club.liberty.asn.au

Hi
I have a 2004 GT auto and I've noticed that it doesn't build boost till 3200ish rpm. It seems to run OK otherwise.
IAM is 1.00, In learned values on btssm I have 7.00% fuel correction at 0.00 maf, and -2.50% at 10.00maf.
-0.70 timing correction 3500rpm 1.90load.

I can post up a log.CSV if needed.
I tried stalling the tc and only got 5psi, once above 3200 it holds 14.5 perfectly.

Where do I look?

Thanks

Previous owner fitted td06....

Haha no. Has the standard turbo.
Should also add that the old motor (200,000 kms) had a big end knock so I got another motor with about 97000kms. When I swapped the turbo there was no noticeable shaft play
Edit, all avcs seems to be working normally, left and right are always within 1deg of each other, for both in and exh.

So many different causes it could be:

Blocked cat (or 2)
Cracked headers / uppipe
Leaking headers / uppipe
Tune out of whack
Inlet leak somewhere
Turbo itself

dr20t wrote:So many different causes it could be:

Blocked cat (or 2)
Cracked headers / uppipe
Leaking headers / uppipe
Tune out of whack
Inlet leak somewhere
Turbo itself

How do I test for blocked cat? When I had the dump pipe off it wasn't rattly. I could undo the center pipe and see if it helps.
Does a Blocked cat muffle the exhaust sound at all?
Cracked or leaking pre turbo exhaust would make a noticeable noise wouldn't it? My ea82t wagon sounded like a chaff cutter when the header cracked and my mates wrx whistles (like a kettle) cos he reused the turbo gaskets
How do I check my tune? I have btssm? I'm roughly halfway between Sydney and Brisbane.
Inlet leak would give poor running \idle symptoms wouldn't it?

Thanks for your input

Here is a screenshot of a log graph from btssm showing boost, rpm and speed. This was in 5th gear
First image shows 4.9psi at 2400rpm and 2nd image 14.3psi by 2771rpm


This is staging with my foot on the brake. First image 2.7psi at 2400 2nd image 14.2rpm at 3022rpm


When I bought this car I was expecting 14 psi to shoot up at 2400 pretty easily

Something's definitely wrong

Just a tip - don't boost in 5th gear under load (wot or uphill or any elevation)

Doing this will result in a blown centre diff in quick succession

Testing for blocked cat will need to be done with cat off (to look through and see if blocked), pressure sensor before and after cat, or just removing it to test it out.

dr20t wrote:Just a tip - don't boost in 5th gear under load (wot or uphill or any elevation)

Doing this will result in a blown centre diff in quick succession

This has be baffled... how?

dr20t wrote:Testing for blocked cat will need to be done with cat off (to look through and see if blocked), pressure sensor before and after cat, or just removing it to test it out.

So if I remove the centre pipe and look into the bottom of the first cat, it will visibly blocked? Like this one from google images?


If I drive without the centre pipe I assume its wise to bypass the factory boost control and run wastegate pressure?

I can do some more logging, what would you like to see?

I pulled the 2nd section of the dump and looked at the bottom of the 1st cat. Looked clean.
Started the car and built boost on the stall, no difference.
I got the Mrs to boost/stall it while I looked around the engine bay, no audible leaks
I pulled the bov hose off and there wasn't any noticeable air coming out at idle, unlike the wrx motor in my Rx. Fee reving the motor made air come out though.
I'll pull the dump off completely and look in from the top after work tomorrow.
I have a bad feeling it might be the turbo itself... Will I be able to tell with the dump pipe off?

I am in Coffs Harbour, happy to take a look and see whats going on

Awesome. I might even get you to do me a tune at some stage
I'll be in coffs on wednesday morning but it will be a rushed trip. Do you have a workshop or do you work from home?

I'll be in contact before Wednesday

Gyro Gearloose wrote:Awesome. I might even get you to do me a tune at some stage
I'll be in coffs on wednesday morning but it will be a rushed trip. Do you have a workshop or do you work from home?

I'll be in contact before Wednesday

Wednesday morning I am at the workshop from 8.30am until midday

Huge thanks to Matt, he discovered that my turbo is a bit lazy, probably getting to the end of its life or insufficient oil supply, and that I have a slight boost leak.

First on the cards is check the throttlebody hose because there is a bit of oil and dust stuck to everything around it and a silicone inlet cos I have to remove the factory one to remove the banjo oil filter. (wish I had have known about this filter 2 months ago when the motor was out)
So then I am looking for either a low km or refirbished VF38, or maybe a kinugawa TD04HLA 19T twin scroll.

Which of the 2 would provide the quickest spooling?

TD04-19t

Id like to get a dump pipe as well but funds are not going to stretch that far.

Has anyone made their own dump pipe? I made one for my Subaru L series wagon with 2 mandrel bends when I turbo converted it and it