to cancel the instructor's session due to a fog delay. We had heavy fog both mornings. It caused more of a delay Saturday than it did Sunday.



Looks rainy, but it wasn't... just the lingering fog that went away shortly after these pics were taken.






The first session was interesting. My last time on track was in July with the GRM UTCC in my father's Panoz... we had nothing but issues culminating in a snapped crankshaft and ruined motor. This previous experience plus having a "brand new" car on track lead to lots of gauge watching and getting a feel for the car. The car performed flawlessly from a mechanical standpoint; everything worked properly. The oil temp wouldn't get out of the low 230s in the cooler morning temps. The high volume oil pump pushing 10w40 Amosil kept the oil pressure gauge pegged at 80, but eventually it came into the high 70s.

Once I was convinced the motor wasn't going to blow up, and that the clutch, transmission, and brakes were performing properly on track, I began to speed up and get a feel for the car. Compared to the Panoz I loved the firmer steering feel of the C5. The Panoz is overboosted and has a dead spot in the middle. It works, but you have to get used to it. In addition to the steering the overall ergonomics were wonderful. Being 6'4" 230 normally I have a hard time fitting in a car correctly. For this car I had a custom Ultrashield made and fitted everything exactly for me (no car sharing compromises). For the first time in my life everything was in the right position. This allowed me to really focus on driving vs. dealing with poor body positioning.

The car is very very quick. 361 rwhp in a 2800lb car will do that. I could instantly feel the benefit of running the super light 17x9.5 Z06 wheel/275 tire combination. The car would pull like no other stockish C5 Corvette I've driven. The car is probably quicker than my old yellow 2001 Z06 that was cam'd making 436 rwhp.

That quickness was offset by a lack of traction. The 275s and lack of any aero required a careful application of the throttle everywhere on track. There was a good bit of drifting and sliding in the first session. Other TTA drivers had warned me that driving on 275s was a bit like ice skating at times and would take some time to get the feel of the car. The other place the car felt entirely deficient vs. the Panoz was the uphill esses. The Panoz is 2700lbs and has basic aero. As a result I can go pretty much flat out through the esses and have no issues with the hump on the first rt had turn. With the Corvette that hump wanted to throw the back end of the car out to the left. After a few laps I got the feel for it and adjusted my line to take that section on a more direct line to keep the rear end planted.

Brakes felt fine, but drastically different than the manual brakes in the Panoz with PFC97 endurance racing pads and PFC floating rotors. On the Z06 I'm running DBA 2-piece front rotors up front and stock in the rear. Pads are Carbotech XP12s up front and XP10s rear with Stoptech SS lines and DRM cooling ducts with ECS spindle ducts. The power brakes felt numb vs. the manual ones, but they stopped the car fine. The equipment performed flawlessly and the brakes worked without issue.

A few shots from later in the day when the sun was out.







The 2nd session on Saturday was much improved over the first. The track had some heat on it and the car was much more planted around course. The "ice skating" wasn't nearly as bad as I thought it would be based on the first session. The car puts the power down pretty good on the 275/17s. I couldn't keep up with Ryan's ST2 car (He's on 315 A6s w/ full aero), but I found that I was very evenly matched with the driver in the Orange GT3 RS Porsche. We had a great time playing lead/follow and pushing each other.

Traqmate showed a max speed of 152 on the back straight. Based on how the car accelerates I believe the car would pull more with a proper run out of Oak Tree and redline shifts. My best lap time was only a 2:11.06 in traffic with a TBL of 2:10.xx. I was hoping for better seeing as I have run high 2:06s in the Panoz and generally run 2:08-2:09s in traffic. The Z06 felt much quicker, but the lap times weren't showing it.

A comparison of the Panoz data to Z06 data showed the Panoz gained it's ground in turn 1 through turn 5, the uphill esses, and the sweeping left-hander after the esses. My feeling is that it all comes down to the car's aero and power delivery. I can go flat out coming out of 2 and through 3 in the Panoz whereas in the Corvette I am peddling the car to maintain traction. Same thing for the uphill esses and the left turn after the esses. With the Panoz I am flat out through the esses and can take that left much faster. In the Z06 I have to hit the brakes before entering the esses, then get farther left to straighten up the line over the "hump". At the top on that left sweeper the off-camber transition throws the rear end to the right much more than in the Panoz.

