Steve Duncan

I race (circuit) an FC S5 and i have just purchased a series 8 RS engine & gearbox assembly to drop in it. I currently have a microtech LT10s, custom dump pipe, S5 hi flow turbo, front mount intercooler etc.. S5 engine was stock internally.

I'm fitting the s8 engine in stock and using the s5 hi flow turbo & custom dump pipe, retaining the S8 inlet, injectors etc...

I have heard a lot of hype about the power FC by apexi and i have the opportunity to purchase one with the engine from the S8.

i have been happy with the microtech for the last few years.

Is it worth my time, money and effort to use the power FC ?

misterstyx69

iTrader: (142)

Steve: I am only approving this post as I know that Australians are a Trustworthy bunch!
Read the rest of the Stickies please( numbers 2,3,4)
Besides I find the Build interesting and can't wait to follow this thread!
STYX (Moderator)

Akagis_white_comet

iTrader: (4)

Interesting build, but I'd personally stick with the Microtech over the PFC. While the PFC is a very viable ECU, it is also heavily tailored to the target vehicle's characteristics. My friend ObliqueFD has one in his S6 FD, so I've briefly played around with it. Comparing it to my Haltech PS2K, it is my belief that the PFC is akin to a stopgap measure between a stock ECU and a full standalone such as your Microtech or my Haltech. It has certain items that can be adjusted, but isn't fully adjustable in all manners as with a Haltech/Microtech/etc.

Unless you're running the FD's twin turbos, the Microtech would probably be a better ECU to fit your specific needs. If it's anything like my 20B FC's PS2K, it can be set up to run the twin turbos using a relay and 3 of the ECU's outputs. Mine is set up with a RPM switch for the Pre-Control solenoid, another RPM switch for Turbo Control (Turbo Control 1&2, Charge Relief & Charge Control solenoids) using a relay and the Wastegate set at 10psi. You'll need to play around with the trigger settings and parameters (MAP switch, RPM switch, etc) a bit to get them right, but it should work pretty well that way.

For a single turbo setup such as yours, you'd only need to use one output for the wastegate solenoid, but I'm sure you're familiar with that already.

You can't use the FD's transmission without extensive fabrication to mount it to the transmission tunnel. The FC attaches to the body using a crossmember via four bolts, M10x1.5 I think (check the FAQ to be certain). The FD has the transmission 'floating' between the engine mounts (rear iron of engine) and the differential, with only a single structure piece linking the transmission & differential together (PowerPlant Frame). This is often considered a weakness in the FD's design as it puts more load on the differential's mounts.

Internally, the FD's transmission is just a slightly revised Turbo FC transmission that uses a pull-type clutch instead of the more common push-type that the FC uses. Overall, the simplest way to accomplish your goal would be to get a Turbo FC transmission, clutch and starter. You can use the FD's stock flywheel, or the FD Automatic counterweight (can use S5 automatic counterweight too) with either a Turbo FC or FD lightweight flywheel (they are the same).

You might need to swap your driveshaft as well, depending on what transmission you are currently using. See MAZDATRIX for Mazda RX7, RX8, Rotary Engine Parts and Accessories for more info on driveshafts. they also have a FAQ on engine counterweights too.

On my 20B S4 FC, I'm using a J-spec S5 Turbo transmission, ACT Prolite flywheel from a FD, the stock 20B counterweight, an ACT Xtreme pressure plate & Modified full-face clutch disc for a S5T2 and a S4T2 starter. Linking everything to the differential is a Mazdatrix TII trans to NA Diff driveshaft.

Steve Duncan

Thanks.

Steve Duncan

Thanks for your reply Akagis.....

You have confirmed my thoughts on the power FC. As I'm using a series 5 factory turbo (hi flowed) I have decided to stick with the microtech.

I spent last weekend removing the series 8 engine from its home. A much longer task than I had expected, probably due to removing the entire engine & gearbox assembly complete including harness & everything possible still attached.

As for the gearbox, I have read that the series 5 bell housing and rear housing will bolt straight up (using the series 5 clutch assembly & starter) with the exception of the input shaft being approx 20mm longer on the series 8 box.

I have been advised of 2 options in relation to the input shaft -

1. Use a sandwich plate/adaptor between the bell housing & engine to accommodate for the extra length of the input shaft. I can source one of these made locally (Brisbane) for around $200.

I'm not keen on this method because I don't know how the standard gearbox mount will align ?


2. Strip the gearbox down & swap the series 8 input shaft out & a series 5 input shaft in. I have read that they are interchangeable ?

Akagis_white_comet

iTrader: (4)

Don't pull the engine or transmission apart. The FC mounts the engine at the middle iron, FD on the rear iron. Swapping to a S5 rear iron means you have no way to mount the 13B-REW engine. As for the transmission, every rotary car uses the same bellhousing pattern. Both the FC & FD's input shafts are the same length when measured from the flange surface of the bellhousing.

The simplest solution is to just use a turbo FC transmission, starter & clutch. Bolt everything together, then drop engine & transmission in the car, using the transmission crossmember to locate everything horizontally and vertically. Then either buy or build mounts like these:
13B REW FC engine swap mounts |
There may be a forum vendor that offers 13B-REW FC conversion mounts, so be sure to check there first. I can't really recommend one set over another though as I haven't personally done a 13B-REW swap. If you find a set of good conversion mounts, please let everyone know in the Product Reviews section.

There is no need for a sandwich adapter plate between engine & transmission because all rotaries since I think 1974 have the same bellhousing bolt pattern (check the FAQs to make sure). This is how I'm using a Series 5 manual transmission on a 20B engine. The JC Cosmo was only offered with an automatic transmission.

Going about it this way means that the engine mount brackets are the only customized part, while everything else is strictly off-the-shelf stuff.

misterstyx69

iTrader: (142)

I think Banzai Racing makes an REW engine mount for the FC.