fleming23

First and foremost, I want to clarify that this is a compromise solution and I am aware of that. Obviously I want to add safety to my car and am investing in Schroth Profii belts with a Brey Krause Harness bar and BK lap belt mounts (I also have a Vetteworks belt mount I purchased from a forum member.) I have a C7Z delivering this Friday that will absolutely see track time around the country with various HPDE organizations but will not be a "track car" in the traditional sense. I am not gutting it, and the only cutting will be the interior panels for the harness bar for which I have uncut factory replacements if I ever want to go back stock.

Okay, that out of the way. I need some input on a few options for this vehicle.

Option 1 - Profi II-6 point harness (both lap & sub belt clipped to BK lap belt mounts with sub routed under legs) + HANS

Option 2 - Profi II ASM 4 point (FIA legal) harness and no sub +HANS

Option 3 - stock belts, no hans +hoping I don't crash

My first inclination was for option 1, either with the sub belts clipped to the BK lap belt mount, routed under my legs or the Vetteworks mount and routed through the seat and ultimately under my legs. I see this used, and is the actual design of the Vetteworks system with the belts passing through the lower and upper seat. I feel this option gives me the most secure feeling while tracking the car but am not so sure about safety. I was talking to someone yesterday who stated that if I were to back the car into a wall, this system would allow me to rotate and move upward toward the roof as the sub belt would no longer be under tension.

Option 2 - other than buying all new harnesses, I am so hesitant about doing a 4 point. I know the Scroth ASM belts are about the only 4 point allowed and/or recommended but it just seems....wrong? I discussed how the ASM belts work and how one tears in a collision allowing your body to rotate which apparently prevents the submarine effect other 4-point systems are known for. I would be concerned the belt could slip off the HANS and cause even more problems but apparently this is not a concern.

Option 3 - while I might do one or two events when I first get the car, I think having any sort of harness and HANS should be safer (assuming no rollover) than running just the factory 3 point.

Any opinions or advice? I am also really not looking to swapping seats in and out of the car but that is potentially an option 4 should nothing else really work well. If I do this, I would likely only buy a single seat for the driver which then leaves the occasional passenger unsafely buckled... I think this is probably the "best" option but unfortunately also the most expensive. While I know you can't put a price on safety, my checking account and credit card might say otherwise...

At the end of the day, driving this new C7 should be exponentially safer than I am currently in my 1971 C3, even with the 6 point and harness bar in that car.

Thanks,

Eric

93Rubie

In my semi-informed opinion, unless you want to go all out, the safest bet is to run a modern road car with the stock safety equipment. Think about it, you have SO many air bags its stupid. In the event of a roll over I would NOT want to be in the car with a harness on UNLESS it had a roll bar. Your spine WILL get crushed. If you in a roll over with a 3 point belt, you body can move forward and not be fixed upright. In a head on wall collision, with 3 point again your whole upper torso with your head will move forward and hit the air bag. Which would be IMHO a LOT safer than a harness and NO Hans device.

Unfortunately, I agree with your last statement being safe costs money, how safe do you want to be? I'd leave it stock or go 100% with ALL the right stuff. The in between zone is more dangerous based on my research.

This is yet another reason I'll stick to auto-x. The risk factor MUCH less and I can still have a street car. IMHO, if you want to as safe as you can on track, the car will NOT be safe for street use. Anyone who says a cage on the street is safe, is full of crap. Your head hitting a solid piece of steel is death even with the FIA padding. Technically, one should have a containment seat or center net, because those work in street cars too.....

Bill Dearborn

I went with Option 2. I have the Schroth ASM 4 point belts with a DOT approved latch system so I can use the belts on the street if so desired. I also have the option to add a sub belt so I can sit on it if I want. I will be using them the first weekend of April.

I have a Shark Bar installed and use the BK lap belt mounts. BK says they have enough room to mount both the lap and sub belts but those holes look pretty small.

Option 1 isn't recommended by the Schroth experts since the lap belt mounts behind the seat place the lap belt at the wrong angle and running the sub belt under the seat back can damage the belt. I know when I have placed my hand in that opening I have been able to feel sharp edges in there.

Bill

fleming23

Let me know how you feel with the ASM compared to a traditional 5/6 point.

Bill Dearborn

Will do. I have ridden in BMWs with this setup and it seems to work well. Wish they had a kit like the ones for BMWs, VWs and Ford Focus's that plugs right into the stock lap belt system so we could make use of the pre-tensioners.

The reason I went with the 4 point is the Schroth people demurred on using the 6 point and sitting on the belts. They said this was a configuration that was more appropriate for a Formula car Vs a sedan where the driver is more vertical. They said try this first and then add the sub belt if it seems necessary. They have fitted these systems to a lot of cars over the last few years and know what they are recommending.

Almost forgot that Schroth has belt mounting brackets that are customizable to our stock seat belt mounting points so they are an option other than the BK mounts.

Bill

blackozvet

when I did some research before installing a harness in my road reg c4 I saw a lot of comments on the internet such as "dont install a 4 point harness, you will submarine !" "a 4 point harness is more dangerous than a 3 or 5 point"
I wondered about the credibility of these comments.

