EC's Stage 3 Wildcat 223 built by Red Beard's Garage.

We’re looking at our Stage 3 kit install on the Wildcat 223 engine, answering some more questions, and diving into the latest engine results. 

Why does EC sell stage kits?

Building engines in stages isn't something new but has been used by the engine performance industry for about as long as the industry has existed. The goal is to offer customers a package of components that would increase performance at various levels based on the application and desired driveability. 

The small engine performance market adopted these same ideas. Usually, stage 1 is a jet kit, air cleaner with an adaptor, and an open or less restrictive header. While the kits may have been started by companies in the mini bike or go-karting markets, retailers have flooded eBay and Amazon with very inexpensive and often cheap quality versions due to the components' simplicity. 

We wanted a stage 1 kit to allow improvements that were not as easily duplicated with better advantages. The Tillotson PK carburetors were developed for the 196cc box stock kart class raced on dirt ovals. The carburetor isn't emission-controlled, which allows more tunability, but the design and development gave it enough airflow advantages that it was outlawed in many classes. We decided to create a stage 1 kit that would replace the stock emission-controlled carburetor with a better flowing and better-calibrated carburetor for better overall performance without losing the look and function of a "stock" engine.

Originally, EC's Stage 3 kit was their Stage 2 kit before the release of the Ghost 212. However, the popularity of the Ghost engine and the components used by the engine would fit in terms of performance and drivability. Utilizing only a 22mm round slide carburetor is enough to increase power by around 10-15% and move peak power up around 500rpm higher over stock. To take full advantage of the bigger carburetor and to get more power and range out of the engine, a mild camshaft was added to improve torque without moving peak torque higher in the rpm but moving peak horsepower for a broader powerband with the mannerism and drivability of the Ghost 212 or Briggs LO206. Since most would want to run this kit off the governor, a billet rod and billet flywheel, as well as 26lbs valve springs, were included in the kit.

Stage 3 was formerly Stage 2 because it was similar to other companies' Stage 2, which was usually a billet rod, billet flywheel, knock-off "vm22," and maybe a camshaft, usually a mod2 which is a stock lift with 246 degrees of duration. The combination would increase power but mainly on the top end. When we developed the Tillotson 225RS, we used a .265 cam with 235 degrees of duration. The top-end was similar, but the low-end torque was better than a mod2. The camshaft worked well, and we pushed it as an alternative to the popular mod2 camshaft. It wasn't long before other companies updated their kits to use the .265 lift camshafts.

The knock-off "VM22," which is more of a copy of a PZ26, is very popular and used by many in this stage of the kit. The popularity of this carburetor started with the many kits you find on eBay and Amazon as a bolt-on upgrade. Many companies use the same kits. We found those carburetors very troublesome and cannot be adequately tuned with simple jet changes. After lots of testing and modification, we decided our next step to improve the carburetor was to make our castings and fix most of the issues in the factory. We also changed the style of the enrichment valve/choke so the carburetor can be mounted closer to the cylinder head without interfering with the valve cover. We had to make our own intake manifold to mount the carburetor closer rather than use the cheap Chinese intake. The intake is a better quality. Even though it's a simple piece, the taper is far better from the carburetor to the intake. Overall, the carburetor is better tuned and starts much easier than other knock-off VM22. 

The 26mm round slide carburetor helps to move peak power to the limit of the cylinder head, which is around 6000-6500 rpms for most stock heads. Most stock heads don't flow over 60cfm at a .400 lift and between 45-50cfm at a .250 lift, around the max lift of the .265 camshaft. The carburetor flows around 90cfm. 

Why was EC's stage 3 kit created?

The Stage 3 Kit has identical components to the Tillotson 225R/RS engines and should give you similar performance, especially with engines of similar displacement like the Predator 224, Ducar 224, and Wildcat 223. While the Tillotson R-Series has its advantages, it comes at a higher cost, and most of those advantages are overkill for the level of build. Buying a stage 3 kit to go with your engine will save you money for similar performance. 

What comes in EC's stage 3 kit?

- WC22 26mm Round Slide Carburetor

- Short Billet Intake

- Banzai 265 Camshaft w/26lbs Valve Springs

- Billet Flywheel 34° timing

- EC Pinnacle Forged/Billet Rod

- Head Gasket

- Sidecover Gasket

What does the Wildcat 223 Hemi flow stock vs. ported?

Heads flowed @ 28”

We know from Red Beard's tests comparing carburetors on a stock Predator 212 Hemi that when that same engine was upgraded with a .265 cam, and later 1.2 ratio rockers, that peak horsepower was made at 6500 rpms. We believe the cylinder head, regardless of more lift or even more duration from the camshaft, wasn't flowing enough air to move peak power any further. The power did increase below 6500 rpms but not past it. 

