I've just acquired a '19 7MT Z06 (non-Z07) with comp seats. Previous car was an F80 and I run in the advanced group; I do about 10-12 events a year. It's the middle of winter so obviously haven't had a chance to track the new car yet. But just thinking ahead - what are basic mods recommended for track (if any)? (Not looking for more power or aero for now).

Brake fluid - I like SRF
Any recommendations on pads?

200TW tires - I like ECFs, looks like they're not available for 20" but available in 18"
I've read that some recommend going down to 18" wheels for cheaper/more tire options and less rotating mass, and can fit 315s up front and 345 in the rear.

Any recommendations on a harness bar and harnesses? Any 5/6-points that work well with the comp seats?
Found this thread on alignment which I assume is a good baseline: https://www.corvetteforum.com/forums...t-specs-2.html
Seems like overheating isn't an issue for late model 7MT in most cases but should I do anything for more cooling just in case?

Does anything need to be done with the suspension? Spring rates, sway bars, monoball control arm bushings etc. I have read some threads about people upgrading to Z07 suspension (FE7) springs and dampers and LG sway bars.
Stainless steel brake lines recommended?

Thanks in advance.

 

I drive and track my 2015 Z06 with the M7.

I have the Essex AP Racing Calipers and Rotors front and rear on my car. I had the CCM brake option and it became too costly to replace Ceramic Rotors at big dollars per rotor. The AP front kit paid for itself in two seasons while the AP rear kit paid for itself the day I installed it.

I am somewhat fond of the Ferodo Brake Pads. I liked the 1.1 Compound and am now running the 3.12 compound. If your car has the iron brakes you should look at some of the available disc replacements from Girodisc and AP Racing. Check with KNS brakes to see what they recommend.

As for brake fluid, I have been using AP racings R4 fluid which has a dry boiling point of 644 degrees. I don't worry about the wet boiling point (SRFs claim to fame). I used to use Ferodo's Racing Brake Fluid which has a dry boiling point of 626 degrees. I never had a problem with it but Essex ran short of it one time and I went with the AP and stayed with it.

I have 18 inch wheels and have run Hoosier R7 315s on 18x11 front wheels and 345s on 18x13 wheels. The 18x13 wheels will touch the rear of the upper control arm when the suspension is at full droop so you can't tighten lug nuts until the suspension is depressed some. The touching can be reduced by running a small spacer. I didn't have any issues with it when running that size rear wheel. I now run 18x11 in front with 18x12 in the rear. I run used Pirelli Slicks that are 305/660/18 in front and 325/680/18 in the rear. I have gotten close to 40 heat cycles on a set of the Pirellis though they tend to be a little slippery once they get over 20 heat cycles.

There are two harness bars that you can choose from. They will both work with the stock Competition seat but not the GT seat. These are the BK Auto C7 bar and the lap belt mounts (https://www.bkauto.com/category_s/332.htm ) and the Shark Bar ( https://vetteworksonline.com/catalog...roducts_id=199). The Shark Bar is mounted low and close to the vertical panel behind the seat. It meets the harness manufacturers' mounting recommendations for no more than a 20-degree down angle with the shoulder belts. However, the comp seat pass-throughs are placed about 4 inches lower than those in a regular race seat which complicates usage. If you are approaching 6 ft in height you will need to mock up the bar and belt paths to see where they fall when you are sitting in the seat. The following picture shows what happens when somebody is over 6+ ft tall and attempts to use the shoulder belts. In between the belt's mounting point on the harness bar and the contact point with this person's shoulder, the seat pass-through interferes with the belt's path and bends the belt down. Thus the seat becomes part of the harness and may fail when a hard impact occurs. If you have this situation you need to go with a race seat or continue to use the stock 3 point belts while making sure you use the Corvette's Belt Cinch feature.


The BK bar has two cross bars with one mounted low and the other higher. The low bar is to be used if you have a comp seat while the high bar can be used with a race seat. If you think you might eventually move to race seats this would be the best bar to purchase although the mounting points leave something to be desired from a looks standpoint.








