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The K Series Solution

Toda's New RSX Cams And ECU Package

Gary Castillo
Aug 1, 2003
0308_impp_01_z_+parts+camshafts Photo 1/1   |   The K Series Solution

I remember the days when the non-VTEC engine was king and Honda nerds were too scared to touch an engine with VTEC stamped on it. The B18A had every type of cam package from mild to wild, while the support from the aftermarket left the VTEC valvetrain untouched. A few years down the road the situation was reversed and everybody was sporting the VTEC badge. To this day, cam manufacturers are finding new profiles to squeeze even more horsepower out of the B series engine. When VTEC was first introduced, Honda fans had no idea the advantages of having a low to high cam profile. And from the cam manufactures stand point, they had to figure out two different profiles for the exhaust cam and another two for the intake side. This involves getting the cams to transition smoothly from high to low as well as to handle high rpm. Once efficient grinds were designed it was the time to see how well adjustable cam sprockets would add to the mix.

Adjustable cam sprockets became the key to unlocking power out of any camshaft combination. By simply changing the valves' open and close time on a given camshaft, more power could be unveiled, making the adjustable sprocket a valuable commodity. Cams with adjustable cam sprockets became an absolute must on B series engines. In the long run manufacturers were able to discover what does and does not work; whether their cams were at zero or if adjustable sprockets were used. This isn't to say the B Series cams are a done deal, but with the many different combinations available, the hard part is just finding the right one. With this history lesson done, there's now a whole new can of worms that's been opened when dealing with the new K series engine housed in the new Civic and RSX.

Most cam manufactures have VTEC grinds conquered, but now the aftermarket has to deal with VTC (Valve Timing Control) on the new K Series engine. With a combination of VTEC and VTC, cam profiles and cam sprocket adjustments have been taken to the next level of horsepower. Honda's VTC eliminates the use of an adjustable cam sprocket with an electronic adjustable intake sprocket. One of the major differences from this sprocket to an aftermarket adjustable unit is the K Series ECU can give a plus or minus of 50-degrees of cam timing.

First off, let's start by saying 50 degrees is a shitload of cam timing, in either direction! Most B Series adjustable cam sprockets only allow a plus or minus of 10 degrees. How Honda was able to get away with 50 degrees is rocket science, but if you do the math, this is 100-percent possible. It doesn't mean that you should start notching away at your B Series sprockets to get more out of them; this just means the K Series valvetrain was designed after having this type of tolerance. To start with, the three main reasons this technology was added to the new line of engines was to improve gas mileage, exhaust emissions and performance. At idle, the sprocket is adjusted to the retard position to lower emissions. As the rpm increases, the intake cam is moved to advance the valve timing event, increasing horsepower as well as allowing a complete combustion of air and fuel. One would think that aftermarket cam manufactures wouldn't touch this with a ten-foot pole, but one manufacturer decided to try and tackle Honda's new technology.

TODA "Engine Kit" answered the solution to making more power out of the K Series. TODA Racing has extensive engine development experience with the K20A, starting with development of full race versions for the Japanese N1 and N+ racing series. There are several Japanese N1/+ race teams using TODA K20A engines (example: 5ZIGEN DC5). Now with all the various tuning, involved with the K20 engine's camshafts, TODA had to add a few other necessary components to complete the package: TODA uprated valve springs and ECU ROM tune. The valve springs were added because of the raised rev-limit and higher cam lift. As far as the ECU, raising the rev limiter was only one part of the solution to making more power.

Revised VTEC engagement, a 9000-rpm redline, modifications to the total ignition timing, and a few changes in the fuel curves were other parameters modified through the ECU. One of the key elements on the ECU ROM tune is in the cam timing that TODA uses with their cams. Now that a majority of the newer vehicles seen on the streets today require the O.E. ignition key to be programmed to the factory ECU, this means your ECU must be sent out to TODA for an ECU ROM tune. Although this does cause downtime on the vehicle. Once a customer orders the kit, Toda Racing ships out the camshafts and valve springs in a UPS next day box to the customer. After the customer receives the package, they will remove their stock ECU, ignition immobilizer and ignition keys and place them in the UPS next day box and ship it to TODA Racing. Don't worry, ground shipping costs are paid within the continental United States.

TODA camshafts are developed in Japan as an upgrade for the Japanese DC5 Integra Type-R, and therefore its gains are higher on the U.S.-market RSX Type S which runs a slightly milder cam than the J-Spec Type-R. Traditionally, Spec A cams are mild performance camshafts designed to improve power throughout the powerband without a sacrifice in driveability or reliability. Since these cams are on the mild side, they are the only camshafts authorized by SCCA to be used on the RSX Type-S competing in the SCCA World Challenge. Several teams, including the MUGEN/King Motorsports World Challenge RSX, will be using TODA Spec A camshafts.

The Dyno Before the cams were tested, the car had a few aftermarket components installed to help the engine breathe a little easier. It's always good to add the basic bolt-ons before you install the cams, and our weapons of choice happened to be an Injen air intake, Mugen exhaust and TODA header. With the bolt-ons in place, the car netted a total of 196.2 hp. Considering the car came registered 171.8 hp in O.E. condition we thought the Power Page style combination gave the RSX a crazy amount of power. Then again, the dyno we used was a Dynapak and the numbers were corrected.

Installing the cams is an easy task, with one of the biggest differences being the chain drive system is present on the cam sprockets as well as the VTC sprocket. There's should be a small amount of play in the chain. The trick is to slip a wedge between the tensioner and chain to keep the system timed right. This allows you to slip the cam sprockets off the cams without losing the cam and crank timing, as well as having to not have the tensioner expand. The ECU install was a simple unplug-and-plug-in process, and from there it was strapped to the Dynapak dyno for a power pass. One of the great things about this package is there's no need to add and tune adjustable cam sprockets; just install and go. On this test our install and go run landed us 220 hp and 151.2 lb-ft of torque. In comparison with our bolt-on run of 196.2 hp, the cams netted a total of 23.8 hp. The power increase was across the board, but the highest gains came from 5000 rpm and higher. One problem that was fixed was in the 5800-rpm range. A big dip in power was found at this point, but then power would come right back up. With the TODA cams, power was made throughout the range without any dipping at 5800 rpm.

Sources

Toda Racing USA
714-968-7040
http://www.todaracingusa.com
By Gary Castillo
45 Articles

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