Since the carburetor may be oversized for the cylinder head, more power can be made if the engine has at least a ported cylinder head. The Wildcat 223 has a hemi head, and the angle of the valves is between the Predator 212 Hemi, which is narrower, and the Ducar/Ghost/Tillotson 212E, which is wider. Hemi heads have advantages over the "Non-Hemi" parallel valve heads because a hemi unshrouds the valve from the cylinder as it opens and provides a better port angle from the inlet of the port to the valve.

The Wildcat Hemi head is unique because it has 5mm stem valves vs 5.5, and the valve guide doesn't protrude into the port. However, the ports are smaller, so the airflow is similar to other heads from the factory. The advantage is all the extra material that allows more room for porting. The Wildcat Hemi head can flow into the 80cfm range by .400 with its stock 27mm intake valve when ported. The airflow rivals non-hemi heads with bigger valves and porting. Increasing the airflow will allow us to use the larger carburetor and help support larger cams or more lift. 

How much power does EC's stage 3 kit make?

As you can see, the head is holding the engine back nearly .5ft-lbs of torque, moving peak torque up 800rpms. But the engine doesn't lose torque below 4600rpms; the engine is still making 13ft-lbs at 4100rpms up to 6100rpm. Without porting, the engine made 11ft-lbs from 3800-6400. With porting, it made more than 11ft-lb from 3700, which is 100 rpms sooner until about 7300 rpms. That means the Wildcat stage 3 with porting makes more torque in a 3600rpms range than a stock Ghost does at its peak. Peak Torque for a stage 2 Wildcat is around 12.5; the Wildcat stage 3 with porting makes 12.5ft from 3900-6500rpms, which is the 2600rpms range. It's really incredible what a carburetor and porting can do to a mild engine with only a .265 lift. At this level of power, it's more than what a stock Trailmaster can handle, requiring solid bushings for the engine cradle to prevent misalignment of the chain, which can cause the chain to skip teeth or come off the gear. 

The engine also made 2hp more and moved peak power up 800rpms. If we compare the difference in powerbands between stage 2 and stage 3 kits, while stage 3 still made more power and grew the powerband, the powerband was not as significant as the difference in a ported vs non-ported heads. That data is essential for anyone modifying any small engine; power is made in the cylinder head, and it needs to improve its airflow to see more significant gains from the carburetor and camshafts. Remember, the valve is only being lifted around .265, and the ported head continues to gain cfm up to .400 lift. Adding more camshaft could allow this engine to pick up another 2-3 horsepower. However, by adding more camshaft without porting, you would be lucky to get the same power as the ported head and low lift cam. The other benefit of porting vs. adding more camshaft is gaining more power without compromising reliability, as more lift puts more stress on the valve train. You can also run into problems with piston-to-valve clearance and upgrading the rocker's arms and springs, which will require head modifications to get the installed height set without running into coil bind or other clearance problems. 

How does the Stage 3 Wildcat compare to other engines tested by Red Beard?

Red Beard built and tested a Predator 212 Hemi with a 265 cam and TM24 flat slide carburetor. The TM24 and knock-off "VM22" both flow nearly the same. However, the TM24 made .61 horsepower more than the "VM22" chikuni with a stock cam. After adding the .265 cam and .010 head gasket, billet flywheel, and billet rod, the engine made 12.37ft-lbs and 13.9hp, a gain of .89ft-lbs and 1.98hp. The increase comes from a bigger camshaft and more compression. Besides the displacement and architecture differences between each engine, the Predator 212 Hemi has about 9.9:1 compression with a 24mm flat slide and the Wildcat's 10:1 compression with a 26mm round slide, making the closest match-up from any previous test. 

Interestingly, the Predator 212 hemi and Wildcat 223 made two comparisons in each video. The Predator 212 Hemi compared the stock rockers with 1.2 ratio rockers for a total of .318 lift. The Wildcat 223 stage 2 compares the kit with an unported head vs a ported head.

The Predator 212 Hemi picked up a little more power with the 1.2 ratio rockers but still made peak power at 6500 rpms. If you have the tools, porting can be considered a free upgrade and is recommended for almost every level of build to improve performance. Still, it becomes crucial once the carburetor outflows the cylinder head. Porting can be considered a free upgrade if you have tools available. It's also a great area to practice because of how significant the gains can be and how limited modifications are without more flow from the cylinder head. 

The gains were much more substantial once the Predator 212 Hemi was ported because it could use bigger carburetors and camshafts. The Wildcat 223 proves the extra stroke and displacement has far more low-speed torque and can make as much or more horsepower without adding more lift to the camshaft. 

We currently have stage 4 in the works, and more videos to come.