I want to put a 4 point clip-in harness in our S2000 for racing, but I am having trouble figuring out how to do it without wrecking the trim.

Any suggestions from you guys ???

Cheers,
slick (OZ)

 

4 point harnesses are not recommended due to 'submarining'. You'd probably be safer with the stock 3-point belt.

 

Not to mention spinal compression with out a roll bar. Go with the Elda Engineering roll bar.

You will have to say goodbye to some trim.

 

What about the stock 3-pt harness prevents submarining, that a custom 4-pt wouldn't have?

 

Seat belt retractors

 

Is it not, however, a common practice to intentionally lock up one's stock 3-pt harness before heading out on course, thereby negating any effect from the retractors?

 

Stock seatbelt has more play in the upper part than a 4 pt--so your body flies forward first, which actually tightens the belt across your hips, preventing much movement down low. When you have a 4 pt. the 'slack' in the shoulder harnesses, instead of tightening the lap bellt, pulls it up and this, combined with less body motion up top, can allow the body to slide under the belt. The way to prevent this with a 4 pt. is to make sure that your lap belt is extremely tight. I've been in one frontal accident (and one side) with 4 pt. belts and didn't submarine. If you do submarine, however, your abdomen will suffer serious trauma and, if the car you're in is travelling at even moderate speeds, your back will break. Happened to me while I was in the back seat of an 88 Civic wearing a cost saving 2 pt belt.

 

I don't believe the locking of the belt affects the retractors. The retractors actually have small explosive charges in there designed to remove all slack from the belts instantaneously. Asura also has a very good point in that you don't want your head holding up the car in the event of a rollover. Either run a 5 or 6 point with a bar or stay with the stock 3 point. That is my recommendation. However, I did not sleep at a Holiday Inn last night.

 

 

After studying the issue in detail, I've also decided that the 5 or 6 point restraints, roll bar, and racing seat are all a single package. Either get them all, or get none of them. Most people also recommend staying away from four points completely.

In an impact, with the three point your torso twists. This twist is what prevents submarining. With the four points, there is no twist. Your whole body can slide right under the belts. There is one four-point manufacturer out there who is claiming they have an anti-submarine feature in their 4-points. One of the upper straps gives way a little bit under load. The puts the twist back into the torso.