On the straights the Z06 makes up major ground. It accelerates much more quickly and reaches 152 vs. the Panoz's 138. I would like to try some 275/35/18 tires vs. the 275/40/17s to see if they allow more power application coming out of turns. Also, some sort of rear vertical plane (like Nascar used to be) would probably help. If I continue to run R6s I can spend 3 more points and may try some rear aero.

A few other shots of other cars...





All done... successful weekend overall. She didn't break or make me touch my tools other than rotating the tires on Saturday evening and checking over the brake pads for taper etc. She does burn some oil like most 2001 LS6s, but that's fine... I don't mind adding 2 quarts of oil in the weekend if the 119k motor keeps on making 360 rwhp.



I took some good video as well, but it turns out I need to find a DV cable for my archaic video camera. BestBuy doesn't stock them anymore so I may have to order one.

-Brian

Videos

Passing Mike's Mustang into the esses
http://www.youtube.com/watch?v=6bboMgevvcI

3rd session Saturday
http://www.youtube.com/watch?v=JNJUaWt3YLw

2nd session Sunday
http://www.youtube.com/watch?v=ZDC6AEaa8gc

[boothkc]

Cool car...I was looking for the bottle of Hai Karate, Foster Grants, and big gold chains that our local Vette guys use as their uniform!!!!

I haven't seen a street Vette yet that will keep up with a GTS, but there are some killer tube frame Trans Am Vettes in our area that are awsome ($200k too).

Looks like fun. Tires look like the first weakness. Nice car.

Awsome track too.

cheers,
Kevin
GTS, GTRA
Cirrus SR22

[NZGTRA17]

Brian, great to hear the Vette performed well for you. Did you try playing around with the front to rear roll stiffness in the car to help with traction? I have found this to be an invaluable traction tuning aid in all my race cars. I normally let off some rear bar if rear traction out of corners is an issue and if required also dial in some more front bar.

You didnt mention what torque the Vette produced. I am interested to hear what this figure was as a 20 RWHP difference between the Panoz and the Vette is not much and should not have given an impression of "way more power". I suspect the torque difference is creating that impression.

I will stick my neck out here and risk the wrath of other Panoz owners............. I have no idea what the CD of the Panoz is but I suspect that it is quite a "dirty" car. I have found that as I have added Hp to my car the mph increase on straights has not been as much as expected. Given you have lower entry speeds onto the straights in the Vette and the power difference is only 20 RWHP, the mph difference between the Vette and Panoz is quite marked.

I am looking forward to fitting the 369 engine to my car to further test this "dirty" theory. I consider that the current air dam setup on the cars is very rudimentary and the air flow around the front end and guards is not helping our cause. I suspect that some aero work around the front of the Panoz would help a lot in this respect (speed on long straights).

Kel.

[panozracing]

The only way to find out is keep making changes and see how it reacts. Thats my new mantra at the track. Even if the car feels great right off the trailer it could be better.

Springs, tire pressure, sway bar, etc. need to be adjusted.

Under suggestion from my support team after reviewing the temps/pressures from my last event I am going to try this weekend tire pressures with my hankooks cold around 16psi with a hot target of 24-26psi. Seems low but you gotta do what the data says or at least try it.

This road racing gig is a lot of work :-)

Lets all pool our money and rent a wind tunnel.....DIRTY AERO!

[Cobra4B]

Originally Posted by NZGTRA17

Brian, great to hear the Vette performed well for you. Did you try playing around with the front to rear roll stiffness in the car to help with traction? I have found this to be an invaluable traction tuning aid in all my race cars. I normally let off some rear bar if rear traction out of corners is an issue and if required also dial in some more front bar.

You didnt mention what torque the Vette produced. I am interested to hear what this figure was as a 20 RWHP difference between the Panoz and the Vette is not much and should not have given an impression of "way more power". I suspect the torque difference is creating that impression.

