THSCC Forums

Graham:
Your harness really helps in autocrossing, as you know. But for the higher speeds and MUCH greater potential for unscheduled decellerations , you have three potential issues:
1.) If you have not installed a similar harness set-up for your instructor, this thread is moot. As far as I remember, few instructors will sit in the right seat while using a safety system that is inferior to your protection.

2.) If your crotch belt isn't installed directly to the floor-pan and directly below the seat on a line that at least approximates an imaginary line down your chest, then it won't perform the intended function. That function is to prevent you from "submarining" under the lap belt in a frontal collision.

The fix for the crotch belt is to go with a 6-point set-up, which you can run out through the back of the seat, between the cushions, and hard-mount them to the bulkhead behind the seats. Easier said than done, I know, but actually performs the desired function.

3.) If I understand you correctly, you said that your harness lap belts are mounted to the seat. Not sure that will fly, either. Probably OK for Autocross, but you'll need to hard-mount them if you ever want to run a Time Trial. When you get to the Rockingham school, check out how the other Corvette drivers handled these issues, as I can imagine that mounting anything through that tub will be an adventure.

At any rate, regardless of your restraint system, you will have an ab-so-lute BLAST at one of our HPDE events. Look forward to seeing you after your first session!!!!

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Brad

Is that not the best feeling?

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02 Focus SVT
STF 9

Thanks Brad. Please note that I am not arguing with anyone here about this setup. I know it is not optimal. But I still think it is better than a factory 3-point system.

#1. I have the identical 5-point setup on the passenger side. So I'm providing an exactly equal system on both sides. Be it arguably good or bad.

#2. I understand that part. It is not mounted through the floor at the angle you are referring to. With the stock seat the only real option would be 6-points and sit on them like the pilot style.

#3. It is hard mounted. The whole system uses the B-pillar bolt locations and the seat floor mount locations. So the belts are no more likely to let go than the factory belt or seat would. The sub strap is mounted to a bar that is mounted to the seat frame.

This is a typical solution in a C4 or C5 Vette. The only other option is to go to a roll bar. A 4-point frame welded or bolted bar with re-enforcements. A 6-point roll bar is so intrusive the car has no value or use on the street.

The harness bar I am using is specifically designed for C4 and C5 Vettes only. The guy who builds them also builds 4-point roll bars that can be welded or bolted (R-D Racing). He uses all the legal spec tubing to pass SCCA. The harness bar is pretty solid, but in no way is advertised as a roll bar or safety device. Just a non intrusive way to use 5-point harnesses on the weekend and not be in the way during the week. One of my fellow Z owners uses this setup and has run Tarheels HPDE. I'll ask him if he passed tech with it or had to use the factory belts.

I'm looking forward to it to Brad
Maybe Nov at the Rock. If not then next year.
I'm already signed up to run at RR in a couple of months while I'm down there visiting my daughter.

Graham

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http://www.greywinds.com

Unless I am not understanding the club's policy correctly your car with the harness bar and 5 point harness should be fine for our HPDE's. It is the time trial portion where you are required to have rollover protection and the harness bar would be unacceptable. In any event I would like to know since I have the exact same setup as you.

Guys,



I've been biting my tongue on this one but I've got to chime in and reiterate what Diane, Brad and Ashraf have said. An improperly installed 5-point has the potential to cause more harm than what good it would serve.

If you want, I could point you to some online testimonies where people relate serious injuries they've recieved due to 5 point harness installations that they knew were incorrect all along. Injuries like broken feet, ankles, ribs and damaged internal organs. This is because the 5th strap coming over the top of the seat padding will not stop you from sliding down under the lap belt.

I went through the 5 vs 6 point dilema last year and researched it pretty thoroughly. 6 point wins IMHO. You don't have to cut your seat and I think the 6 point does a better job of keeping your pelvis fixed in the seat. This will really come into play should you ever include a head and neck restraint into your safety arsenal.

Our tech inspection will not pass an improper 5-point installation. Anchoring shoulder straps to the harness bar is not permitted. Harness bars serve to guide/align the straps only. All straps must be mounted to the car's structure. If you have to drill extra holes to provide mounting points, a 4"x4"x1/8" doubler plate will be required on the exterior of the hole. For HPDE, properly installed harnesses are permitted. Additionally, hard top and T-top cars don't require a roll bar for HPDE. If you haven't yet, please carefully read the Tech Guide available on our Time Trial web page.

The harnesses will be fine for autox, but please give serious consideration to not using them on track unless you have an adequate roll bar. I know you don't plan on flipping your car or hitting a jersey wall, but face it, being on track is very serious business with potentially deadly consequences. It is a commonly practiced rule of thumb to not employ harnesses without a roll bar, despite what tech requirements may say. A stock 3-point harness will let your body move out of the way when necessary, where a harness allows for no movement. With no roll bar to protect you, your harness-fixed head and shoulders would be directly subjected to what ever changes that occur to the vehicle's structure. Also, harnesses are not intended and shouldn't be used for the street whether you have a roll bar or not.

We aren't trying to hurt your feelings and don't want to come across as know-it-alls but rather ... Bud Light commercial segue... We love you man! Honestly, we care what happens to our friends and just want to make sure you have a fun and SAFE time at the track. (Stepping off soap box).

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“I feel safer on a racetrack than I do on Houston's freeways.” - A.J. Foyt

Kevin Butler
Mobetta Autosport Spec E30 #612
2003 C5 Z06 Corvette
AFR Miata, SM2 61, '93 w/200 SC'd RWHP - soon to be resurrected
Waaaay too many other projects....

Please provide some tech to back this up.

