Unusual RX8 Engine Swap
10-17-2016, 11:46 PM
#1
RX8 Honda V6 Engine Swap
Hello everyone, Just here to give you all a glimpse of my project RX8 until i can post the entire project in the correct topic location.
First things first the car is completed 100% and has been daily driven for the entire summer. I did not want to be another guy that post's his build and never finished.
So the project car is a 2004 RX8 6 speed. Recently swapped to an Acura 3.5L V6 engine!
This was a project that took over 2 years to build on/off on the weekends when i had time to work on it. 100% of the swap was completed by myself. The project was to challenge myself and not just swap another engine into a car but to engineer the whole project, as well as to demonstrate to everyone that anything can be done regardless of what people think.
Here are a few pics
First things first the car is completed 100% and has been daily driven for the entire summer. I did not want to be another guy that post's his build and never finished.
So the project car is a 2004 RX8 6 speed. Recently swapped to an Acura 3.5L V6 engine!
This was a project that took over 2 years to build on/off on the weekends when i had time to work on it. 100% of the swap was completed by myself. The project was to challenge myself and not just swap another engine into a car but to engineer the whole project, as well as to demonstrate to everyone that anything can be done regardless of what people think.
Here are a few pics
Last edited by RX8J35; 10-20-2016 at 08:25 PM. Reason: more descriptive title
Nice work
10-18-2016, 12:25 PM
#9
Thanks for the comments.
It is a J35a3 (orginally started out with the j32a2 260hp)
Power: 248 hp (185 kW) @ 5800 rpm
Torque: 242 lb·ft (328 N·m) @ 4500 rpm
Not sure of power right now haven't dyno'ed it yet
Heads and intake PNP
Type S Cams
80mm Throttle Body
Ebay headers modded for 2inch downpipes to a 3 inch to stock exhaust with electronic cutout.
Chromoly Rx8 flywheel
Spec stage 2 clutch
Tuned with Mega squirt
Stock Rx8 transmission
Stock drive shaft, PPF, Diff
Chose this motor because of Power/Price/Weight/Size
Motor fully dressed with adapter plate and flywheel adapter, engine mounts, and headers weighed in at approx 320lbs. If i remember correctly i weighed the rotary engine at 280lbs.
Engine sits approx 1.5inches closer to the steering rack than the rotary.
Also to mention i bought this car 4yrs back for next to nothing, previous owner wrecked the car blew the gaskets on the rotary. I had fixed it all and driven it for a year as well as tracked it a few times. thought about boosting it and other rotary swaps but ended up doing this.
My goals with the build was to do it as if the car came with this motor. so everything else had to still function properly.
To be honest on the street I don't really notice the difference in handling the car still feels well balanced and controllable. 1st, 2nd is a bit touchy due to wheel spin even with good tires. I have not tracked it yet to really tell. I think the only way to know for sure is to drive a rotary and mine back to back. I believe an experienced driver will be able to note the change in handling. I've done my best during the install to minimize the impact to handling.
It is a J35a3 (orginally started out with the j32a2 260hp)
Power: 248 hp (185 kW) @ 5800 rpm
Torque: 242 lb·ft (328 N·m) @ 4500 rpm
Not sure of power right now haven't dyno'ed it yet
Heads and intake PNP
Type S Cams
80mm Throttle Body
Ebay headers modded for 2inch downpipes to a 3 inch to stock exhaust with electronic cutout.
Chromoly Rx8 flywheel
Spec stage 2 clutch
Tuned with Mega squirt
Stock Rx8 transmission
Stock drive shaft, PPF, Diff
Chose this motor because of Power/Price/Weight/Size
Motor fully dressed with adapter plate and flywheel adapter, engine mounts, and headers weighed in at approx 320lbs. If i remember correctly i weighed the rotary engine at 280lbs.
Engine sits approx 1.5inches closer to the steering rack than the rotary.
Also to mention i bought this car 4yrs back for next to nothing, previous owner wrecked the car blew the gaskets on the rotary. I had fixed it all and driven it for a year as well as tracked it a few times. thought about boosting it and other rotary swaps but ended up doing this.
My goals with the build was to do it as if the car came with this motor. so everything else had to still function properly.
To be honest on the street I don't really notice the difference in handling the car still feels well balanced and controllable. 1st, 2nd is a bit touchy due to wheel spin even with good tires. I have not tracked it yet to really tell. I think the only way to know for sure is to drive a rotary and mine back to back. I believe an experienced driver will be able to note the change in handling. I've done my best during the install to minimize the impact to handling.
Last edited by RX8J35; 10-18-2016 at 12:35 PM.
05-05-2018, 05:54 AM
#17
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How has this swap held up over time?
Interested in doing a j35 swap into my rx8. How has this swap held up over time? Did you make the adapter for engine to trans or is it commercially available? If you made it are you willing to share the files?
06-16-2018, 11:50 AM
#18
I have been daily driving it over the summers. and a few autocross events. haven't had any issues yet. still the same gearbox. lots of fun. I have done hard launches and beaten on this car every week.
yes I'm willing to help others achieve a goal hence another purpose of the build. i did make the adapter my self however I do have drawings for the flywheel adapter not the trans. it was a one off thing. I would recommend looking into the j swap miata kits. less headaches.
Last edited by RX8J35; 06-16-2018 at 12:13 PM. Reason: add information
06-16-2018, 12:19 PM
#19
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How has this swap held up over time?
You said you have the flywheel adapter drawn up. Would you be able to email it to me? I know the guys that make the j miata kit. And while it's a nice kit I don't like convertibles. What did you do for an engine computer? Thanks, Mike
06-19-2018, 10:23 AM
#20
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06-20-2018, 06:57 AM
#21
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Pretty Awesome, One of the many Non Rotary Swaps in my head is a Mitsubishi V6 paired to the stock RX-8 Transmission.... They make some really good power with basic mods while staying Naturally Aspirated, and are extremely reliable and easy to maintain (Parts can get pricey sometimes) and the Engines themselves can be found for pennies.
07-14-2019, 12:51 AM
#22
I’m very interested in this swap. I’ve thought about this exact thing on and off for several years. I also love that you picked the j35a3, forged internals from the factory, very nice. From what I can see, you didn’t have to remove toooo much of the firewall? I’m hoping you didn’t need to remove the heater core, as you said the car must function as stock. Any extra information you can provide would be GREATLY appreciated. I’m picking up an RX8 this summer, and am trying to plan a possible piston swap for the future. I DO want to keep the rotary, ultimately, but the fuel economy will be a factor. The Honda v6 will be reliable, consume far less fuel, and have much more horsepower, AND torque. Rod bolts and cl type s cams and this should rev to 8k no problem. As long as it fits without having to reposition the steering rack, I really believe this is the best option available, in terms of a piston engine swap. These Honda j series are routinely turbocharged to over 800hp with stock internals. They’re light and strong. This man is onto something.
07-14-2019, 01:57 PM
#24
Smoking turbo yay
J35 is an okay engine, I guess... If(and that's purely theoretical because I would never do it) I have to consider a piston swap, good'ld LS will be it. It makes much more reliable power stock and doesn't really burn much more gas than a J35. J35 also has a timing belt and in a long run, can be a bit of a headache and extra work. And it's SOHC... I can at least see OHV in the LS being compact and have low centre of gravity, but otherwise why not pick something DOHC?
Last edited by UnknownJinX; 07-14-2019 at 02:02 PM.