I will stick my neck out here and risk the wrath of other Panoz owners............. I have no idea what the CD of the Panoz is but I suspect that it is quite a "dirty" car. I have found that as I have added Hp to my car the mph increase on straights has not been as much as expected. Given you have lower entry speeds onto the straights in the Vette and the power difference is only 20 RWHP, the mph difference between the Vette and Panoz is quite marked.

I am looking forward to fitting the 369 engine to my car to further test this "dirty" theory. I consider that the current air dam setup on the cars is very rudimentary and the air flow around the front end and guards is not helping our cause. I suspect that some aero work around the front of the Panoz would help a lot in this respect (speed on long straights).

Kel.

Thanks Kel... the front T1 bar is non-adjustable and the rear bar was set on full soft. The main issue is that I'm running relatively small tires for the size/power of the car. I may try some 275/35/18s on a set of 18x10.5 rear Z06 wheels all around. From what I hear this is a more stable setup due to a bit less sidewall and wider contact patch. However, running a 275/40/17 was the logical choice since we have plenty of tires in that size.

All my Panoz data was from when the car had 315 rwhp.... I never got any data from when we had it re-tuned making 341.... it felt much better, but it kept throwing belts and snapped the crank. The C5 is very very slippery when to comes to aero especially vs. the Panoz. Also.... the Z06 had similar exit speeds though Oak Tree and Hog's Pen which are the respective turns before the back and front straights. The Panoz would corner faster where aero really made a difference.

Can't do much to a TTA car.... so like I said I may try the 18" wheel setup but still run the 275s per the rules/setup and try a rear vertical "spoiler"/plane.

Originally Posted by panozracing

The only way to find out is keep making changes and see how it reacts. Thats my new mantra at the track. Even if the car feels great right off the trailer it could be better.

Springs, tire pressure, sway bar, etc. need to be adjusted.

Under suggestion from my support team after reviewing the temps/pressures from my last event I am going to try this weekend tire pressures with my hankooks cold around 16psi with a hot target of 24-26psi. Seems low but you gotta do what the data says or at least try it.

This road racing gig is a lot of work :-)

Lets all pool our money and rent a wind tunnel.....DIRTY AERO!

I agree... need to tweak a few things and just get more seat time.

[Cobra4B]

Guys do you see the original post? All I see is Kel and Brian G's responses and then mine, but no OP????

[cvbowers]

Brian, your post is not visible here as well. Somehow Kel is seeing it in order to respond.

[Cobrafang]

Originally Posted by Cobra4B

Guys do you see the original post? All I see is Kel and Brian G's responses and then mine, but no OP????

Same here. I don't see your orignial recap.

td

[Cobra4B]

Originally Posted by boothkc

Cool car...I was looking for the bottle of Hai Karate, Foster Grants, and big gold chains that our local Vette guys use as their uniform!!!!

I haven't seen a street Vette yet that will keep up with a GTS, but there are some killer tube frame Trans Am Vettes in our area that are awsome ($200k too).

Looks like fun. Tires look like the first weakness. Nice car.

Awsome track too.

cheers,
Kevin
GTS, GTRA
Cirrus SR22

Hmmm.... around here a C6Z06 with stickey tires would have no issues w/ a GTS... it'd be a good match.

I'm running the small tires because of TTA rules. It allows me to run at 8.3 lbs/horse vs. 8.7 lbs/horse.

Originally Posted by cvbowers

Brian, your post is not visible here as well. Somehow Kel is seeing it in order to respond.

Originally Posted by Cobrafang

Same here. I don't see your orignial recap.

td

They're back.... oddly when I first replied the only posts I saw were Kel's and Brian G's.... nothing from Boothkc.

[NZGTRA17]

Brian, yes can still see all your original post at this end. The site has been playing up a bit here though and has been hard to access.

Are you able to run a slide adjustable front bar in the car? If so this is a great tuning tool and easy to make changes quickly at the track. I would even try completely disconnecting the rear bar Brian. May not be the ticket for your car but I still run the Panoz without a rear bar and we have progressively reduced track times by around 8 seconds per lap on a track that is just over a minute per lap.

