Been keeping an eye on this thread but haven't posted in a while. Great progress getting the subframes in there. Your approach is similar to mine - cut away as little as possible to sneak the new subframe in, get it kinda locked in place then cut away the rest once it's all reinforced. The NB rear subframe required basically the entire frame rail to be cut out from the spare tire well to the front of the bin area as well. I have not overly thrilled with how it all came out and will probably have a version 2 of the car in the future, but it's good enough for the "prototype" phase.

Brandon from Rotary Engineering seems like a good dude - I bought their fiberglass hood last year. Very nice quality. I also see he has a Group C kit now, which means I will be poor forever...

 

Dang it. I wanted to know that, but I didn't *need* to know that...

 

Exactly... I was super excited to see a US vendor making the group c kit, but also very disappointed at the same time because now I need to buy it and go deeper into debt lol.

 

Speaking of debt ... the kit got here. First trial fit below. The fit has a few problems as most fiberglass body panels do. My front wheels are almost perfect, but the rears are a bit too wide. They will need to be sent back to Forgeline to be modified for more back spacing.

 

Thats looking really good!

 

That looks amazing!!!

 

My air compressor went **** up on me. I need to get it out of the corner in the garage to diagnose what went wrong this time. In order to get at it I needed to put the car on the ground and roll it outside, so I thought I would get a couple more pictures of the kit while I have more room around it. The red '88 SE will be making it to DGRR, but the SA won't unfortunately. I will need to address the wheel openings for the larger wheels, especially in the back. The chassis is sitting dead level right now, but I plan to raise the rear about 3/4".

 

Car is looking awesome - great option to cover the wider Rx8 track width.

Just googled your town and realized how much further you are from DGRR than me (and I'm already over 10 hours away lol) - good luck on the trip!

 

I think your SA look totally Bad A**. Keep posting!

 

Man that looks good!!

It'll be good to see you again at Deals Gap, we're riding up Wednesday morning. I am bringing my red pre production FC and black RX8 (a ratty track car, #789 on the side, you can't miss it)

 

Thanks guys. Just got back from DGRR. It was great meeting many of you. I have to fix my air compressor then I can get back to it.

 

Air compressor is fixed. Needed a new motor. I have been doing a lot of research with Tire Rack's charts and online backspace/offset charts trying to figure out what I need to do to make these wheels fit under the fenders. After confusing the hell out of myself I just modified the rear wheel openings so the larger tires wouldn't look quite so awkward, and trial fitted them. It appears that I am going to need to push the rears inboard about one inch and narrow them to 12.5". The fronts will remain at 11" and need to be pushed in about 3/4". I plan to go to a 295/30/18 at the front as they are readily available from more manufacturers (plus bigger has to be better, right?). Both front and rear sets were close but will likely rub when the suspension cycles. I used the lip from the original quarter panel to form the top of the arch and opened up the wheel opening about an inch on the sides and 3 1/2" up top. I tried to copy the shape of the original wheel opening as much as I could while making room for a 26" tire. Unfortunately, I screwed up the passenger side lip so I need to source another quarter panel or just the lip. I plan to transplant the front wheel lip from the original steel fenders to the front fiberglass fenders but the only other alteration they should require is some reshaping behind the tire for turning clearance.
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Upon further review it doesn't look like I will need to modify my wheels at all. By moving the flare up about 3/4" The tire should clear fine. The front wheels should also be fine once I graft in the flares.
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Beautiful shot there, that is going to look so good! Hats off to you for having the ***** to cut into that body kit

 

This kit was originally molded for the early to mid 80s GTO cars, so the fit and finish isn't all that great. The racers weren't overly concerned about a show quality finish. It requires some modifications just to fit the car. The other reason for my mods was that back in the day they used a shorter tire and had them heavily tucked under the fenders. You can see this especially with the rear fenders in the old racing photos. I am trying for a slightly more muscular look that hopefully stays with the look that I am shooting for by bringing the outside of the tires closer to the fender opening. I had to open the rear fenders up and incorporate the factory flare to accommodate this. The rear openings were surprisingly small as molded. The front openings were OK but I'm doing the factory flare on them so they match.
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PS It turns out that the actual wheel openings for the kit are set up for a 96" wheelbase. I had the wheelbase set for the stock 95.3". This does cause me some problems that I could have avoided had I waited to finalize the front suspension position until I had the kit. Lesson learned. Don't be a dumbass like me. Check everything first, even if having to wait for it to arrive is a PITA.
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PPS On the other hand the extra room I gain by moving the whole subframe/engine/transmission forward invalidates my having to modify the firewall leaving far more room behind the engine. It also improves the position of the shifter. Silver lining.

 

