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Its been a while since my last real post on this forum. K20a.org has been a great site for knowledge and connecting with the rest of the world. Im going to share with you guys what we have been working on the past 4months for one of our good client.

If you have liked us on Facebook, then you would have seen some of the updates and build thread on Project RHONDA. if you haven't liked us yet, be sure to check us out - BYP Racing and Developments

Long story short, our client Adrian has converted himself after seeing the results of his turbocharged B16a EK civic that he uses for circuit work. He's heart was set on a RWD platform and had always loved the RX7 FD3s shape. After seeing KTUEND's Kswap RX7 and after doing some research, we said its more than possible to get it done. The rest is history and everything started to snowball to the finished K20 turbo swap

Project "RHONDA" at the most recent Motorkhana trackway


The completed engine bay


Im going to back track little and do a breakdown of this conversion for those are keen to see what we did with this conversion

First step, removed the old 13B power plant. This car was 100% stock


We put together a dummy K20 engine and with a adaptor plate matched the S2000 6 speed gearbox to it


For this project, we had chosen to use the Innovative Kswap engine mounts made for the S2000 and adapt it to this project. We sent the car to our mates over at Impossible Fabrication to modify the subframe, mount engine, mount gearbox, rear diff support and make the turbo manifold and dump pipe







After the parts were fabricated, we got the car back for parts to be sent for powder coating while we got a K20 engine ready. Since Adrian will be using this car for circuit work and time attack orientated events, we had to take care some aspect of the engine. Head is fitted with supertech dual valve springs and a clockwise baffle kit to reduce oil surge. Due to the design of the engine mounts, we used a late model K20 engine to follow the same engine points as the K24

Going off the experience we had with our personal S2000 with a K24 swap, we use what we learnt from that RWD conversion and follow the same concept to this project. F20C inlet manifold fitted with an adaptor plate, F20c adaptor plate for transmission, Clutchmaster K2F flywheel, Clutchmaster FX300 clutch kit





Parts came back from high temp and powder coating and it was time to mount the Garett GT3076R turbo onto the motor. We had preassembled basically the whole running gear before fitting it into the car. Plenty of room to make oil and water lines and all the small fiddly things





Once we have everything preassemble, it was time to lower the chassis onto the prepped engine package. Fitment was tight towards the firewall and we had to make changes to the CAM sensors on the back of the head (angle of fitment) to give enough room against the firewall. After 6 or so attempt, we were happy with fitment and tighten up the crossmember to the chassis



We had quite a discussion deciding with the intercooler configuration we were going to go with but seeing the goal and intention of the customer, we decided to make the system as efficient as possible and spent the extra time to do a custom V mount set-up. We left this job for our other fabricator and he did an outstanding job









We also sent the custom V mount items off for black powder coating and to keep with the clean look theme. While these parts were away, we spent time to do the rest of the things around the engine which was the most time consuming thing. We reused the two OEM oil cooler, one for oil cooler and the other for power steering cooling. We have opted to go with an electric power steering unit from a mercedes. Its a light and compact unit and its quiet on operation



In terms of electronic, we are running an 02-04 K20 engine harness with Hybrid Racing universal race Kswap harness. A Hondata KPROv4 controls the operation of the engine with a Hondata 4 port boost solenoid taking care of boost control. We have got the cluster to work 100% but Adrian didn't mind so much since we will be moving to a race orientated dash display i,e Motec

The V mount parts came back from the powder coaters and they looked amazing. We fitted the V mount for the final time and turn over the motor for the first time with no issues at all. Car turned over first go



The car needed one last trip to the fabricators for a custom 3inch exhaust system. Again with the direction of the car, we opted to use the exotic material - Titanium to make the exhaust system. We stock and sell Titanium exhaust materials so it was easy for us to make this exhaust with our fabricator. With only 1mm thickness, we have a flow diameter of 74mm to optimise exhaust flow for the K20 turbo set-up. We fitted one 3inch titanium resonator to keep noise down



Before the car hit the dyno, we fill it up with pump E85 (about 10mins from the shop) and starting the process of dyno tuning the setup. It was no different to all the other Honda's we tuned and it was very rewarding to see the car make great power with no issues on the very first attempt





Running on base waste gate pressure (16psi), we ended up with 316kw at the rear wheels. We are going to leave it at this power for a few months to nut out anything teething issue and for Adrian to get used to the power. It will be quite reliable at this power level on the stock K20 for track work

On top of the conversion, we also upgraded the stock suspension to coilover, retro fitted EVO X 4 pot brembo callipers and 2 pieice rotors and Cusco front and rear sway bay





Adrian has put on a few miles on the setup to date and competed at the most recent motorkhana in the car




And on this passing weekend, he attended the drag strip with the car. Without any tacho and instruments, he recorded a [email protected] missing 3rd gear. He only did 2 runs and had to head off early for family commitments



So there you have it guys, Honda K-series powered Mazda RX7 FD3s. We are extremely happy with the outcome and this car has heaps of potential as a great all rounder. The response has been mixed (can't win them all) but people have seen the value in this type of conversion especially if your a track enthusiast who loves the RX7

Feel free to ask question and ill try my best to answer it within reason. We can offer these kits or any parts to help people get started with their very own Honda powered RX7 FD3s!
 

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Nice work Jimmy and Benny, and informative write-up too!

Peter
 

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I'm looking to use either the s2k transmission or a later model 6 speed mazda miata trans for my rwd k24 build. How strong/ relibale has the s2k trans been??? any modifications to the internals of it??
 
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