SA22c Renesis rotating assembly killer bee swap
 

So as the title states, this swap involves the rotating assembly out of an RX-8 renesis engine. The car this will be done on is my Junkyard bought 1980 RX-7 SA22C LS (Leather Sport) which already has a very impressive swapped setup. The setup the car already has is a Killer bee from Rotary Reliability & Racing which uses 12A street ported irons and 13B housings from an RX-5 Cosmo. The engine is paired to an RX-5 5 speed rib-case trans and also has a 465 cfm holley and full header back exhaust from racing beat. The car was bought from a nearby junkyard in Ogden, UT for $1,000 as a non-runner, but after replacing the battery, ignition switch and adding fuel+premix, she fired right up on the first try and after some basic maintenance and replacing some old failing parts it is currently my daily driver and having put just short of 6,000 miles on it since buying it in August of this year. So far it's been great, it's very quick and has a very noticeable power difference vs. my old stock 83' FB and overall has given me very few issues (all issues were just old failing parts, the engine is rock solid).

Anyway, as much as I love this setup, it can definitely do more and I had already planned to rebuild the engine just due to it's completely unknown history (All I know about the car are the parts it has and that it was at Laguna Seca in October 1992 - sticker in the windshield) after I had finished my #R3S1 RX-8 build and begin dailying that instead of the SA. Then one day I was tagged in a facebook post on a local rotary page about an RX-8 at another nearby junkyard that was mostly complete and then the idea for this swap went through my mind and I wasted no time getting to it the next morning after I got off work. A friend of mine needed some things too, so we took his van and headed out. Luckily the engine was already completely separated and just floating in the engine bay when I got to the junkyard (I felt bad, because that day I was that douchebag that yanked someone elses catch lol), so I picked off all of the parts I needed for my RX-8 and then yanked the engine and then brought it home. At the junkyard I told them it was "Just a bare block" and nothing more and they charge me for "Just a bare block" and ended up being $81 before core and flywheel charge (Couldn't take the flywheel off at the yard:/). I have absolutely no doubt in my mind that this renesis would've ran just fine if swapped into another RX-8 as, when turned by hand, all 6 compression pulses sounded very strong and upon tear down all irons and both housings were in good shape (C+ - B- condition) and of course the rotating assembly as well. I then listed everything I didn't need (irons and housings) and ended up selling all of them together for $500 ($100 each), so not a bad profit at all.

Now onto the actual swap. Now I know I could've just gone the recommended route which would be to use S5 rotors instead, but the only downside to that would be settling for 9.7 rotors instead of the 10.0 renesis rotors plus the engine the renny rotors came out of was only $81, the last pair of S5 rotors I saw were $100 + shipping for the pair, just a bigger bang for the buck is all. And from what i've read about going from 9.4 rotors to 9.7 is the end result is only an 8HP gain, so going off of that figure, using renesis rotors should give me a 16HP gain, but that's not the goal of this build, it's just a nice incentive is all or I guess 1/3 of the motivation to go through with it. The main goal for this build is to increase acceleration with a high compression, low mass rotating assembly and by low mass I mean having the rotors lightened.

The rotors will be sent off to Built 2 Apex to be lightened (front and rear faces only) and milled for tall 2MM apex seals to accommodate the peripheral exhaust ports along with the complete rotating renesis assembly, light weight fly wheel and S5 rear counter weight and all will be re-balanced at mazdatrix which is right next door to Built 2 Apex (and no I don't mind how mazdatrix adds weight to the rear counter where needed, if it does it's job, I really don't care how it looks - 2 people have already talked to me about this, so just getting it out of the way). And new bearings will be installed on the rotors and stationary gears. The renesis oil pressure regulators will also be used in this build.

And just to reiterate, this will be a slow progression build dependent only on the completion of my other build on my RX-8 as this car is my daily driver.

And for anyone interested in following my #R3S1 #MazdaspeedR3 build, here's the link to it: Complete R3/S2 drivetrain swap on my S1 - RX8Club.com

*If anyone would like to comment any suggestion or any input at all about this build, feel free to leave a comment (and no the ports will not be modified at all either, the setup is pretty much perfect as is, this build is only aimed at making it just a tiny bit better)

A 13B-MSP in a first gen :)

well kind of I guess, but not really. Just the rotating assembly from one. I'd love to do a complete renesis swap, but that would be way too much work for what I want to do with the car which is just daily it mainly and i'd like to just keep the car as simple as it already is, but just give it a tiny bit more power (whatever power gains are to be had anyway, not actually expecting anything really), but the acceleration from the lighter rotors and flywheel spinning at 9,000 rpm should be fun:)

This is great! Really like the car and look forward to your progress.

Glad you made a thread! Facebook gets hard to follow consecutively at times. Looking forward to this build as always!

nice find on the the SA and motor. and both at a terrific deal! subscribing to check on upcoming updates.

MSP stands for MultiSidePort and that is what the 13B in de RX8 is ;)

I know, I was just clarifying so others didn't get this confused with a renesis swap (about 3 others have done so already, i'm still not sure where the miscommunication about this is lol)

nice 7

Nice.
Do you know how to port by making your own templates?

If so. you will see that Mazda moving the sideseals where they meet the corner seals on the RX-8 rotors allows for porting to an earlier port opening timing when using RX-8 rotors.

OFC, if you do that you can never go back to old 13B rotors, so a turbo build off those plates would be out...

I know that I can, but I have no plans at all to port the irons anymore than they already are as well as I have no desire for FI in either of my cars, both will remain NA for the duration of their mechanical lives. The only objective for this build is faster acceleration in a daily driven application.

also interested in updates

i'm definitely in for this build. i'm very curious to see how your results stack up to others i have seen.