As for harnesses I use the Schroth Profi II ASM harness. The ASM harness resists submarining under the lap belt by making a 4-point harness behave like a 3-point during the initial phase of an impact which lets the upper portion of the body pivot over the lap belt before the second shoulder harness restricts forward motion. The harness will also let you add a 2-point sub belt if you want to have a sub belt for organizations that won't let you run the ASM. The BK Lap Belt mounts should be used with the BK Bar or the Shark Bar. You don't want to use mounts that mount the belts at the rear of the seat. You can install the sub belt to the lap belt mounts and use it in a Formula configuration where the occupant sits on the belts or have an upholsterer add a sleeve through the seat bottom (at a crease) and fasten the sub belt to a cross bar that is part of the seat track.

As for alignment, I run -2.2 to -2.3 camber, +7.4 caster and 0.0 toe in the front. I run -1.9 camber, 0.0 caster, 0.0 toe and 0.0 thrust angle in the rear.

I usually run my car at VIR and have had it on track when temps were in the low 90s with no overheating issues. Typical temps when I am running are in the low 70s to mid 80s and I have no problems with those temps.

I have had problems with charge air cooling due to too much air in the intercooler. It is hard to bleed the air out even with a vacuum filler and it can take several hours to get the air out. You want no more air in the top of the reservoir than two bubbles the size of US Quarters. If it isn't filled properly you can get misfires on Cylinders 7 and 8 that will cause a reduction in power at WOT over 5K rpm.

Bill

 

If you’re an advanced driver I’d skip the ECFs and go for something with more grip. The ECFs do last and the grip falls off predictably, but they aren’t a fast tire by any means.

I’m currently running ECFs at intermediate/advanced pace (newish to trackdays with sim racing and motorcycle trackday experience) and am already itching for them to wear out to run something stickier. Trying Supercar 3R for my next set.

Nankang AR1 is a popular choice in the 100tw category that is supposed to last (for a track tire). Supercar 3 is another alternative in the 200tw category with sizes that’ll work on 19”s, or the new Nankang CRS. Just depends if you are looking for a do-it-all or dedicated track day tire.

 

@Bill Dearborn

Thank you very much for the detailed response - very kind. I'm 5'11 so I think I will run the much sleeker Sharkbar with the ASMs and a lap belt.

I am curious how much the gearing shortens when going down to 18" front and back. On some napkin math, where 4th gear redline on M7 is about 146mph, it would decrease to ~139mph.

Does your car have the Z07 package?

As someone without the Z07 package, it seems that suspension upgrade routes are generally either:
1. FE7 springs, bushings, shocks + DSC controller
2. DSC package with controller and Tractive shocks

And in terms of sway bars, the LG motorsport bars or Hotchkiss

I am leaning towards getting the FE7 suspension parts based on everything I read; want to stay within whatever OEM had set up in their testing but also the improved damping changes from the DSC controller that has received glowing reviews on this forum. But let me know if I'm missing anything here on suspension.

@KawiZX10r

I am optimizing for cost and seat time for now, not pace. ECFs have lasted longer than other tires I've tried so will run with them this season and consider something faster next season.

 

Brake fluid and pads at minimum. I ran a harness bar/Hans/6 pt to prioritize safety but after seeing other C7’s damage after a rollover there is no way I would run that setup again in a Corvette since they don’t have rollover protection standards like a coupe. Do it right with a cage or run the 3pt IMO.



http://www.youtube.com/watch?si=3Yyi4QZVudmTTmhC&v=wOL2inpR0GE& feature=youtu.be

 

Tire diameter stays close enough to stock there is no real difference. The Pirelli 660 mm diameter tires (25.98425) are close to the stock front PSS ZP 25.8 inch diameter and the rear 680 mm diameter tires (26.77165 ) are close to the stock rear PSS ZP 26.6 inch diameter.

My 2015 Z06 does have the Z07 package and I purchased the GM upgraded calibration settings to bring the suspension up to 2019 levels.

With the LT4 running just short of the rev limiter the car hits 152 mph in 4th gear and 123 mph in 3rd gear.

As for wearing harnesses Vs the 3 point belts. There are a lot of myths about roll overs and the first one is how often they happen. The occurrence is very rare. I have been participating in HPDEs since 1992 with thousands of laps and many days at the track. I have only been at 3 HPDEs in 31 years where a car has rolled over. Second, the typical rollover injury and some films demonstrate this is a head injury due to the head being tossed sideways through the window and impacting the ground as the car rolls. Third, most Corvettes that roll without a cage have damage like this:




I witnessed this car rollover while my student was following it into T6 at the Glen. We were about 100 ft behind it when it climbed the tire wall and then flipped onto its roof, dropping at least 4 ft straight from the tire wall onto the roof. The A pillars are the parts that collapse but even on this car only the passenger side A-pillar collapsed. When I took this picture the hatch had just been opened. The owner had the car towed about 300 miles home but I might have been tempted to drive it home when it was dark. The passenger side headlight could have been taped into place and the outside mirrors removed. The car was still drivable as none of the power train or the brakes had been damaged.

