What non-turbo and non-supercharged 4 cylinder engines are the most powerful?

I'm not sure but I believe Toyota used to put radial engines in Celicas. This is the same technology as aircraft engines.

In just hp ratings I think the most recent Toyota celica engine, which made about 180hp would be one of the most powerful but it would be close to the Honda B series engines (which can range up to 180hp) and the Honda K-series engines which can range up to 200hp stock. The Toyota engine and the Honda B-series engines are very plentiful but the K-series are very new and will be more expensive and more difficult to find.

If you are allowed to use the wankel rotary engines that mazda makes and puts in the Rx-7 and rx-8 then you will be able to get over 200hp. Bear in mind that rotary engines don't have cylinders like a piston engine they have rotors. These engines may be more difficult to find than the others but offer a clear hp advantage.

Also, the other answerer is wrong about aircraft engines in Toyota Celica. No major car company since WW2 has ever put a radial engine in a car. Plus mazda is only company to put a rotary engine in a car.

Most Powerful 4 Cylinder

Is there a displacement requirement? And do they have to be stock?

Honda B-series engines are a good choice. There is large aftermarket for these engines. They can be found stock for up to 195hp, but those are rare so most likely you will be getting a 160hp one. You can easily and cheaply build even a low end B series engine up to the early 200s.

The only real problem is most (99%) Honda's use front wheel drive, so I don't know if you need rear wheel drive or if that can be a problem for you.

All those car are great for specific output but the most overall from a naturally aspirated 4 is a 3.0 litre 92 through 95 Porsche 968 at 236hp.

Go old school and find a Cosworth 4 cycl. but since they are arar engine to find I would have to say the Quad 4 out of the 91 Grand AM.

go the the honda's new k'series motor like from the rsx type s 200hp with a goos 6spd trans for fwd, but if it could be a rwd than go with the s2000 f20b 240hp redlines at 9000rpm.

the best answer is Honda K20A from the integra type-R model couple with 2.2 stroker kit from Spoon Sports and running on motec M800 stand-alone EMS..

We've raced against the quad 4 HO. Like you said about 180 hp. We race dirt track cars. That car was a beast. All stock. This year I'm driving a Cobalt SS with the 2.4 Ecotec VVT engine. I'm coming after him! The ecotecs are bullet proof and they are plentiful here.

Look to SCCA showroom stock for your answer. Sounds to me as though you are running a class similar to SS "C". Think mazda3, chevy cobalt or Honda civic.