Rollbar / seats / harness stuff, yet again...
 

I know, this topic is a source of endless noob questions. Here comes another:

So my current situation is stock belts, no roll-bar/cage at all, and a set of reclinable pseudo-racing seats with a composite shell. The car is still used at least partially on the street, and will be for a while (even if I pick up another DD soon, I won't likely be picking up a truck and trailer, so still a lot of highway miles to tracks, etc).

I'm aware that all things considered, there's actually only a very narrow set of safe upgrades you can do that are anywhere in-between "fully stock" and "fully caged race car" when it comes to cage/bar/seats/harness stuff, which cuts out a lot of options right off the bat.

Over the past week or two I had pretty much settled on my next upgrade being a a custom-welded 4-point cage in the rear (high/back enough that my head can't smack it, and of the right dimensions that I could add a forward portion later and meet current SCCA/NASA rules), combined with Scroth 4-point harnesses with their ASM system to prevent submarining (since my reclinables don't have seat floor holes for 5/6/7-point anti-sub straps). This is of course leaving the front airbags working, and leaving the stock belts in for street use.

This seems like it avoids all the big obvious street+track config safety problems. It would be more-ideal if my seats had anti-sub holes and I could install a 6-point, but I think the Scroth ASM thing seems like a pretty decent solution to that problem for now.

I've seen some references to the idea of using a 6-point harness without seat-floor holes (and without the stupid move of going over the front of the seat), by basically routing them under your *** and out the same exit as the lap belts, apparently used in some formula cars. The concept and mounting angles and effectiveness of that setup are a little unclear to me though.

My bigger concern is this: is it safe to put a 4-point cage behind a reclinable, composite seat? It seems like even good-quality ones are subject to hinge failure in serious accidents (esp if rear-ended). If it lays over into the floor in the rear that's a relatively livable outcome. But with the cage bars immediately behind it (and we are talking like 6-8 inches tops), would it smack into them with enough force to crack the composite shell, and subsequently my spine?

I should add: it's pretty much a given that if I upgrade to a full cage down the road, I'd also swap in solid aluminum seats with a bolted or welded seat-back brace to the cage, but I don't think such seats are appropriate at this stage :)

Well first off, I think you would be surprised at how much you actually move around in the event of a roll over or big impact. Second if your cage was truly far enough back that you couldn't hit your head on it, then its too far back to protect you in a roll over anyway. No matter which way you argue it, this debate is very black & white. There are no gray areas, safety will have to be compromised one way or another.

So your recommendation is (ignoring the reclining seat thing for a moment), "don't put even a 4-point in a car you'd ever drive without a helmet"?

As for rollbar placement, well there's really only two possible spots for the main hoop on the 370. They're definitely close enough for rollover protection. I wouldn't think my head could go both up + back that far, but I'll take your word on it that wreck movement can be more than expected :)

I second that. I have seen two guys lost their lives over little accidents on the street thanks to the bar on the street even though they have the racing seat and harness. They were all fairly minor impacts too. Btw, aren't the side airbags from the seats?

I wouldn't run a harness on the street regardless, it's too restrictive for turning your head, etc. These two stories you're talking about were un-helmeted heads hitting 4-pt rollbars?

And yes, the side airbags are in the stock seats, whereas the curtain ones come from the roof. No doubt everything is tradeoff, I'm just trying to find a reasonable tradeoff. I'm a pretty safe driver on the street, I think, but I can't predict what other idiots will do nearby me with infinite precision :)

I guess I should preface all of this with those sorts of blanket statements about how most people survived ok before the advent of X, and all modern safety features as for corner cases, it's all a percentage game, blah blah. I get all of that, hence finding a reasonable tradeoff. I just don't want to do something in the name of increased *track* safety that seems like a really stupid (and life-altering) decision due to an unpredictable street collision, in hindsight, because it made the situation far worse.

Perhaps a better way to word my immediate concern: would it be a significantly better idea if I held off on a 4-point rollbar until I can get some fixed-back seats in there at the same time?

