hey guys, so ive done some looking around and cant really find a deffinative aswer with the search so here it goes.

i picked up some 4pt harness's for my 90 iroc, now i dont really wanna put in a big *** roll cage, is there anyway i can safely set these up without one? im re building the car so ive got no problem with custom stuff and fabrication, but i still need the backseat to be usable.
any ideas/thoughts would be great.


also whats the lowest number of pts a roll cage can have? 4-5? can these still have back seat use?(safely)

 

I believe a roll cage typically has at least 10 points and a roll bar has a minimum of 4 points. No passenger is safe in the back seats with either of them.

Since your car is a 1990, it should have rear shoulder belts. Just make something similar to what the fourth gen cars use.

 

If you do a search, you can find pictures of harness bars that others have fabricated. It's a little useless to have a 4 or 5 point harness without a roll bar. Some autocross racers use a harness bar because they don't need a roll bar but still want to use a 5 point harness.

The trouble with using a 5 point harness, if it's done up properly, your body should not move in the seat. This means everything needs to be within arms reach. For street driving you can't lean to reach anything unlike an OEM belt will allow.

The autocross racers will use both. The OEM belts are kept in the car for street driving and the 5 point harness is used on the track.

 

i did some reading and was just concerned about if i was in a crash that it would adversley affect me, ie the roof crushing my head in a rollover and the belt compressing my spine .

 

That's why a lot of people with only harness bars use the stock seat belt for the street and the harness for the racing.

 

Your right. The factory belt is designed to allow the upper torso to fold over in the event of a roof pancake. 5 point harness not-so-much.

I wouldn't use a 5 point harness without a roll bar behind me for much more than an autocross. On a race track or street you should use the factory belts.

 

yea i tihnk im just gunna go without them now, ive got BRIDE racing seats and theyll hold me in just fine for racing/auto-x. just really liked the look of the 4 point, especially with the seats. there isnt a different 4 point style is there? or a after market 3 pt???

 

If you are planning on keeping the rear seat, forget about installing a roll bar. There is not way possible to properly build a roll bar with the rear seat in the way. The back stays need to mount to the rear shock mounts, NO WHERE ELSE IS APPROPRIATE, PERIOD. You can't mount the cage to the rear shock towers with the rear seat in the way. For those that have put the back stays clear back in the rear well, they've just intruded into the crumple zone and insured that if they get rear ended, they'll get a main hoop right in the back of the head. Also those that bend the back stays to go over the rear seat are just wasting their time as well. They've pre-bent their tubes so in the case of a roll over they will just continue bending. Plus with them bent, you've just made a big spring out of them and they will offer little to no structural support.