:mad0259: Inertial stuff is sooo much simpler...

What I'm trying to figure out is whether or not there will be a reflection at the 1-2 transition. Then what happens if they are different lengths and (because they are not synched) when one positive is coming down and a negative is going up, what happens?

Also does diameter have any effect on the waves?

I'm not really clear on this stuff, I think the diameter would affect it because we're not just talking about a standing wave, but the air actually has a net movement. Waves don't reflect though, they just "combine" (interference).

Is this my vertical dual runner idea in the FA20???

http://i15.photobucket.com/albums/a3...fb20vsfa20.jpg

Dunno dude, I can't tell what those drawings actually depict. Too fuzzy.

Since this thread is hopefully alive again, I am going to say again, I have STRONG feelings this engine will get a major update. 30mpg they say? Ain't gonna cut it when EPA says this is a small car that should get 40 in a test that makes you use the brakes (anyone ever seen the EPA cycle? highway test is definitely not what a typical day of driving looks like, even in traffic). 197hp is also pretty pathetic considering the 2ZZ made like what 189? It doesn't matter that the EPA wants less CO/hydrocarbon whatever emissions, if 197 is correct they don't have much to show for all the effort that went into this engine...

Considering how the phase in of direct injection and legit VVT is not going as fast as originally promised, I think this is just an interim engine that they're sticking into this car so it can be released in 2012, not 2014.

This was mentioned in the CoG, Weight distribution thread.


This is not even an issue. Delphi DI engine efficiency look at the picture of pistons for a DI engine at the top of page 4.

The article is largely about Ethanol blends and thermodynamic efficiency but since it uses DI with various compression ratios it is completely relevant. High octane gasoline is only US 91 octane, BTW. Note that the engine is a 2.0L Ecotec with a 86mm square bore x stroke. That is the turbo engine, I believe. :iono: I think the N/A Ecotecs are all 2.4L in size.

Any turbo build needs to be compared with doing a swap. EJ207 ftw.

Not necessarily. Going back to my torque conspiracy theory, it is the torque curve, not the max power that will show off any accomplishments in the motor's development.

The 200PS/197 bhp was probably a design target. Making 200 hp from a 2.0L motor is old news, so it would be up to the engine team to optimize emissions, economy and power delivery.

Imagine if the C&D number of ~170 (I'm going to pick 168) lb-ft @ 4000 rpm is correct. Now imagine that the brochure number of 151 lb-ft (which would be 90% of the peak using 168 lb-ft) @ 6600 rpm is also correct. And the peak power of 197 bhp @ 7000 rpm and the 7400 rpm redline are correct, too.

That would be an outstanding 197 bhp NA performance motor. It would pull from everywhere.

So much smart guy talk goin on in here! Love it. Always something to learn.

Anyways, I've been scratching my head over a particular thing. I own an Accord with a J30 in it and have been looking into the J32 swaps. I came across a couple of dyno sheets, and I was wondering, how come they look so much more predictable and ideal than 4 cyl engines? Is it just a matter of displacement?

http://i130.photobucket.com/albums/p...tqj32a2teg.jpg

A possibility is larger cylinders makes thermal losses through the water cooling system smaller, and so it varies less across rpms. I wouldn't know though. Perhaps smaller displacement engines are considered too "weak" and thus are more optimized for certain rpm ranges.

To make it look pretty the smoothing factor is high and the window has been stretched. It's a common trick used by tuners. Go to the Dynojet website and install their free WinPEP7 software. Play around with it and you'll see what I mean. I have a side business tuning cars. Aftermarket performance tuning is on a day-to-day level a completely unregulated industry... there's a lot of Wizard of Oz/smoke and mirrors stuff that goes on.

Hmmm, I'm familiar with the smoothing, but hadn't heard about the stretching part.

I read a Grassroots Motorsports article where they had a pedal bike on a Dyno-dynamics just for fun, and it was sensitive enough to spike with each pedal push when the smoothing was low.

Smoothing works both ways with shady dyno sheets. Some parts installs claim gains from the highest spike on a sheet with low smoothing, even if it's anomalous.

The scaling of each axis can cause different visual effects. It gets even more confusing when you have a bunch of data plots on each graph, and each plot has its own scaling apart from the scaling of the chart.

absolutely. Some chassis dynos (as opposed to research-lab engine dynos) are more noisy than others so that contributes to it. The most blatantly inflated dyno sheets are those on a Dynojet with smoothing set to "0" and correction factor set to "STD"

So what you are suggesting is that these dyno sheets can't be trusted?

