g6civcx
10-17-2009, 08:37 AM
A bunch of members requested me to do this so don't flame me if the information already exists and/or not interesting.
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The stock S13 has 37.8" of headroom (source:Edmunds.com): 1990 Nissan 240SX specs, auto safety at Edmunds (http://www.edmunds.com/used/1990/nissan/240sx/1546/specs.html)
I measured the bottom of the seat to the headliner on my seafam green fastback with no sunroof and it appears to be about 37.5":
http://nguyenconsult.com/zilvia/SeatRails/Rail1.JPG
The first thing you'll need to do is remove the seat. There are two (2) bolts on the front. Use a 14mm socket.
http://nguyenconsult.com/zilvia/SeatRails/Rail2.JPG
And two (2) more in the back. Also 14mm. Pop out the plastic trim pieces to expose the bolt and nut.
http://nguyenconsult.com/zilvia/SeatRails/Rail3.JPG
Tips: if you have problems with the bolts/nut, dab them with a little bit of PB Blaster and let soak. Use a breaker bar and apply gentle pressure.
It's easy to strip the threads here so be careful. Install and remove bolts slowly. Try to hold the seat up to take the pressure of the bolts so you don't shear them on the seat rail.
Remember to unplug the seatbelt sensor.
Then bolt up the aftermarket rails using the stock bolts and nut. This is a Bride FG. Note the extra hole on the left rail. Apparently it's to fit the Skyline.
http://nguyenconsult.com/zilvia/SeatRails/Rail4.JPG
This is the crucial part. I measured everything myself so dimensions are approximate.
The rails come with brackets to bolt on to the side of the seat. They do have some adjustment.
The biggest seat they can fit is about 16" outside width.
You can also move the brackets in to accomodate a smaller seat. I have them set at the thinnest position possible and they appear to fit a seat with 15" outside width.
Anything smaller or larger than 15-16" and you'll have to fabricate your own mounting brackets.
I also measured the maximum height possible.
The seat can go as low as possible until it hits the catalytic converter hump. The seat goes between the rails so there's nothing on the bottom of the rails to stop the seat (as stated by some of the members here). Basically you can go as low as you want until you hit the floor.
I measured from the highest point of the floor, the cat hump, straight up to the headliner. It's about 36.5".
As far as length goes, I suppose that anything that can fit between the steering wheel and the rear seat would work.
So let's say using a Bride FG sidemount rail on a stock S13:
15-16" outside diameter. other sizes need custom brackets. You can squeeze something up to 17" but you'll lose about 1-2" of helmet clearance because the seat has to go over the rails and not between.
Anything over 17" you'll have to start modding the brackets to extend and move the locking handles out so the handles don't get trapped under the seat. Look at the picture and think about how you need to mount the seat to ride on the rails.
Obviously anything that's too wide to fit between the transmission hump and the door panel won't work. Use common sense here.
I went ahead and measured between the door panel and the transmission hump. A seat that is wider than 21.5" at the base will not physically fit unless you start hacking up stuff. So keep that in mind while trying to fit some of the bigger seats.
Let's say 36" max height. Anything higher than this won't physically fit between the cat hump and the headliner.
Length let's say be reasonable. If it can't fit between the steering wheel and the rear seat then obviously it won't fit at all.
I also have another solution for people who want maximum lowness. The Dent Sport Garage car gave me some inspiration. Stay tuned.
==================================
The stock S13 has 37.8" of headroom (source:Edmunds.com): 1990 Nissan 240SX specs, auto safety at Edmunds (http://www.edmunds.com/used/1990/nissan/240sx/1546/specs.html)
I measured the bottom of the seat to the headliner on my seafam green fastback with no sunroof and it appears to be about 37.5":
http://nguyenconsult.com/zilvia/SeatRails/Rail1.JPG
The first thing you'll need to do is remove the seat. There are two (2) bolts on the front. Use a 14mm socket.
http://nguyenconsult.com/zilvia/SeatRails/Rail2.JPG
And two (2) more in the back. Also 14mm. Pop out the plastic trim pieces to expose the bolt and nut.
http://nguyenconsult.com/zilvia/SeatRails/Rail3.JPG
Tips: if you have problems with the bolts/nut, dab them with a little bit of PB Blaster and let soak. Use a breaker bar and apply gentle pressure.
It's easy to strip the threads here so be careful. Install and remove bolts slowly. Try to hold the seat up to take the pressure of the bolts so you don't shear them on the seat rail.
Remember to unplug the seatbelt sensor.
Then bolt up the aftermarket rails using the stock bolts and nut. This is a Bride FG. Note the extra hole on the left rail. Apparently it's to fit the Skyline.
http://nguyenconsult.com/zilvia/SeatRails/Rail4.JPG
This is the crucial part. I measured everything myself so dimensions are approximate.
The rails come with brackets to bolt on to the side of the seat. They do have some adjustment.
The biggest seat they can fit is about 16" outside width.
You can also move the brackets in to accomodate a smaller seat. I have them set at the thinnest position possible and they appear to fit a seat with 15" outside width.
Anything smaller or larger than 15-16" and you'll have to fabricate your own mounting brackets.
I also measured the maximum height possible.
The seat can go as low as possible until it hits the catalytic converter hump. The seat goes between the rails so there's nothing on the bottom of the rails to stop the seat (as stated by some of the members here). Basically you can go as low as you want until you hit the floor.
I measured from the highest point of the floor, the cat hump, straight up to the headliner. It's about 36.5".
As far as length goes, I suppose that anything that can fit between the steering wheel and the rear seat would work.
So let's say using a Bride FG sidemount rail on a stock S13:
15-16" outside diameter. other sizes need custom brackets. You can squeeze something up to 17" but you'll lose about 1-2" of helmet clearance because the seat has to go over the rails and not between.
Anything over 17" you'll have to start modding the brackets to extend and move the locking handles out so the handles don't get trapped under the seat. Look at the picture and think about how you need to mount the seat to ride on the rails.
Obviously anything that's too wide to fit between the transmission hump and the door panel won't work. Use common sense here.
I went ahead and measured between the door panel and the transmission hump. A seat that is wider than 21.5" at the base will not physically fit unless you start hacking up stuff. So keep that in mind while trying to fit some of the bigger seats.
Let's say 36" max height. Anything higher than this won't physically fit between the cat hump and the headliner.
Length let's say be reasonable. If it can't fit between the steering wheel and the rear seat then obviously it won't fit at all.
I also have another solution for people who want maximum lowness. The Dent Sport Garage car gave me some inspiration. Stay tuned.