Personally I would skip it all together until you are ready to get a decent cage or decide to not drive the car daily again

Seats aren't as much of a concern to me as head impact. So I would say hold off on a roll bar until you're ready to wear a helmet every time you're in the car. No shame in rocking a helmet/hans on the highway haha.

I guess I could add that a "daily" driver for me isn't daily to begin with. I have no commute or traffic, I work from home and occasionally take it down the road to pick up fast food or car parts or whatever. But yeah I guess I'm just grasping for excuses at this point.

Mostly, the whole drive behind this is that even with the high-bolster seats I have now, I don't like my torso swaying around while I'm trying to steer through things (and shifting forward under braking, too). It's just a world of difference compared to being strapped into harnesses in the passenger side of an instructor's car. And then logically following: can't have harnesses without semi-proper seats and a 4-point cage at least.

Hah! Is that even legal, for driving to/from events?

Aren't most track side injuries related to side impact more than rollovers?

No idea here. As I said above, the point of contemplating the 4-point was less about rollover worry than about safely mounting harnesses for better driving, without upgrading a rare rollover event into a suicidal event.

I really don't expect my car to roll over at an HPDE at all, it seems far more likely that I get an angled hit on a (hopefully tire) wall, get rear-ended coming down into a corner by some guy with a brake problem, or something of that nature. I suppose a side-hit would be likely if I spun out and came back across the track into someone's path.

Probably bad luck to even mention it, but I've never had real, complete spin in this car. My closest call was on my very first time at a road course ever (direct link to a few seconds before: MSR Aug11). That was technically a spin in the sense of "off-track excursion", but meh that's semantics. I've never lost control to the point that the car went back-end-first or even fully sideways towards anything, and I really don't plan on it. You know how plans go, though ;)

In any case, thanks for the feedback you two, it's really helped to put this all in perspective. I've been pushing myself and my car to get more serious, but there's a big gap in front of me between where I'm at now, and where I'd like to be, and I really need to step back from this and cross the gap rationally. I've been trying to find a way to make the care more-race-able without giving it up as a street car for now, but it's just not possible in this direction (4 point).

I'll keep going with the other minor upgrades for now. I've been trying to limit my further upgrades to happening in response to actually feeling out limitations, which is why I held off on coilover upgrades for so long: it wasn't until my most recent event that I actually felt limited by the stock ones (the car was poirposing too much in some short braking zones, probably contributed to ice-mode come to think of it).

I'm at a point now where I feel the need for harnesses on the track, but I think I have to live with that limitation for now, until the car becomes more-dedicated to the purpose at hand (which in turn means I pretty much have to budget out a new DD first, and then get back on the car-building process).

Either that or completely reverse course, undo a bit of the more aggressive Z mods, keep it as a DD, and buy some cheaper caged car for track use (e.g. all the SpecZ thread action going on around here). I'd hate to have to give up my cheater paddle shifters though! :)

Try a CG-Lock for now. It at least keeps your lap belt tight, and its only $60. Can be used on any car with 3-point belts too. I still use the one I bought 6 years ago.

Car Booster Seat Safety - CG-Lock.com

Hah, you read my mind, I just ordered one through Amazon about 10 minutes before I posted above :) I'm a little bit dubious of it, but I'm sure it'll be better than nothing.

I would be willing to argue that a roll bar with some good foam padding is no more deadly than something like the hoop on the older Z verts or even your top windshield frame. neither are going to give at all if your un-helmeted head hits them.

How well do the B pillars hold up in a Z rollover?

If thats the case... no one makes a harness bar for these things?

and if you are planning on finding a mounting point for your eventual hoop, why not just have it made half height for now to strap harnesses to?

Most of the stock parts are designed to give. Even the "hard" bits on them. They'd really hurt to smash your head on, but they *will* give a little. That rollbar won't give, ever. Top windshield frame is kind of out of the picture though, unless you have no seatbelts and no airbags.

