This article’s focus will mainly be insight on the FD2 powertrain variants with some misc chassis info.
While the overall FD2 CTR and its Mugen variants are ultra intriguing, I find the powertrain most interesting because of Honda’s special treatment it received in its succession over past K20A Type R engines, mainly due to being the final naturally aspirated Civic Type R Honda will ever make (per them).
Below, I’ve rounded up various FD2 CTR, Mugen RR, Mugen RR AC info off the net and do not take any credit on any images used/borrowed. Some of these things are getting scarce to find!
There are three FD2 CTR variants – your basic bitch FD2 CTR, the Mugen RR, and final boss: Mugen RR AC (Advance Concept / Experimental). All bad ass in their own right.
The basic bitch standard FD2 CTR
The initial debut of the JDM FD2 CTR was in late 2006 but early 2007and ended production in 2010. Power output is rated at 225ps/215nm. Don’t trip on the basic bitch titling. Out of the JDM K20A Type-R engine family, this is the ZADDY of the bunch putting down the most oem power (excluding the rare af Mugen RR and RR AC engines).
Basic FD2 CTR engine received the following updates over its EP3/DC5/CL7/FN2 K20R predecessors:
Click for full FD2 CTR specs via TOVA article
- RSP cylinder head
Received a better flowing head (stamped RSP) with an NSX-like port job treatment, meaning, a refined manufactured casting process that offered a smoother surface (similar to being hand ported but not hand ported), thus ramping up the highest CFM flow over any previous generation K20R PRB and RBC cylinder heads. The RSP head resembles the casting of an RBC (and K24A RBB) head but is nowhere near the same port wise! Stock vs stock this is the best OEM head around and guess what? It’s also found on the UK/AUS FN2 CTR K20Z4 engine. - Updated camshafts + valvetrain info
Camshaft centerlines were changed up by a few degrees. Lift and duration is mostly the same vs predecessor K20R camshafts. Allegedly, our USDM 05-06 RSX Type-S K20Z1 camshafts are the same as these FD2 CTR cams. Valetrain contains single spring on both sides of the head (intake springs have light blue paint marks, exhaust springs have brown paint marks), unlike dual springs found on the DC5/EP3 K20R engines. Valve sizing remained the same with standard 35mm intake and 30mm exhaust. - Updated intake manifold & throttle body bore size
Has the infamous RRC intake manifold. Stock vs stock is a much better flowing and power making manifold over the RBC and arguably all other factory K manifolds, offering both good midrange and top end power gains. Drive-by-wire throttle body size is 64mm as opposed to the 62mm on predecessor engines. - Updated exhaust manifold and system (but no care for kswap 90’s era chassis’!)
The FD2 exhaust manifold design was changed in comparison to EP3/DC5, designed to have less restriction and back pressure. - Updated pistons & compression ratio
Honda bumped the compression ratio up .2 points, putting out 11.7 with the updated RRC pistons. Predecessor K20R’s have 11.5cr PRC pistons. Not to forget, the JDM FN2 CTR K20A and UK/AUS FN2 CTR K20Z4 is rated at 11.0cr with its PRB pistons – same pistons also found in the USDM 02-06 RSX Type-S, 06-11 Civic Si FA5 K20Z3, and UK/AUS EP3 CTR. - Updated rods & crankshaft
Received high strength material made rods and high strength + high rigidity crankshaft. But, after researching FD2 K20A crank and rod part numbers, it appears they’re no different than K20A2/Z1 PRB crank and rods…womp womp. Bore and stroke remain the same. RRC crank pulley is 5.5″ diameter which is the smallest factory diameter damper available (also found on EP3/DC5 K20R and USDM K20Z1 engines). - Balance shaft-less oil pump
Like the DC5/EP3 K20R engines, the FD2 K20A received its own similar pump. It’s exactly the same pump in fact, but only difference is a lower hanging pickup/sump respective to the RRC oil pan for the FD2 (and FA/FG) chassis. The oil pump chain tensioner bolt pattern is slightly different as well. This pump’s webbing is pre-cut from the factory to fit around the girdle hump. - Transmission specs
Received a 5.0 final drive and retains a factory lightened flywheel like previous generation K20R’s. 1-6 gear ratios are the same as RSX Type-S K20A2/Z1 ratios. Helical LSD equipped of course. Received new style synchro’s. Received an updated internal resin baffle plates to avoid oil starvation during high cornering speeds.
Mugen RR CTR
The Mugen RR debuted sometime in 2007 and was a limited release of 300 units worldwide and only available in Milano Red color. Powertrain wise had minor enhancements internally: Mugen camshafts + valve spring upgrade along with supporting external mods such as ECU remapping, Mugen 421 header and exhaust system w/hi-flo cat, all helping bump power from 225ps to 240ps. The drivetrain was not touched sticking with a standard FD2R LSD transmission. However, there were a sleewww of interior/exterior/suspension/wheel/and brake upgrades. A plethora of carbon fiber parts helped shave overall vehicle weight from 1270 kilograms (2800lbs) to 1253 kilograms (2767lbs). Here’s a little fun fact: During the production of the Mugen RR CTR, Mugen came up with their own “REV-R” synthetic oil for K-series VTEC engines that is 5w40 based. You can read about it here using your browser’s translator.
Powertrain updates:
- Mugen camshafts & valvetrain upgrade
Received Mugen camshafts w/supporting stiffer dual valve springs. - Mugen intake air box upgrade
Received a full carbon fiber air intake box that pulls air through a bumper vent and also eliminated the resonator box (compared to the OEM resonated air box and pipe routing). - Mugen header and full exhaust system
Received upgraded exhaust system w/4-2-1 exhaust manifold and hi-flo cat. - ECU remapped
Exterior/Interior/Suspension/Brake updates:
- Lots of Mugen carbon bits introduced to shave that weight..
Carbon vented hood
Front and rear bumper styling updated both made from carbon fiber!
Carbon front grill w/mesh and Mugen RR emblem
Carbon intake manifold cover w/Mugen RR emblem
Carbon Mugen rear spoiler
Carbon Recaro SP-X bucket seats w/embroidered Mugen RR logo - Mugen 18″ light weight forged wheels w/Bridgestone RE070 tires
- Brembo big brake kit
- Mugen suspension (dampers & springs)
- Mugen shifter
- Mugen gauge cluster
- Integrated analog dash gauges for oil pressure, oil temp, and water temp
Mugen RR Experimental / Advanced Concept
The Mugen RR Experimental was a precursor to the final boss and polished up version dubbed: Mugen RR Advanced Concept.