13bpower

So my REPU has been sitting in storage for 8 months now. That will change soon. I have never driven my repu. I bought is with a bad engine. The engine has been removed and torn down. I am starting a fat new job in 2 weeks with a huge pay bump. That means I am starting to look for a place of my own with a garage. A garage all to myself.... that is priority #1. So the Repu project will start soon. So the planning and research begins right now.

The Vehicle: 1 1974 Mazda Repu convertable
Status: aquired

The engine: 1 1987 T2 engine, high compression + Streetport
Status: Currently powering my 87 Turbo 2. This engine has 12k miles on its rebuild and pulls strong. 9.4 compression rotors, a streetport and 12psi, controlled by the Rtek 1.7 with 750cc secondiaries.
Est: 275 flyweel HP, 260 flywheel torque

(the T2 will recieve a fresh engine, new housings and all)

The transmission: FC N/A tranny
Status: Installed on the REPU

Previous owner told me that it is a FC N/A transmission. This part worries me. This is right at the NA trannys "breaking point". I don't know how well it will hold up.

The stock Repu diff and driveshaft mated right up to this FC tranny and the transmission mount was modified as well as the shifter location to fit the REPU.

I would rather use a T2 transmission but I do not believe it would be easy, and sticking with what is already there, is very easy. At this point I plan on installing a s4 NA flywheel on the T2 engine and getting a street/strip NA clutch PP combo to handle the power.

Intercooler: Custom front mount.
Status: non-existant

The intercooler will be custom all around. I plan on buying a new core and having a shop make the pipes for me and weld on a mounting plate to the intercooler.

ECU: I am going to use the Rtek 1.7 that is in my turbo 2 now. along with the wire harness and all sensors. The T2 will be standalone and wont need any of it.

Exhaust: Custom
Status: non-existant
This will have to be done after the engine is installed. I will try to find a place that will make me a 3" turbo back to a single muffler.

Potential problems:
I have yet to sit down and reseach these yet but I would love to hear how anyone else would solve these issues.
-coils
-gauges
-fuel pump

There is alot of other work to do on this truck. It needs a top, an interior, paint, seats, ect.... It will be quite the project. This thing will be FAST when up and running. When done I will be looking at a 300 hp sub 2800lb truck. with a 4.77 rear differential. I can see the STI and Evo drives jaws dropping now..... It might never get a top, just keep it in the garage till a sunny day comes along.

My goal for having it on the road is April 2006. Cross your fingers for me and throw some knowledge my way.

Jeff20B

iTrader: (13)

Just drive with that tranny until it breaks. Then throw a T2 in there.

What were you going to do with your old exhaust? My red truck could use a little something. If you're going to throw it away, maybe you could throw it my way.

As for coils, I've had good luck mounting a 3rd coil to the other two using a long (size 104) hose clamp and a small bracket. It looks kinda funky, but it works quite well and doesn't get in the way. If your aftermarket ECU is fuel only, that would work out great.

I think you're going to need to deal with the oil cooler because it may still have bearing material in it. That might be why the engine spun a bearing (or whatever happend to it).

There should be plenty of space for an EFI fuel pump such as a Walbro or whatever in the stock location. I recently installed a Carter in mine and it went well. For a feed line, you could take out the tank drain plug, drill, tap NPT, install a 90° fitting, and use that as your send line. Or better yet, install a high volume carb pump that flows into a surge tank and then an EFI pump from the surge tank to the rails. I don't know how the stock siphon tube is positioned inside the tank, and since all the REPUs I've ever encountered (in real life) have all had carbs, it is hard to know if there has ever been a time when the fuel pump sucked air during hard cornering etc since the float bowls can handle brief periods of interupted fuel flow. A boosted EFI engine certainly can't.

There once was a time when that truck experienced surging on the freeway due to an inadequate fuel pump. It was one of those stupid Facet pumps that Racing Beat and local rotary shops recommended for many years. Well, my friend installed something else (Carter? Holley?) and that cured it.

Within the local circle of REPUs, that blue one was the fastest for several years. It looks like now it may be able to reclaim its former glory. Well, not until April I suppose. Have fun.

Edit: by the way, was the S4 NA flywheel going to be the type that bolts to a counterweight? Or a stocker with the imbalance already built into the flywheel? Is there an NA flywheel that will work correctly with a T2 rotating assembly? These trucks tend to be ok with light aftermarket flywheels thanks to the low 4.6 geared diff. What year was yours again?

13bpower

That is what I was figuring. I just hope it will last a little while.

I only looked at it briefly. It looks as though it will have to be chopped in a couple places to get it off. It is all one piece from header to exhaust tip. I haden't thought about what I will do with it but I am sure I would trade it for a little help installing some things that I am less experienced with.

This part gets fuzzy to me. I don't know what controls the Repu stock coils. So getting them to work on the T2 engine is over my head as of yet.

Very good advice. I should just use a stock second gen oil cooler that goes with the T2 engine.

Humm, the surge tank Idea sounds like a good idea. Keeping the stock fueltank setup pumping fuel out of the tank to a separate tank and having an independent efi pump for supplying fuel to the engine.

Being I have never worked on a carbed vehicle I can honestly say I am not familiar with the workings of the intank fuel delivery components of a REPU.

So a Carter or Holley would be the High flow carb pump that you mentioned?

If I have anything to say about it, yes. I have always been interested in having a sleeper. Something that is really fast that nobody would think is fast.... and of course it has to be a rotary. This is my only way. I see this as a life long project. It needs so much work, but relativly little to get it back on the road.

The s4 and s5 flywheels are all internally balanced. All s4 rotating asymblys are weighted the same and all s5 rotating asymblys are weighted the same. So all I will have to do is remove the s4 turbo flywheel and install a s4 N/A flywheel. The rotors already are s4 N/A rotors! Is the rear a 4.6? I remember reading somewhere that it was 4.77. My repu is a 74.

Jeff20B

iTrader: (13)

A Carter or Holley is the High flow carb pump that I was talking about. I've seen both on REPUs, and they both work great.

The '74 REPU is geared 4.6something. I think the breakdown is like this:

manual/auto
'74 4.6/4.3
'75 4.3/4.11
'76 4.11/3.9
'77 3.9/uh 3.9 maybe