Engine technology thread.

[Nurburgring]

Originally Posted by serialk11r

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.

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

[Gardus@Supersprint]

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.

[arghx7]

Originally Posted by Nurburgring

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

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

- 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

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.

[Dimman]

Originally Posted by Gardus

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.

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.

[Gardus@Supersprint]

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

[Nurburgring]

Originally Posted by arghx7

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

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!

[serialk11r]

Originally Posted by Dimman

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.

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.

[Dimman]

Originally Posted by serialk11r

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.

[serialk11r]

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.

[Dimman]

Originally Posted by serialk11r

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

[arghx7]

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

[Dimman]

Originally Posted by arghx7

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.

[madfast]

Originally Posted by Dimman

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?

[arghx7]

Originally Posted by Dimman

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.

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.