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Rich
http://www.v8mongrel.com/

Off the top of my head and the way I understand it is that the release mechanism in the sholder belt lets the top of your body pivot such that you will not slide underneath the lap belt if you are wearing the 3-pt belt correctly. Yet another thing to add to the mix is that IIRC, airbag equipped cars have a "strap" around the stock 3-pt belt that in the event of an accident is meant to snap so that you come forward and meet the airbag and correct impact absorption happens. I'd have to do some more digging around to see which part of the "system" is letting your torso move so that you don't slide under the lap belt.

The Schroth ASM system mimics the the stock 3-pt system and hence why it is DOT approved and the recommended solution because it is designed and the installation is ceritifed for a specific vehicle setup. You can go to their website and read more about it and the Tech Guide has a list of vehicle applications as well.

The thing is, someone besides you will have to look over your car and your installation, Graham. This is not an insult to your mechanical skills but part of the reason why we have tech inspections. We care about your safety. Since you are new to this game, you don't know all the rules. I had to learn the long and hard way since I started with other track groups that aren't as safety conscious, consider yourself lucky you are hearing this now instead of many events later or when it is too late.

With a newer car like a C5, you shouldn't have many other issues on the chassis to deal with correcting (the tech inspection also covers the basic mechanical aspects of the car) but you would be surprised at what you can find on a car when you put it on a lift, especially if you aren't constantly working on it and regularly check over all the various systems - this is yet another reason for the tech inspection. I actually try to go over my car before each event (which is not required per se, but recommended, at least certain basics) if events are several months apart because it gets driven on the street and things do wear (and I have had to order and replace parts the week before an event because I found something marginal that wasn't the last time I looked at it). Ron Spencer or Chuck Hawks (or other classroom instructor) should go over basics of car upkeep/maintenance with the novice students, so you can look forward to hearing this again and in more details at an actual event.

Personally, I would argue that race harnesses not installed right are not a good idea in any circumstance (including autocross) because you never know when you will need them and during an impact at moderate/highway speed, several G's of force will need to be absorbed through the harnesses. It may not be very likely to "need" them at an autocross, but at some points, you ARE travelling at highway speeds...so there is a risk...again, we are just trying to helpful and overprotective.

The bottom line is to first be safe and then have lots of fun!

Hmmm, my Miata currently has improper 6-pointers installed and has THSCC and Car Guys tech stickers from the previous owner. Needless to say that if I were to take her on track, I'd fix the problem pronto.

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Has no responsibility whatsoever.

Hmm...that's interesting. What's the date on the THSCC sticker and what is that you have found to be incorrect?

I agree, and there is a designed in amount of stretch in the factory belts that allow for movement towards the airbag. However, I have yet to see a single indication anywhere that the factory three point system is designed to accommodate occupant movement in a predictable fashion during a rollover. If you hit hard enough to stretch the belts, then your body may indeed be shoved out of the way by a collapsing roof. However, barring and impact strong enough to significantly stretch the belts, I don't see how and occupant can move with a three point belt on that has been pyrotechnic ally pretensioned and is now locked.

Understanding that a rollover is a frightening event, it is not one of great impact. The vehicle typically has a lot of energy and continues to roll or move after the first action. Compare that to a hit into the wall, when the car stops immediately, and I think that the likelihood of seat belt stretch in a rollover would have to be low. Otherwise, in a serious collision the belt would stretch too far. Thus, I don't see how a three point system is any safer in a rollover than a four, five or six point.

I am glad no one is hanging on to the idea that in a three point, you can duck during a rollover!

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Rich
http://www.v8mongrel.com/

I'm sure it's from the same era (years ago) as mine is prior to all the discussion/realization of proper submarine belt positioning using a stock seat. Mine are bolted to the floor in front of the seat. I have $10 that says that's the case with Wes', or that they are bolted to the front bolts of the seat.

Diane

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Diane (Hall) Bundas
1992 Spec Miata #48 - 1997 Chevy Tahoe - 2007 Honda Civic Coupe

It's older, early 00s. Like Diane suggested, it's mounted to the front seat bolts. And they stay unused hidden under the seat.

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Has no responsibility whatsoever.

I never said one could "duck", but that one had more of a chance of moving sideways out of the way (whether intentional or due to the forces of the rolling car moving you around) than the immoble state you are in wearing a harness. A harness holds both of your shoulders (and your hips) stationary. The 3 point only holds 1 shoulder stationary (and your hips).

I'm curious now. I teach again 8/20-21. Among other things, we have the kids do a full ABS stop. I'll see if, while hanging from the belts, it would be possible to slide my upper body sideways such that I wouldn't be in the way of the roof collapse. Hum.

Diane

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Diane (Hall) Bundas
1992 Spec Miata #48 - 1997 Chevy Tahoe - 2007 Honda Civic Coupe

I'm SO sorry Rich. I must have hit edit instead of QUOTE. I'll find out from Jason if there is a way to restore your post.

Diane

In addition to what I quoted below, Rich had stated that he would prefer to be held as closely to the seat as possible since the B pillar seems to hold up better in crashes than the A or C pillars do.

Rich, again, I am so sorry about this. Feel free to further edit to correct me if I misrepresented what you said. I have asked in the moderators forum if there is a way to restore your post.

Feel free to come smack me at Rockingham in NOV in you want to.

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Rich
http://www.v8mongrel.com/

lol... in a full ABS stop with me hanging from the belts, the belt is most definitely locked.

They aren't doing it right if the belt isn't locked. I do know that my shoulders are several inches off the back of the seat when hanging in the locked belts. I'll report back if the thread is still active and if anyone still cares in 2 weeks.

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Diane (Hall) Bundas
1992 Spec Miata #48 - 1997 Chevy Tahoe - 2007 Honda Civic Coupe