Being strapped into a harness without a rollbar over your head is definitely-bad. You roll over and you're basically dead.

a B pillar will not give... it is designed as a 'roll bar'. you think a b-pillar will give if your head hits it, but won't give if the car actually rolls over? (its designed purpose)

and as far as the windshield frame goes (see above)... but also you'd be surprised how much stretching and movement goes on in a crash.


agreed that being strapped in w/o roll over protection CAN be bad. thats why i was asking how they hold up in a roll over. if they hold up pretty well, then i'd rather gamble that my odds of hitting something sideways, or head on, were much greater than being involved in a roll over.

tracking cars safely usually comes down to playing odds...

chances are you are going to hit something at an angle... rollovers are a long shot compared to impact.

in this case he is saying he is going to track the car anyway, and only place a little emphasis on safety for now... fine... his call.

factor in the odds of an 'earnhardt' vs a roll over... how well the OEM roof holds up... the fact that he is going to run 4-pts (available submarine room)... and a reclinable seat (available collapse room).

my money is on harness bar and HANS...

This is pretty much exactly what I've decided to do. I like driving the Z on the street too much to give it up right now.

CG-Locks are AWESOME. Really helps with the left leg fatigue. I've used them since about half way through my first season doing HPDEs.



Glad to read this thread. It sort-of backs up the decisions I made this winter about my car and streetability. I AM still going to toss in race seats and 6pt harnesses with a harness bar though. I figure it's an acceptable risk in my calculations. I actually just sent an email to a local shop I trust to do the install since I don't know that I will have time before my first event.

I don't think the stock B-pillars are design to hold up the car like a rollbar. They might help a little, but they're gonna collapse. I also don't see hitting the B-pillar with your head as being a very likely scenario (at least, not as probably as hitting a rollbar).

If the car distorts enough to bring the windshield frame into my head, I don't think it's gonna be very solid anymore. If I distort enough to reach the windshield frame with airbags and belts/harnesses worn, I don't think it matters what else happens to me at that point heh.


This confused me for a second with the pronouns. I was the OP and the person you're replying to :). It's not that I'm only placing a little emphasis on safety. I'm putting a lot of emphasis on safety in general. I think the part you're mis-interpreting there is: the desire for the rollbar wasn't driven by safety concerns, and I don't want to compromise existing safety just to feel more connected to the car in a harness.

The complete OEM system of seats, belts, bags, body is well-engineered and crash-tested. It's not as safe as being in a caged race car, with harnesses, helmet, and HANS, but the big non-obvious point is that most halfway solutions which aren't completely stock or completely race are actually worse than either of them. Everything is intertwined in the safety systems and it's hard to touch just one aspect of it without screwing up the rest.

The stock roof won't probably hold for jack. In a hard rollover this car's gonna be pancaked to the top edge of the doors like a barless convertible, IMHO. It's be nice if that weren't true, and it might not be true, but I haven't seen any evidence of that (including having stripped out my upper interior and looked at it myself).

The 4-point harnesses I was considering are the Scroth ASM ones: they have a mechanism (like many OEM belts) where an extra loop of harness on one shoulder is folded over on itself and lightly stitched. In a wreck, the light stitching rips out and one shoulder comes forward more than the other, putting a slight twist in the body that greatly reduces the odds of submarining, much like an OEM 3-point does.

The reclineable seat definitely can collapse, agreed; that concern was really the point of starting this thread.

My money is on this getting you killed in a rollover.

What do you think they are designed for? They are the 'roll bar' for a car with out a roll bar.


http://image.stockcarracing.com/f/94...crash_test.jpg


oops... short attention span... my bad.


Not always true.


http://www.350z-tech.com/forums/atta...k-dsc01691.jpg

http://www.autoguide.com/auto-news/w...sonville-4.jpg


I'm sorry... i don't get the point.. to just plant you in the seat better?


I'll take those odds any day.


