Jstyle007

I’ve been a long time track junkie and I’m looking to make my c8 track worthy. I’m a firm believer that a seat and harness takes a second off of your lap

That being said, I’m kinda shocked at the amount of people that run harness bars instead of roll bars…. I always thought that running a harness where your body, head and neck are in a fixed position could potentially be a fatal situation if the car rolls over. Is there something about vettes where they are much better reinforced and this isn’t a problem or what’s the deal?

Just trying to understand.

davidfarmer

your logic us sound, but roll-overs are extremely rare in track-days. I've only seen 1 or 2 in 30 years of driving/instructing/racing . Nothing is going to make driving 170mph around a race track "safe", it's a choice to make driving more pleasant. I consider harness bars a comfort feature, not a safety feature.

bynummustang

I will be putting one in this winter to hold me in place while driving. I agree that a harness bar isn't safety, it is more "retention while driving"

Jstyle007

Again I totally understand it’s about comfort and holding you in the seat but if you roll the car with just a harness bar the roof will crumple and your head and neck are held in place and you will likely die. I was just at VIR earlier this year and someone dropped fluid and my friend rolled her Clubsport. She is a de4 driver but a very very non aggressive de4 driver.

I just feel like for a couple hundred more the juice is worth the squeeze. Or lack of squeeze when the car is no longer shiny side up.

ariZona06

First off, is your C8 going to be a track only car or a double-duty hobby machine? Roll bars are a great safety addition BUT in a street driven vehicle with no helmet being worn a minor accident can turn into a life altering catastrophe if your skull makes contact with it. Track safety items can be a slippery slope. Containment seat? Air bag delete? Hans device? Fire suit? Fire suppression? The gm factory stuff is pretty good for hobbyist HPDE. Get above that level and you really need a well coordinated comprehensive safety ensemble. Keep in mind if you get a harness bar and belts those belts might not be DOT approved. Try explaining that to the other drivers insurance company in the event of an injury accident.

Jstyle007

Very fair. Mine is going to be nearly 100% track I guess I didn’t think about the non dedicated side.

davidfarmer

this wasn't an issue in the Steel framed corvettes. The OEM hoops were nearly as strong as 1.75" cage tubing. If I had a C8 and tracked it, I might indeed add a roll-over hoop, it would be pretty easy to do in the engine bay (behind the glass).

You aren't getting a competition style roll bar for a "couple hundred more" dollars

mfain

I haven't yet made the commitment to cut my C8Z up and add a roll cage to make it a track-only car, but I do run track events and I use a Paragon harness bar to secure the shoulder harness - better than the single shoulder strap. In a roll-over I am more concerned about the strength of the A-pillar than the B-pillar, and the only way to fix that is a full cage - not a roll bar. Attaching a quality steel roll cage to an aluminum chassis is not for the faint of heart. If you look at the cut-aways of the C6, C7, and C8 below, it appears the C8 may have a little beefier B-pillar construction. Still not roll cage quality, but strong enough that I am not overly concerned about it collapsing other than a hard impact against something solid on the roof rather than a simple road course roll-over. I have been considering trying to fabricate a "back brace" to the factory aluminum hoop, similar to the way the C8R braces the roll bar hoop portion of the cage. That would add a lot of strength but would be a little complicated ($$$) and would require a different shaped rear glass.


C6 Z06

C7

C8

fatbillybob

I would not place a lot of stock in 4pt bolt in 1/2 cages. 99% of those bolt-in to existing anchors never designed for that purpose. A 4pt rollover 1/2 cage supported and welded with proper pintle boxed in to the unibody or frame is a very different animal hence Farmer's statement of comfort statement. There is nothing harder to build than a "safe"dual use car.

bynummustang

No one has asked for my reasoning and because its the internet I'll give it freely.

I have a '07 z51. It is street and HPDE use (honestly driven to/on/from the track more miles than street). The stock seat is trash on track, I think everyone can agree there My left hinge on the factor seat broke at VIR in T5a. It scared the poop out of me and had the catch the car. I have the plan to drive the car with stock seat while doing street driving and toss the bucket in when going to the track. Harness bar will help hold me in place for what I'm doing. I have tons of work to do in my development path as a driver before I really care too much about speed/times. I look at lap times to measure progress (I love data). I would love for this to become a full blown track car (cage, fire supression, spherical bushings, gutted, etc) but that isn't a realistic opportunity. I also don't have a truck/trailer and don't want the hassle of renting both any time I want to drive to the track. It is much cheaper to buy a track prepped C5 than prep my C6.