I have seen other pictures of C7s with the roof collapsed like the one in the previous post. However, there was a video with one of the pictures and it showed how the tow truck driver dragged the Corvette across the ground upside down so he could flip it onto its wheels. I suspect the dragging across the ground had some factor in the total collapse of the halo panel.

The truth is the odds are better if you have a harness that holds you in the seat from both a driving and a collision standpoint.

Bill

 

Definitely switch over brake fluid. Lots of people use SRF with great results, we use Endless RF650. There is also a newer Redline Oil RL-700 that worked very well in the testing we've done with it.
Pad choice depends on if you'll be swapping before track days or just looking for an all around pad.

18's open up tire choices massively. I'd put harnesses in the car, you can't be 100% focused if you're constantly bracing yourself.

For tire longevity

Front
-2.0 Camber
0 Toe

Rear
-1.5 Camber
1/8" Total Toe In
0 Caster



Our C7 Sway Bars are much stronger and better balanced than factory. I'd definitely get rear tie rods, factory tie rods deflect and are nearly impossible to dial in. Monoball control arm bushings aren't required but they make a massive difference in feel, direction change accuracy and overall predictability.

 

2019 Z06 M7 FE6 (non-Z07) here and ran ~30 track days in 2023. I run SRF in the brakes and clutch with great success. My long time friend and track prep shop owner dialed in my alignment with the following Front: -2.5°, 0 toe, max caster; Rear -2°, fraction of toe (practically zero), 0 caster. Tire wear has been incredibly even and consistent so no inclination to change. Brake pads are kinda like religion; opinions and experience vary dramatically.. Honestly the stock pads worked very well for me on an endurance 200TW (Conti ECF) but the life was abysmal - 10 sessions and they were completely cooked. They are (or were) relatively cheap, though, and rotors will last a loooong time with them. Powerstop Track Day pads were an incredible bang for the buck (I thought) but I found they destroyed rotors quickly, so ended up more costly in the long run. I last ran DBA front rings, Girodisc GP40 (same as CSG C21) front and CSG CE1 rear. They were phenomenal at VIR; 165MPH down the back straight, 158 up the front all day and never faded. But they were $$$. I just went with the Essex AP Racing 9668/9450 kit with Ferodo 1.11 but haven't run the car yet. Tires.. Conti ECF are a great true dual purpose endurance 200TW, but they aren't quick. I put several thousand street miles and 10-12 track days on a set and they still had tread but were heat cycled out. Nankang AR-1 were instantly 2 sec quicker but lasted 3 days at best. Nankang CR-S v2 are essentially as quick as the AR-1 but will last 5-6 days. Going to Pirelli scrubs in '24 now. Zero issues with heat, even in the dead of summer, but the car definitely slows down a bit, but no limp mode, etc... At worst coolant temps will be high 220s and oil in the 260s, trans 200s. I did however do the EOS catless downpipes and X-pipe as 'preventative maintenance' since cat failures tend to be mildly common with heavily tracked cars. I imagine this helps a bit with heat management as well.

 

Very, very helpful - thank you. Really appreciate the alignment settings, I think I will do that - 0 front toe will be good for wear on the street as I won't be trailering the car to the track.

If you don't mind me asking, what fast lap pace do you set on VIR with the ECFs and FE6 suspension? And are you on stock power?

 

I've only been there twice (excuses) but pretty consistent 2:04s with some traffic. I really need to nut up in the upper esses.. Goal for '24 is sub-2s but it's going to take some seat time! CMP is my home track and I've been consistent 1:40.0s on ECF and 1:38s on AR-1, which I'm pretty proud of. The car is stock except the tires, brakes and alignment - stock power, just the cat delete, so maybe another 10ish..? I am planning to do sway bars and a few other things (probably aero) this year but still recovering from the AP brake kits. Also, RE: FE7 upgrades -- the more I look into that it seems the consensus is just save up for coilovers.

 

2:04s on ECFs is quick! My F80 was nowhere close to that. I'm assuming you're on stock rims and not 18"? Wonder if you could gain a second or two with 315s up front and 345s in the rear.

