A new challenger 'The Beast from the East'

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Threesevens
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Re: A new challenger 'The Beast from the East'

Post by Threesevens »

rotarypower wrote: Thu Mar 25, 2021 6:15 pm
Threesevens wrote: Thu Mar 25, 2021 12:20 pm
rotarypower wrote: Tue Jun 02, 2020 11:43 am NLA Europe as well as the UK which is all he could check.
I checked with my local Mazda dealer and they can order you one from Japan. £43.68 + vat. Take up to 2 months for delivery
They weren't as helpful with me. Just said no.
I got mine delivered from Japan, just not through the Mazda dealer.
My dealer in Romford has always tried to help.
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Re: A new challenger 'The Beast from the East'

Post by rotarypower »

So its been a long while since I posted much meaningful on this thread, unfortunately after a few months of no work last year in which I didn't do much, I've been working overseas in Dubai & Mozambique, as well as being snowed under with boat projects, having to dedicate time to a relationship, house projects etc.
So the RX7 had been put on hold a bit.

Well I decided that if the thing was going to get finished in my lifetime then it was time to send it somewhere for a rust delete, they'd do a better job than me, quicker, yes it would cost money, but learning to weld on a driveway has been no fun & I simply don't have the time to learn right now, not at least to the standard I wanted on the car.

So I started looking for places to send it, as I looked at standard restoration shops an idea was lurking at the back of my mind, I'd always disliked the rear solid axle and the recirc ball steering on the car, it was I thought a real shame that the car never came with IRS and a proper rack like the later MX5, I wanted more power which meant an axle upgrade & parts were getting thin on the ground anyway.

Some of you might recall my musings on the IRS & how I'd been comparing dimensions with the MX5 and other small cars, while I concluded that it was possible with some loss of boot space, it wasn't possible for someone who couldn't even weld.
So I started looking at some of the more 'out there' garages, the ones that produce quality custom work, good engineering, not just flashy custom bodywork but shops that could make modifications along those lines.

I contacted a few & in general encountered two problems, garages that didn't take me seriously, not because the work was impossible, but presumably because they get a lot of dreamers who won't see it through, and garages that claimed to be able to do that work, but seemed unable to engage on the technicalities or show any enthusiasm 'Yeah we can do that for you no problem, just drop it off!'.

Anyway I finally found someone who had produced good work in the past, was enthusiastic, willing to discuss all the points I wanted looking at, made suggestions, listened to mine etc and just came across as professional. We agreed on a project scope & not without some trepidation I prepped the RX7 for surgery & then sent it off on the back off a wagon.

This is getting long winded so I'll continue in a second post.

Refitting the rear axle to get the shell rolling:
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Filling the housing chambers with oil before removing to try and preserve the engine for its next owner.
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On its way out:
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Looks empty:
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Ready to go for surgery:
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Re: A new challenger 'The Beast from the East'

Post by rotarypower »

To continue the last post, the scope that we agreed on and the plan for the car was roughly as follows:

- Swap in an MX5 Rear IRS, so the subframe & suitable reinforcement, fabricate shock mounting towers etc.
- Swap in the front MX5 subframe including the Rack & Pinion steering rack, potentially power steering
- Fit the new engine & gearbox I had chosen for the car.
- Repair of rusted underbody / panel etc.
- Fuel tank either modifications to fit or something custom.

Electrical work was / is to be done by myself.

All of the above done in such a way that unless you knew an FB, it wouldn't be obvious what had been done, not only did I want the car to look like a stock(ish) RX7 from the outside, I wanted everything engineered & tied into the unibody the way it would be stock, none of this daft full length frames that you see in so many conversions online.

There is additional scope in place for replacing some parts of the HVAC system with MX5 ones, the MX5s I've owned have all had much better heaters & blowers, and with a retrofit there was potential for air conditioning.

The engine I picked for the car was (sorry rotary purists) a V6, and even worse an American one. I apologise to the rotary purists, I really do. I've got a loft full of 13b bits, it was going to be 13b turbo all the way. But somewhere down the line I started to have misgivings about the rotary reliability & the skyrocketing prices for any of the parts.
In the end I settled on the American made LFX V6. Its a 3.6 producing 323hp at 7200 rpm. Yes its not rotary, but it revs higher than the redline on the existing 12a, is lightweight & should make the car fly.
Hopefully it suits the car as much as I think it will.

To the end of all the above I needed an engine & a donor MX5.
Here they are:
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The MX5 was a complete Rotbox, but only cost £600. Easily recoverable just from selling the parts from it.

The guy doing the work has been entrusted with some other nice rides:
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Re: A new challenger 'The Beast from the East'

Post by rotarypower »

Finally we get to where we are now.

I'm only posting a few photos of the many that I have, the car is very much work in progress but much progress is being made.
Right now its welded to a chassis jig, and the rear is being worked on. Once this is rebuilt and stiffness restored to the body then work can transfer to the front.

Much care has been taken to locate the bits exactly where they should be, not just in relation to the body itself, but also in relation to each other as they would have been in the MX5 with the exception of the wheelbase being a little longer.

Car in the workshop:
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Some preliminary measurement taking:
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Some holes were discovered under the soundproofing.
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Lots of chopping:
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Re: A new challenger 'The Beast from the East'

Post by rotarypower »

Suspension locater jig in place & beginnings of chassis frame rails.
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And that concludes it, I'll try and keep this thread more updated with progress in the future should people still find it interesting.
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Re: A new challenger 'The Beast from the East'

Post by A7RXY »

Good luck, shame about the engine l, but that is your choice.
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Re: A new challenger 'The Beast from the East'

Post by spirit r »

I like the 1000kg lightweight of the S3 so much. I hope you can hold the weight. Good luck.
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Re: A new challenger 'The Beast from the East'

Post by rotarypower »

It shouldn't be adding too much weight.
Unfortunately its very hard to get exact figures, but the weight is I believe comparable with a twin turbo 13b-REW engine once you add in the turbos, manifolds etc.

I'm more concerned with the weight placement, getting the engine as far back into the car as possible.
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Re: A new challenger 'The Beast from the East'

Post by spirit r »

The stronger rear axle ford or hilux will help you to get the rear end more heavy.
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Re: A new challenger 'The Beast from the East'

Post by rotarypower »

Actually Thomas, the rear suspension from an MX5 is being swapped across.
So no axle per say, fully independent and adjustable double wishbone suspension :D .

The peak advantage of the rotary is not so much its weight (although the 12a is quite light) as the turbo ones aren't all that light, its the placement, it lets you get the weight towards the centre of the car, unfortunately I am going to lose some of that.

If I hate it then I can always go Renesis or something similar, but I wanted big power & reliable. In that respect the LFX is perfect, all alloy, direct injection, high revving.

I realise its not too everyone's taste, but the car is still common enough that I don't feel guilty about this!
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