Floor drop kits
 

Anyone have any input on floor lowering kits? I have the tools and ability to do the install, but not the actual sheet metal fabrication.

So far, I'm only finding two kits out there, Advanced Autosport and Hanks Hot Rods:

Advanced Autosports kit

Hanks Hot Rods Floor kit

Quality? Install difficulty?

Any reason to spend 30% more on the HHR kit over AAS?

Any other kits I'm missing?

There's this one too: https://mazdaracers.com/store/produc...or-drop-panel/

Thanks, I figured there had to be other kits out there...

Iv installed 2 mazdaracer ones. They aren’t perfect but they fit pretty well. I drilled and plug welded both. it was lots of work but both turned out great.

I went with the DIY route on mine, it's not terribly hard to make yourself, its not pretty but I doubt after the beating a few years of racing dishes out the pre-bent ones would likely look just the same.

The HHR kit is longer and has the rocker panel side portion and opening for the lap belt already.

I made mine too. Had it done before UPS could have delivered one. I'll try to find some pics.

The advanced kit is designed for the main hoop cage footings on the floor. The HHR likely is using the seat belt tower/parcel shelf location and can extend the floor pan. The ESR kit is the best looking one in my opinion with dimples and takes you farther back and has a 45 slant up front

https://cimg0.ibsrv.net/gimg/www.mia...5e0cbeab31.jpg
Dug up an old pic of what a zero metal skills DIY floor pan looks like. Got my head away from the cage so I was happy with it.

Looks pretty good for not using a brake... what gauge material did you use?

Thanks, like I said it looked decent enough, after years of racing they get beat up a bit.

Whatever the SCCA spec was for Spec Miata, 16guage 0.065" I guess.

I ended up with some reinforcements around the seat anchor points for peace of mind, 1/8" IIRC

I wasn't happy with what was offered so I decided to make a custom kit for my car earlier this year. We have a handful of sets I could package up and ship out.

Basics

• CAD, CNC cut, bent, etc - Gr50 on the thinner stuff, 3/16 Gr36 on the seat brackets (per FIA spec)
• Weld nuts, etc where appropriate so no necessary fumbling - JIS metric aside from std SAE 7/16-20 for belt pickups
• Overlapping or T joints to facilitate errors in cutting/deformation during welding, relieved for weld fillets on overlaps.
• Designed to HTE400 centered on steering wheel, should be able to accommodate others...ask
• Sparco Corbeau double-locking sliders bolt directly to reinforcements, including provisions for 6X M8 instead of standard 4X M8 (we noticed an unsettling amount of deformation on a slider rear bolt hole after a high-speed crash in another car)
• With sliders, HTE400 in rearmost position height is the same as sitting on the stock floor. I'm 6' and can't see comfortably over the dash if I go any lower. You can go down 20-25mm if you loose the sliders. -5mm if you're aggressive with positioning the seat on the side brackets.
• Sliders on angle, set to equal eye height for 5'5 120# F through 6'0 220# M. Sub belt pickups set similarly (no need to adjust between occupants). Long-torso 6'2 M was fine as well, I didn't measure helmet height but no issues with OE hardtop/harddog bar.
• OE seat bolts in (with 3pt as well), so any existing direct-mount brackets should as well.
• Swap from race seat/harness to stock seat is minutes
• Front, rear cross car reinforcements - care taken to blend into side rails to maintain lateral crash load path. Longitudinal load path is maintained as well (continuous box section)
• Minimal tunnel intrusion - plenty of clearance to my 5+'' OD resonator in that area - ultimately, the seat -> exhaust -> transmission constrained the package
• Generous approach angle for impacts
• Full drop distance
• Seat goes back to bulkhead
• Side brackets that allow height adjust by only loosening the bolts (if you've messed with this before, removing tunnel-side bolts on a centered, side-mounted seat is always a nightmare). Oversized washers are used to ensure the seat is well-retained even if the bolts come loose or stretch in an accident.
• Frame rails for both sides (driver/passenger), including evenly-spaced pickups to mount your flat bottom, underbody reinforcements, whatever.
• All sorts of adjustability side-side and seat goes back to the bulkhead at min height.
• Brackets are powder coated semi gloss black
• OE carpet basically reusable with a few cuts near the seat base. My '99 has a full interior, including door cards and hardtop side latches.

Shoot me a PM or FB message at the link below if anyone is interested in a set. I have photos showing the build process, but haven't prepared instructions or packaging yet, so it'll take me a few days to ship out. It'll cost a hair more than the alternatives (but includes side brackets, frame rails, hardware). If you want them, sliders are separate (~$60 from summit IIRC)

Cheers,
Chris

www.facebook.com/GuarinoWatsonRacing

https://cimg4.ibsrv.net/gimg/www.mia...c9d515a72e.jpg
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Mods, let me know if this post breaks any rules and I'll adjust-as needed.

^ Nice!

cwatson, that looks fantastic.

I sent you a PM.

How many hours should it take a race shop to install one of these kits? Or conversely, how long would it take a qualified welder to weld it all in once it has been fitted into place?

