Well I’m no professional porting specialist, but good enough for my purposes. Finally got one of the generators going and made some progress hogging out the turbine inlet ports for the BW S262SX-E hybrid turbo tonight. It was surprising how shrouded the divided flow paths inside the turbine were by the T3 ports. They expand larger an inch or two inward, likely due to the largish A/R needed with the “70” turbine wheel. The exhaust gas flow will transition more smoothly with the T4 openings. The casting is thinned out in a few spots, but hopefully enough overall to keep from cracking. 🙏


https://cimg9.ibsrv.net/gimg/www.rx8...5fa565be3.jpeg

https://cimg1.ibsrv.net/gimg/www.rx8...88e343b38.jpeg
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Finally getting somewhere; turbo is more or less installed this evening. It was pretty much a bolt-in affair once the turbine housing inlets were ported. Despite the smaller 70mm turbine size the external turbine housing dimensions are the same as the S369SX-E 76mm housing. Which is my main reason for going this way as the easy initial testing choice. The S257SX-E compressor housing is a lot smaller though, but being fitted with the S362SX-E compressor wheel I’m hoping for it to be a hyper version of same. With the correct silicone adapter it still bolted up to FMIC piping fine too.

Still have a few other minor things to do before getting it rolling again. Which I did reconfigure the oil feed assembly for the CHRA during the turbo install; positioning it further out to the side and forward. Mostly because the pressure gauge was too close to the turbine housing and the plastic gauge face was overheating and melting. I had already replaced it and the fuel pressure regulator gauge back in Nov/2021. New larger air filter too and relocated the power steering module from in front of the filter over to the side.


https://cimg5.ibsrv.net/gimg/www.rx8...59a161b08.jpeg

So learning the hard way how this all needs to be disassembled and then put back together. Had to reloosen all the bolts for the CHRA/Housings because it needed to rotate in order for the oil drain hose to be threaded on and tightened into place. Super tight clearances . Took a while to deal with all that and have everything positioned just right, but got ‘er done.

The OE Mazda RX8 oil switch threaded easily into the REW iron; confirming it is 1/8 bspt. Even was able to use a big 24mm box wrench to tighten it down. Also jettisoned the A/C compressor, drive belt, and belt adjuster weight off the car since they’re not hooked up and I have no plans to ever make it operational.

Put in a lot of hours today. It I have the energy tomorrow the car may be up and running, but do need to run over to Summit Racing for a few fittings to make that happen. Really advantageous to have them locally available 7 days a week.

This is just temporary because eventually pretty much all the oil cooling lines will eventually be reworked with a remote bypass/oil filter assembly, but for now the oil pressure gauge sensor was placed in a straight AN adapter (male & female AN ends with a 1/8” NPT threaded hole in the center) and placed at the oil cooler return inlet into the filter pedestal. The gauge will read a bit high being pre-filter, but the OE pressure sensor in the rear iron position is serving the purpose of safe-guarding the engine. This will serve to keep the gauge from flashing/alarming, been a bit of an annoyance.

https://cimg8.ibsrv.net/gimg/www.rx8...ad1095300.jpeg


Another tip is spend the extra and don’t try to save a few bucks buying Summit Racing AN fittings. They likely install fine, but many of the female hose ends are binding up. Which ends up being a real pain trying to align the hose end and starting the female end threading on the male attachment side. As in bound up to where it won’t thread on by hand, but instead requires using the AN wrench to try and thread it on. Major pain in tight spaces.

The sensor adapter fitting above was from Fragola and their AN fittings have always been top notch.
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Cranked right up last night and warmed up fine. One minor leak to tidy up on the CHRA oil pressure feed line, but everything else was functioning fine as far as I can tell. Still have a few other things to address before taking the car out to assess the changes.

:icon_tup:

Funny, I noticed this with a Summit Racing fitting on my FPR over the winter so I ended up replacing it with another brand for the exact same reason. I wasn't even able to spin the female end by hand when it was just free (not even attempting to thread it onto the male end).

getting the spark plugs out/in is a different story :rolleyes:

guess my REW noob is showing 😂 since I don’t have the special ground/machined spark plug socket for changing the plugs. No way am I going to give Racing Beat $132 for one either. 😱
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Interesting you bring this up..... might be my newb showing as well then. Since I've only used NGK BUR9 plugs so far, the 13/16" socket I have in my tool kit has not problem getting plugs in and out. Eventually I'll be swapping to some R7420-10's but I wasn't aware a thin wall socket would be required for these.....

maybe your housings were machined unless they changed the castings? or maybe mine are actually REW housings? I thought they were the same though.

