Speed Perf6manc3 just found the limits of the Ford Focus ST engine block. They’ve been chasing the goal of reaching 1,000 wheel horsepower; although they knew the stock cylinder block wouldn’t be able to handle that kind of power, they decided to find the limits anyway. Nishan Gharibian from Speed Per6manc3 shared the details with us regarding what they discovered.

When Are Beefier Internals Required?

The Focus ST makes around 250 horsepower and 270 lb-ft of torque in its stock configuration. With a larger turbo and some bolt-on performance items, 360 whp can be reached easily, but as you push the limits upgraded internals are needed.

“Upgrading the internals is typically a necessity once you get up to 450 wheel horsepower. Even at 450 however, the engine is still at risk of failure, but with proper tuning and good fuel and parts it can last a while,” says Nishan.

The 770WHP Build Sheet

Of course, we want to know how they were able to squeeze so much power out of a stock-block Focus ST. After all, reliably getting that much power out of a little 2.3-liter four-cylinder engine isn’t exactly easy.


At this power level head studs are necessary to maintain the cylinder-head-to-block seal.

“The cylinder head is an EcoBoost 2.3-liter head. It has our Stage 3 camshafts, valve springs, stock intake valves and 2mm-larger exhaust valves as well as our in-house head port and polishing,” says Nishan.

Those Stage 3 cams aren’t available for production just yet, so he didn’t reveal the specifications.


A Precision Turbo 6466 running at 38 psi of boost pressure is underhood.

“The fuel system has our SP63 Port Fuel Injection system for secondary injection, as well as our prototype dual-Walbro 450lph Surge Tank fuel system. This setup can run on 100-percent E85 fuel, but we chose to do E50 for comparison testing,” he says.

The ECU is a stock Ford unit with custom tuning done by Nishan through a Cobb Accessport. As far as the transmission goes they’re using a Clutchmasters 750 Twin Disc Clutch, M-Factory differential, and they will be adding SP63 brass syncros to the transmission in the near future.

All of this is paired with their custom 2.3-liter stroker kit. Their stroker kit uses a custom rod length and is not the same as the 2.3-liter OEM Ecoboost engine.

Finding the Limits

After previously reaching 710 whp at 35 psi of boost pressure, they checked everything over. They changed all the fluids, did a compression and leakdown test, then decided it was time to crank the boost up.

Notice the massive cracking in cylinder number 2.

“The block was unable to withstand the cylinder pressure that was present to produce the power levels we were achieving. The sleeve on cylinder number 2 cracked and then punctured a hole in the liner. The hole was punctured right behind the coolant jackets where there is the least cylinder support,” says Nishan.

Despite the demolished cylinder wall, the pistons still appear to be in excellent condition.

There were no signs of any issues and the engine was running great at full power, right up until the cylinder liner completely failed. This engine was running their 1/2-inch ARP Custom Age 625+ head studs, and they verified that head lift was not an issue. Now that they’ve found the limits of the stock cylinder liner, they’re ready to swap in an aftermarket sleeved block and continue their journey of reaching 1,000 wheel horsepower.

The curve shows that even though the engine found itself in dire need of replacement, the power still held steady throughout.