Subaru EZ30-R 3.0 dyno power+torque curve

[Monster]

This thread is probably only for Martinbo and me.

I received an email from MRT performance and found something interesting. Here is an extract from the email:

LIBERTY 3.0L (3.0R, 3.0RB, Outback 3.0L)

Over the past few weeks the decision was made to invest significantly more time (and money) in seeing what is feasible with the current generation Liberty and Outback models fitted with Subaru’s 3.0L naturally aspirated engine. With the completion of testing on our MY07 STI development mule, we decided to get our hands on a MY09 Liberty 3.0RB for a heap more in depth R&D.

We’ve been getting buckets of calls from owners of these models unhappy with the performance of their vehicles over the years and, after an extended initial drive, frankly we can see why. Despite Subaru selling the 3.0RB with sporting pretensions, it is falls shorty of the 2.5L GT models in terms of drivability, mid range torque, fuel economy and outright power.

After over 1000kms of driving in all road conditions, we weren't certain the car had 180kw despite Subaru's claims. It certainly didn't feel like it had similar power levels to the 2.5L GT. The car was put on our dyno for some base power runs in standard spec (with EcuTek support now configured for the tuning side of things), and the results pretty much confirmed our suspicions and feel on the road. If you ever needed a reason to believe that small capacity, high efficiency turbocharged engines are the future of all things automotive, Subaru’s 3.0L 6 cylinder engine lends solid support to the theory – it uses more fuel and does less with it compared to the 2.5L turbo engine fitted to the GT models. In driving to date it has easily used 1.0-1.5L/100km more than the 2.5L turbo model under similar conditions with notably less performance.

MY09 Liberty 3.0RB S# mode vs I mode

Case in point, we tuned a standard Forester XT (which runs a similar 2.5L engine with smaller turbo than the Liberty GT model) with just 152kms on the odometer the morning before we ran the Liberty 3.0RB up on the dyno. We figured it would be interesting to compare the results – the Forester (in simple XA spec tune) makes up to 76% more torque and 40kw more power through the most driven areas of the rev range AND prior testing tells us it uses less fuel while doing it under just about all road conditions. With larger turbo, the Liberty GT models with XA spec tune put even more shame to the 3.0L engine. Check the power kit document on our website here for further information on upgrades for those models.


In the interim, if you are planning on buying either of these cars and are weighing up the differences, based upon our experience we would recommend the 2.5L GT over the 3.0RB without hesitation. Our aim is to give the 3.0RB the engine we think it should have, but until we achieve it we would have to recommend the 2.5L GT everytime due to it having less weight over the front wheels (and therefore less understeer), more power & torque, better fuel economy and more potential for improvement.

Here is the dyno result:

The car was tested in sports and intelligent mode, with 95 RON fuel. They didn't provide much information about the dyno run, but I certain that they run it on a chassis dyno and then calculate the power at the flywheel using various correction factors.

IMO these graphs are not 100% accurate but it is interesting to see anyway. Factors such as the ramp rate of the dyno, temperature and the way the operator press the accelerator can all influence the shape of the curve as well as the numerical values of the results. I am only focusing on the dyno run done in Sport mode.

I am half surprised by these numbers because my car never felt like it has 180kW. The 1st thing that caught my attention was the torque curve, I have never seen such fluctuations of a torque curve before, but it seems about right to me, despite the much lower figures. I always felt the engine needs around 2800rpm to really get moving, and the engine kicks up a gear at around 4000rpm (if I remember correctly it is when the valves increases its lift?). It pulls well until after 5000rpm. The numbers are definitely disappointing, the peak torque 260 Nm, which is well down on the factory figure of 297 Nm. The peak power output is also way down at 150kW-ish. From past experiences, variations in environmental conditions contributes to approx 5% error of the results. This alone won't contribute to the huge variation between the factory figures and the figures obtained by these people.

Any thoughts Martinbo? Do you know more about this or have any other info?
I am tempted to do a dyno run but it won't be any time soon.

[martinbo]

Hi Monster my brother...

In my experience regarding the 3.0R:

1. With just 1000 km on the odometer (this is what the writing suggests the mileage is) the EZ30 feels really, really tight. It needs at least 6000 - 8000 km of hard driving to feel looser and more powerful. It certainly isn't giving its best at 1000 km.
2. I believe that Subaru have over-optimistically stated engine power at 180 kW and 297 Nm of torque under the very best, most optimum conditions possible. Even when the engine does loosen up it never feels 10 kW stronger than the M54 3.0 six from BMW. Much of this I have put down to the AWD drivetrain.
3. If I recall correctly 180 kW is on 98 RON fuel.
4. I once raced my good mate Camo in his 2004 WRX at the coast while driving the 3.0R at night and the result was a) quite close b) perfectly in line with my expectations of the heavier, less-torquey Legacy. It acquitted itself well.
5. The variable valve timing "kick" at 4000 rpm is especially prevalent. On the slow, climbing, hairpin-righthander at Gerotek's dynamic handling circuit if I cocked my line up into the clipping point, understeer causes speed to scrub off and I'd sit in 2nd gear just below 4000 rpm waiting for the power delivery to kick for a fraction of a second.
6. Your car is an auto if I recall correctly - with 5 speeds. These longer ratios also make the Legacy feel quite a bit less sprightly than the sublime 6 speed manual.

Overall, in my experience, the Legacy 3.0R never feels like the 330i beater it was touted to be - it just simply isn't as fast for a number of reasons (above). However, what I will say is that, from a character point-of-view it is far more tuneful than the anodyne-sounding - but far faster and a little more agile - arc-scroll turbo'd 2.5 LGT.

The 3.0R Legacy, despite not living up to its on-paper credentials has to be one of the very nicest Subarus I've ever had the privilege of demonstrating.