Thanks!

^ You went down only to go up

I'm not a qualified fabricator or welder. Considering that, I'd estimate a solid day's work for cutout through welding from a competent race shop, not including finishing (paint, seal, paint for all-weather protection in my case). Half a day with a MIG and sander/grinder for the edges once the initial prep has been complete. We'll make an installation guide this weekend and your fabricator can quote from that (or the pictures above may suffice).

Careful DIY for me was a moderate weekend and a couple of weeknights painting and final fitting. That included grinding down welds, seam sealing, and painting all hidden surfaces.

:) The net result is where we wanted to be in the car for visibility. We're accustomed to a decent lay-back angle from formula cars (much nicer on the spine too), so no need to slam it. For those who want ultimate low, this design allows you to get 10-15mm lower than the others if you choose to leave the longitudinal reinforcement out, which I think is fair for a car with a full cage. I'd be cautious to do so on one with a partial cage.

Thanks
Chris

heat wrap material?
 

Very nice Seat Drop Set up Cwatson. I install the Hanks Hotrod Pan kit, simple design, but easy install. What heat wrap material are you using on the exhaust pipe? Very clean looking.

I'm in the process of installing cwatson's kit... I'll post an update when I'm finished.

For now, there's no turning back... :p

https://live.staticflickr.com/65535/...a4fa1287_c.jpg

Use fender washers on these bolts.
As it is, you barely using 20% or so of the surface of the bolt as the clamping area, it's rather unsafe and can tear right through in a crash.

You're referring to the side bracket to slider bolts, right?

Yes.

Good advice. I'll definitely do that when putting mine together.

Thanks!

Thank you, here are the details: I have it directly on the manifold and wastegate too - no issues even with track use. 0.25'' thick stuff where space is tight, 0.50'' where there's more space. Don't wrap a catalytic converter, excessive heat can damage it. And leave a gap to allow moisture to escape.

Material
https://www.heatshieldproducts.com/heatshield-armor
Ties
https://www.summitracing.com/parts/sum-350129/overview/
Tool
https://www.summitracing.com/parts/dei-010220

Materials for chassis-side heat shielding:
https://www.heatshieldproducts.com/hp-sticky-shield
https://www.designengineering.com/fl...e-heat-shield/

Good point, thank you for bring this to our attention. We allow for 8 bolts for the side bracket to slider interface but some normal-sized washers to this location would definitely add some security. There are a few mm from the bolt head to the seat bottom that allow for this. We had an uncomfortable amount of deformation near a rear slider bolt after hitting a wall at WGI around 80mph with 4X SHCS on the sliders to chassis interface, which is why we allow for 4 bolts on the rear of the sliders (6 total) and use the button-heads which fill out the available space in the sliders. We use some huge washers on the seat bracket to seat interface to prevent pullout there:

https://cimg7.ibsrv.net/gimg/www.mia...5a8a54f926.jpg

Thanks to Roda's willingness to trial the installation process, we've uploaded some more images of the various bits and installation along with getting a guide started: https://drive.google.com/open?id=1QF...GA3Y5sfQFAU-vJ

-Chris

Twibs, we put this together to try and better explain the height and fore/aft position:

https://cimg1.ibsrv.net/gimg/www.mia...64d41c0bf2.jpg

https://cimg9.ibsrv.net/gimg/www.mia...8e3e29eca5.jpg

I'm making progress on my installation, and hope to finish welding today. Here's a shot of the final fitting:

https://live.staticflickr.com/65535/...907224c8_c.jpg

Actually this is overkill in this case because those bolts are loaded in sheer, so a normal size washer to increase the clamping surface just a little bit more than the head of the bolt is going to work A-okay.
For that interface I would typically use a 12.9 grade bolts.

The bolts I noted in the previous post are loaded in tension, which is where the washer is required to increase the clamping area.
The slots also appear to be slightly oversized for an M8 bolt, my eyechrometer says it's around 3/8" of slot width which is too much... I realize it makes installation easier but it's at the expense of clamping area, so I'd spec it to a more appropriate slot width of D+1/32" if it must be a slot, but always prefer a hole over a slot if the option exists.

Here are pictures of the floor drop kit from Hanksvilles Hot installed. Miata Floor Lowering Kit - Hanksville Hot Rods I took about 7 hours to install from start to finish. I cut the floor out and was welded in by a local welder. The seat sits on the floor pan in the rear and with a 2" bar in the front mounting of the seat to give it about a 20 deg of tilt. I am 6'-3", so I was looking to get the sit as low as possible and as far back to the rear bulkhead. This kit achieved just that. No adjustable slider, I am the only one driving this track car. My head now with helmet is approx 3" below the roll bar.
https://cimg9.ibsrv.net/gimg/www.mia...0c0962c44d.jpg
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Thank you again for the feedback - we opted for 10.9 for the flange heads (making interface with a wrench next to the tunnel much easier), JIS consistency/availability, the compromise of strength/elongation/impact energy, and consideration of the FIA's spec of 4X M8 8.8, as referenced by OMP (Schroth specifies 8.8 for belt fasteners as well). The brackets allow for seat height and angle adjustment without removing the fasteners, which requires some extra space in the slots to be able to move the seat from one position to another. The oversized washers on the side are used to ensure the seat remains contained even if a bolt becomes loose (due to installation error or elongation) and the "fingers" separating each slot are never in bending.