Regardless, the flat torque curve is the most appealing aspect of the dyno result. Is there a reason this engine nailed that characteristic?

What he is suggesting is that by using a lot of 'smoothing' (averages more of the data points is a way to describe it, sort of...) and stretching the graph horizontally, it makes the curve look way flatter than it really is.

There are a lot of games played by tuners and dyno shops. The stuff I'm familiar with involves rather questionable claims of what constitutes a 'stock' bottom end for certain Supra claims. Fiddling with dyno charts is another.

I don't want to say too much about a blurry cellphone camera shot of a dyno sheet. If I had the actual run file I could load it into the software and look through it more to have a better idea of that specific run.

There is an SAE standard, J1349, which shows how many manufacturer dyno tests are done (GM & Ford follow this standard more than most other manufacturers). You can PM me about this if you would like more information. Those tests are done under very precisely controlled conditions and must be certified by an independent monitor. A chassis dyno pull at Billy Bob's performance is a very different animal. There's just more room for error and manipulation.

Performance shops have every incentive to manipulate the numbers. Manufacturer dyno tests still have the potential to be manipulated but overall they are done under much more controlled conditions (even though those conditions may not always represent the real world).

Thanks for the insight.

I totally agree, we have a very precise dyno at work (it's a Maha 4x4) and we often have people coming in with tuned cars. The charts the tuner gives to them is most of the time manipulated or plain wrong.
The most evident case was a C 63 AMG where the tuner just modified the speed limiter and claimed the car had 50 more hp.
Reality was the map was bog standard and the 50 hp more of crank power came from a different loss of power (in one test there was 70 hp of power loss, in the next one 120, the whp was the same but as the cranks is the sum of the two obviously it was showing 50 hp of crank power more).

This is one of our dyno charts (it's my car actually).
100 nm are 73.7 lbft
We do 3-4 runs in second from the last gear (this for example was in 4th).

For comparison, this has 140 lbft at 4000 rpm, peak is 152 at 5465, and at 7k is down to 125.
170 lbft (equal to 230 nm) at 4000 is A LOT of torque from a 2l NA engine.
Good NA engine struggles to get over 100 nm/liter.



http://www.supersprintfiles.com/cliomappa1-1.jpg

Variable valve timing
 

Does anyone know if this engine will have any type of variable valve timing?

It'll have cam phasing for sure, and almost certainly no lift/duration adjustment. Aka one cam profile. Not ideal...I am still a long ways off from needing a car, but when I get one, it won't be a first gen FR-S. I smell a better one coming out later.

I plan on waiting until at least year 2 for the same reason. Maybe the mid-model refresh. We'll see how my current vehicle holds up though.

I'm still kind of baffled why we don't have full VVT though. Unless they're saving it to one-up a competitor later.

Toyota and Subaru have stopped using variable lift in basically all their engines for whatever reason lately. Toyota promised Valvematic would appear in many models in the near future back in 2007, but so far it's only made it to European/Japanese Corollas and similar cars. Most companies have just a cam phasing system in place nowadays, of course with the exception of Honda which has 2 stage lift on basically everything, and BMW/Nissan which have the most advanced continuously variable duration/lift systems on most engines.

My guess is Toyota, for whatever reason, feels like it is not ready to release these new valve control mechanisms everywhere yet. It could be that they don't want to retool factories too soon, although it's not REALLY that big of an add-on. The FT86 on the other hand had to be released sometime around now, as they can't just keep telling people to wait, and so they kinda half-assed the engine a little and got the car to production first.

Eventually, we'll see Valvematic everywhere for fuel economy regulation reasons, but they are really delaying it. We can only hope that a mid-cycle refresh will have a better engine, it's not a guarantee as Toyota seems to be pretty good at squeezing cheap mpgs out of their cars to meet CAFE standards.

Expecting them, in the 2012 marketplace, to use both continuously variable valve lift and an expensive direct injection system on a supposedly affordable sports car is just too much. They have to control costs, and this car is not based on currently mass-produced models.

Be realistic.

If Japanese Corollas get continuously variable lift, I don't think it's a really big deal. If Hyundai can direct inject everything...

