kurt M

This drums been beat into the ground so far it came out the other side and someone put a made in China sticker on it. The "you can't duck" thing is like a chimera of mushrooms and crab grass.

ECS

I just went through the same thought process with my 997S. I had a gt3 with the full setup but had some issues doing the same thing with my 997. Spoke to a bunch of people and bottom line is that the chances for rollover in a p-car is very low given its low center of gravity compared to cars like the Subi STi. And, even if it does happen the structural integrity of Porsches is pretty good. Bottom line is I ended up with a harness bar, harnesses and a head restraint device (R3). Not perfect but pretty good.

mglobe

Funny thing is that I posted essentially the same question just a few weeks ago, & got a ration of crap from people about how you need to consider a harness and roll cage as a system, & you shouldn't only do a harness bar, its not safe, yadda yadda...

FWIW Farnbacher Loles sells a Cayman harness bar. http://www.farnbacherloles.com/st/products.asp

Sparco makes a harness bar for the 996 that I'm guessing will work for the 997 as well. http://www.sparcousa.com/pharness_bars.asp?id=604

RedlineMan

But...

...it's not dead yet.

RedlineMan

Sorry I let you down, Mike;

Missed that one. I must have hit the red zone on dispensing reason & reality at that particular time. I'll try not to slip again.

Sounds like you waded through it OK.

APKhaos

But wait.......there's more........

In best ghoulish fashion, I bought that very rollbar from that very incident for my 85 911. Turns out that the bar was finished like a concours body at great expense in Glasurit paint that precisely matched the car's color. When I picked up the bar, there was not a single blemish on the top of the main hoop. It was pristine. Its still in the 911, with its new owner, and its still pristine.

What's more, he had a higher than market value agreed with his insurer based on the concours condition of the car, and they paid out in full. There was a nice new 28' trailer containing a shiny new G car parked in the driveway. See? Some total write-offs have a very happy ending.

gums

The HANS isn't what's going to be holding you upright, the harness is. Nevertheless, you can't drive your car properly if you're not held in securely. Harnesses go in first, with or without a bar. HANS as well, it saved my neck once I'm absolutely certain, without a rollover. This was moments after I had voiced how much I didn't like wearing it. When you find a bar that works for you, it comes next.

Circuit Motorsports

That is where a seat is important. The 6 point harness is not keeping you from moving laterally nearly as much as a good bolstered seat will.

RedlineMan

But wait....

I should have mentioned that as the angle of the car's direction strays from straight ahead (i.e. sliding sideways toward an impact), the value of the cradle effect offered by a properly mounted 6-point sub system diminshes, probably rapidly. The effectiveness of 5 and 6-point systems starts to equalize here, as the sub is now merely holding the lap belt low and not stopping hip motion directly. A properly installed 5-point is the BEST at doing the important low-lap-belt job.

At what point this convergence of performance takes place is open to debate, and could be discovered if you had the test budget and the inclination. Suffice it to say that I bet my 85% effectiveness figure is proably quite pessimistic. I'm betting they are a lot closer in overall performance than that, in many instances.

This is not by way of saying that a 6-point is a waste. Get the best if it fits your plan, of course. it would be silly not to. Just don't get blinded by the numbers, because the real world effect is probably far smaller than the "hype" would lead you to believe. I am always skeptical of those that pound the table and say "you must have this or that, or you will die!!" A lot of folks lived through 5-point crashes for many years.

The guy that says "I'm not going to ride in this student's car because he does not have 6-points" should be publicly flogged with a greasy mop. Naked, if possible.

RDL

These discussions are always interesting since I often get caught in the "system" discussion with friends and associates.
I have been driving with a Corbeu race seat and harnesses attached to the rear seat mounts and over a harness guide bar mounted at the "C" pillar.
In your opinion am I making a drastic mistake in using the harness without a HANS? Will the inherent stretch of the long harness effectively slow the body down in a severe incedent to reduce the potential neck injury? In essence are we saying if you have a harness you must have a HANS? No HANS your safer with the stock 3 point belt?

kurt M

(Caution internet babble to follow. This is not a drill. This is actual internet babble. If you are sensitive avert you eyes now.) Drastic? No many drive without H&N every day and most have walked from all kinds of wrecks. Could H&N be added with the only down side being less rich? I would guess yes, so long as the device requirements can be met by your setup. Should it? If I could I would. You make you own call its your neck so to speak.
As to your buddies beating on you setup. You have added to your car. The problem some might have is that you have used methods that are not as good as you might have been able to use. 1. Guide bars make for long straps. Long straps make for larger take up times and movment. Large take up times and movement = less good and should be avoided if you can. Take up time and movment does not = more shock absorbtion! More take up time = more energy to deal with at the bitter end. In a real hard foward hit you might be using the wheel to stop your head given body shape change, belt give and neck movment. 30 mph delta hit is almost 40Gs. Not hard to make a 30 mph delta. Hit something at 60 or more with some offset and you are taking even complete full race systems to task. Phisikzx is a bitch.

