6G Celicas Forums

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

this is very old news

http://www.celicatech.com/forums/showthrea...orced-induction

Well that link doesn't work but I found another link!

http://warp.scl.utah.edu/mr2/200rwhp5sfe.html

welcome to 2005

Lol trust me we have scraped the bottom of the bowl clean when it comes to 6gc info on the interwebs or google.

Except nobody has ever built a 200hp 5sfe on pump gas without forced induction. closest as of today is a 5s with 3s head running on e85 that got 180whp.

the design of the engine just cant support it. you will need cams, larger intake, larger valves or head swap. just too many things and the cost isnt worth it.

It mainly lacks compression, intake manifold and throttle body, rev limit and conviction.

A similar engine is the VW ABF engine which is a 2.0L. It has a very similar head design (the valves are at an even narrower angle than on the 5S head)

We got out 142whp with cams and a Megasquirt-I with bad rings from one of those. Normal compression numbers on those engines are 210psi on each cylinder, this one was throwing out 150 with the cylinders dry, 205 with cylinders wet with oil, so the rings were definitely bad. It's coming back with even more compression this time around. When I get a dyno sheet of the new engine, I'll post it up.

180whp out of this engine is entirely possible on 91 octane. I think the intake manifold can handle it, but a bigger throttle body is needed, as well as good cams and a set of rods to take it up to at least 7200rpm. I'm thinking 11.0:1 compression ratio in a 5S will make for good power with proper supporting mods.

9.5:1 compression is way too low for NA, I think it's what's killing the engine the most, then the cams, then the TB, then the stock exhaust, and then headwork if needed, but I doubt it is for ~180whp.

Nobody has ever tried. That's the main issue. If I didn't want forced induction I'd shave the head and get 88mm pistons for at least 10:1 CR and do the whole NA mods and see how much I can get with a megasquirt-III running on 91 and then on 100-116oct.

Knowing you, you'd argue a V6 swap is much more feasible for NA power and while I'll say you're right, the point is that nobody has tried it because they take the easy way out. It's possible to do, just no one has had the balls to be the first one.

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.

Good information, since every high revving engine I've ever looked at specs for was square or under square I just assumed that there was a reason for it.

A couple things that may help you understand the bore/stroke relationship-

The stroke is determined by the throws on the crankshaft. The farther the rod-journals are from the center of the crankshaft(the main journals), the more mechanical advantage the piston rod has on the crankshaft. The 3sgte has an 86mm stroke, this equals 43mm for each crank throw or half the stroke. The 5sfe is ~91mm stroke which means each crank throw is 45.5mm off centerline of the crank. So even if both engines produced exactly the same amount of force with each combustion stroke, the 5sfe would generate more torque because the crankshaft has a greater mechanical advantage.

The 3s is square and the 5s is undersquare. Increasing the bore unshrouds the valves(moves them farther from the cylinderwall=more power) and provides more room for larger valves. The undersquare engine has the advantage of having a larger stroke which pulls more air/fuel into the cylinder each stroke at lower engine speeds.

I love where this post is going. A lot of good information. I really wished I cam do a V6 swap without going through the ridiculous paper work and BAR. Tsk.

once i go to the BAR ill document everything. the V6 swap is really not that demanding. a 2002 Solara has a 5 speed. just use that setup and get the EVAP system working and you are set. The only thing holding me up is mounting the charcoal canister.

How much do you expect to spend for engine and parts and documenting papers. Going through BAR and DMV and all the fees. How much many do you think it'll be?