I have been considering changing out my seats on and off for a while. I track my car a fair amount but do still drive it on the street. I have decided to keep them for a number of reasons, many of which I have read about on Prime: 1-it is hard to find a lower seat, especially with a thin bottom cushion. Also am reading about issues with seat/rail combos. 2- They are easy to get in and out of vs a race seat with a high bolster. 3- I like the adjustability. 4- they are reasonably light. I have decided to modify them a bit so I don't slide around quite as much. I am going to have the center portion of the seat changed out to ultrasuede to get a bit more grip. I am also going to add some ultrasuede to the upper corners of the side bolsters where my shoulders rub the seat. The shop I am using is going to create slots for the shoulder belts of my 5 pt harness to go through. I think this will make a big difference as they currently run over the top of my seat which is less than ideal. I am curious of others experience with doing this- especially the slots for the shoulder harness to feed through which makes me a bit nervous. I have a quote to have all of this done for $1200 for both seats, including them making a quality thin cushion for the driver seat to replace the cheapo but decent Dali cushion. The cost of this is less than buying one decent race seat. Would appreciate thoughts/feedback.Thanks
-
Protip: Profile posts are public! Use Conversations to message other members privately. Everyone can see the content of a profile post.
Modifying OEM seats
- Thread starter whitebois
- Start date
I have tracked my NSX's for years with the factory seats having the bottom cushion either replaced with the Dali unit or no bottom cushion at all (just a black bath towel laying over the seat floor). I have run with and without harness bars in both 4 and 5 point setups. I think the biggest issue is your build/body type and preferred seating position.
I like an upright seating position while on track and close enough to the wheel to allow the wheel to touch my arm about 1-2 inches past my wrist when extended fully, this is a little closer than others recommend but I am comfortable there. I am 6 ft tall about 200lbs, not really FAT but over-weight non the less. The kicker for me is my height is in my torso, not my legs. This is my primary issue with the NSX, in an upright seating position and a taller than average torso there is no real room for a helmet without removing the seat bottom cushion. In the coupes this worked out well I could sit up and had little issue being comfortable and finding a position I liked. Now I own a T and due to the roof design I have to adjust my seat position to a slightly more reclined position and a slightly longer reach to the wheel. I have adjusted to it but my comfort level at the extremes is just not there yet.
I used a four and five point setup in my coupes, both with the Dali harness bar. I had zero issues with the shoulder belts sliding around and for me the seat holes would have been of little to no benefit as my shoulder height is high enough in the seat for the holes not to factor into the belts ability to hold me into the seat. I also had my belts attached to the harness bar so they could not slide on the bar and change the belt position or angle to the seat. If you are a shorter guy or all your height is in your legs with a short torso this may not hold true for you. The Dali and I believe most of the bars made for the NSX do a good job of keeping the shoulder belts level with the top of the seat and that is what you want.
If you have issues with the belts wanting to slide off your shoulders, you can try having a shoulder belt tie made, we have these made for the Corvette guys because their OEM seats are horrible for track use. These tie straps are made of the same seat belt webbing used in the belts and are measured and made for each guys shoulder width, but what it does is hold the two shoulder straps at the exact width needed to fit your shoulders correctly in the seat and will not let them go any wider or slide off the shoulder down the sides of the seat. They are cheap to have made and I can have my harness guy make them if needed. I have not tried one in an NSX but I have not needed one as our seat design with a proper harness bar works well together and I have not had any issues, the C6 seat design has nothing to keep the belts in place on top of the shoulders and the more you tighten the belt the more they want to spread apart and slide down the sides of the seat. Really a bad design for a performance car seat.
Dave
I like an upright seating position while on track and close enough to the wheel to allow the wheel to touch my arm about 1-2 inches past my wrist when extended fully, this is a little closer than others recommend but I am comfortable there. I am 6 ft tall about 200lbs, not really FAT but over-weight non the less. The kicker for me is my height is in my torso, not my legs. This is my primary issue with the NSX, in an upright seating position and a taller than average torso there is no real room for a helmet without removing the seat bottom cushion. In the coupes this worked out well I could sit up and had little issue being comfortable and finding a position I liked. Now I own a T and due to the roof design I have to adjust my seat position to a slightly more reclined position and a slightly longer reach to the wheel. I have adjusted to it but my comfort level at the extremes is just not there yet.
I used a four and five point setup in my coupes, both with the Dali harness bar. I had zero issues with the shoulder belts sliding around and for me the seat holes would have been of little to no benefit as my shoulder height is high enough in the seat for the holes not to factor into the belts ability to hold me into the seat. I also had my belts attached to the harness bar so they could not slide on the bar and change the belt position or angle to the seat. If you are a shorter guy or all your height is in your legs with a short torso this may not hold true for you. The Dali and I believe most of the bars made for the NSX do a good job of keeping the shoulder belts level with the top of the seat and that is what you want.