Jstyle007

Well you can... Here is a harness bar for 1k:
https://competitionmotorsport.com/pr...hoC6BcQAvD_BwE

Here is a full SCCA legal roll bar for 1500.
https://www.rpmrollbar.com/products/...-coupe-rollbar

Yes you can go cheaper or more expensive on both.

Jfryjfry

That’s pretty interesting how inexpensive the 4-pt bar is.

I wonder what it attaches to? I believe there are some rollbars for the c6z at least (by rpm?) that are nhra certified but don’t actually attach to the frame.

also, if you get the roll bar pictured, you’d still need the harness bar because the roll bar doesn’t have anything low enough to use as a proper mount for the shoulder straps of a harness.

Jstyle007

It actually has an option to add the harness bar.

mfain

You don't just bolt a cage to an aluminum frame, and NASA and SCCA require very specific mounting provisions. Here is a quote from Trackspec regarding their cage for a C6Z Corvette, which had a hydroformed aluminum frame. The C8 will probably be even more complicated to develop a properly engineered solution due to its construction. The trick will be design of adequate mounting plates that have sufficient contact area and are fastened in a way that does not compromise the structural integrity of the factory frame structure. You don't just start drilling holes in a fabricated frame rail or other structural component without an analysis of the "unintended consequences".

From Trackspec: "ALUMINUM FRAME C6 Z06 Corvette Cage Kit The most comprehensive and installer friendly kit on the market. This cage kit is a collaboration of SPEC Corvette series drivers, engineers, and fabricators to produce not only the best fitting kit on the market, but one that can be easily installed as a DIY kit. The aluminum frame of the C6 Z06 Corvette makes caging these cars extremely expensive and labor intensive. We have seen many different shops cage these cars with most being questionable mounting methods at best. At Trackspec, we took an engineering and driver point of view and combined it with the latest in 3D scanning technology. By scanning the frame, we were able to engineer THE BEST SOLUTION ON THE MARKET. Our billet aluminum landing plates have the exact contours of the C6 Z frame and allow for a 100% contact patch for bonding and thru bolting to the frame as per NASA and SCCA specs. The billet plates then create a flat surface for you to land the cage on. This is an industry first and patent pending process."

blckss

I don't understand why people remark about a roll cage being lethal in a street car. I mean, I do understand what you are saying - but you can "pad" the bar in areas of concern. It's not like the hard plastic panels, which are mounted to sheetmetal, are going to be very forgiving on your noggin'. No, I do understand if the side curtain airbags are now ineffective because of that. BUT - you can wrap and pad/protect the bar above and beside your head.

vettehardt

All of the plastic pieces inside the car have been tested and developed with the passengers safety in mind. They are designed to give to soften the deceleration of the body part that hits it. They have been crash tested and passed DOT/NHSTA standards.

Rollbars add a solid surface to hit. A little bit of padding will help very little in a crash.

mfain

Agree. Have you ever ridden in a 1984 C4 Corvette with Z-51 suspension? It was known for bashing the driver's head against the roof frame just above the side window. I think I still have lumps on my head from those days.

davidfarmer

boys that's a nice piece of ballast (in an already 3700lb car) that doubles as a steel head-rest. All of this is false sense of security.

NSFW

If a car lands on its roof hard enough to crush the B-pillar, the occupants aren't going to magically bend their way to safety. That line of thinking might be intuitive but it doesn't seem realistic. The same forces that drove the chassis into the ground hard enough to crush the B-pillars are driving the occupants' bodies into the ground as well.

Citation

I have the dubious credentials of going upside down in a C7 at WGI. It was a slow speed roll over the car did not fly and “land” on its roof. One of the A pillars collapsed but the halo bar B pillar structure did not move one millimeter. I have a lot of faith in the B pillar structure at least on the C7. We repaired the car and I drive it today five years later. I had stock touring seats and belts. No injuries including my instructor passenger.