A standard thinwall 13/16” socket is nowhere near going on the plugs for me. Thought I was going to be smart and take my 21mm thinwall lugnut socket and then pull the outer plastic protective sleeve off. Even without the sleeve it was a larger OD than my spark plug socket :rolleyes:

The RB website states the machined socket ends up being only 0.028” (0.71mm) thick at the inner 13/16” hex corners and needing to be a bit careful torquing them on/off.

https://www.racingbeat.com/RX7-1993-...ion/11529.html


did you start with the latest new REW engine from Mazda?
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I had this engine built for me, I don't believe they were brand new housings though. I have a disassembled engine on my bench at home, but again the aren't brand new housings. I'm going to thread a BUR9 spark plug in tonight and snap some photos, see what it looks like.... but with my current engine and BUR9 plugs I get on them with a standard 13/16 socket without any issue whatsoever. Here's my current engine:

https://cimg2.ibsrv.net/gimg/www.rx8...594bc580fc.jpg

well looking at my installed plugs pretty much matches the dimension stated on the RB site for the socket. There is very little clearance between the 13/16” spark plug hex corners and the housing. Whether the housings on this junkyard engine are REW or not is unknown to me, but RB has the socket listed under the FD3 RX7 TT parts listings. All of the rotary racing plugs use a 13/16” hex that I’m aware of. Stroker told me he had to grind a socket down using a non-rotary 13/16” NGK plug per the link below. Which is what I’m wanting to replace

https://www.rx8club.com/rotary-swaps...9/#post4915104

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Here's some photo's of the other engine I have on my bench and the plug just hand tightened in as far as they'll go. These are used BUR9 spark plugs, so the washers on them are already somewhat flattened. Confirmed my set of R7420-10's are the same dimensions as the BUR9's. Yeah was reading the RB website too; but I also notice they sell a thin wall socket for the Renesis too, and I've never needed anything special for that engine. Very curious to find out what the differences between our housings would be.... what spark plugs do you currently have installed?

https://cimg3.ibsrv.net/gimg/www.rx8...70cc1e35ee.jpg
https://cimg3.ibsrv.net/gimg/www.rx8...5ea58b7c19.jpg

are those threaded in all the way?

the hex on mine are way inside the housing, maybe it’s the plug and not the housing?
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Yes, as far as possible by hand, but even with a socket on my current engine I can get them as tight as possible with a 1/2" ratchet and still get on the hex. I'm thinking it's a spark plug thing, that's why I was asking what plugs you are using in my previous post?

The RB website is a bit ambiguous; it says for spark plugs that aren't stock replacements; and also says NGK plugs starting with a B. My understanding is that the BUR are the stock plugs (or an equivalent) but also start with a B and can be removed with a standard socket..... so consider me confused lol

It's easy to make a socket... just use something to turn the socket and an angle grinder

A lathe is an easy way... just don't get it too hot.

You can use an drill driver to spin the socket and an angle grinder lf you pit it in a vice or get a friend to help

as usual :suspect: they’re those cheap junk non-rotary B plugs per the link I posted above: NGK BR10EIX 6801

so I shouldn’t have that problem once I get them out. I have a 12” diameter bench sander that I can grind a socket on while rotating it with a hand drill. However, since I only need it once to remove the existing plugs I may see if I can get them out by grabbing the exposed ceramic end first. It make break/shatter though and then no choice but to make one. If they’re not too tight and come out then no need to bother.

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Looking like no choice but to make a socket. Of course the plugs have the threaded rather than solid terminal ends and it started screwing off instead. Though I might try some rubber hose on the ceramic end and then attempt to clamp on it with some vice grips to see if that will work. I feel like those plugs aren't letting the engine reach full power. It does fire right up and operate ok in general though. So I could be wrong on that, but a proper set of 10.5 iridium rotary race plugs won’t hurt

Anyway, had a oil leak right at the CHRA oil feed inlet and some exhaust leaks/sounds in the forward section. Wasn’t happy with the brass fittings purchased locally for the CHRA oil feed. Went a bit overboard ordering some high pressure stainless instrumentation fittings and swapped it all out, again. Resolved that one and then no oil leaks at the OE or oil pressure sensors now, or either of the CHRA drain fittings either.

Which is an improvement over the engine and various lines leaking like a sieve previously. It still has a few other nuisance leaks; oil pan seems to be the worst, but will whittle them all down in time. Figured out there’s just a procedure for fitting the downpipe first and then bringing the rest of the exhaust to it and it’s sealed up good now.

