The naturally aspirated 400+hp 348, yes for real

For a long time I have been of the opinion that the F119 engine is restricted in it's breathing. Because of the restricted breathing it can't reach its full power potential. I had been talking with different engine builders about how they achieve more power with different intake systems they had used.

Some of you may remember the twin turbo 348 Challenge I made a thread about a couple of years ago. It put down over 600+hp to the wheels. Well this time I bring you a naturally aspirated 348 that produces over 400hp. It was designed and built by none other than Mr. Steve Maxwell, the same mad genius the built the 348TT. Steve designed and engineered a new intake plenum that truly releases the breathing potential of the F119.

Here it is sitting inside the engine bay of Steve's 348.
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A look inside Steve's car reveals an interior built for business, complete with racing seats, racing harnesses, a roll cage, and yes, a 6 speed from a 355.
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A peak though the read window gives a nice view of Steve's latest creation.
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Steve opened up the engine cover to reveal the master piece. And yes you are reading that correct, it does say 375 on it.

I ask him what the deal was with the 375, and he tells me that's the displacement of an individual cylinder for a new engine he's working on. Another engine?!?!?!? Yup another engine. He bolted this intake, on the engine seen here, to test it out an see what it could do on a bone stock F119.
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Inside the shop he rolls out a new monster he is creating.

SAY WHAT?!?!

ANOTHER TWIN TURBO?!?!?!?
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Turbos need air, and lots of it. Like wise, naturally aspirated engine need plenty of air too.

To give you an idea of how restricted the F119 is, here is a side by side of Steve's intake plenum versus the factory plenum. Steve ran loads of calculations, simulations, and testing before he finalized his design. You can clearly see how his plenum dwarfs the stock unit. It also shows how badly the engine is being choked in stock form.
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Another choking point is the throttle bodies.

Not only did Steve manufacture the intake he also manufactured new throttle bodies. The stock throttle bodies are tiny, measuring 54mm at the throttle plate. Steve TBs are 80mm, and there are two of them. Yeah that will free up breathing. You can see the stock tb is so small that the entire thing can fit inside the opening of Steve's tb.
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Then I get to play with some goodies!!!

Steve was kind enough to allow me to see the individual parts, and to mock up an intake. I was like a kid in a candy store.

He pulls out a box full of runners. Each runner is machined from billet in his personal CNC machine. The craftsmanship, engineering, and design he put into all these parts was simply AWESOME!!

Forgive me if some of the pics are blurry, I was using the camera on my cell phone.
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To enable air to flow into the runners efficiently Steve designed velocity stacks of various lengths. You can run all one length, or stagger the lengths, run all short, all long, or half an half. The purpose of this is to take advantage of different harmonic resonances at different rpms. The way the velocity stacks are arranged in this pic was just us playing around with the arrangements.
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To give the engine bay a clean look Steve incorporated the fuel delivery system inside of the Intake. Here you can see the fittings machined into the bottom of the intake.
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But the real reason is that he is running F1 style rain injectors. The fuel rail runs inside the plenum housing the injectors. This place the injectors in the optimum location for atomization. The one injector pictured here was just held there to give an idea of how they would squirt down the runner. They actually sit dead center and above the v-stacks when everything is screwed down properly.

You can also see how we changed the location of the v-stacks, again playing around with configurations.
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The attention to detail, thought, and engineering Steve put into this is something you would see in a F1 race team.

Check this out.

He even engineered and machined all the linkage for the throttle bodies. I'm telling you the ENTIRE thing is engineer, machined, and built by Steve in his shop. He is truly a master at what he does.
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Steve had a stock F119 engine he was planning on rebuilding, so he wanted to test the outer limits of the stock engine. Just what would it do with modern technology? He didn't care if it blew up because it was gonna get torn apart anyway. So he bolted everything on, tuned it, then strapped it to the dyno.

The result?

340.9hp to the wheels.

He said that was more power than a stock CS on the same dyno, and I believe it.
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Here is a dyno sheet from my 348 on the exact same dyno Steve ran his car on. Mine put down 259hp. On a Dynapack I managed to do 305hp at the hubs. That would put Steve's car in the 385-390hp range at the hubs on a Dynapack. That translates into solid 400+hp at the crank for his car.
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I would like to extend a huge thanks to Steve for giving me the pleasure of hanging out with him for practically an entire day, and for sharing his work of beauty with me.