Miata seat mounting

Progress on my Miata is coming along nicely -- my new roll bar is installed, and now it's time to mount my Kirkeys. I shelled out for these aluminum side mounts, but I can't make them work.

(Ignore the horrible submarine belt mounting point, that was the PO and will not be reused).

No matter how I finagle it, the transmission tunnel pushes the inboard bracket too far to the left, which puts the seat back into the main roll hoop. After a little head scratching and some googling, I've decided to abandon the side mounts and make some bottom mounts similar to this:

One piece of bent stock to connect the front and rear OEM mounting points, and a second piece coming up in the front to set the appropriate angle, terminating just in front of the rear mounting bump. My vision looks very similar to this picture I found except I planned on using 1/8" aluminum flat stock instead of steel, and I hadn't planned on making a cross piece. Also, instead of welding I was just going to use the front floor bolt and the rear seat bolt to hold the two pieces together I figure the seat itself will connect the two pieces side to side.

Seems strong enough to me but the mounting solutions I've seen on google for SM and whatnot run the gamut from "Really? You're doing that?" to "I used up all of the metal in my shop to make these." I want to make sure I'm not being foolish. I considered boxing them in and having someone skilled in welding aluminum make them more solid, but I'm not sure that's necessary. Thoughts?

Watching intently. Going to attempt to weld my Cobra side brackets to a pair of stock sliders in the next few days for my own car.

Previous thread i had on the subject, might be something helpful in there for you!

https://grassrootsmotorsports.com/forum/grm/budget-miata-buckets/97992/page1/

Thanks for the link. What I'm learning is that everything in this car is a game of millimeters. The new roll bar has bought my precious millimeters of seat layback, my steering wheel bought my precious millimeters of leg room, and with some strategic removal of bits of carpet and by carefully following the contour of the floor, I just might get these seats to work. Even with the bottom of the seat touching the floor I'm sweating the broomstick test. I couldn't even imagine adding sliders to the mix.

I lucked out in that i'm only 5'9".

I think Keith has sliders in the Targa car, though. I think. He's taller than me, and i think those Corbeau FX1 Pros naturally sit higher than some of the other offerings. He may have modded the bottom cushions though.

I believe some people bash in the trans tunnel a bit to get the rail moved out far enough. The second set of mounts looks like what I have but I just used the flat bar to mount the side-mounts to.

Beware that the driver's inside front bolt is significantly offset from the rear bolt. If you want to get them both on the same piece of bar stock, it's going to have to be pretty wide.

How do you plan to make the bends for the brackets you described?

Have you checked that 1/8" aluminum is sufficient for your needs? I went with 1/8" steel on my brackets because that was the minimum FIA spec for steel seat brackets. Aluminum brackets needed to be thicker, IIRC.

Woody had a thread on here years back about mounting Miata seats, you might look at that.

peter wrote: Beware that the driver's inside front bolt is significantly offset from the rear bolt. If you want to get them both on the same piece of bar stock, it's going to have to be pretty wide.

Crap, thanks for the heads up. I was eyeballing it and they looked parallel. I'm using 2" stock, this could be an issue. I'll go measure some more.

peter wrote: How do you plan to make the bends for the brackets you described?

With a little help from our good friends at HF. :) I've bent a lot of brackets out of aluminum stock before using a vice and a hammer, but for something my butt's going to be on I decided I'm going to pick up an actual bender and cross my fingers.

peter wrote: Have you checked that 1/8" aluminum is sufficient for your needs? I went with 1/8" steel on my brackets because that was the minimum FIA spec for steel seat brackets. Aluminum brackets needed to be thicker, IIRC.

This is an HPDE car, and I haven't been able to find any generally accepted club requirements. I know the brackets I'd planned on using, the Kirkey aluminum side brackets, are only 1/8" thick and are simply bent aluminum stock, so I was using those as a rough guideline. The seats themselves aren't FIA approved (Kirkey Intermediates).

EvanB wrote: I believe some people bash in the trans tunnel a bit to get the rail moved out far enough. The second set of mounts looks like what I have but I just used the flat bar to mount the side-mounts to.

For what it's worth, some of us SM guys do some cutting of the tunnel and install this notch-out panel instead which gives all the room you need to install seats.

http://mazdaracers.com/store/product/59-tunnel-notch-out-panel/

Most also eliminate the rear seat mounts and mount to the floor with the appropriate backing plate as required by the rules - and common sense.

Here is an example: http://www.gforce.com/products/harness/100H.php

steronz wrote: my steering wheel bought my precious millimeters of leg room

Which wheel did you go with? Did it need any adapters to install?

