Very useful information on building a 5sfe, mr2.com link Options

[ILoveMySilly97]

I myself have a 5sfe and this is good heads up info if I ever decide and working on building power for my car. Sadly I'm restricted since I live in Cali.

http://www.mr2.com/forums/non-turbo-engine...-induction.html

[Bitter]

I think there's also the issue of the bore vs stroke keeping it from revving. Take a look at all the S series engines that are noted for being able to turn higher RPM and noted for making good power (NA or FI), notice something? Square engines. Bore=stroke and they have a good rod ratio. The 5S is designed from the ground up to be a low revving economy engine. You can get stronger rods and pistons and rev it higher, but it doesn't take to it like other S series engines do. Trying to totally redesign an engine to be something it was never built to be is hard. There's engines that drop right in and off the bat are designed for higher performance which means they take to modifications much better. I think in the end the theory will remain just that as I highly doubt anyone can hit 200whp feasibly. You'd dump in more money than a V6 swap, BEAMS, or 3S-GTE and have a lesser engine still.

[Syaoran]

I think there's also the issue of the bore vs stroke keeping it from revving. Take a look at all the S series engines that are noted for being able to turn higher RPM and noted for making good power (NA or FI), notice something? Square engines. Bore=stroke and they have a good rod ratio. The 5S is designed from the ground up to be a low revving economy engine. You can get stronger rods and pistons and rev it higher, but it doesn't take to it like other S series engines do. Trying to totally redesign an engine to be something it was never built to be is hard. There's engines that drop right in and off the bat are designed for higher performance which means they take to modifications much better. I think in the end the theory will remain just that as I highly doubt anyone can hit 200whp feasibly. You'd dump in more money than a V6 swap, BEAMS, or 3S-GTE and have a lesser engine still.

Piston speeds don't start getting awful until past 7000-some RPM on a 5S-FE, according to theory. The main reason those engines rev higher stock is because they have the (more expensive to produce) parts required to get them to rev as high.

Practice is better than theory, and I've witnessed engines that aren't meant to rev past 6500 RPM due to ridiculous stroke and rod lengths get revved to almost 8000 RPM and nothing bad has happened for years (one case as long as 4 years).

Anywho, most Honda engines aren't square engines, and those can rev pretty high and make nice power. A square engine is not a requirement for high revving nor for making power. It's just a design preference. You can make 2.0L out of a 86x86 engine or out of a 89x80 engine, for example, each having their own characteristics. Toyota opted for 2.0L because of Rally restrictions most likely, and opted for 86x86 most likely because the longer stroke helps generate more torque than the 89x80 example.

A K24 engine has a much longer stroke than the 5S-FE does and the redline on one of the variations is 7600 RPM on the stock engine.

In fact, here's some numbers:

A 3SGTE at 8000 RPM: 75.240593832 Feet per second
A 5SFE at 8000 RPM: 79.527559 Feet per second
A K20a at 8000 RPM: same as the 3SGTE

Now a K24a2 at 7600 RPM: 82.283465 feet per second.

You be the judge.