Then there’s something going on in the rear muffler section that I’m not clear on what the actual problem is yet. It has exhaust wrap on the entire length of it, but seems like there’s a slip joint under there that doesn’t have a clamp or something. So need to strip that all off and have a closer look at it. Everything else seems fine wrt temps, pressures, etc. Will begin calling around next week and see if I can get a dyno session lined up in the not so distant future.
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Got this part wrapped up. Put the EPS controller back to in front of the air filter. Too many other things to address still and eventually this will all change to a low-mount / V-mount configuration instead anyway. All that is easier addressed then. Still a few more things to do before being ready to test and dyno.


https://cimg6.ibsrv.net/gimg/www.rx8...752494967.jpeg

So there was a wrap around band clamp at the rear muffler that had come loose and was letting it flop around. From the looks of it this wasn’t the first time it had been a problem. Those things are notorious for stretching and they require some serious muscle to get them so tight that they reach the stretch limit. Also made some other adjustments to the exhaust sections leading up to it that ended with everything positioned and hung well.

I really laid all I could on the band clamp bolts (was worried they might snap or strip) so we’ll see, but there will likely be some piping rework done down the road. Because I was a bit disappointed to find after removing the wrap off that last section of pipe to the muffler that it’s carbon steel material. The rest of the exhaust up to it and the rear muffler is all stainless steel. So I’ll likely get the rusty carbon piping swapped out and also have a proper slip joint put on at the muffler inlet instead.


https://cimg8.ibsrv.net/gimg/www.rx8...179cdfc11.jpeg


next up on the list, never hang the plastic AI tank from the top two bolts only; hopefully Stroker won’t get too upset with me hanging out the dirty laundry :suspect: I have plenty of my own too :yesnod:


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it’s all par for the course, not the least bit disappointed in the car and there’s a lot of good too. 👍
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Take that AI system off , run high % ethanol .......................and prosper........................... IMHO

Took the car out for an initial shakedown spin. Didn’t have the laptop with me, so no logs and also the boost controller software is still set on 30 psig peak from back on the last dyno session. Which is quite a bit over the top for the S262SXE turbo. So nothing too crazy :suspect: 20-ish psig or so. Much more linear and responsive than the S369SXE as expected, especially off/on throttle lifts. Even just part-throttle with little-no boost it really picks up and scoots on down the road from low-mid 3000 rpm or so. Don’t think it will need much before putting it on the dyno.
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I have to actually and that’s the plan. For now it’s just an added safety factor as I familiarize myself with what exists and then transition. It’s not so easy buying someone else’s car and try to figure it all out without much documentation on the changes.

But because the racing organization I run with permits water injection only (no alcohol addition) my intention is to swap to full E85. Now with the smaller turbo it has enough injector for it. For full E85 on the S369 it would need to have swapped out the the pair of 1600cc injectors for 2600cc. I’m pretty sure it has too much AI nozzle for the current E50 and will be cutting them back to lower flow.
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At 14 seconds you will see where the AI container broke along with the radio faceplate.
Too bad I blew a vacuum line off at the 1/8th mile and lost all the boost or I would have flown by that Charger.... :( Car only picked up like 13 mph from the 1/8 to the 1/4 without boost...

If anyone is interested, I am in the middle of building my Supra with a cast manifold 6466 setup, 264/272 cams, and Haltech 2500 w/traction control, close loop boost control, boost by MPH, etc. https://www.supraforums.com/threads/...-build.1124818

Can't wait to see how the new turbo runs, you'll probably need to really tighten up the timing and fuel map since that turbo will be in whole different part of that map I never tuned for....

Honestly, as those past issues are all being worked through and solved, I'm more concerned with having the spark plugs swapped out; local RX7 guy says he has a modified socket I can use. Didn't want to be bothered with modifying a socket for a one time use. So hopefully soon. Will likely go ahead and run a compression test then too The engine starts fine hot and reasonable vacuum so likely still acceptable.

With the engine being BP'd the boost is never going to come on strong at low rpm like with a SP. It's probably not too much different than when you had the S362SXE on it I'd imagine since it more or less mimics it in a smaller package. If anything it may be back-pressured slightly more which is in conflict with the BP performance. That it zipped right up to 20 psig was a good sign though. A BP'd 13B with EFR7670 would never achieve that. So the higher A/R 70mm turbine housing coupled with the S362SXE compressor wheel are working well together. Just not sure how well yet, but we're going to find out. :)
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The last time I put the motor together compression on both rotors was between 90-100. But I had that issue a few years back where the rear third stage injector (1650) wasn't firing and it damn near melted the ground strap on the spark plug completely off. I eventually replaced the entire engine harness and it fixed the issue.

I am 99% sure that the rear rotor was probably getting EGTs in the 2000F+ range as it was likely extremely lean. The corner seals springs are probably flat and I wouldn't be shocked if the apex seals have a bit of arch in them. Since the car still started, ran, and made power, I never made the effort to rebuild. Once you get everything running top notch, a fresh motor may be the last thing it will need....