MattGent wrote: Which wheel did you go with? Did it need any adapters to install?

Old Momo wheel with a 3" spacer and the Works Bell short hub. I already had the first two things from my old car, I went with the short hub because the measurements worked out.

Miata seat installation threads make my brain chafe, but this really is your best starting point:

http://www.good-win-racing.com/Mazda-Performance-Part/61-0555B.html

Swank Force One wrote: I lucked out in that i'm only 5'9".

The best way to gain height is to cut the rear seat mounts out of the chassis and weld in flat plates instead. That knocks the rear of the seat down by an inch or two.

My idea didn't work.

Cutting out the rear seat mounts isn't going to fix all of it either. Anyone have input on cutting out the fronts as well? Or should i just give up on the sliders and just bolt the Cobra side mounts directly to the floor behind the front mounts and hope i'm not too far back?

I just can't make it work; millimeters aren't cutting it for me. All paths I take lead to the same conclusion -- berkeley the transmission tunnel. I went ahead and ordered the cutout pan that amg_rx7 linked to. Thanks for that! It wouldn't have occurred to me.

Man, I wonder if it's thin seats or what. I have a MOMO Corsa seat on factory miata sliders and it works perfectly. Easy to adjust and more than an inch lower seating position from the stock seat. I did have to reshape the seat in the left shoulder region so the door could shut but otherwise, simple bolt in.

KyAllroad wrote: Man, I wonder if it's thin seats or what. I have a MOMO Corsa seat on factory miata sliders and it works perfectly. Easy to adjust and more than an inch lower seating position from the stock seat. I did have to reshape the seat in the left shoulder region so the door could shut but otherwise, simple bolt in.

How tall are you?

5'9"

Swank Force One wrote: I lucked out in that i'm only 5'9". I think Keith has sliders in the Targa car, though. I think. He's taller than me, and i think those Corbeau FX1 Pros naturally sit higher than some of the other offerings. He may have modded the bottom cushions though.

Targa car setup: Corbeau FX1 Pro with the rear extensions removed, factory seat mounting points removed, foam replaced with Backsaver memory foam, seats bolted right through the floor, hammer time on the tunnel. I did everything I could to get myself low. My setup wouldn't fit on a car with an interior, the wings on the seats hit the doors. More hammer time.

We use Planted brackets and Sparco seats at FM.

Buying a pair of PCI brackets. Will keep everyone posted on how it works. Looks like i should be able to drop at least 2" off where i am now.

I've got a still in the box Bride lowmax bracket for the passenger side still uninstalled, and use the drivers side one in my car you cant find pics/it would help. My seat is definitely multiple inches lower especially if you pull the rather tall cushion out of the bride seat

Update time! I've been travelling a lot lately, but it's getting down to crunch time to get this thing buttoned up. I went ahead and installed the transmission tunnel cutout linked above. This involved drilling out the spot welds for the two of the three stock seat mounts. I had someone extend them to the new trans tunnel and weld them back in.

That done, I went about making some brackets similar to many of the ones linked above, basically drawing a straight line between the front and rear mounting pads:

That didn't work so well:

So back to the drawing board for some low pro brackets:

Probably not as strong but I figure with a seat back brace (ordered) it'll work.

No picture of that seating position yet, I've spent the last 2 days moving all of the pedals forward 2+ inches so my knees won't hit the steering column. More to follow.

First post!

I had a similar issue. I'm 6'0", and thin build. Millimeters to spare in any direction. I went with the UltraShield Rally Pro seats from TrackDog Racing (not affiliated, just a customer and fan). In order for me to clear the roll bar, I decided to go with their "driver's side LOW" floor mount. The seat is bolted directly to this mount, which as you can see gets directly bolted to the floor. The LOW version removes the rear elevated mounting points, saving a lot of space. I can now easily clear the broomstick test, with room to spare. In summary, the seat, bracket, removal of rear elevated mounting points, got me more than low enough.

This worked for me. Good luck.

When I had my SpecMiata I used an Ultrashield seat and ran bolts through the seat bottom and the floor . You can't get any lower than that without lowering the car floor.

Woody wrote: Miata seat installation threads make my brain chafe, but this really is your best starting point: http://www.good-win-racing.com/Mazda-Performance-Part/61-0555B.html

Yeah, I have my FX-1 Pros mounted on Corbeau sliders mounted to a set of those. They're pretty solid and fit nicely. I'll probably have to take the seat pads out to pass a serious broomstick test, but they just velcro in.