Scion FR-S dyno by Insideline = 173 whp @ 7000 RPM, 143 lb-ft @ 2800 RPM

[86'd]

Originally Posted by ZDan

Similar to the S2000, gaining 10% isn't going to be cake. Don't see it making more than ~190rwhp without more significant mods than intake/header/exhaust/tune, and that might be optimistic. There's just not that much to be gained from a 7400rpm 2.0.

This is what I kinda expect as well.

I've never tuned a car, just installed parts, but just being on Honda forums for 15+ years you can assume that you're not getting 25hp with just an intake on engines like these.

The good thing with I/H/E is that those *can* be compatible with S/C setups so its not a total waste, if from that point you want to go all NA, or S/C.

Plus in addition to the curve, a lot of NA boxer engines have that very pronounced dip there, even in Porsches, even my Civic SI '02 has it (albeit a smaller one) and I'm guessing things like VTEC were made to remove that dip, or put it higher in the rev range.

I'll probably should ask questions like this in the engine thread.

Anyway, I don't want an overly loud car, so at most I'd do I/H + Tune and maybe a midpipe (or conservative exhaust, like the TRD), if just for the weight loss.

[Sport-Tech]

Originally Posted by MmmHamSandwich

The FA20 is only rated at 12 lb/ft more than the K20Z3. Aside from the sudden stock vtec changover, their powerbands will likely feel pretty similar.

The Toyobaru is also over 100 lbs lighter than his 2006 Si, which will give it a slight advantage.

[MmmHamSandwich]

Originally Posted by Scion FR-S

The Toyobaru is also over 100 lbs lighter than his 2006 Si, which will give it a slight advantage.

The Si's drivetrain is more efficient though, enough to make up the weight difference? Tough to say, but other factors might be at play. There aren't many publications that have tested quarter mile times on the BRZ, but Inside Line and MotorTrend both have them neck and neck...

IL
Si: 15.1 @ 93.8
86: 15.3 @ 92.1

MT
Si: 14.9 @ 94.7
86: 14.9 @ 95.5

[Sport-Tech]

^ Obviously differences in torque curves and perhaps the less performance-oriented rubber on the FR-S come into play here as well.

No test on C&D yet, what are they doing over there??

[Future]

Very happy with that Dyno... I just wanted to see something similar/better than my previous IS300...

is300: 167.1 rwhp/165.2 lb-ft + 540 pounds

[Allch Chcar]

Originally Posted by MmmHamSandwich

The Si's drivetrain is more efficient though, enough to make up the weight difference? Tough to say, but other factors might be at play. There aren't many publications that have tested quarter mile times on the BRZ, but Inside Line and MotorTrend both have them neck and neck...

IL
Si: 15.1 @ 93.8
86: 15.3 @ 92.1

MT
Si: 14.9 @ 94.7
86: 14.9 @ 95.5

Which year are you talking about?

[Lighting Red]

Originally Posted by mspeed6

i was expecting it least making 200whp underrated like most cars now days. Turbocharging a engine with a compression high as this is end up costing min 10k with a full engine rebuild. If you're gonna dump that kinda money might as well buy a m3.

Truly spoken like somebody from DC.

Trust me, having driven the car, it has more than enough ass to have fun. Also notice the hp curve, this engine was made for fun because you have to work it to get the most from it. When you work a car, you bond with it, and the more you bond with it - the better you get to know it - the better driver you become.

Learning to be confident in what the car can do is fun! The more confident in the car you are => the more fun you have. The more fun you have => the faster you can go. Rinse and repeat.

Besides a = (F/m). You don't need a lot of 'F' when you minimize 'm.'

[WolfpackS2k]

Originally Posted by ahausheer

Also what octane was used. Car will have more Hp with 93 than 91 but it can take up to a few tanks for the ECU to fully adjust. I've heard of some cars loosing 10 hp going from 91 to 87 because the engine pulls allot of timing.

[NO]

Sorry that's not how it works. This engine was designed for 91 octane so it will make it's advertised horsepower with that fuel. Perhaps it "could" make more on 93 octane, but only if it is tuned specifically for it. And it's not.

[MmmHamSandwich]

Originally Posted by Allch Chcar

Which year are you talking about?

2006-2011 Si. These are the years featuring the K20.

[Spaceywilly]

Originally Posted by WolfpackS2k

[NO]

Sorry that's not how it works. This engine was designed for 91 octane so it will make it's advertised horsepower with that fuel. Perhaps it "could" make more on 93 octane, but only if it is tuned specifically for it. And it's not.

Nope, the ECU will make more power on higher octane fuel. It pulls ignition timing until it detects knock and then steps it back. On higher octane fuel you can have more timing advance without knocking. The ECU is optimized for a specific octane but it will still make more power on higher octane, or less power on lower octane. I think it is actually optimized for 93 octane anyways, I believe that's what's listed on the gas door. It probably is not a huge difference between 91 and 93, maybe 5hp.

[Jordo!]

Well, anyway, I'd like to next see a dyno of the AT to compare and contrast.

[Fenrir]

Originally Posted by Jordo!

Well, anyway, I'd like to next see a dyno of the AT to compare and contrast.

(INTERNET SARCASM DISCLAIMER)

96whp/87lb-ft with AT. If you can find anyone who even bought one.

But anyway, nice to see that the drivetrain loss is minimal. Makes me happy.

[serialk11r]

Originally Posted by ZDan

Dip is a function of cam and tuning for max power at 7000. Tune for 7000 rpm peak and apparently you get anti-tuning at ~half that. I have (had) the same dip on my tweaked 240z 3.1. Doesn't matter what you do with the fuel maps and ignition timing if the engine simiply isn't breathing well at that rpm.

Forced induction should minimize the dip. You're no longer relying as much on low pressure in the cylinder to draw charge in better as the intake opens.

It wouldn't be cams, a high strung cam has limited VE at low engine speed because it ends up pushing charge out of the cylinder. Intake tuning + intake cam advance can attempt to fix this but you're going to be limited by the exhaust gases "poisoning" the charge.

Because the cam appears to be a high rpm cam, there are no variable intakes, the torque down low approximately matches the torque peak, and the peak torque is quite low by performance engine standards, I think the most logical conclusion is that they intentionally tuned the intake for low rpm. This gives the car "better driveability" (as if you're actually going to floor it while getting groceries :P), and the kick of torque that people like to feel at low speed.

I haven't really thought or read in detail on how intake harmonics work though, so I may be missing something important.

[Allch Chcar]

Originally Posted by MmmHamSandwich

2006-2011 Si. These are the years featuring the K20.

Okay, I was just checking since you didn't mention K20 or the last gen Civic.

Originally Posted by WolfpackS2k

[NO]

Sorry that's not how it works. This engine was designed for 91 octane so it will make it's advertised horsepower with that fuel. Perhaps it "could" make more on 93 octane, but only if it is tuned specifically for it. And it's not.

Did you read the owner's manual? Page 74.

Fuel types

Unleaded gasoline (93 AKI [Research Octane Number 98] or higher)

If unleaded gasoline with an octane rating of 93 AKI (98 RON) is not avail-
able, unleaded gasoline with an octane rating of 91 AKI (95 RON) may be
used with no detriment to engine durability or driveability.

It's safe to run 91 AKI but the recommended fuel is in fact 93 AKI(98RON).