FL5 Civic Type R - 4P TR2 Camshaft Install and Dyno Test

 +21-42whp / +20-45wtq on PUMP GAS.

In 2021 we had released a line of camshafts that we were using in our racing engines so that K20C1 owners could benefit from the power gains, extended RPM capability, and the sounds of more aggressive VTEC transition that all of us Honda lovers have come to love.

This writeup is to cover the 4P TR2 Drop-In billet camshaft installation into the newest Honda masterpiece…the FL5 Civic Type R.

Thank you to the people that facilitated this...

• HondaProJason for urging us to do the test and for sending his car over
• Hondata for the tuning platform
• John Pierro at FK8TD.com for providing his expertise in Hondata mapping. I work with a lot of tuners on these cars, and John has proven to get the job done right.  He has a great handle on tuning these with our camshafts.
• Last but not least....our guys at 4 Piston who squeezed this project in by putting in some extra hours right in the middle of peak race season.

The K20C1 in the FL5 does have some minor internal and external differences compared to the engine found in the FK8, but for the most part it is the same hardware.  The turbo is smaller, the piston has a coated top ring, the chain guides are different, the ignition coils are different, the balancer is different....amongst other things. From a camshaft installation standpoint, the engine is the same and the installation procedure is identical.  You will run into some minor difference in behavior when tuning, mostly because the tuning software is a little different and the turbo runs out of breath a little earlier. There are some tables that aren’t opened yet in the FL5 Hondata software and there are not LIVE tuning tables activated yet.  Despite that, Hondata was extremely easy to use and these cams were easy to tune using their software.

The Car

The test car is a Championship White FL5 Civic Type R owned by Honda Pro Jason. This car was dropped off at 4 Piston with some previously installed modifications from PRL.  This car has a stock airbox with PRL silicon pipe, PRL Intercooler, and an AWE Exhaust.

Installation is easy, and the FL5 engine bay affords you some extra room over the FK8.  This extra room really doesn’t benefit you on a camshaft install, but it will later when working with the car on fitting larger turbochargers and cooling mods.

A bone stock FL5 on our Dynojet makes power just like an FK8….280-290whp.  If anything I do feel that the power comes in a touch more responsive on the low end with the FL5 having a smaller turbo, but in stock form they are pretty comparable.

Since this car did have some bolt-ons, we did a baseline pull with the OEM Honda ECU calibration and these bolt-on mods certainly offer you some healthy gains even without a tune.  The baseline is 313whp and 318wtq...a substantial gain over a completely stock car even without any mapping changes.

Dyno Below:  The next order of business was to add the Hondata Flashpro.  This is very easy and Hondata provides you with clear instructions for anyone to easily accomplish this.  After loading the off the shelf Hondata 93 map, you’ll feel a good kick in the seat with the extra torque and midrange power.  The tune is pretty conservative, but the boost mapping is much more aggressive than OEM.  What you feel in the seat is that big torque surge from the 26+psi and as you climb in RPM the turbo is running out of steam.

Dyno Below:  The next task is to tune the car on the completely stock engine so that we get a good baseline for the camshaft swap.  Even with less boost (to get rid of some exhaust heat), you can find big gains with minimal tuning.  Add 2 deg of ignition timing and pull the rich mixture back a touch, and you should see some pretty significant gains over the base file.

Now that we have the car tuned, it is onto the camshaft installation.  This camshaft installation is very easy and should take you 3 hours if you are taking your time and paying attention.

Tech tip:  You do not need to remove the timing chain case cover.  Remove the tensioner cover and relieve the tension, hold the timing chain up to the hood with a bungee cord so that it doesn’t fall off the crank gear.  Change one cam at a time.  It is really easy.  Don’t forget to set lash 😊  I’ve had guys forget that part after all the hard work.

 Now it is time to strap back on the dyno...

Dyno Below:  What happens if you just install the cams and don’t do any tuning?  This right here. Untouched mapping, just a cam install...the engine comes ALIVE.  You don’t want to run it like this because there are some fueling tables that need to be fixed as well as some VTC commands to keep this thing from jumping between tables.  That big dip in power is at the more aggressive VTEC crossover at 4200 rpm.  Eliminating this is accomplished by moving the VTEC engagement point up, and working with the ignition timing table to eliminate some bouncing around that the ECU wants to do on that crossover. 

Dyno Below:  The graph below is the custom tuned stock engine vs. the tuned TR2 Camshaft.  This is an otherwise stock engine, just with the camshaft installed.  Stock valve spring is still in the engine.  The actual boost logs will show ~1-1.5psi less boost on the RED chart with TR2 camshaft, and even a degree less on ignition timing because we wanted to send this thing home to Jason with a 100% knock free tune-up.  Horsepower gains vary throughout the range from 21-42whp, torque gains vary from 20-45wtq.

Tuning Note 1:  It was tricky to eliminate the dip at VTEC crossover because the stock ECU loses 1 degree of ignition timing for 300 rpm at the VTEC crossover no matter where you put it.  That 1 deg of timing has a significant impact on power.  No matter what you call for in the timing tables, it is going to drop a degree regardless.  As Hondata opens up the tables in Flashpro with similar capabilities to the FK8 software, you will have ways to work around this.  The one positive thing that comes from the “dip”…..you feel and hear that VTEC transition a lot more which is fun for the driving experience and a nice sound to your ears.  The smoother the transition, the less you “feel and hear” your VTEC.

Tuning Note 2:  There has been a lot of talk about the FL5 turbo superiority over the FK8, and I’m not sure where that information comes from.  The FL5 has a substantially smaller compressor side.  It runs out of breath early and flat out makes less power at full swing.  With a race intake, some cool intake charges, and an oversized intercooler….you’ll see cars get close to 400whp on pump gas, and obviously more on ethanol or race fuel.  I don’t expect it to make the peak numbers the FK8 does simply due to the smaller compressor wheel.  23-26psi, 9 deg ignition timing, 93 octane fuel from Speedway.