I haven't progressed at all as far as this or my other build goes, right now it's just too damn cold to really do any work other than simple stuff like oil changes seeing as the temps here have been in the 1º-10º range. So far i've just been looking at different options for the machine work and balancing on the rotors and rotating assembly which I know I said built 2 apex and mazdatrix already, but never hurts to shop around, but as for updates id probably say expect some around the end of this month or sometime in February. everything will likely be sent off by then and once received back i'll post pics of the work done.

But I guess I can give somewhat of an update in the meantime. A friend of mine put up a streetported RX-5 engine for sale he had laying around for $150 and I know how hard RX-5 housings can be to come by so I went and picked in up (and yes in the SA lol). Anyway from that engine only 1 housing was good, 1 rotor was good and all 3 irons were good as well and it had a gsl se front cover and tapped oil pan (I believe it was for an oil feed line for a turbo as I think he boosted it when he used it til it died) so i'll likely end up selling those two (no need). And unfortunately the exhaust port has been ported with the sleeve removed so I may not be able to use it as I don't plan to modify my intake or exhaust ports at all (just wanted spare housings which is why I bought the engine). But with the good parts and tracking down a good set of housings I can probably build another engine later down the road for some other car I buy, idk, but good parts are good parts and that's just fine by me. But also something else I noticed comparing the stationary gear from the renesis to the ones on this rx-5 engine are the improved oil passages (which I assume the ones in my engine now are likely similar, so looks like a nice oiling system upgrade can be expected from this build as well (renesis gears are the bronzeish colored ones in the pics - pics of the tanked rotor and housing are also included and yes it's sadness and stuff I know��)

You have modern nitrided R5 irons and a matching dead rotor housing. They came with rings instead of sleeves, which is why the PO removed it. Then he ported it pretty large.

the irons from the keg I picked up are all Y irons, but I did check and confirm that the center iron on the engine in the car is R5. Rear iron is apparently a Y iron based on the amount of material under the filter pedestal and front should be as well, but I can't see the casting stamp on either so can't confirm, but looks like I was wrong and I do infact have a full 13B engine instead of a 12A/13B hybrid like I previously thought, still a mut engine either way lol

No updates as of yet regarding the build itself, however, I was able to get the car onto a dyno finally and now I at least have some numbers to show. Some things to keep in mind though is that the end results of this build may very well show a higher increase in output than should be realistically expected if someone else was to take on a project like this for a few reasons. First off engine mileage and compression numbers (until next weekend when I do a comp. test) is unknown, the car is 37 years old with an engine setup that was likely built in the early 80s by Nick at RRR from what was told to me by him, so engine wear HP loss is a factor. Second the housings and irons will be resurfaced giving a better sealing surface and of course new seals and springs will give optimal output after break in and third I believe my carb may have been slightly out of tune at the time the car was dyno'd, so I may get it back on the dyno after a bit of fine tuning.

But with all that said I was very impressed with the results and honestly have little desire to change anything about the setup aside from what is already planned, but here's the video of the car being dyno'd

That's pretty cool!

So it's been forever I know, but I do have some good news regarding this build. First I have purchased another set of renesis rotors that are already milled for tall 2mm apex seals that came with a brand new set of bearings as well, I bought these as an alternative to having the junkyard ones milled because the total cost having the apex slots milled plus buying and having new bearings pressed in would be more than just buying these ones. They are not balanced (as in precision balanced by a 3rd party), so that will still need to be done, but regardless I still saved a few bucks plus whatever I'm able to sell the other renesis rotors for (as they are for sale now).

Aside from that I also got some good news concerning my accident I was involved in over a year ago where my FB was totaled. The lawyers that are handling my case for pain and suffering were able to net a settlement offer that puts $4,400 in my pocket, so it's from those funds that will be funding the rest of this build project which should have an end total cost of around $2,500 - $3,000, but of course this build is still on hold for the time being as my RX-8 still isn't finished and has many bugs left to work out before I can daily drive it, but I can at least have the rotating assembly balanced and ready to go in the mean time.

Rotors and rotating assembly are all packed up and going out on Monday to CLR Motorsports for balancing. Next on my list of shit to buy is the rebuild kit which I will be ordering through Atkins rotary that will consist of all OEM seals and springs and will also be ordering an elite rotary 10MM stud kit for better strength and a more consistent tension bolt torque. As for when the actual engine build will take place though I can't really say just yet as the RX-8 isn't up and running yet and the SA is still my daily (now sitting at over 20,000 miles out of the junkyard and still going strong :) ), so for now I'm just getting everything in place now so I don't have to do all of this later.

Rotors were shipped out to CLR Motorsports today, Rebuild kit from Atkins Rotary and a 10MM stud kit from elite rotary have been ordered and are on the way as well:)

Are you just going to swap the rotating assembly or will you be changing other things at the same time? ie: porting, carb, etc.

It would be really cool to have a direct side by side comparison since you have a dyno of the engine in its current state.

Matt

Once I rebuild the engine I will keep the same carb (racing beat 465 cfm Holley) for comparison and may get the car back on the dyno before I take it apart just to make sure nothing has changed as I've made a few changes under the hood since the car was last on the dyno (plus I've put over 12,000 miles on the car since then too). But the engine will be 9,000 rpm capable (reliably) as I'll be using renesis stationary gears as well, so after I dyno the car with the renesis rotors and get my comparison results, I may upgrade to a 650 or 750 CFM Holley since the 465 Holley just cant deliver enough fuel to get passed 7,000 rpm