miataman86 New Reader
Feb. 26, 2012 4:41 p.m.

I'm looking to replace the seats in my 91 Miata. I will be doing some autocross soon and I want something thats more supportive because lets face it, the factory seats really have no lateral support. I'm not really too sure what size will fit without having to do modifications to the transmission tunnel. I will be driving it mainly on street as my DD, but I'm looking for a seat that will give me more support when I get into autocross and future HPDE. Dont want to break the bank, but I dont want something that will be a crapcan of a seat after a few months or so. Any suggestions on getting a fixed position or a reclining type? I'm mainly looking for a driver seat mainly. The passenger seat can come a later date.

BoxheadTim SuperDork
Feb. 26, 2012 4:45 p.m.

Foamectomy seems to provide a little more lateral support - might be worth a try.

miataman86 New Reader
Feb. 26, 2012 5:06 p.m.

Ive thought about that too. What would be the cost of doing that? How would I go about getting it done?

BoxheadTim SuperDork
Feb. 26, 2012 5:12 p.m.

Just Google for foamectomy - from reading up on it (I haven't done it on my Miata yet, but I've been in cars that have had it done) you should be able to DIY that. In my case the cost is likely to be the cost of an electric carving knife and the various trim installation tools.

In my case I also have to get the cover repaired as the leather seats on mine are suffering from the usual splitting vinyl but other than that I think it's something the average GRM should be able to do.

miataman86 New Reader
Feb. 26, 2012 5:16 p.m.

Cool. I will look into it. I might opt for a fixed type racing seat too still. I got a 5 point harness coming soon and I will be soon placing the order for a harness bar. The thought of a 5 point harness in a non race type seat seems a little wierd, but i will still look into it. perhaps doing a foamectomy on the race seat would be an option.

JoeyM SuperDork
Feb. 26, 2012 5:25 p.m.
miataman86 wrote: Ive thought about that too. What would be the cost of doing that? How would I go about getting it done?

Keith's locost book has a few pages on seats. He used wire cutter to remove the hog rings, then took the upholstery off. He cut the excess foam with a serrated knife. I am sure that - with the word miata in the title - he will chime in with more details.

miataman86 New Reader
Feb. 26, 2012 5:26 p.m.

Lemme refraise that....the option of getting a fixed seat and getting the custom mold of my body to the padding like they do for F1, NASCAR, and such is what I meant. With the styrofaom pellets, bean bag, and the resin they use. Involves A LOT of sitting, but its a one make type seat.

Keith SuperDork
Feb. 26, 2012 6:35 p.m.

The new Miata book has a bit on modifying Miata seats too. You can make a pretty significant difference with some good foam carving. Most people just carve the bottoms, I do the back too and build in some nice lateral support.

If you want a foamed seat, check Pegasus racing. They'll have the materials. Get yourself a used Spec Miata aluminum job as a start.

Some Confor foam in an aluminum Spec seat might also be fairly comfortable.

racerboy000 Reader
Feb. 26, 2012 6:38 p.m.

any suggestions for fat boy seats ? Car has a roll bar and my head is a little too close to it.

JoeyM SuperDork
Feb. 26, 2012 6:48 p.m.
racerboy000 wrote: any suggestions for fat boy seats ? Car has a roll bar and my head is a little too close to it.

Carve the bottom foam out of it like Keith suggested.

Also look at this recent thread

fastoldfart New Reader
Feb. 26, 2012 7:22 p.m.

The foamectomy on the base of my NA helped gain a bit of headroom but didn't do much for support. The spec Miata seat looks like it would provide support but is probably a bit hardcore for street driving. http://www.ultrashieldrace.com/prod.php?id=9

Keith SuperDork
Feb. 26, 2012 9:04 p.m.

That's why I carve into the backrest as well. Here's one in progress, I think I took an inch or so out of the back. After the picture was taken, I carved into the shoulder area a bit - because I have wide shoulders and I cut this seat to fit me Made a big difference in comfort and lateral retention.

Then we reupholstered it with suede in the middle for more traction.

Similar work, different application. But you can see the cuts on the back of the seat.

DaveEstey Dork
Feb. 27, 2012 6:53 a.m.

I did the foamectomy on my Miata seats, bottom and back for the driver's seat and just the bottom for the passenger seat.

I did mine with a Henckle bread knife but if I was going to do another set I'd buy an electric carving knife just to make it a little quicker.

Totally worth the effort though.

kazoospec Reader
Feb. 27, 2012 7:22 a.m.

For what its worth, if you don't want to do it yourself, I was quoted $150 by a local uphostery shop to dissassemble the seat and custom cut the foam for the depth of seat and backing I wanted, then re-assemble. I've read the "How to's" enough that I think I can handle it (even though I'm not very mechanical) and, once the weather breaks, I'll do it myself. From what I understand, as long as you cut carefully and don't hack everything up, you can just put the pieces back in if you don't like it. Seems fairly low risk to me.

miataman86 New Reader
Feb. 27, 2012 7:30 a.m.

Im 5'8" and about 170 lbs. Any suggestions as to which size seat i should get? 16 or 17 inches? Im gonna go with the NRG fixed type seat? They make them in Large, Medium, and Small. I know the small wont fit me, so should I go with the medium or large?

mistanfo
mistanfo SuperDork
Feb. 27, 2012 7:54 a.m.

15 or 16. I am 260lbs, though admittedly deeper than wide, and can sit in a 16.

