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So I'm not dead. I've had a lot of life happening since i last posted, but i still have the car, still have the renesis swap going. Here's some update pictures:
Moving the car into my new duty station in South Carolina. Pulled the old intake off in preparation for a weber and adapter plate Weber in! Removed the Renesis front cover, swapped the OMP drive gear with one from the 12A motor. 12A front cover is installed! Distributor, aluminum radiator are in.
Thanks! Anybody have any ideas on a throttle cable setup? I bought the bell crank from racing beat but it doesn't seem to work in any of the possible orientations.
You got your 1st Gen / Renesis Swap running under it's own power before I got mine done.
To be fair, this project is almost 5 years old now. I also didn't set up EFI, while you did. Love watching your project. Funny how different our cars are despite starting on the same idea.
After looking at the costs of putting a properly built 13B NA Carb'd engine together, I was thinking that a Carb'd Renesis makes a lot of sense. A new Renesis short engine assembly from Mazda is quite affordable when you start to price out the cost of finding 13B parts and properly rebuilding it (all new seals, maybe rotor housings, lap+Nitride irons etc)
Your build is well documented.
Do I understand correctly, that you can remove the Renesis front cover, install a 12A distributor gear, and 12A front cover, keep the Rensis oil pan, and be able to use the FB engine mount arrangement? I know that Racing Beat makes a 12A engine mount for 13B swaps to correct for engine length/position.
Next question, what about front pulley arrangement and water pump?
After looking at the costs of putting a properly built 13B NA Carb'd engine together, I was thinking that a Carb'd Renesis makes a lot of sense. A new Renesis short engine assembly from Mazda is quite affordable when you start to price out the cost of finding 13B parts and properly rebuilding it (all new seals, maybe rotor housings, lap+Nitride irons etc)
Your build is well documented.
Do I understand correctly, that you can remove the Renesis front cover, install a 12A distributor gear, and 12A front cover, keep the Rensis oil pan, and be able to use the FB engine mount arrangement? I know that Racing Beat makes a 12A engine mount for 13B swaps to correct for engine length/position.
Next question, what about front pulley arrangement and water pump?
Hi Tommy,
A few challenges you will run into with a Renesis Swap:
• The Renesis 13B is physically longer than a standard 13B due to the increased thickness of the front and rear irons to accommodate the side exhaust ports. The internal volume is the same (1308cc). The 12A to 13B engine mount from Racing Beat will not work.
• The Renesis oil pan will not clear the factory steering system in your FB (unless you converted to a front mount rack). A 13B GSL-SE oil pan is not long enough (see above). The easiest solution is to cut and weld (2) GSL-SE oil pans together.
• You can use a 12A or 13B GSL-SE front cover and distributor. You could also opt for a Trigger Kit if you want something more advanced than a 40-year old distributor.
• You can use a standard FD water pump.
• The Renesis intake system is arguably the most advanced high performance N/A intake available for a rotary engine. You can use a carb .. however you would probably be farther ahead to start with a standard 13B (S3, S4, S5) instead of a Renesis 13B.
I should have my car back from Chip in the spring. You are more than welcome to check it out in person.
-I will take pictures of my oil pan when I can. Not sure why everyone thinks that the Renesis oil pan won't clear the stock steering rack, mine clears just fine. I made a Frankenstein pan out of forward most ~1" of the stock 12A pan, and the rest is all stock Renesis pan.
-The FC water pump housing is also an option, this is what I used on my car.
-I used the 12A Engine mount bracket. With a little bit of fabrication it can be made to fit. Not worth buying the RB unit IMO, especially since it too will need modification to fit properly.
Hopefully I can get this thing on the Dyno soon. Curious to see if it'll crack 200 whp with the carby. This motor does have a pretty aggressive Street port... Hmmm
Doing a full Renesis swap has involved a lot more fabrication than I had originally planned .. partially because of some of the design choices that I made.
The Renesis OE intake sits pretty high on top of the engine. This required mounting my engine lower in the engine bay with shorter engine mount pucks and a custom oil pan to clear the steering.
If I was to do another Renesis swap .. I would focus on areas where I could simplify the project and save some fabrication time and costs. Maybe a 4-port Renesis with an IDA throttle body.
Doing a full Renesis swap has involved a lot more fabrication than I had originally planned .. partially because of some of the design choices that I made.
The Renesis OE intake sits pretty high on top of the engine. This required mounting my engine lower in the engine bay with shorter engine mount pucks and a custom oil pan to clear the steering.
If I was to do another Renesis swap .. I would focus on areas where I could simplify the project and save some fabrication time and costs. Maybe a 4-port Renesis with an IDA throttle body.
Okay I understand the oil pan now, that makes sense. I have a ton of clearance but only because my intake is very short compared to the reni intake. Your car is a lot more professional and clean than mine is. Two very different routes to achieve the same goal. I never wanted this swap to take so long. The original point of this project was to get a new engine in the car so I could get seat time on track. 5 years later and the car is now more street car than race car, and I have spent about 10 hours on track total in that time, in an entirely different car. Definitely a lot more complicated than 16 year old me initially anticipated.
How did you correct the pinion angle after lowering the engine closer to the subframe? Did it not change enough to matter, or did you have to do something with the transmission mount to compensate?
