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

[Sport-Tech]

Originally Posted by CSOCSO

premium required. Don't even talk about 91.

In certain parts of NA premium is 91. We get 94 at some stations here but that has ethanol added which might be an issue (see the rennsport forums for Porsche owner experiences).

[WolfpackS2k]

Originally Posted by Allch Chcar

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



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


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

Thanks for correcting me! That's pretty interesting.

Also, sucks for anyone in the western US, lol

[OrbitalEllipses]

Originally Posted by Scion FR-S

In certain parts of NA premium is 91. We get 94 at some stations here but that has ethanol added which might be an issue (see the rennsport forums for Porsche owner experiences).

Eh. Higher octanes aren't needed at higher elevations due to...the density of the air, I'm guessing.

[track_warrior]

Perfect for what i need, Intake, Tune, Exhaust and cams should bring this thing to 200-210 WHP perfect for road racing with a car this light.

[mines13]

Originally Posted by pcasso87

Perfect for what i need, Intake, Tune, Exhaust and cams should bring this thing to 200-210 WHP perfect for road racing with a car this light.

Quite optimistic aren't you?

[ZDan]

Originally Posted by serialk11r

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.

You say "It wouldn't be cams", then go on to describe exactly why it probably *is* the cams.

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,

143 rw lb-ft out of 2.0 liters is pretty tremendous, actually. Scaling by the same amount to equate 173rwhp to get 200hp at the flywheel, we get 165 lb-ft at the engine, 83 lb-ft/liter!

2.0 S2000s typically put ~135 lb-ft to the wheels.

[edit]Oh, wait, looks like you might mean that the peak torque *rpm* is low. IMO, peak torque rpm is usually a useless number. The engine pretty much makes the same torque from 2600-3200, and then from 4600 up to 6400rpm. It's not like they tuned for maximum torque at 3000. The tiniest, most real-world meaningless wiggle up top would change peak torque rpm from 2800rpm to 6400rpm, without changing the character of the engine's output.

Logical conclusion to me is: They good job maximizing power from 2.0 liters and limited to 7400rpm peak while also giving good low-rpm driveability.

I've seen "the dip" on a ton of dyno graphs, IMO it's a low V.E. region due primarily to cammage.

I don't see the dip as a problem, nor do I see it as something that's going to be easily gotten rid of...

[serialk11r]

Sorry maybe I wasn't being clear, what I meant was that the cams don't make a dip in the middle only, the further you get from the "cam peak" let's call it, the worse the VE, so if the dip in the middle was primarily due to cams then it should continue into the low rpm range. That's why I think there's a significant intake tuning effect going on.

[Draco-REX]

Originally Posted by serialk11r

Sorry maybe I wasn't being clear, what I meant was that the cams don't make a dip in the middle only, the further you get from the "cam peak" let's call it, the worse the VE, so if the dip in the middle was primarily due to cams then it should continue into the low rpm range. That's why I think there's a significant intake tuning effect going on.

Don't forget that the FA20 has variable cam timing.

[serialk11r]

Originally Posted by Draco-REX

Don't forget that the FA20 has variable cam timing.

Yea I've written about it several times, the way volumetric efficiency is "modified " shall we say, by a cam phasing system is by changing the point at which the cam closes. They can make it close earlier to prevent air from being pushed out the cylinder, but you can only advance the cam a certain amount before you're getting a lot of hot exhaust gas stuck in the cylinder (and possibly pushed into the intake tract at some point), and this creates a knock (remember fresh exhaust gas is at like 700C or higher under load!) and efficiency problem.

According to the 2GR-FSE paper that's been referred to a lot in the Engine subforum, the "internal EGR limit" is about "20%" (whatever that means). Since the cam is optimized for a good 1000rpm or so higher than on a lazy high displacement engine like the 2GR which makes max torque much earlier, the cam duration is going to be rather long, and because the limit to how much exhaust gas you can trap is still about the same, you inevitably lose VE across a greater range of engine speed. As you can see on the dyno chart, at 1000rpm or so the engine has abysmal torque, about 1/2 of its peak torque rating! That means the cam is pushing something like half the air back out even on maximum allowable advance.

This is basically why having 2 cams like VTEC is so nice, because the cam intended for running best at 7000-8000rpm cannot be advanced to get any sort of reasonable low end torque because it just has way too much duration. Of course it's much much better if you can adjust duration continuously but a fully variable system like that either needs more moving parts or is much more expensive.

[iforyou]

Hi all, I was just browsing the internet to find a bit more info on the FR-S/BRZ and came upon this forum. Even though I'm a Honda guy, I really like the new FT-86.

I thought I could add a bit to this forum. I noticed that some of you have posted dynos of the K20 from RSX-S as well as the 8th gen Civic Si. I'd like to add that the 2011 8th gen Civic Si (right before they change to the new 2.4L model) seems to make quite a bit more power than the 2007-2010 Civic Si. As we have seen from the dynos here, the 2007 Civic Si is good for around 180whp. However, the 2011 Civic Si has been tested to achieve over 190whp consistently in more than one car.

Here is a dyno curve of the 2011 Civic Si:


The dyno plot is from Temple of Vtec: http://www.vtec.net/news/news-item?news_item_id=960681

Here is a quote from that site:

"... Shawn Church (owner of a dyno/car tuning shop) told me he had just dynoed a 2011 Civic Si (customer car) and in bone stock form it put down 14 more hp than any other Civic Si he had previously tested. The "bone stock" curve on the '11 Si I tested obliterates the results of my own 2008 Civic Si, so it seems like Honda has possibly made some unannounced enhancements to the K20Z at some point."

Just thought you guys might be interested to know this as you guys are talking about dynos and stuff. Obviously, without direct injection, and as a 1 year-old design, the K series can't really match the torque output of the FA20.

[mrtodd]

Originally Posted by serialk11r

This is basically why having 2 cams like VTEC is so nice, because the cam intended for running best at 7000-8000rpm cannot be advanced to get any sort of reasonable low end torque because it just has way too much duration.

^This.

I really appreciate the dyno chart comparison that Deslock posted earlier in the thread, it gives us a good contrast as to just how much low end + mid range power the FA20 is giving when compared to another well built 2.0 liter engine (ie the K20). Even so, I still can't but help imagine how much better it would be if Toyota/Subaru were to add variable lift + duration! That is, considering it's going to stay NA.

[MONTEMEX3]

tuning sounds expensive. I was thinking about installing a NOS in my fr-s. does it really work?

[OrbitalEllipses]

Originally Posted by MONTEMEX3

tuning sounds expensive. I was thinking about installing a NOS in my fr-s. does it really work?

Just buy a can of NOS energy drink stuff at the grocery store, pour it in your crankcase. INSTANT +75hp.

[Spaceywilly]

Originally Posted by MONTEMEX3

tuning sounds expensive. I was thinking about installing a NOS in my fr-s. does it really work?

Just be careful that hundred shot of nos don't blow the welds on your intake.