 

Actually, I need to correct myself RE: lap times on ECF. I ran the ECF last Feb on 19" Apex wheels 295/30/19, 325/30/19 and was consistent 2:06s with traffic. I think I had one or two high 2:05s best Sunday morning in the gooood weather. Last Nov I ran the CR-S V2 305/30/19, 325/30/19 and was low 2:04s all day in about 25° warmer weather than Feb. 2:01.94 theoretical, but you know how that goes... I do think now I could replicate the 04s on the ECF in cool weather, though. The ECF seem to work really well in the cold.

The 305/30/19s do rub the fender a bit under heavy compression so I think a 315 will only work on an 18"; may still rub a little. Unfortunately the 345 ECF for the rears have been on perpetual backorder for years and the Nankangs only go up to 325 in 19". That said, if I had to choose between a 315 up front or a 345 in the rear, I would take the front grip all day. I initially got the 19s because I had only planned to run street tires/dual purpose at the time. Now I would suggest going straight to 18s which opens up a lot more options and will help marginally with cost. These cars EAT tires and brake pads.

 

2:02 theoretical is a nice carrot on stick to aim for - you'll definitely get there over time.

It does look like the 345 ECFs are sold out everywhere, but the the 335/30R18 is available as well as a 335/30R18 CR-S, so may run those on the 18x12.5s I'm planning to get. Any other good 200TW options for 18x11 and 18x12.5?

 

It was great chatting with you yesterday!

If you have any videos of your laps at VIR, I'm happy to take a look at give you some pointers where there is time to make up. Uphill esses is the area everyone can improve on, but the risk / reward can be catastrophic. Looking forward to this year's track season!

 

------------------------------------------
I have over 125 sessions in past 3 years on my 2017 M7 Z06, I have LG's sway bars, end kits, monoballs and cooling kit (and more)
...........all this have made my car faster and feel better
Dane, Sergio & LG gang, all know what works for Corvettes

 

What is the cooling kit you added?

Think the first batch of work that I will do will be for baseline quality of life (harnesses and 18" rims for better tire options, cooling), then further down the road for pace/dialing in balance (sways, FE7 springs, monoballs).

 

I'm trying to visualize this. So the sub belt connects to the BK lap belt mounts and runs through the gap between the seat back and seat bottom, and the driver sits on the sub belts?

I want to run 6-points, but want to retain the competition seats and don't want to create holes in them.

 

no. Sub belt mounts to bk lap mounts, you sit on the sub belts. You also mount the lap belts to the same bk mounts. You need to enlarge the holes on the bk lap belt mounts slightly.

if you want to do this method, I have bk lap belt mounts with the holes already modified I can sell to you. Also include the passenger (untouched, never used brand new) mounts.

this method is a big compromise and honestly I’m not 100% sure the result in a hard crash. Probably still better than 4 point. I also ran it before switching to a race seat. It’s not uncomfortable or anything like that.

 

for future reference, at 6’1”, the shark bar worked for both comp seat and a OMP HTE-R 400 on AMT low profile seat mounts for me with no problems. Obviously it depends on torso/leg length, etc.

 

The BK lap belt mounts attach to the same points as the stock seat belts and are next to the seat Vs behind it. The formula mounting shown in the old Schroth Competition Instructions shows the lap belt and sub belt mounts are co-located as shown in this picture:

This is how they look when installed on the BK mounts in my car:

This picture shows the sub belts installed.



This picture shows the sub belt with the lap belts installed to the same mounts.

If you decide to go with mounting the sub belts behind the seat do not mount your lap belts there. They need to be beside the seat so they maintain the proper angle across your pelvis and they shouldn't wrap around the rear of the seat bottom, there has to be a direct path from your lap to the mounting point, the BK lap belt mounts provide a direct path. As for mounting the sub belts behind the seat be aware the space between the seat back and the seat bottom is very small and there is a chance of damaging the sub belts when they run through that space. The advertising picture on the website for the belt mount shows damage to the belt they used for the picture.


I sit on the sub belt, fasten it to the bottom of the cam lock and then fasten my lap belts and get them tight. Then I fasten the shoulder belts move the seat forward and tilt the seat back forward so I am sitting in a more vertical position which will tighten the shoulder belts. The lap and sub belts will remain as tightened before since their mounts move with the seat.

Bill.