If you have issues with the belts wanting to slide off your shoulders, you can try having a shoulder belt tie made, we have these made for the Corvette guys because their OEM seats are horrible for track use. These tie straps are made of the same seat belt webbing used in the belts and are measured and made for each guys shoulder width, but what it does is hold the two shoulder straps at the exact width needed to fit your shoulders correctly in the seat and will not let them go any wider or slide off the shoulder down the sides of the seat. They are cheap to have made and I can have my harness guy make them if needed. I have not tried one in an NSX but I have not needed one as our seat design with a proper harness bar works well together and I have not had any issues, the C6 seat design has nothing to keep the belts in place on top of the shoulders and the more you tighten the belt the more they want to spread apart and slide down the sides of the seat. Really a bad design for a performance car seat.
Dave
Last edited:
I was just talking about this to a guy that owns a local track and safety gear shop in my area. Very knowledgeable guys of 30+ years experience and a serious shop. They told me not to use the harness I have with the stock seat because in a side impact the harness will not hold around the shoulder area. I didn't quite understand if he meant the body will slide out or the belt will slip off but he cited some examples of injury and even a death because of this. He recommended I have hoops made to attach to the seat for the belts or change the seat.
I've just about had it sliding around in my 3 point, it makes driving a chore, I literally have changed my shift points at Watkins Glen because around some high speed turns I am being pulled and I need to hold on to the wheel and don't want one hand on the shift knob.
Dave I am trying to picture either of the two things you are talking about and cannot. Can you post pics or elaborate a bit please?
I've just about had it sliding around in my 3 point, it makes driving a chore, I literally have changed my shift points at Watkins Glen because around some high speed turns I am being pulled and I need to hold on to the wheel and don't want one hand on the shift knob.
Dave I am trying to picture either of the two things you are talking about and cannot. Can you post pics or elaborate a bit please?
See if this drawing helps. Did the guy look at your seats and belts with you sitting in the seat and the belts on? Do you have either belt stops or a way to keep the belts from sliding on the harness bar? Everyone will have an opinion on what is safe and what is not, while I do not make a practice of rolling my car or studying those that have, anything you can do to keep you in your seat and able to concentrate on controlling the car in stead of holding your body in the seat will most likely be a plus.
Dave
Attachments
No they didn't see the car they looked at photos of the seats on google. This was a phone conversation and I will be seeing them next week.
So this strip just ties the two shoulder belts together? can't they both still slide on the harness bar left or right?
So this strip just ties the two shoulder belts together? can't they both still slide on the harness bar left or right?
The strap is not ment to stop the straps from moving on the harness bar. You can either weld in metal loops to the harness bar to stop the straps from moving on the bar or use bolt on collars on the harness bars on both sides of the straps.
The tie strap is ment to be at the seat back to keep the harness shoulder belts tied together to prevent one or both from sliding off your shoulders. The strap can be used either on the back of the seat or on the front of your seat between you and the seat back. Both methods work but behind the seat is more comfortable, in front of the seat back is easier to keep possitioned correctly when you are belting yourself.
I will be at Barber this weekend with two corvettes we run this setup on I will try and snap a few pics of it in use on a vett.
Dave
The tie strap is ment to be at the seat back to keep the harness shoulder belts tied together to prevent one or both from sliding off your shoulders. The strap can be used either on the back of the seat or on the front of your seat between you and the seat back. Both methods work but behind the seat is more comfortable, in front of the seat back is easier to keep possitioned correctly when you are belting yourself.
I will be at Barber this weekend with two corvettes we run this setup on I will try and snap a few pics of it in use on a vett.
Dave
Not sure I should keep doing your homework for you but here you go.
http://www.mcmaster.com/#shaft-collars/=oitbc7
Dave
Thanks for the very thoughtful response. I too am 6' and a long torso. I can fit in the car comfortably, but not with a helmet. So the Dali cushion helps. I did put some zip ties on the sides of the belts on the harness bar but I think adding a collar like you say could be useful. I may be a tad shorter than you as I feel like if I get the seats slotted the belt will come through onto my shoulder yet still be roughly level with the bar. This might lessen the feeling of moving around. Part of my problem is I have a tendency to sit forward and not press against the seat back. This is bad because to do this, I have to pull on the wheel- less than ideal... So I think I am going to go ahead with the seat slots. Its reversible by simply not using the slots. I may also fab up a tie- it should be pretty simple. So thanks for the good suggestions.
Update? Did you get your seats modified?
I did but i learned a few things. I had alcantara done for the inserts and that helped a lot as far as the sliding around goes. I found out you cannot just get holes for The shoulder belts cut into the seats due to the fact that there are steel bars inside the seat that hold the headrest extensions. So i had the shop make some nylon loops tied in to the top of the seat that hold the shoulder belt inplace. I will try to post a picture later. Also got rid of the wrinkly leather on the door inserts and replace with alcantara. Looks a lot better.