If Honda can have stepped variable lift (which probably costs as much as continuously variable, having its sliding pins and whatever which are more difficult to ensure reliable operation) on Civics, and Toyota is giving us just a simple cam actuating valves directly (okay okay through a follower maybe), I'd say there's something missing.

The most advanced and flexible system is the one used by Fiat, the "Multiair" system, that allows valve opening independent from the cam profile:
http://en.wikipedia.org/wiki/Multiair
It's used on cheap cars like the Grande Punto / Alfa MiTo.
BMW uses the Valvetronic on the Mini Cooper and S.
I think Toyota could afford to use a similar system on the FT but there is the problem of the two heads, so every part has to be mirrored...
I don't think they were able to extract 200 hp from a NA 2.0 without any kind of valve lift or timing control.
Renault on the Clio RS engine has it, even if it's a basic system, since the 1st '98 model.

Well, the 2ZZ had variable lift, and this engine doesn´t. Pretty significant advantage.

Although I concur with you and would have liked to see higher numbers, 200hp/151lb-ft is not too bad considering:
- It´s not a clean sheet design but heavily based on an emissions/economy-driven engine (Subaru FB20)
- Limited R&D budget given this engine will not be shared with any other model, and its definetly a low-volume car
- Production costs must be kept low to reach its price target

I just hope the direct injection won't be a limiting factor to the potential. It's a "square" engine, so it could revs higher than the claimed 7500 rpm (the Civit type R ha the same bore&stroke...ok it's a L4 but still...). If I'm not mistaken the turbo Spec C engine revs to 8k?
If you can get this engine run to 8k safely and make it breathe a bit better (exhaust, intake, ported heads...cams maybe?) I think 240-250 cv are achievable.

The FA has direct injection, the 2ZZ doesn't. Pretty significant advantage.

Yes, this is why I was saying that people need to be realistic. I'm sure they weight the option of using a variable lift system and determined that it wasn't worth the cost to achieve their goals.

I'm beginning to consider this motor as an extension of the auto-tuned BEAMS 3SGE, which produced 197 bhp @ 7000 rpm and 159 lb-ft @ 4800 rpm. Same 86mm X 86mm BxS, same developer Yamaha.

The BEAMS did those numbers on 11.1:1 compression, port fuel injection, and bucket/shim lifters, without some of the inherent better balance/vibration elements of the H4.

We're looking at 12.5:1 CR with significantly better combustion from the D4-S (which, coincidentally, Yamaha, along with Denso and Toyota was a primary developer on) reduced valvetrain friction with finger followers on needle bearings, and the better balance and vibration properties of the H4.

168 lb-ft is realistic.

Also given the 86mm stroke, 7500 rpm (redline has been listed at 7400) put the mean piston speed at around 4200 ft/min which is often the upper range of production cars, especially those that involve a cost factor.

Isn't the K20 86x86? It runs much higher than 7500...

That's true. It's also 200cc down. And emissions were not much of an issue when designed.

A comparison that I find more relevant and interesting is to the highly regarded Honda K20-series engine. The K20Z3, found in 2006-2011 Civic Si, is remarkably similar: 1998cc, 86mm x 86mm bore/stroke, variable lift and cam phasing but no direct injection, result: 197 bhp @ 7800 rpm, Torque: 140 ft·lbf (189 N·m) @ 6200 rpm. A pretty close match!

Dimman, sorry to disagree, this car will not make anywhere close to 168lb-ft.
The quoted official figure of 151lb-ft sound pretty realistic to me. It should be a quite nice, flat torque curve too, we shall see.

PD: Gardus, didn´t see your post until I had finished mine, nice thought transmission lol!

Now that you mention it, I'm starting to think you may be onto something. The 3S didn't have variable lift afaik...
HOWEVER that makes 197hp peak even more fishy. Something isn't right.

As for the rpm, I computed a rod:stroke ratio of 1.55, which may or may not be an issue. Using simple geometry, increasing it to 1.60 which a lot of 8000rpm engines use decreases bearing load by about 3% which isn't much, but there's a reason they set the limit there.

Not really. Going by some old (slide rule era...) tuner 'rules of thumb' for valve and port sizing, an 86mm bore and stroke, with valves 40% of bore and throats 80% of valve, this thing would be drawing in intake air at 50m/s (peak torque inlet speed, again old 'rule of thumb')at ~4500 rpm and 80m/s (peak power speed) at ~7100 rpm. These are for inertial effects only (no pulse stuff). Very close to the real 4800/7000 of the BEAMS. If it could use the TGV's variable area to increase inlet speed only 500 rpm sooner, we get the 4000 rpm number.

