Gen V - how to get more bottom end power

[Fish Jetski]

I am now somewhat down the tuning path (viewtopic.php?f=56&t=22811) and with some minor mods I am at 176.6kw ATW. The power from about 3200RPM is great, but it is nowhere near where I want it to be from 1500RPM to 2400RPM. My MY09 Forester with the same mods (152.6kw ATW on same dyno), but with a TD04 turbo not the VF54 of the Gen V eats it for breakfast in that rev range.

So much so that with the slightly longer gearing of the Liberty, I find myself a gear lower at 40km/h (2nd in Liberty vs 3rd in Forester), 50km/h (3rd vs 4th) and 70km/h (4th vs 5th). Also most city roads are either 60km/hr (4th in Liberty) and 80km/h (5th in Liberty) and at these speeds in those gears the car feels relatively unresponsive. I have to drop a cog or two to make good progress. This feels totally against the 'GT' moniker of the car, and I don't know if I can change anything to fix or at least improve this.

My mates MY09 tuned with TBE WRX (171kw ATW) had the same problem but that was due to the larger turbo.

I can add an intercooler, extractors etc, but I don't think these will help too much in terms of response - just reduce heat loss. Please don't mention E85 - I am too stock for that!

Any thoughts?

[KiDo_Tuning]

I am now somewhat down the tuning path (viewtopic.php?f=56&t=22811) and with some minor mods I am at 176.6kw ATW. The power from about 3200RPM is great, but it is nowhere near where I want it to be from 1500RPM to 2400RPM. My MY09 Forester with the same mods (152.6kw ATW on same dyno), but with a TD04 turbo not the VF54 of the Gen V eats it for breakfast in that rev range.

So much so that with the slightly longer gearing of the Liberty, I find myself a gear lower at 40km/h (2nd in Liberty vs 3rd in Forester), 50km/h (3rd vs 4th) and 70km/h (4th vs 5th). Also most city roads are either 60km/hr (4th in Liberty) and 80km/h (5th in Liberty) and at these speeds in those gears the car feels relatively unresponsive. I have to drop a cog or two to make good progress. This feels totally against the 'GT' moniker of the car, and I don't know if I can change anything to fix or at least improve this.

My mates MY09 tuned with TBE WRX (171kw ATW) had the same problem but that was due to the larger turbo.

I can add an intercooler, extractors etc, but I don't think these will help too much in terms of response - just reduce heat loss. Please don't mention E85 - I am too stock for that!

Any thoughts?

It is tune related. They are capable of pulling from 1200rpm no issues in 6th gear

[HighTech RedNeck]

and i was to about say let matt from kido give it a tune. my gen 4 pulls harder then a school boy after his tune with no cost to economy

[Fish Jetski]

and i was to about say let matt from kido give it a tune. my gen 4 pulls harder then a school boy after his tune with no cost to economy

Gen V works totally different from Gen IV - bigger turbo for starters in a different spot.

Kido is not an option - I have Ecutek and chose to go down that path as I want to be able to tune locally and have it serviced where it is tuned so that there is no excuse when things are 'missed'.

[gen3v8]

and i was to about say let matt from kido give it a tune. my gen 4 pulls harder then a school boy after his tune with no cost to economy

Gen V works totally different from Gen IV - bigger turbo for starters in a different spot.

Kido is not an option - I have Ecutek and chose to go down that path as I want to be able to tune locally and have it serviced where it is tuned so that there is no excuse when things are 'missed'.

I think they have `missed` things!

[Fish Jetski]

I think they have `missed` things!

What do you mean?

[KiDo_Tuning]

and i was to about say let matt from kido give it a tune. my gen 4 pulls harder then a school boy after his tune with no cost to economy

Gen V works totally different from Gen IV - bigger turbo for starters in a different spot.

Kido is not an option - I have Ecutek and chose to go down that path as I want to be able to tune locally and have it serviced where it is tuned so that there is no excuse when things are 'missed'.

I am happy to speak to Trent.

Low mount turbo spools faster and earlier due to more direct headers. Torque from full torque from 2400rpm is possible

[Fish Jetski]

I am happy to speak to Trent.

Low mount turbo spools faster and earlier due to more direct headers. Torque from full torque from 2400rpm is possible

That sounds great - pm me on the next step?

[Fish Jetski]

I thought I would plot like for like Dyno's for my MY09 Foz vs MY10 Lib with Dump and tune by same tuner on same dyno. As you can see from the graph below the cross over point for power is 2400 RPM.

The power shortfall of the Liberty is exacerbated by its longer gearing which means that at 60km/h in 4th I am doing 1930RPM with 43kw ATW, compared to the Forester which has 55kw ATW revving at 2025RPM (same gear ratio, 8% shorter final gear at 4.444 vs 4.111 and 3% taller tyre). That's over 25% more power and their respective weight is within 20kg's (it's always me onboard with two childseats ). No wonder the Forester feels urgent, while the Liberty feels lethargic!

Don't get me wrong, the Lib really goes from about 3000RPM, but even then about half of its advantage is eaten up by taller gearing until the TD04 starts to run out of puff at 4200 RPM whereas the VF54 goes a lot stronger to about 5000RPM where it too starts to hit its limit.

Happy to get some feedback!

Dyno Comparison

Power Comparison.jpg (111.07 KiB) Viewed 3444 times