sureshot

Do you guys think it looks stupid to have 4 point harnesses with a back seat still in? Im asking because you cant really fit anyone back there with the harnesses attached to the rear seat belt attachments. This is your only SAFE option to put in harnesses unless you have a custom harness bar, so you dont end up with spinal compression.

StrikeEagle

Yep. At the very least take out your back seats.

Turboron_99

Yea, also the only company that makes DOT Harness's from the get go, is Scroth, and they dont make sh*t for a Hyundai. If you want a Harness setup you have to go custom. There really inst a good way to do it, with out a roll cage or harness bar.. As you stated.



Also might as well just take out the back seat, it will be a few pounds lighter and looks more sporty from the inside,



This is my setup, Also you must realize that if a cop wants to, he cant give you a ticket, like my car, i setup mine so it erased the stock belts and replaced it with the harness bar, So far i have been lucky, one cop pulled me over, no ticket, and actually said nice job, he was happy to see the harness setup right, walked away said have a good day!

Tomte

Actually the company is called Schroth. I've been to the production facility several times. Spinal compression is not the word you are looking for unless you have shitty headrests or the habit of cruising with your seats almost horizontal . For safety reasons you need a seat that has either been tested with Schroth seatbelts (Tiburon seats were not tested) or one that has guides like the ones shown in the picture by Turboron 99. You can install them besides your normal seatbelts quite easily (Schroth has an adapter) and remove them if needed to use your normal seatbelts (also good for the cops) and you don't loose your rear seat. They also have self tightening mechanisms like your normal seatbelts (ASM-autocontrol II cost around 130€ incl shipping over here) which can also be swithed off for sporty driving with an additional adapter (button). Over here it is possible to get a clearance certificate from Schroth if the Schroth seatbelts are put in together with approved seats (eg Recaro) on approved mounting brackets (eg Recaro Tiburon specific). This does circumvent approval.

Regarding looks: I personally think that the car looks better with rear seats. It also makes the car more usable (taking friends with you etc) and dampens a lot of noise from the trunk (wheels etc). I would first try driving around with no rear seat(remove both parts - bottom + top) to see whether the noise doesn't bother you.

Stocker

The other concern with spinal compression is the shoulder belt rearward angle to the shoulder belt mounting points. Some people have seats with guides in the back, but they bolt the shoulder belts to the floor immediately behind the seat. In a crash as the person goes forward the belts pull down on their shoulders, sometimes with enough force to tear through the back of the seat. Your forward momentum is transferred to downward force, crushing down on the spinal column by pulling down on the shoulders. SFI says the shoulder belts need to be -5 to +30 degrees from straight back, from the shoulders to the belt mounts. Without a super-dee-uber strong seat, floor mounting the rear belts is potentially a severe hazard.



Low-quality SFI illustration here



In America, people get strange ideas. This thread shows both excellent shoulder belt mounting:







As well as the result of a visit from the Good Idea fairy:

(hint: this is bad)





While looking for images for this post, I also found this company that somehow has not been regulated out of existence for selling four-points INTENDED to bolt to the floor!

Tomte

I have to differ with the other comments on some points:

Seats: They do not need to be super strong. You can use normal seats with Schroth belts if your car has type approval (The Hyundai Tiburon doesn't have type approval). Here is a test video with normal seats. The S-coupe for example has type approval for the belts. For the Tiburon your only chance of getting a clearance certificate from Schroth is by installing one of these seats with an approved bracket (seat and bracket are equally important!).

Mounting points: You do NOT need a cage. I think you need one for FIA homologation, but that does not seem to be the case if the OP wants passengers in the back. Still the mounting points in the second picture (Flyride's car?) are wrong, because the car does not have type approval and you can't get a clearance certificate for the so-called D-Spot. You have to go to the mounting point on the C-pillar. For reference please check the manual of the belts. It is in german, but the pictures should be self explanatory (Contact me if there are language issues ).

Spinal Compression: There seem to be some severe misunderstandings about the nature of the injury. Essentially you have to worry about thge following things: One is the movement of your head to the back (headrest issues, sitting position, no headrests), failing of the seat (usually dislocation of the seat), failing of the headrest-seat connection (only the hip belt retains its function) and cutting your throat due to the inappropriate seat+belt configuration. What stocker discribes is spinal COLUMN compression which is very different from spinal CANAL/CORD compression and spinal CORD hyperextension. The latter two are far more likely to occur and given proper treatment reversible in most cases. Spinal column compression severe enough to occur in a young adult is rare/unlikely even in the stated case.



Summary for the OP: Since you are in the US the rules for a clearance certificate may be different even though the regulations in Europe are a lot stricter. Call Schroth (they are really friendly - at least at the german headoffice) about obtaining a clearance certificate and ask them what seats they would advise given the need for brackets. I'm doing the exact same thing now (I'm going to get the asm autocontrol II+Recaro seat and bracket).