Alright back to actual content that may be of some help to others. Seeing as how I have to disassemble everything and move my front subframe forward AGAIN, this is the perfect time to do this.
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I am ditching the electric power steering setup from the RX8. I have heard too many horror stories of them developing connector problems and turning full lock at an inopportune moment. Other than that, and the wiring headaches, they seem to work well on the stock RX8. I prefer to keep it simple by going to the hydraulic steering system from the NC Miata and avoid all the drama. The suspension parts for the RX8 and the NC Miata are mostly interchangeable. The front subframes will bolt in place of each other but there are differences. If a person wanted to swap a 2.0 four into an RX8 or the Renesis into the NC Miata you would only need to swap the front subframes (plus all the other problems that would crop up ).
RX8 top, NC bottom -
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NC top, RX8 bottom -
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I laid out the NC and RX8 steering racks side by side. They are the same length, but the mounts are completely different. RX8 rack at the top and the NC Miata rack on the bottom. As you can see the RX8 mounts are angled in relation to the subframe, and the NC mounts are flat.
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A shot of the mounts on the two different subframes. RX8 -
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and the NC -
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Once the NC subframe is placed under the Renesis and frame rails more issues become apparent. Other than the lack of stock RX8 motor mount points there is plenty of room on the left/driver's side.
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The right/passenger side is an entirely different kettle of smelly fish. If you try to lift the subframe into position the right rear corner of the Renesis oil pan that sticks out will hit on the NC subframe where it is cutting back toward the rear mount, The RX8 subframe's rails go straight back for this and the engine mount problem in the next pictures. It might be possible to modify the subframe to clear the oil pan but there is no way to modify it enough to clear the engine mount frame that surrounds the exhaust manifold/header. It would compromise the strength of the part to unacceptable levels. There is a lot of stress on this piece and redneck engineering it would probably be an unwise move.
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So, my alternate plan is to graft the Miata steering rack mounts onto the RX8 frame. If a person were using an earlier rotary, and fabricating your own engine mounts, the NC subframe would likely work (hint, hint, REW swap guys). From measurements the header would clear the frame, barely, but it should clear without that mount frame in the way.

 

NC Miata hydraulic power steering on an RX8 subframe.
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I will explain how I approached this problem. I will only post two more pictures this time unless someone requests more.
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I cut the mounts off the Miata subframe keeping them as intact as possible. I then tacked a 2" pipe in the cradle formed by the RX8 rack mounts. I did this to maintain the position of where the rack needed to be as designed. The RX8 mounts were then cut away to make room for the new mounts. I bolted the Miata mounts to the pipe and welded them to the subframe making sure the rack was centered and correctly rotated for the steering column to match up. I tried to get the mounts sitting as close to how they were on the Miata frame as I could get them. (photo 1). I then built up the structure to remain similar to how Mazda designed the subframe for the Miata. There is more metal under the rack on the Miata than the RX8. This provides the necessary stiffening and support as the Miata rack mounting points are almost laying down as compared to the RX8 rack which are almost standing up. (photo 2)
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I plan to address the steering pump issue with the EPAS hydroelectric steering pump system. This will allow me to run a hydraulic system without mounting a pump on the engine and having to deal with the rpms generated by the Renesis. It is a bit pricey but keeping the optimum pressure at all times would be nice and it solves so very many problems.

 

Here is the picture of it back in the car showing the fit around the engine. Plenty of room everywhere except the oil filter. It clears the oil filter but getting it to spin off will require taking the steering rack loose every time. Big fat nope on that. The S2 has the filter at the bottom left side. If you have the S1 engine this is not a problem. I will be doing an oil filter relocation. This is not a bad thing as the oil filter is in a PITA spot anyway.
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<dumbass alert> If anybody does attempt this in the future, make sure to leave the frame bolted to the body when you weld the new structure onto the front. Even though I did not cut anywhere on the subframe it still warped slightly. It required a few adjustments to get it bolting up to the car correctly again. This was extra work that shouldn't have been necessary.
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Impressive progress! No doubt that NC rack is the better one to use. I have heard similar scary stories about the electric RX8 racks. Love seeing your updates!

 

Yeah I agree, the NC rack is the better way to go.

 

Thanks guys. I'm a bit of a Luddite when it comes to new tech. If I don't see a genuine need for it, I would rather stay with the tried and true. It is usually just more stuff to break. I think it frequently happens so someone at the Company can leave their mark. (Kind of like a dog with a fire hydrant). Generals are really good at this one.
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After thrashing with my rear mounting points, it appears that I can get to the oil filter on the S2 after all. If I reach in from the wheel well, I can spin off the filter. It will require removing the driver's side tire each time but that is far more doable than removing the steering rack.

 

^that's good about the filter. And yeah, something nice about keeping it simple. I am not the biggest fan of electric steering racks for the aformentioned issues, as well as their overall bulk in the engine bay. I do like the idea of an electric powered steering column though as that has much more aftermarket support and they generally seem to be robust. Also does a good job of hiding clutter from the engine bay up under the dash. I depowered the NB rack on my Miata subframe swap project and will see how I like it completely manual. If it's too heavy I have the power column from a 02'ish Chevy Equinox/Saturn Vue that I can use. That's the column that epowersteering and Kpower use for the K swap miatas (among other cars).

Either way - the NC rack you have will be good. What pump are you planning to go with? The MR2 pump used to be the go-to, but the supply dried up. I know there are a few Volvo ones guys use and apparently the Mazda 3 (2015ish?? Not sure on the specifics) also has a pump that will work without CAN messaging.

 

Planning to go with the EPAS hydroelectric steering pump. They have a website which I am sure you can find. They also have the steering column systems that you mentioned. The one I am eyeing is an electrically driven pump which gives you the instant on advantage of electric steering, consistent hydraulic pressure without having to worry about the high rpms of the Renesis, and simplified wiring to their self-contained control box. If it does decide to break on you it will be the normal armstrong steering problem, not the "let's head for the ditch" problem. Not having to figure out how to mount a hydraulic pump and modify the RX8 belt system is also a plus for me.

 

Ah I see it on google now - I didn't realize that was a brand since "EPAS" is usually just the acronym that gets thrown around for electric power assisted steering.

Nice to see that you can get everything already setup in one package from them.

 

I had some problems with the power steering fluid overheating and boiling out of the FC while on the Dragon. I'm a little gun shy on the power steering problems right now. I have heard the RedLine fluid helps alleviate this but I don't know that for a fact.