Google images for 'nissan Z crash'... would you have rather been wearing a good harness and HANS, or only the OEM stuff because you didn't have a roll bar?

http://a57.foxnews.com/video.foxnews..._CRASHTEST.jpg

Good thread, some good info in here. I too am going the route of a harness bar with 5-point harness/racing seats for the track. Several reasons, however the primary two are:

1) I agree that a roll bar is the best solution to help ensure you are not crushed in a rollover while wearing a harness, however I do not believe that the car was built with the concept of your body 'falling' into the middle to protect you from being crushed in a roll. This is what the B Pillars are there for, and while certainly not as effective as a roll bar, I am confident that they will in many cases prevent the roof from crushing in on you.

2) The only time I will be wearing the harness is at the track. I think it can be reasonably said that in any type of a crash where you are wearing a harness, that does not involve a roll (assuming a hans device is used with the harness), you are better protected with the harness than without it, regardless of whether it is fastened to a harness bar or roll bar. Also, based on the tracks/Auto-x places I will be going to, the chances of a roll are slim to none, which means despite that added risk in one, unlikely type of crash, the added safety in all other possible crashes more than makes up for it.

I believe there is a picture/post on here of a member that rolled his 350Z down a hill while wearing a harness, without a roll bar, who stated that wearing the harness likely made a big difference. (In that he was uninjured)

Obviously the decision to use a harness without a roll bar is going to come down to what each person is comfortable with (and regulations of the tracks you are at) but for me, the harness bar is a more than acceptable alternative to a roll bar/full cage.

They may help, but think about it: there's a reason race cars built on cars with B-pillars still get roll-bars. The B-pillar's aren't perfect, even in your own second pic, you can see where the pillar went over sideways and let the roof come in partially.

re: the windshield frame:

Your pic about this doesn't show a head anywhere near the frame of the windshield. The head has arced down to where the steering wheel / dashboard is. I think hitting your head on the windshield frame itself would suck, but again I still have airbags, and I don't think the arc of my body straining against any belt system will let me head go simultaneously that far high and forward.


Man, this forum sucks at lengthy nested quoting I guess. The point of wanting harnesses at this stage was yes, to plant me in the seat better so my chest isn't moving forward so much on braking, or sliding around on corners. My *** is planted reasonably-well by the aftermarket seat bolsters, but that doesn't do much up top. It's just a night and day difference how connected I feel in the passenger seat of a harnessed car versus the driver's seat of mine.

Well, ideally I'd like the whole world to sense my impending crash and instantly transmute itself to NERF material :)

I agree that in a non-rollover track accident, I'd be better off with a harness bar, harness, helmet, and HANS than I would be with stock belts and just a helmet. And if I avoid the harnesses on the street (which I would), there'd be no compromise there as well.

However, in the current mostly-stock configuration a track rollover would be pretty survivable all things considered, because the stock system lets my body cave inwards and avoid being destroyed by the roof (3-point belt config, and might still be in the hospital of course). I think with the harness bar instead of a rollover bar, and me strapped in with harnesses, a track rollover would result in my neck easily getting locked into taking way more force than it should, causing a high risk of paralysis or death.

So in order to avoid that fate, I had decided on a 4-point cage to use the harnesses with, thus track rollovers while harnessed aren't so fatal. But then that raises the issue others brought up on the first page: me bashing an un-helmeted head into the nearby rollbar in a street accident.

It definitely is designed around this concept. The 3-point belts do this automatically by design (allow you to fall to the inside). Re: the B-pillar, I'll say what I said 30 seconds ago in the other post: it helps, but it can be pushed over or flattened depending on the accident. And if the B-pillar falls, and you're locked into a harness, your neck is the next thing in line for the car's force.

I'm going to really miss my SRM when I go Spec Z!

use an auto then :p!