Good eyechrometer - the slots on the bracket to slider interface are cut at 10mm wide (a bit less with powder coating) and could stand to be a bit tighter. We don't think this is a concern using up to 8X flange head bolts with washers.

-Chris

Well, life got in the way a bit, but I finished up my install today.

https://live.staticflickr.com/65535/...1f4f6833_c.jpg

Seat going back in with a new harness tomorrow.

So, a couple final pics, and my thoughts on the Watson Racing kit...

Seat in, with new harness
https://live.staticflickr.com/65535/...68c98234_c.jpg

Underside:
https://live.staticflickr.com/65535/...73d5c16b_c.jpg

I really like this kit! Our car is an HPDE/TT car, which my wife and I both drive. I needed sliders to accomodate both of us comfortably, and this kit goes far beyond the other available kits in how well thought out and complete it is. Previously I had the seat mounted on a PCI fixed bracket on the stock mounts. Even with the sliders, the seat ended up ~1" lower after the installation of the kit.

The kit fit just about perfectly, and contained all of the parts needed for the install. For what you are getting, it is very reasonably priced, IMHO. And kudos to CWatson, whose communication throughout the process was fantastic. :likecat:

Quick update - we made some revisions to our kit based on our usage over the past year and feedback from our other users. We have a handful available to ship first thing in October. Please use FB messenger to contact us (facebook.com/GuarinoWatsonRacing) with any questions, it takes a while for me to see PMs. Here be details: https://docs.google.com/presentation/d/1eYNphsjCqokin5Y5AlKrlJUBJDrrN7lXwPp5qrnZIeY/edit?usp=sharing

Sent you a message on fb.

This fits NA right.?? I noticed it is based on a '99 NB but floor looks the same to me.

Yes, as far as we know. Roda's car above is an NA. V2 brackets are designed to work with the NB sliders, Corbeau Sliders, or bolt directly to the chassis. We don't know if they work with NA sliders. Hole spacing is 300mm if you wish to check.

-Chris

I've been looking through the instructions and pictures. The kit replaces at least sections of the factory frame rail. I have the KPower (KMiata) BMW 6 speed swap, which includes frame rail reinforcements that the transmission mounts to. Will aftermarket frame rail reinforcements bolt up to these like stock? Am I looking at this wrong, and typical frame rail reinforcements are in a different place?

https://kpower.industries/pages/installation-guides its the 4th one down.

https://cimg0.ibsrv.net/gimg/www.mia...167d32ddc8.png

Dan, have you had a chance to determine if and what modifications are needed to work with the Kmiata brace?

If any others are wondering, here are measurements from the interior rear bulkhead (V2 kits). Our frame rail wraps closely around the OE frame rail (~2mm or so). https://cimg9.ibsrv.net/gimg/www.mia...ca2671110f.jpg
Additional images here.
Description here.

-Chris

Chris, I have not yet. My plan is to have a shop install the drop floor first, then make the K Power kit work second. Ultimately, its more important to me that my rollbar not split my head open in a fender bender than having a BMW trans. The drop floor will probably go in around the Jan-Feb time frame, and the transmission in the spring once the weather is warm. I'll post an update once I make some progress

Just finishing up my install of the GuarinoWatsonRacing kit. Will be posting pictures soon. My car has the full Boss Frog LS swap setup including the front subframe, trans crossmember and rear subframe. Also dual exhaust. I went ahead and made a notch in the front inside corner of the pan once installed and fabricated a panel to allow for more clearance for the exhaust, this seems like it was unnecessary though. Looks like the trans crossmember and exhaust could fit without interference as provided.

I definitely DID have to modify two things:
1. The Boss Frog rear subframe forward brace (same as the rear subframe ladder braces on a stock subframe) had to be shortened to clear the floor drop. The mounting point was not impacted, only the extra material on the brace past the mounting point was removed.
2. The frame rail had to be modified. I considered two options: Using Chris' supplied brace and adding a mounting location for the trans crossmember, or shortening the Boss Frog brace. I chose to shorten the Boss Frog brace and boxed the end at an angle that mimicked Chris' supplied parts. I made mine bolt-on instead of weld-on by retaining the flange and drilling holes for mounting on the floor pan drop.

End of the day, only issue was putting the cross member into location with the frame braces tight to the car. It meant sliding in from the front instead of the back and that required some BFH assistance as the exhaust notches had interference with the passenger side floor.

Here are two pics that show the clearance of the trans crossmember to the t56 with the Boss Frog kit and the GuarinoWatsonRacing kit. Pics also show the modified frame rail brace.

https://cimg5.ibsrv.net/gimg/www.mia...85ababbf8a.jpg
View from center under car
https://cimg6.ibsrv.net/gimg/www.mia...2ad3c5f7af.jpg
View from driver side under car