Now the hp number is all about how quickly the BMEP drops from its torque peak. At 168 lb-ft (208 psi BMEP) it has to carry just 88% (Error correction: Original 86.5% drop was if it made 197 bhp at 7100 rpm) over 3000 rpm, which is very realistic.

I'll see if I can drag up some numbers I did on the progression of the 3MZFE (bucket tappets, port injection like the BEAMS) to 2GRFE (rollerized finger followers, port injection) to 2GRFSE (rollerized finger followers, D4-S, lke the FA20). Cliffnotes are that the BEAMS only needs half the gains above to make its 208 psi BMEP.

My point is that there are a lot of similarities; same bore/stroke, only cam phasing available, same power peak. Considering the FA20 theoretically has the D4S advantage on top of this, it's hard to see how it couldn't do better or at least the same. If it can make more torque at some certain point, it's not likely the torque will drop down even faster given the similarities. Just speaking strictly from a..."comparison" point of view.

In my example it wouldn't be dropping 'faster' but slightly 'more' over a longer rev range. Increase the peak lower, have it drop off not too much worse, but over a wider power band allows a couple things. The response that some of the people here that are crying for massive torque numbers want. And by keeping the power peak lower than say the K20, and therefore mean piston speed, they lower reduce stress on the motor. They can get away with using conventional connecting rods compared to the 2ZZGE's vanadium steel rods for example, or lighter ones which again adds to response.

(This motor will also have less valvetrain friction than the 3S, and possibly less losses from vibration/balance due to the nature of the H4.)

Edit:

Food for thought...

3SGE BEAMS, high-power manual version
207 bhp @ 7600 rpm BMEP ~177 psi ~90% of peak torque
159 lb-ft @ 6400 rpm BMEP ~197 psi

1200 rpm separation

GT5 FA20
220 (b?)hp @ 8000 rpm BMEP ~178 psi ~85% of peak torque
170 lb-ft @ 6500 rpm BMEP ~ 210 psi

1500 rpm separation

Porsche GT3 (3.8L)
435 @ 7600 BMEP ~196 psi ~95% of peak torque
317 @ 6250 BMEP ~206 psi

1350 rpm separation

There's a lot of faith in rule-of-thumb engineering here... without manufacturer data there's not much we can really do with these BMEP numbers and targets

It gets close and worked for the beginnings of a few motors that start with the letters 'DF'... And coupled with comparisons to existing cars also shows that 197 bhp @ 7000 and 151 lb-ft PEAK @ 6600 doesn't make sense.

would it make sense if they artificially detuned the engine? i mean we're comparing a GT3 and a Scion here... from a marketing standpoint, maybe the subaru does have a bit more power and costs a bit more? :iono:

I have actual manufacturer BMEP and torque curves for the 2GR-FSE, which is the IS350 engine using the D-4S system. I'd like to hear what your predictions are before I reveal them.

The BEAMS vs FA20 vs GT3 just above, aren't the numbers I am basing my assumptions on. They are the high-output BEAMS and the fantasy GT5 version of the FA20 and they are not as highly tuned as the GT3. Basically to show that even the GT5 output numbers are quite feasible (ie an STI version or something...)

The automatic-tuned BEAMS and what I think the FA20 will start with are as follows:

BEAMS 3S for automatic (11.1:1 CR, port injection)
197 bhp @ 7000 rpm BMEP ~183 psi ~93% of max
159 lb-ft @ 4800 rpm BMEP ~197 psi

2200 rpm separation

FA20 'base' (12.5:1 CR, port/direct injection)
197 bhp @ 7000 rpm BMEP ~183 psi ~88% of max
168 lb-ft @ 4000 rpm BMEP ~208 psi

3000 rpm separation

Hardly a far-fetched prediction, compared with the 13ish year-old BEAMS motor.

Okay you're saying this engine is tuned for a bit more grunt at a very low rpm to make people like SUB FT-86 "happy" (but really, do you think they will be? lol. turbo motors have ridiculous torque peaks that are more than 20% greater than torque at the power peak), since it has only one cam profile it won't be very optimized for high rpm operation. Got it.