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Posted by: matthepcat May 16 2016, 12:37 PM

I am a complete noob when it comes to Mazda rotary engines. Having just purchased a 13b conversion car, I am lucky enough to have found this one which runs excellent.

I am 95% sure that this car is running a Holley, but there are no distinguishing markings anywhere on the carburetor.

Here are a few pictures:




Is this enough for someone out there to say, "yep that's a Holley"?

The only strange characteristic of this carburetor is when I aggressively accelerate up to the 9k RPM range, it will sometimes sputter as I let off the gas like it runs out of fuel. I am assuming that this is a problem with the fuel pump being able to provide enough fuel pressure to flow at that RPM.

Reading online I see that most of the racing/high performance rotary guys run a fuel surge tank. Could this help cure this issue, or would a slightly higher performance pump with a good fuel pressure regulator cure the fuel starvation problem?

I currently run a Carter fuel pump that is probably old.

Posted by: ssuperflyoldguy May 16 2016, 02:29 PM

I'm thinking that is part of a fuel injection system....

Posted by: matthepcat May 16 2016, 03:28 PM

Not sure how that would be possible?

QUOTE(ssuperflyoldguy @ May 16 2016, 01:29 PM)

Posted by: Mike Bellis May 16 2016, 03:36 PM

It's definitely special for the rotary. I would run a high flow pump with a return regulator to keep the pressure low enough for the carb.

Wait, I would replace that with a 48 IDA single down draft carb and manifold.

I don't think you can go out and buy a new double pumper and get it to work correctly. I will say there is quite a bit of polishing in that top hat.

Parts are impossible to come by at your FLAPS. You will need to mail order most of your parts. I used to get a lot from Atkins Rotary. http://atkinsrotary.com/store/

Posted by: Mike Bellis May 16 2016, 03:38 PM

Posted by: matthepcat May 16 2016, 04:18 PM

Thanks..lol

I think Mike is the winner winner here. Looks like a heavily modified/ported Nikki carb.

QUOTE(Mike Bellis @ May 16 2016, 02:38 PM)

Posted by: matthepcat May 16 2016, 04:26 PM

I think I am going to run a fuel injection system using somthing like these:



http://www.borlainduction.com/throttle-bodies-components.html


I will run Megasquirt or there is a simple cheap solution through a company called Ecotrons.

http://www.ecotrons.com/products/wankel_engine_fuel_injection_kit/

Posted by: Mowog4 May 16 2016, 04:27 PM

i am running a Holley Blue fuel pump knockoff on my Bugeye Sprite with a 13B in it. I am switching to fuel injection in the next few weeks, you are welcome to the pump and regulator if you want it. Send me a pm and I will drop it in the mail. 13B's use a lot of gas, they need enough volume to make it run correctly. Ed

Posted by: matthepcat May 16 2016, 04:29 PM

QUOTE(Mowog4 @ May 16 2016, 03:27 PM)

Posted by: Mowog4 May 16 2016, 04:38 PM

I am running a Jenvey Throttle body, racing beat intake, MegaSquirt MS3 Pro, and a Walbro fuel pump. It is sitting in a box waiting for installation. The engine is a large street port. I wired the actuators open and am still using the oil metering pump. I will start on it in a couple of weeks.

Posted by: matthepcat May 16 2016, 04:47 PM

very cool. I would be interested to see your set-up completed.

I have little to no documentation on this engine, but based off its idle I think that it is bridge ported. I like the idea of getting more fuel efficient with FI, and I read you can get a more usable torque curve over carburetor.

QUOTE(Mowog4 @ May 16 2016, 03:38 PM)

Posted by: Mowog4 May 16 2016, 05:07 PM

I will send you some photos when I get it going. There is a very good write up from a guy named Aaron Cake at the rx7 forum about doing a MegaSquirt conversion. It is worth the read.

Posted by: Mike Bellis May 16 2016, 05:22 PM

If you keep the distributor and coils, you can use megasquirt. If you want ignition control you will need to go with a Haltech rotary ECU or similar.

Posted by: matthepcat May 16 2016, 05:57 PM

QUOTE(Mike Bellis @ May 16 2016, 04:22 PM)

Posted by: Mowog4 May 16 2016, 07:03 PM

I am doing both ignition and fuel with the MegaSquirt 3 pro. I am using a Full Function Engineering crank drive with the RX 7 coil pack.there is a bunch of data on DIY fuel injection

Posted by: Mike Bellis May 16 2016, 08:10 PM

Mat, I have a crank angle sensor (looks kind of like a distributor) to replace the distributor if you go with ignition timing. I don't think I have any other rotary EFI stuff anymore. I sold it all off. But my blown motor has the crank sensor intact. You can have the blown motor too. Just needs an apex seal.

Posted by: matthepcat May 16 2016, 11:42 PM

Free blown motor! Sweet!

Thanks Mike, at least I can pull it apart and learn about these motors.