Agree on running wider rims for the 275's Brian. I have found the optimum size on the 9's is a 255. A 275 is to "baggy" for my liking and seems to fit best on a 10" rim. I would note that I have also run 275/50/15 R6 Hoosiers on 10" rims on a live rear axle car with 460 RWHP Brian. We managed to tune the suspension so that it would put this power down very well. If the tyres went away (i.e. to many cycles) it got real exciting pretty damn fast, but otherwise tons of grip on power down with freash tyres. This was a light car as well at around 2700lbs and a not so great C of G. We also tried A6's on this car and they were quite OK wear wise. Came on quicker than the R6's but after a few cycles were quite similar.

Yes, I think the Vette would be a lot slipperyier as well. I think not having inner gaurds on the Panoz does not help us at all. The way the bonnet on the cars bulges tells us there is a considerable pressure area in the engine bay. I am seriously considering canting the radiator forward and ducting the cooling air out and up through the bonnet of the car. I think Panoz did this with the GTLM car. A couple of the cars that I run enduro against have done this mod (Ford GT is one). Reduces drag and adds downforce to the front. There are a few other aero tricks I want to try as well but as always, time and $$ are at a premium (so sorry Brian G, no contribution to the windtunnel fund from this Kiwi!!).

Kel.

[PanozDuke]

Brian,
Nice to see all that work and prior experience pay off so well. Beautiful car and awesome project.

Mike

[Cobra4B]

Forum posts are screwed up again....

Anyway... Kel I'm not familiar with a slide adjustable swaybar? The bars I am running are GM's T1 racing bars which are pretty much the go-to setup with these cars.

I think I will try the 275/18s with the bar on full-soft, then try the bar in the middle setting if needed.

The TTA lap record holder at VIR runs the 275/35/18s and doesn't care for the 17s all around.... specifically that the car feels less planted which is precisely what I was experienceing. He runs the rear bar on full soft and found the car to be too tail happy with it in the middle setting.

Most ST2 racers who run T1 bars run it in the middle setting, but they're running a 315 tire most of the time.

[Panoz26]

There is a wind tunnel in Charlotte (Mooresville) that is inexpensive

http://www.a2wt.com/

I have talked to these guys and am very interested in doing this -- we can get group rates on full day or more days....

Devin

[NZGTRA17]

Originally Posted by Panoz26

There is a wind tunnel in Charlotte (Mooresville) that is inexpensive

http://www.a2wt.com/

I have talked to these guys and am very interested in doing this -- we can get group rates on full day or more days....

Devin

Would be a very interesting exercise Devin. You would need to do a lot of prep beforehand though as you would need to make up all pieces that you wished to test.

I have been collecting all the E articles I can find on aero's and have concluded from what I have read that the best opportunities for us around dealing with airflow around the engine (underhood) and turning the underside into a true flat bottom with diffuser. Diffuser theory makes interesting reading as the actual physics are the opposite of what you would expect from P1V1T1 = P2V2T2. I.e. encouraging airflow to accelerate by using half of a divergent duct.

Perhaps we sould start an Aero dedicated thread.

Kel.

[NZGTRA17]

Originally Posted by Cobra4B

Forum posts are screwed up again....

Anyway... Kel I'm not familiar with a slide adjustable swaybar? The bars I am running are GM's T1 racing bars which are pretty much the go-to setup with these cars.

I think I will try the 275/18s with the bar on full-soft, then try the bar in the middle setting if needed.

The TTA lap record holder at VIR runs the 275/35/18s and doesn't care for the 17s all around.... specifically that the car feels less planted which is precisely what I was experienceing. He runs the rear bar on full soft and found the car to be too tail happy with it in the middle setting.

Most ST2 racers who run T1 bars run it in the middle setting, but they're running a 315 tire most of the time.

The slode adjustable bars that I was using were made by K-Mac in Australia. They use a slide coupling on each side of the bar for the drop links. The slide has a friction lock set up whereby you undo a nut, slide the fitting/droplink along the bar to your desired setting and then tighten. Adjustment can be done very quickly. I used this to tune all the time at the track. Way more utility than the likes of the bar on the front of the Panoz.

You may be able to convert your bars, a mod worth looking at if legal. Other option is in car blade adjustable bars. These are way more expensive though.

Kel.