2. mounting to the seat. Now you are only relying on the seat mounts for a lot of work. Many DE groups do not condone seat mounting of the lap and sub belts and for good reasons. As far as i know all the Racing groups ban this method. Look at the seat to car mounting.

Do the best you can in a compromise car. All cars are compromise cars. Street driven DE cars are the highest form of a compromise car.

APKhos I flat out forgot thay you ended up with that bar. Small world.

RedlineMan

EEEEEEEK!

You've got a whopper of a misconception in there, but a common one. Not yelling at you here, but it still keeps coming back time and again, and it is high time this old horse get put to pasture, for good.

SLOWING THE BODY GRADUALLY IS AN OLD PARADIGM THAT HAS BEEN FOUND TO BE UTTERLY FALSE, AND COMPLETELY OPPOSITE OF WHAT IS SAFEST!!!!!!!!!!

Now, first off, your belt system should be dumped IMMEDIATELY. The long belt path you have is the WORST in terms of load entered into the body, most notably the neck.

The longer the body is unrestrained, the more kinetic energy builds (it builds as a function of time). Your belts will stretch a lot as a simple function of their length, and when they finally take up fully, they will have allowed a tremendous increase in kinetic energy to occur.

You could set up a hypothetical test sled situation that would demostrate this. Using a neck tension value known to be at the cusp of theoretical surviveability, you could set up a test where the difference between living and dieing hinged solely on the length of the shoulder belt. Yes, it is that critical.

You need to shorten your shoulder belt path. You need a harness or roll bar that the belts will mount to directly, and that ideally offers you a belt length to the seat opening of no more than 20".

Since they restrain you to a far higher degree, having a harness system DOES INDEED increase the potential for neck injury if the head is left unrestrained. Given what we now know about this stuff, you might indeed be "safer" in the stock belts in some instances.

Your system is likely worse than either a stock belt, or a short length harness!

RDL

John and Kurt, Thanks for the info/comments.
My car is a street driven DE car. I would love to install one of the Redline roll bars, but two kids in the back seat preclude the roll bar installation. I need to clarify something on my previous post and questions. As a beginning DE participant several years ago I purchased the "system" I described upon the recommendation of several friends who were "in the know". As I became more educated on my own I have eliminated the use of the harness and have been using the bolstered seat with the 3 point factory belt. My opinion (I stress opinion not backed by practical knowledge) is that the seat does a reasonably good job keeping me in place to properly control the car, factory belt does a reasonably good job at protecting me during an impact (air bags help also).
COMPROMISE is by far the operative word when discussing DE safety equipment. How do the enthusiasts protect themselves the best withtout being detrimental to the street use.
John and Kurt, keep up the preaching!!!! Your practicle knowledge and thoughtfull analysis is very helpful and very important. Furthermore I recommend you become more involved in the PCA national DE structure. I believe John has had conversations with Pete Tremper about the safety guidelines and recommendations. I believe they have not all been met with a great response. John, I hope you will look at becoming part of the committee and work to change popular thought from the inside.
Thanks again for your input.

RedlineMan

Cool;

You show a good sense of balance and analytical acumen. That's alll I've got to go on. It is NOT rocket science. Heck, if I can grasp it... It is a bit tricky to put the entire puzzle together, however. It takes study and reasoning. For whatever reason, and to the extent I am successful, it just all seems to make perfect sense to me. It seems very intuitive.

Regarding my roll bar, it is so easy to take in and out that it really does not make sense to not go for the best system you can create. You really can have the best of both worlds here.

Well...

Your equally reasoned & salient participation is quite welcome!

Speaking for Kurt, if I might be so bold, he has done his time, locally. As for me, I'm afraid it is a waste of time getting hooked up with National. I don't know whether it is ego or power or near-sightedness or what, but my efforts have been for naught. Knowing most of the people involved personally has not helped. And so, as some suggested to me early on, I am beating the drum here, at the grass roots. If you can't educate the leadership, then educate the constituency.

I don't pretend to have all the answers, but I know what I know, and I know what is wrong. Hopefully, I have a big enough mouth to make a difference!

Craig 88

This isn't complicated. Use a 5/6 point harness with the shoulder belts mounted to a harness bar and use a Hans device. Get the rollbar when you can. Anyone using a harness at track speeds is risking a basal skull fracture ( always fatal ) in even a moderate frontal impact, see Dale Ernhardt.