My goal was OEM Plus. Your goal was track. This is good reference material for other members that consider this swap.
I opted to pair my Renesis engine with an RX8 transmission. This required a custom transmission mount and a custom driveshaft. This would most definitely be one of the areas that I would simplify next time in an effort to save some fabrication time and costs.
Sorry for the mild thread revive. Just curious about a few things.
With the carb setup, you lose the 8's fancy multi port system. So would this mean you won't get the same HP as the Renesis, or would it be like wiring the ports on a 6port FC open, in that you still get the same peak power but lose out on low end torque?
What does the RX8's PCM do in this setup? Spark, gauges, anything else? Could it be left out and a 12a distributor used instead?
I'm considering possibilites for what I want to do with my FC and I think a carbed Renesis swap might be a good, potentially lower cost option vs 6 port turbo.
Sorry for the mild thread revive. Just curious about a few things.
With the carb setup, you lose the 8's fancy multi port system. So would this mean you won't get the same HP as the Renesis, or would it be like wiring the ports on a 6port FC open, in that you still get the same peak power but lose out on low end torque?
What does the RX8's PCM do in this setup? Spark, gauges, anything else? Could it be left out and a 12a distributor used instead?
I'm considering possibilites for what I want to do with my FC and I think a carbed Renesis swap might be a good, potentially lower cost option vs 6 port turbo.
The RX-8 pcm is sitting in a box waiting for someone to buy it. After doing the dizzy swap, it is not needed for anything on the car anymore. I have no answer yet on your power question. I'm sure that a Weber makes less power 99% of the time than the stock EFI does. I could see it making more power at high RPM under certain conditions but I really don't think I gained anything by going to a carb. Anything, except the clout of being one of the only people who has one, as well as a pretty neat looking engine. To each their own. After spending 3 years working around and on 600+ horsepower cars I kinda just don't care about power anymore. Power alone doesn't make a car fun, it's a delicate balancing act. Speaking of, just realized that I never actually swapped out my master cylinder with a GSL-SE one. That explains the fear I had of my own brakes, whoops. I'll fix that soon.
After spending a couple weeks at sea aboard USS Nimitz with nothing to read besides the "Weber Tuning white pages", I decided to try and add to the resources out there for tuning these carburetors. Attached is a concise procedure for how to tune these carburetors based on the white pages, the Weber Tuning Manual, and the lean best idle procedure, as well as all of the knowledge I've soaked up on this forum. I hope it can be of use to y'all.
Been busy with work but I got some more little stuff done:
Got the battery relocated to the bin behind the passenger seat. Cleaned up the wiring here in the engine bay a bit. Got some fancy wiring shroud stuff put on, I gotta be careful or it's going to start looking a little too good for me. I installed a fan controller for my electric fans, a MSD Blaster high vibration coil for the leading plugs, and finally got a GSL-SE brake master cylinder installed too. Installed an S5 alternator for better juices. This made a world of difference. Went from 11.9 to 13.8 volts at the coils, even after the battery relocation. I'm guessing the old one just couldn't keep up with the radiator fans, or maybe it was just on it's way out.
Next fix is going to be some new rear speakers and a new headunit so I can get some tunes going on in this thing. I also plan on trying to lay some sound deadening where I can reach as I'm running wiring for the new speakers. I don't really want to pull the carpet all the way out, but I'll do whatever I can reach. I already fully lined the rear hatch area with some killmat, it's pretty good stuff.
The car is going to it's first autocross this Sunday at Bremerton Raceway. Looking forward to giving it a bit of a shakedown, and seeing what breaks(hopefully nothing major). I have a go pro so I'll try and get some good footage of it.
Here's a video of it running in it's most up to date form:
I'm curious about your Weber setup. Is it the 13B 6-port intake? What did it take to make an adapter plate?
I know they aren't as efficient as EFI but I love those wrapover intakes, they just look so cool. That setup also aligns with the eventual goals for my FB, which is a more balanced car with around 175-200 hp with a carb setup that's more for weekend drives in the mountains and occasional longish drives to meets. I've been thinking about building a 13B hybrid with Renesis rotating gear but a carb'd Renesis sounds easier and possibly cheaper.
I'm curious about your Weber setup. Is it the 13B 6-port intake? What did it take to make an adapter plate?
I know they aren't as efficient as EFI but I love those wrapover intakes, they just look so cool. That setup also aligns with the eventual goals for my FB, which is a more balanced car with around 175-200 hp with a carb setup that's more for weekend drives in the mountains and occasional longish drives to meets. I've been thinking about building a 13B hybrid with Renesis rotating gear but a carb'd Renesis sounds easier and possibly cheaper.
My goal here was to get something similar in function to the original engine, but with the power of a big ported old school motor and more part availability. This was the best way for me to do that.
As far as the intake, the carb and manifold I purchased from atkins rotary as a set ( https://www.atkinsrotary.com/store/8...are705k48.html ). The adapter is an off the shelf racing beat unit, or should I say WAS an off the shelf unit. So far as I can tell, these are NLA. Their website no longer has any trace of them ever existing. I'm sure you could contact them and try to have them make one up for you. If not, I'm not sure how you could do what I did other than making your own intake manifold using an RX-8 intake flange.
08-29-21, 07:47 AM