BoxheadTim SuperDork
Feb. 27, 2012 9:14 a.m.
miataman86 wrote: Im 5'8" and about 170 lbs. Any suggestions as to which size seat i should get? 16 or 17 inches? Im gonna go with the NRG fixed type seat? They make them in Large, Medium, and Small. I know the small wont fit me, so should I go with the medium or large?

Have you checked that all those sizes would fit a Miata? You're pretty constrained as to what you can fit to the car and the larger seats might not even fit.

failboat Dork
Feb. 27, 2012 9:40 a.m.

i did a quick and dirty foamectomy on mine when I had it (1993) I am 6' and 170lbs. Tilt your seat forward and slide it all the way forward, needlenose pliers prys open the 3 rings at the bottom of the seat back that hold the back cushion upholstery shut, I simply removed the back cushion completely and didnt alter the side bolster foam. Re-use the same 3 rings to close everything back up.

Only takes a few minutes to do and is completely reversible if you dont like it. And its free. Worth a try first before you go cutting stuff.

It does allow you to sink into the seat more for more lateral support.

miataman86 New Reader
Feb. 27, 2012 2:32 p.m.
BoxheadTim wrote:
miataman86 wrote: Im 5'8" and about 170 lbs. Any suggestions as to which size seat i should get? 16 or 17 inches? Im gonna go with the NRG fixed type seat? They make them in Large, Medium, and Small. I know the small wont fit me, so should I go with the medium or large?

Have you checked that all those sizes would fit a Miata? You're pretty constrained as to what you can fit to the car and the larger seats might not even fit.

I'm gonna contact NRG about the sizings and thouroghly check to make sure that it will fit in my Miata.

Ian F SuperDork
Feb. 27, 2012 3:46 p.m.
BoxheadTim wrote: Have you checked that all those sizes would fit a Miata? You're pretty constrained as to what you can fit to the car and the larger seats might not even fit.

Given that Miata seats are some of the few that will fit (with modifications) into a Spitfire, I would also suggest further investigation.

When you do the foamectomy, is it hard to get the existing seat cover to fit back on tightly? I'm planning to do this for my GT6.

miataman86 New Reader
Feb. 28, 2012 9:32 a.m.

Like I stated before: I'm going to contact NRG in regards to the seat being able to fit. Its always best to know before you go. Going to contact them later this afternoon.

BoxheadTim SuperDork
Feb. 28, 2012 9:34 a.m.

Mind letting us know the outcome, please?

miataman86 New Reader
Feb. 28, 2012 1:42 p.m.

I shall let you all know the outcome.

miataman86 New Reader
Feb. 28, 2012 2:29 p.m.

Ok...I called NRG and they directed me towards a seat measurement spec list on thier site and I took some measurements. The seat width of an NA factory seat is 20" with the seat back width being 11 or 12" where my back sits. The width of the seat where my posterior goes is 11" at the back of it and where my thighs rest, the width is 13". The seat height is 33" with 7" or so clearance from the roof. The bottom of the seat length is 20" so I do think the NRG FRP-320 would work. may be a tad snug, but the FRP-310 would be a tad too big for me and it may not fit without the necessary modifications made. Rather have the seat fit like a glove and completely fill it in than have extra space, especially if I plan on doing autocross soon with HPDE in the near future. The only question remaining would be where do I find the necessary brackets to fit the sliders in and fully anchor down the seat?

You'll need to log in to post.

Also on Grassroots Motorsports

Modern Day Track Junkie

23 hours ago in Articles

Christina Lam went from the sidelines to full-on track enthusiast in 8 simple steps.

How Ben_Modified Wows the Crowd: 1 Part Imagination, 2 Parts Fabrication

1 day ago in News

Ben_Modified's build combines some of our favorite things.

2017 Audi A8 L

2 days ago in New Car Reviews

When it comes to luxury sedans, Audis are usually front-runners. The A8 L is the biggest and maybe most comfortable ...

Slight Project Pause for Our BMW M3

2 days ago in Project Cars

Few things slow down our project car progress more effectively than a broken arm.

Grassroots Motorsports Experience Ticket Renewals Have Been Sent

2 days ago in News

Check your inbox for our Grassroots Motorsports Experience renewals.

First Drive: Turbo ND MX-5

3 days ago in News

We hit the track with Flyin' Miata's latest power adder.

Project Turbo Miata: Fire Fighting

3 days ago in Project Cars

We transfer the fire system to our new Miata.

Vintage Views: GMC Syclone and Typhoon

4 days ago in Articles

All-wheel drive, turbo power and a Q-ship’s stealth.

Classic Motorsports Mitty Presented by Hagerty Celebrates Porsche

5 days ago in News

Gearhead heaven? We think it looks something like this.

Meet the Rebels Who Started the Cannonball Run

5 days ago in News

Relive those desperado days through movie excerpts, and hear the real facts and wild stories from the legends themselves.

This Weekend at the Mitty: The Ultimate Auto Festival

1 week ago in News

Gates open this Friday for the Classic Motorsports Mitty at Road Atlanta.

ND Miata Turbo Kits Now Available!

1 week ago in News

Add 70 horsepower and 70 ft.-lbs!

OUR SPONSORS

Grassroots Motorsports Magazine

Subscribe Today

Also get your instant access to the digital edition of Grassroots Motorsports Magazine!

Learn More
9jgWlOIdXdEsDk14hpCSXQpY7XlvBjUK