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uspspro · 04-10-2012, 08:11 PM

Some quick math...

HP = (TQ*RPM)5252

So here are some numbers:

150 ft lb @ 8500 rpm = 243 hp
150 ft lb @ 8000 rpm = 228 hp
150 ft lb @ 7500 rpm = 214 hp
150 ft lb @ 7000 rpm = 200 hp

Same thing for 155ft lb

155 ft lb @ 8500 rpm = 251 hp
155 ft lb @ 8000 rpm = 236 hp
155 ft lb @ 7500 rpm = 221 hp
155 ft lb @ 7000 rpm = 207 hp

Same thing for 160ft lb

160 ft lb @ 8500 rpm = 259 hp
160 ft lb @ 8000 rpm = 244 hp
160 ft lb @ 7500 rpm = 228 hp
160 ft lb @ 7000 rpm = 213 hp

Same thing for 165ft lb

165 ft lb @ 8500 rpm = 267 hp
165 ft lb @ 8000 rpm = 251 hp
165 ft lb @ 7500 rpm = 236 hp
165 ft lb @ 7000 rpm = 220 hp
165 ft lb @ 6500 rpm = 204 hp

To be be realistic about a 2.0L NA engine, consider the following:

- It's not going to make much more than about 165 ft lb of torque, just looking at what's out there. A beams 3SGE makes 162 ft lb with 11.5:1 c/r with the same bore & stroke. The FA20 c/r is higher, and DI should allow for more timing advance. But essentially this is what a NA 2.0L I-4 can do (maybe 170?).

- To make good power it needs to keep that torque going into the high RPM range.

.

So for a hypothetical modified FA20, let's say we can bring the peak torque to about 165 ft lb and being able to hold onto much of that beyond 7000:

165 lb ft (100% of peak) @ 6500 = 204 hp
160 lb ft (97% of peak) @ 7000 = 213 hp
155 lb ft (94% of peak) @ 7500 = 221 hp
150 lb ft (91% of peak) @ 8000 = 228 hp

This is what I have in my mind for an NA modified FA20 (breathing mods and tuning, +500 rpm)

So 225-230 hp is probably what's possible without a crazy redline.

With 9000 revs, then even 145 lb ft gets you to 248 hp. With serious cams, that number can go over 250 hp.

IMHO, if the parts come out to get the NA FA20 to 230+ hp that would be a very tempting option

Although I am still thinking that the Rotrex kit will be my preferred poison. something like 190-200 lb ft at around redline, still with that crisp NA-like transient response

That said, I myself am happy it's NA. I can do bolt-on NA mods, or do a Rotrex, or whatever I want. I am just glad they didn't stick us with a turbo

It sounds like the "character" of this engine is just right, and a few mods will help erk out some more.

04-10-2012, 08:11 PM	#447
uspspro Senior Member Join Date: Mar 2012 Drives: DGM BRZ, MR-S 3.5L V6 swap (sold) Location: Bay Area, CA Posts: 602 Thanks: 28 Thanked 188 Times in 121 Posts Mentioned: 1 Post(s) Tagged: 1 Thread(s)	Some quick math... HP = (TQRPM)5252 So here are some numbers: 150 ft lb @ 8500 rpm = 243 hp 150 ft lb @ 8000 rpm = 228 hp 150 ft lb @ 7500 rpm = 214 hp 150 ft lb @ 7000 rpm = 200 hp Same thing for 155ft lb 155 ft lb @ 8500 rpm = 251 hp 155 ft lb @ 8000 rpm = 236 hp 155 ft lb @ 7500 rpm = 221 hp 155 ft lb @ 7000 rpm = 207 hp Same thing for 160ft lb 160 ft lb @ 8500 rpm = 259 hp 160 ft lb @ 8000 rpm = 244 hp 160 ft lb @ 7500 rpm = 228 hp 160 ft lb @ 7000 rpm = 213 hp Same thing for 165ft lb 165 ft lb @ 8500 rpm = 267 hp 165 ft lb @ 8000 rpm = 251 hp 165 ft lb @ 7500 rpm = 236 hp 165 ft lb @ 7000 rpm = 220 hp 165 ft lb @ 6500 rpm = 204 hp To be be realistic about a 2.0L NA engine, consider the following:* - It's not going to make much more than about 165 ft lb of torque, just looking at what's out there. A beams 3SGE makes 162 ft lb with 11.5:1 c/r with the same bore & stroke. The FA20 c/r is higher, and DI should allow for more timing advance. But essentially this is what a NA 2.0L I-4 can do (maybe 170?). - To make good power it needs to keep that torque going into the high RPM range. . So for a hypothetical modified FA20, let's say we can bring the peak torque to about 165 ft lb and being able to hold onto much of that beyond 7000: 165 lb ft (100% of peak) @ 6500 = 204 hp 160 lb ft (97% of peak) @ 7000 = 213 hp 155 lb ft (94% of peak) @ 7500 = 221 hp 150 lb ft (91% of peak) @ 8000 = 228 hp This is what I have in my mind for an NA modified FA20 (breathing mods and tuning, +500 rpm) So 225-230 hp is probably what's possible without a crazy redline. With 9000 revs, then even 145 lb ft gets you to 248 hp. With serious cams, that number can go over 250 hp. IMHO, if the parts come out to get the NA FA20 to 230+ hp that would be a very tempting option Although I am still thinking that the Rotrex kit will be my preferred poison. something like 190-200 lb ft at around redline, still with that crisp NA-like transient response That said, I myself am happy it's NA. I can do bolt-on NA mods, or do a Rotrex, or whatever I want. I am just glad they didn't stick us with a turbo It sounds like the "character" of this engine is just right, and a few mods will help erk out some more.