That was me. And it sure did. I had seats, harness, and a harness bar that did brace between the stock seatbelt mounts. I rolled four times side over side hitting some big rocks. The first roll was a straight drop of about 30 foot plus. I was very supported within the car. The roof did hit my head but it wasn't bad nor did hurt me. I was just a little shaken up. Mostly nerves. Not to say luck didn't play a part. I see where both of you other guys are coming from.

http://i1109.photobucket.com/albums/...lspohn/005.jpg

http://i1109.photobucket.com/albums/...lspohn/006.jpg

http://i1109.photobucket.com/albums/...lspohn/007.jpg

http://i1109.photobucket.com/albums/...lspohn/009.jpg

damn why did you do a baja race on a street car lol jkkk. Glad u walked on that one!

That's why I quit school. Because the have recess and I don't play.:tup:

that is the only reason i posted in this thread... the almost elitist version of 'you're an idiot if you use a harness with out a full cage' has magically been accepted as law, and is now the first response you hear when the question is asked.

lots of different factors need to be weighed.. if you're in a cobra or miata with no hoop, a big tall seat with 6 pts is probably a bad idea. if you're in a mini-van with huge head room and proven roll over protection you'd be stupid not to wear a harness.

in a perfect world, everyone would have full cages and NASCAR bars... but thats not the case... and i don't feel that the only opinion given should be 'full race or OEM, with nothing in between'.

We aren't talking perfect. we are talking compromise.

you do realize that is more of a sedan.. i can almost press my forehead on my Z windshield frame even while 50 Gs aren't pulling my head forward.



this is where people get in to trouble putting speed before safety... yeah it sucks to slide around in the seat... i have put many a pressure dent in speaker grills from my knees crushing them to brace myself.. but i figure that maybe its the car gods way of telling us thats about as fast as you should go with out a cage.




So what you are saying is that in the case of (probably) 99% of all track incidents, you would be better off with a harness and HANS than you would be with stock belts... but in order to prepare for the 1% (and even smaller fraction of that where severe neck injury occurs) you would rather use a seat belt solution that allows your body to flop around in the car bouncing off anything hard, so that your head is free to not be crushed by the roof in case (again an even smaller fraction) it completely pancakes.

:tup:

I think your statistical argument makes perfect sense (well, other than it's probably not quite 99%-vs-1%) if we were talking about some efficiency thing, or odds of losing a chunk of money, or something of that nature. But you're also talking about increased safety in a scenario that's normally going to be non-lethal in the first place, versus decreasing the safety of a rollover to, IMHO, more likely to be lethal. It's hard to play odds against increased lethality because you don't recover from that :)

that was my whole point... i just don't think that the 'possible' safety advantages of good belts for track day guys should be completely ruled out, just because you have no cage... everyone should listen to us idiots on the internet with a grain of salt and make their own decisions.




PS. I roll in a full SCCA/NASA stamped 1.75 x.12 DOM 6-pt cage with 3 bar NASCAR door bars, FIA seat, Teamtech Ram-pac 6-pts and HANS.

PPS. Will I do some laps a big willow in the Z roadster just to see how it does and embarrass clint?... most likely.

Backtracking a bit, does anyone have any better info on this aspect:

Is it possible to safely use a 6-point and get the anti-sub benefits without having anti-sub seat holes? If so, do you mount them to the same anchor as the lap belt, after routing them under your *** and out the same area of the seat as the lap belt?

What about the formula style 6 point belts? Have you considered those? I believe they route through with the lap belts but anchor differently.

TeamTech Motorsports - Racing Harness - Jet Pilot Harness

I am amazed that no one has suggested locking the 3-point seatbelt. I don't know why many more people don't use this technique to keep themselves planted.

Sit in the car and slide the seat all the way back, buckle your seatbelt, pull the lap belt tight and then the shoulder strap (running you hand from bottom left to right then top left if you're driving), jerk the seatbelt forward to engage the locking mechanism with a quick short motion, lean into the seatbelt to keep tension and slide the seat forward.

Couldn't find a video. If anyone is confused I can whip one up.

Works fine if you can slide the seat forward. :) I for one am too tall.

CGLocks are way easier to use.

I use that method ^ . Its certainly an improvement over normal when braking and some better when turning.