So I had this crazy idea, do some research from people who know what they are talking about !
Im guessing the Society of American Engineers know something on the subject, and they did crash tests using human cadavers and 4 point harnesses and compared the results against 3 point seatbelts.

http://papers.sae.org/2003-22-0017/

unfortunately you have pay to view full paper but you can click on preview technical paper.
there are other similiar tests done using 5 and 6 point harnesses if you keep searching.
(apparently 5 point harnesses are dangerous to the family jewels !)

Bad Karma

Perhaps an option 4?

https://www.corvetteforum.com/forums...using-one.html

blackozvet

A few other things I learnt while researching the subject,

4 point harnesses are designed to be used with stock type seats, stock seats do not have provision for the 5/6th point belt to go under the driver at the correct location (and be secure).

5/6 point harnesses are designed to be used with race seats, the seats have the provision to fit the 5/6th point under the driver and locate at the correct points and angles.

so the choice is pretty straightforward there, choose and seat and then a harness. People who are using a stock type seat because they have a dual use (street/track) car are restricted to a 4 point harness.

5 point harnesses will hurt the family jewels (and can be just as nasty for female drivers) in a hard impact, that is why the 6th point harness belt was introduced.

4 point harnesses are safer than a 3 point seatbelt, the crash tests prove it. I have read the ASE crash test paper and they proved it using human cadavers in crash testing. In frontal impacts the upper torso bends forward above the lap belts due to the g force. a V shaped 4 point belt will secure the upper body better and resulted in less internal damage to the body (as proven in the crash tests)

'Submarining' out of a 4 point harness is pretty much an old wives tale. It was something that happened many years ago in open wheel race cars with a lie down seating position when they first started using 4 point harnesses. that is one of the reasons the 5 point harness was introduced. It is not something that happens in upright seating positions, again the crash tests prove that.

the other reason the 5th belt was introduced was to secure the harness in the correct position. The big mistake 4 point users make is they tighten the shoulder harnesses too much and it pulls the linkage point up and instead of the lap belts going around the hips, it is now up around the stomach. In the event of a crash they are susceptible to internal damage - which is attributed to 'submarining' !

3 point seatbelt v 4 point harness = does a seatbelt do a good job of holding you into a seat while throwing the car around, not a whole lot - they are not designed to do that - they are designed to hold you into a seat in the event of a collision, a correctly fitted 4 point harness will do a better job, that means you can concentrate on driving the car quicker/faster without having to use legs and arms to hold you back into the seat.

as for hans and roll cages, well thats a whole different discussion !

Bill Dearborn

The 3 point belt system lets the occupant swivel forward around the diagonal belt across the torso. This helps prevent the occupant from submarining under the lap belt since the body weight is moving forward above the lap belt. The Schroth 4 point ASM system works similar to the 3 point belt. We are not talking about taking a 5 or 6 point belt system and not using the sub belts. With the Schroth system the inside shoulder harness has a section with a small loop sewn inside it. In an impact the threads tear and the loop permits a small movement of the upper body similar to what a 3 point belt system does. Schroth has tested this system and it is DOT approved. It is a different ball game than the old 4 point systems.

The system I will be installing in my car is DOT approved which means it can be used on the street (unlike 5 or 6 point standard racing belts) and it permits the use of a HANS.

Bill

blackozvet

Schroth are the worst at banging on about submarining !

The proof of their harness being a letter from 1993 stating that to comply their harnesses must be used in conjunction with the original seatbelt to make it legal ?? read page 4 of the "letter of approval"

It also states that the 4 point harness is tested to FMVSS 209, this test is applicable to 3 point seatbelt systems.

TrackAire

I had never heard about "sitting" on the crotch belts until a friend offered me a ride in his Boss 302 and he had the Schroth Profi II system where the crotch belts were on top of the seat. Once I was buckled in, I was surprised that I did not even notice them or any discomfort on the track.

After looking into it, I found out that a lot of Formula 1 type race cars use this type of arrangement since there is not seat bottom or space under the seat...the driver is essentially sitting on the floor of the car.

I'm not sure I buy into all the different reasons behind where and how to attach the anti submarine belts to the floor since the main purpose is to keep you from sliding forward and under the lap belt. As long as it keeps your crotch from sliding forward, I can't see how it matters if it's mounted under the seat at 10%-20% angle back, behind the seat on the floor or if you're sitting on the anti submarine belts and they're attached behind the seat on the floor. Not every accident is identical to their testing sled...angles change, multiple hits from different angles, etc. I don't think any manufacturer can verify their system for every real world situation. As long as the system stops the body from sliding under the lap belt, it is doing its job IMO.

The key for me is this, if using a harness you have to incorporate some sort of HAN's device and preferably at least a roll bar or cage.

