Has anyone done this before? (seat rails inside)
 

I'm trying to get rid of some height and weight. I previously had my old bottom mount MOMO Start seat bolted to some stock rails.

Has anyone chopped up a stock rail and used it to make some rails?

I've got the top part off, I just have to grind off the rivets, cut a piece to length, and bolt it to the old rivet holes.
Attachment 189330

Bad idea? Just make it new out of the same steel strips?

Bad picture, I know, but it's of the bottom half of a stock rail. I'll be cutting bits off to only leave the front and rear pieces. Hoping it'll save me about an 1" of height, letting me pass the broomstick test without chopping up the floor.

For the amount of work it is to make a solid mount out of flat steel I wouldnt bother with the stock one. And it won't get you very low

Btw I pass the broomstick test with helmet with 2" to spare and I'm 6' tall. That's with my custom mount that was designed to have the seat as low as possible without cutting the humps. The rear part of the shell on my seat touches the floor.

Glad to hear it can be done without cutting the humps. It's still street legal, I wouldn't mind throwing a stock seat in there for a summer or spring for some DD comfort. Of course now I need new rails.

Just in case anyone is reading this in the future, y'all were right. It's much easier and more beneficial to just use two strips of metal.

I used the front and rear brackets from the stock rails, and although it took away about .75" of height, it still wasn't enough, and I couldn't access the rear bolts to tighten them. Waste of $4.89.

$9.78 later, I had two more strips of metal, and drilled some holes about 4" further back from the stock rear holes, so I could bolt it up behind the seat. They're lighter, lower, and easier to make. Lesson learned.

Now to sign up for a track day so I can actually use my new broom stick test passable car.

Pics of your fab work?

I'll take a few, they won't be great though. It's a pain reaching under the car for the two back bolts. I was planning on painting them, probably won't because of that. I'll snap what I can.

Haha.. yeah it takes a while to get my seat bolted in. I have a shorty 14mm spanner. And threading the bolts is annoying.

I got some spare rails in my garage if you really want them. Shoot me a pm.

Sort of off topic, but what thickness of steel are you guys using for the seat mounts? I need to mount mine soon.

I used 1/8", for the short length that's required it seems strong. If I did it again, since I'm now using a slightly longer length, I might have gone with 3/16" or 1/4". Would've been a bitch to bend though.

I used 3/16, bent it with propane no problem. Threw it in the vice heated up the joints and pushed where I needed it. Would have been even easier with MAPP gas. I'm a tiny fucker too.

so you made two new rear holes? did you get any pics?

Its not terribly interesting. Rails had to extend behind the seat since there's no way a wrench was getting under it to the stock rear holes.

I just used a hammer/bench vice.

I'm also struggling to picture this, if anyone has pictures of the brackets mounted, would be appreciated.

Seats out of the car, so this is the best I can do.
Endless tire pile:
https://www.miataturbo.net/attachmen...ine=1322748356
https://www.miataturbo.net/attachmen...ine=1322748356

Aha, thats great, thank you. That doesn't seem so hard.

i made the same but was able to bolt to factory locations. i have an aluminum seat though, so i used hardened steel washers and bolts to attach the seat to the rails. theres enough room to reach under the seat to bolt them on. i just have to bolt the rails down first, then attach the seat. beacuse i have an aluminum seat, i also made a bracket for the seat back that connects it to the roll bar and makes it rock solid.

Those home made brackets would work well/better with side mount seats. I presume you could then mount the seat in afterwards.... giving beter access to the seat mount to chassis bolts ..............?

Yes, it's easier, but making side mount brackets at home is much harder than bottom mount.

Keeping two square bolt patterns inline, both side/side for tranny/door clearance, and front/back for foot/beer belly clearance was difficult enough. Trying to keep track of all that plus back/forth tilt and having one of the bolt patterns in another plane doesn't sound fun.

depending on the width of the seat and the size of the "feet" on the side mount, you will not be able to line up the side mount on the steel strips and the 2 humps in the floor.

Ultimately you probably could, but on the driver's side I wasn't able to get the last bit to fit. 2" was too wide and impacted on the transmission tunnel, but 1.75" wasn't wide enough to get the bolt holes to line up on the stock mounts. so therefor, I just cut the rear humps and then made a 6"x4" plate backing plate and bolted it to the floor.

I was more thinking the commercial side brackets you can buy to match the seats. I thought they had a lot of room on the bottom part of the "L" shape to match whatever spacing you owuld need but sounds like I am wrong.

As far as the tilt, that is taken care of by the commercial brackets having multiple postioning holes pre drilled.......isn't it?

Well, like I said, some may work and some may not work. I was able to get my passenger's side to work fine, but the driver's side a lot more difficult thanks to our tapering transmission tunnel bullshit. You will just have to try it out and see.

The tilting can be taken care of. if you have multiple holes then yes it will be taken care of. If you don't you can always add some. Also, if you cut the rear humps, you will have some angle naturally added in.

Even with the stock humps left in there is a little bit of angle.

I have side mounts installed using strap steel/aftermarket side plates. It's difficult to get to the trans tunnel bolts after the seat is in so I install it assembled. Only difficult part was beating in the trans tunnel/door panel to get the seat to fit straight.

Ah, yes, premade brackets. Thought you might be making them yourself, which sounds like no fun.

Whatever you do, I'd suggest buying something like the MOMO Start (newer version) which has both side and bottom mounts, so you have a variety of options.

Solution:
https://www.miataturbo.net/attachmen...ine=1322788908

I hammered it plenty, but I Guess not enough. waht size hammer did you use? and did you hammer at the front mount or what?

I didn't have to, with a first gen MOMO Start, although it's slightly off center, making it a little painful on my arthritic knees.

The slightly off-center part is what I can't stand, and with bad knees I'd put up with it even less. No way round that but to do it proper. It's either a lot of work or costs a bit to have someone do it, but it is 100% worth it. My Sparco Circuit is an incredibly narrow bottomed seat, and still, with the butt 1/2" off the tub, to center it the trans tunnel needed alteration.
I'm a die-hard DIYer and on a tight budget, but that was one thing I was happy to pay to have done. I don't think you'd regret it.