Turbo Upgrade / Replacement (MY04/05?)

[kiahatsiu]

My wagon was 1670* with me, the spare, a few tools and a full tank.
I am 77kgs.



*i think I recall.

[jslayz]

I predict Low 13 coming up.

Ahh I'll revise that, you are auto.
Should get into 13s

[2jz929]

Busy night. Only got two runs. Best was:

13.8@96.9mph with a 1.89 60'.

Runs hard for the 8th mile but seems to lack top end. I logged the runs and were only getting a peak of 247g/s on the MAF, which is way down on the 261g/s I was getting Wednesday night. It was a fairly warm night so maybe that was a contributing factor. Haven't looked at the loss yet though.

[2jz929]

Just looked at my logs. Wasn't getting fullboost Down 1-2 psi throughout the top end which explains the 15g/s it was down. Spewing. Should have checked the logs earlier.

[dr20t]

That's a shame about being down on boost but still a good time for a 1.9 60 ft

[jslayz]

13.8 is certainly respectable, good work.
Track down your leak or lower boost cause and go again?

[Archie01]

Nice one!
Was hoping you'd get 100mph.
Maybe next time out after fixing issue re power dropping off at the top end

[alexeiwoody]

Nice one!
Was hoping you'd get 100mph.
Maybe next time out after fixing issue re power dropping off at the top end

247g/s to 260 is about 15hp loss. That's 11kw.

In theory that kind of loss is only enough to get you another 1.5mph max. Not really something I'd call "down on power".

I'm not saying you couldn't have run a better time or mph - maybe there's another reason you're down on power, but the g/s difference does not indicate a significant loss of power.

[2jz929]

I think you'll find the 13.8 is the better indication of how the car goes as it struggles to put on pace in the top end like it should. The commodore I raced that ran 95.5mph put on an extra 5mph than me in the second half. Most cars need 98+mph to run a 13.8 so it reasonable power. I blame it on the insufficient intercooling and would like to switch to a fmic and I think the extra 2-4mph would reappear. The tuning is not complete either.
As for finding the missing boost I'll probably start with blocking the factory BOV to rule it out.

Here's the slips:

[Gyro Gearloose]

Just curious, as a cheaper option if the housings arent damaged on my original VF38...
http://shopping.kinugawaturbo.com/rebuiltturbocartridgeihirhf5hvf38vf40subarulegacylibertygt04-06.aspx
Kinugawa Turbo Cartridge IHI RHF5H VF38 VF40 SUBARU Legacy Liberty GT 04-06 Price: $599.00

Application MY04~06 SUBARU LEGACY GT / Liberty
Bearing Type Journal Bearing
Cooling System Water cooled
Compressor Wheel 43.3 / 56 mm ( Inducer / Exducer)
Turbine Wheel 40.4 / 53.3 mm (Inducer / Exducer) Inconel Wheel
Condition CHRA was balanced by Schenck MBRS 110 From Germany.

Being an inconel wheel, I'd expect spool to be slower than the lightweight titanium wheel of the standard turbo but all other specs should be the same?

[Archie01]

Nice one!
Was hoping you'd get 100mph.
Maybe next time out after fixing issue re power dropping off at the top end

247g/s to 260 is about 15hp loss. That's 11kw.

In theory that kind of loss is only enough to get you another 1.5mph max. Not really something I'd call "down on power".

I'm not saying you couldn't have run a better time or mph - maybe there's another reason you're down on power, but the g/s difference does not indicate a significant loss of power.

What specific point are you trying to make with regards to what I stated in my post?

[dr20t]

Alexei I agree with you however something to remember is WHERE in the power band does the peak airflow occur.

Now I'm making some assumptions here, but given the small turbo, id say it would occur pretty early on in the rev range, meaning peak torque would be affected by the drop in airflow.

This peak torque is what would assist in hauling out of the hole and also from half track to increase acceleration.

This would impact both et and trap speed

Mick

[2jz929]

Here's the vid.

https://youtu.be/haS8TN8PYxA

I'm pretty set on a fmic now as i'm sure it's not keeping up and costing me top end. It's also stinking hot before the run so just not a good design.

[alexeiwoody]

Alexei I agree with you however something to remember is WHERE in the power band does the peak airflow occur.

Now I'm making some assumptions here, but given the small turbo, id say it would occur pretty early on in the rev range, meaning peak torque would be affected by the drop in airflow.

This peak torque is what would assist in hauling out of the hole and also from half track to increase acceleration.

This would impact both et and trap speed

Mick

The 20T may be not a big turbo, but my tiny stock vf46 was flowing peak power - 250g/s, between 5000 and 6000rpm (ie it would reach 230 by 4800, rise to 250 by 5500, and hold until 6000, and still holding 235 by 6700), dropping from 16psi to 10psi by 6700rpm. And mine is a 2.5 - 6500 IS the redline, while the 2.0L keeps going.

If the 20T somehow makes peak power before 5000, and then just dies off - there's something wrong with the setup. Peak airflow as measured in g/s will occur at peak power, which should be somewhere after 5000-5500rpm, which is by no means 'early in the rev range'?? It almost sounds like you're talking about peak torque - which would be measured by g/rev. (Just checked - yes you started talking about power, and then ended up talking about peak torque. tsk tsk. SMH!)

Moving on - if I read correctly - 2jz929 was quite happy with the first half track, so that's again not indicative of peak torque being the issue...

76MPH at half track is also not showing anything lacking or out of place with the 13.8s.

If anything - the 13.8 is a decent time to run at 96mph. It just goes to show that this thing does have really good low end torque, and simply lacks top end power.

OP - the +13 g/s won't get you to 100mph. A FMIC + retune should. But then you'll be flowing over 260 g/s at peak

Archie - as you probably noticed I was more replying to 2jz929, but quoted you to touch on the point that 13g/s does not amount to 3-4mph (to run a 100); it would need to gain closer to 30-40g/s.

[2jz929]

Peak air flow is 6500+.

As said, I'm happy with the 13.8 is believe it is a good time and a good indication of the cars power. The 96mph is the part that I believe is misleading due to it nosing over in the top end mostly likely due to insufficient intercooling or just simply a small turbo. Mid-range torque is strong. I'm leaving the line on 18psi. It currently peaks at 18.4psi and will taper off to an average of around 14.5-15.5psi depending on gear. It was only tapering to 16.5psi when it was reading 260g/s.

As I said its a good result and I'm looking forward to slowly improving on it. Its a little engine with a little turbo in a heavy wagon (I didn't take anything out) with a heavy driver.