Twiggs

Bill,

Are you picking up the PROFI II ASM FE? I just was reading up on it and I was wondering if it would be safe for use in my car, with Corbeau A4 seats and a rollbar / harness bar on the b pillar. Going into the shute and T1 at the Glen really had me moving around a bit, and the psychological feeling of being tucked in with a harness / hans has real value to me. If I could use that 4 point with my seats as is I'd love to get going on that.

blackozvet

Im not sure how sitting on the 5th belt will affect how it performs, unfortunately there is only one way to find out !

Your right about crash testing, it is only done in certain ways and may not always replicate how a car will impact on something.

As far as the Schroth harness goes, I would read the fine print carefully, street use is only legal with the push in (seatbelt type) fittings. The Shroth ASM system is not compatible with a HANS device for racing.

fleming23

That isn't true, this is straight from Schroth's page.

"We have recently tested this harness with a HANS device, and the results were great. You can use 4 point ASM Harnesses with a HANS device."

blackozvet

oh yes, it is true,
this if also straight from the Schroth site, under the Engineering tab.

SCHROTH harnesses designed for use on public roads (FE push button models) or those likely to be used as 4-points come with the asm® safety system. The performance of the SCHROTH asm® safety system has also been positively tested in conjunction with airbags.
Current Head And Neck Supports (HANS®) provide further reduction of head deceleration and neck bending.
The asm® system on all SCHROTH Rallye and QuickFit belts - excluding the new QuickFit Pro - is not compatible the with HANS®. Only belts having a center RFR Cam lock can be used with HANS®.

so if you want a street compliant belt you must use the push button model ASM, but the push button ASM system is not compatible with HANS.

forgot to add this bit too,
We recommend that only non asm® belts be used in competition harnessbelts.

fleming23

Not trying to argue but, I read that as the ASM - Rallye is not compatible as it is a "tuning" belt, but it explicitly states on the Profi II ASM FE that you can use a Hans with the ASM as those belts do fall into their Competition series. Regardless of lock style, I don't plan on using these on the street anyway and will retain my factory belt for that.

I listed my Profi II 6 point belts for sale. If those are sold, I'll buy the Profi ASM, if they don't sell it looks like I am sitting on the sub belts. Either way it looks like a bit of a compromise.

Edit - you may be correct about the Hans, although I do want to contact Schroth to confirm as I have been told by someone who deals with Schroth that the Profi ASM was compatible. On another site I found the following, "The only thing you cannot do with this belt is use a HANS device. The HANS device and the ASM do not work together." But again, I question if this is not just generic language relating to the Rallye or Quickfit (both of which are ASM and not Hans compatible) belts rather than the Profi II ASM.

blackozvet

if your using a quick release competition latch then the set up is ok for racing use,

just sayin that people who are thinking the ASM harness with click in fittings is a street AND track set up (that is compatible with a HANS) should read the fine print and do their homework first.

Bill Dearborn

The main purpose of the so called anti sub belts is to keep the lap belt in place when the shoulder harness is pulling up on the lap belt. If the lap belt is held in its proper position across your pelvis you will not submarine under it. The success of the 3 point system is due to other parts in the car. First there is a pad that goes under the dash the knees hit when the belts start to stretch and the body starts to move forward in an impact. At the same time the upper body isn't restrained on the inside so it pivots forward and outward around the shoulder belt which does two things: 1) Reduce the chance of sliding under the lap belt; 2) Separate the melons during the crash process by sending them in opposite directions.

With the newer cars we also have a pre-tensioner that cinches down the lap belt during an impact. They have this in place because the vast majority of people don't wear the belt properly. It is across their abdomen Vs their pelvis and usually very loose.

Some of the Schroth 4 point systems are certified to be DOT legal. To get one of those you need to buy the belt with the DOT certified release system so emergency workers can get into the car and push the red button to get you out. Some work with the stock belt systems to make use of the stock mounts and pre-tensioners (BMW, VW, Ford Focus) and others are tested (not mathematically but with a real crash test sled) to work on track with a HANS device. We aren't talking about Joe Blow doing this but a corporation that certifies their belt systems for European and US regulatory agencies, FIA, SFI and actually provides a large portion of the NASCAR Cup Cars with their safety restraints. Simpson, G-Force and others make products for the top tier of NASCAR but they aren't being installed while Schroth belt systems are being installed. I don't follow NASCAR that closely but they are far ahead of other organizations when it comes to driver safety. I figure it doesn't hurt to follow their lead when it comes to choosing the company and its US distributor to purchase products from.

Bill

Bill Dearborn

You need to look a little further. This is the info off the web page of Schroth's only US Distributor:
https://www.hmsmotorsport.com/products/profi-ii-asm

Look at the bottom of the web page where they sell the belt with the DOT legal latch.

By the way the guys at HMS are well known in racing circles as restraint systems experts and they are the ones that work with the NASCAR teams. They updated their home page last week since one of their Customers (Jimmy Johnson) won the race at Atlanta. They also supplied the belts to the 500 winner. I know Joe Marko the owner. He instructs with BMW and PCA Chapters and provides safety advice to them and the participants at their HPDEs and Club Races. If he says your system is unsafe it really is unsafe and if he says it is safe there is a high probability it is safe.

Bill