You are here: Home / 2012 One Lap of America / 4B11 Magnus pistons
4B11 Magnus pistons

4B11 Magnus pistons

Part of the engine build up for the Evo X this year is a new set of pistons from Magnus Motorsports.

I am humbled in saying that I only thought I knew what went into piston design before talking with Marco on this new setup. It turns out I know very little about pistons. Even now I can hear Marco cringing somewhere in Toronto at my fumbling of words on the topic. It won’t stop me from trying, because from what I can see, this piston is the most engineered design available for this motor.

The first thing our experts will notice is that the picture you see isn’t the 4B11 piston. Marco didn’t exactly want them floating around before he was able to get the product online. What I do have is the piston that revolutionized the 4G63 platform. The engineering that went into this piston helped influence the 4B11 piston. It is that same engineering went into creating motors that would support 1000+ HP in generations past allowed Magnus Motorsports to produce the fastest 4G63 motor on earth.

The new Magnus 4B11 piston is a piston designed for race motors and is a far cry from any other piston on the market for this Evo X. We are no only proud to help Magnus bring this to market, we are a little overwhelmed by the offer to run such an elite design. It is sort of like watching everybody else put motors together with legos, while Enzo Ferrari sculpts out or pieces to a precision that we can not comprehend.

Instead of designing the piston to simply be stronger clone of the factory pistons, Magnus has specific objectives in mind. For instance, they focus on making a piston that will travel silently in it’s bore. I get a little foggy on the details, but supposedly this was tied to the secret sauce that allowed them to produce more horsepower out of the same four cylinders than anybody else. They pull from have a pile of tricks that allow them to make this happen, most of which I will now destroy in my attempts to explain what I only loosely understand.

Pistons are not perfectly cylindrical. Let’s pretend I actually knew that one. They have a unique shape that balances with the harmonics of the motor. If you think about where the pressure is applied on the piston, it isn’t from straight down as the crank pushes the connecting rods. It is offset. Marco holds that magic equation somewhere in that huge cranium of his and transfers it down to the parts he makes when he needs it.

The new piston has beefed up with the quench pad on the top to accomodate more heat dissipation. Good news for us as we like to heat pistons to the point of melting. They have also already accommodated for people planning on running larger valves by sizing the recesses to already have the tolerance they need to clear.

The shape of the piston quench pad on the top is intended to drive the flame of the explosion forward which creates more power for the power stroke. That shape also assists in swirling the air before ignition to optimize the saturation of fuel and air. Because apparently you can affect this with small changes in dishing angles that your eye will never see.

All of this equates to the best race worthy piston to come out for the Evo X yet.

There is a really good set of photos and a write up of how Magnus went about measuring the tolerances to make this piston on the EvoXForums last year.

TheNEWB 2.3L Stroker Build Thread

If you have had Magnus build you motor for a 4B11 this past year, you might already have one of these pistons. The good news is that last week Magnus made them available for sale for anybody looking to build up their motor through their online store. They also have a much more accurate description than what I was trying to communicate.

Magnus 4B11 Piston

About Stephen Burke

Leave a Reply

Scroll To Top