wrathchild_78

iTrader: (3)

Hi everyone,

I have a subaru impreza Turbo MY00 about 2 years now and a few months ago, I bought a TD05-18G, oil cooler, new fmic and some other minor stuff from fellow SN members. My goal is 360+ bhp safe and reliable.

My car's spec is as follows:

2.0lt engine
Ross custom pistons (92.5mm)
Crower rods
Clevite77 bearings
ARP studs
STI head gasket
Nismo 740cc injectors
TD05-18G turbo
Setrab Oil cooler kit
BOV Greddy RS
ECU APEXi POWER FC + Hand Commander
APEXi AVCR boost controller
STI new age - ported headers
Unknown up pipe (previous owner had this changed)
Full turboback stainless steel exhaust 76mm with cat on the downpipe
SAMCO silicon hoses
Spark plugs denso IK27
HDi type FM I/C
Forge wastegate (1 bar actuator spring)
6MT from STI '02 JDM

The AVCR is set to operate at 1.8bar and gradually lowers the pressure to 1.35 (at 5th and 6th gears). It feels stronger than before but still no more than 340bhp. Problem is that I expected to have full boost at 2nd-3rd gear around 4000rpm but in fact this comes at 4500+!!!!

I have no idea what causes this, so I checked the following:

-Forge wastegate, tested spring - all ok
-Old HKS fmic removed. New HDi installed - no joy
-Checked cat on downpipe and leaks on headers/uppipe - all ok, nothing changed
-Had my programmer double check the Apexi AVCR settings and duties. We did many test runs with different settings. Nothing changed.
-Had my programmer double check the Apexi maps. We did test runs with the car having aggressive maps, lean and rich AFRs. No matter what we tested, full boost was always coming after 4400rpm.

On Monday, I will have the turbo rebuild but this will cost some money and I want to make sure that I am doing the right thing. Please see the pics. Maybe someone can see if this is a cheap copy or not.

Is there any other thing that I should check? ANY idea you may have, might help, so please free your mind and write in this thread whatever comes to your mind. Maybe some brainstorming will reveal the culprit for me.

thank you all in advance

regards
Odysseas





A few pics of the turbo in question:



Please have in mind that the previous owner told me that he had full boost @ 3600rpm and he made 340bhp @ 1.4bar with conservative tune.

KAS35RSTI

iTrader: (73)

Who is your programmer?

wrathchild_78

iTrader: (3)

A friend of mine which does this as a second job. He is very good at this and has mapped other cars with very good results. He is an impreza owner himself and knows a great deal about them.

I don't believe it is his fault anyway. We tried so many different maps and the max boost was always the same.

KAS35RSTI

iTrader: (73)

Hmm

prodriverules

iTrader: (52)

If your not acheiveing full boost in 2nd-3rd gear until 4500rpm then you defo have a problem,sometimes to large a uppipe bore can cause lag but it would have to be VERY much to large to cause that much lag on a 18g in 2nd gear!

wrathchild_78

iTrader: (3)

I will definnitely check the uppipe. It is on my to do list.
What do you suggest I replace it with?

Other ideas??

Glowplug

iTrader: (8)

Clutch slipping a tad.

She is 11 years old with a lot of mods and no mention of a recent change.

You did say, "free your mind".

wrathchild_78

iTrader: (3)

hehe bring it on guys...more crazy ideas






P.S. Clutch is 4 months old

Glowplug

iTrader: (8)

With out knowing how detailed your mappers logging was, it is hard to know where to start. Add to that, my knowledge of the APEXi PFC + AVCR is at best limited, (in fact i don't even know what i'm doing here.).
I felt sure that any mapper worth his salt would of detected slip, but as i said...

How has the loss come about, over a period of time or overnight??

And.

What boost do you see now @4k in 2 and 3?

wrathchild_78

iTrader: (3)

when i first bought the car, it had a VF34 but i changed injectors to 740cc and had the car mapped. At that time I was very afraid that the engine will break because I had no idea what services the previous owner had made.
Thus the final tune was VERY VERY preservative.

When I changed the turbo with the TD05-18G, i had late full boost which I attributed to the tune. But now, that I have a much more aggressive mapping, the problem persists.

At 4000rpm, I see around 0.8 - 1 bar of boost in 2nd-3rd.

Glowplug

iTrader: (8)

Nice to see some one coming on and discussing their issues prior to steaming in and then coming on crying about it.

The turbo imho requires at least removing for inspection, if only to rule it out.

Just re-read and now it would seem to me, not so clear cut.

It may well be the turbo unit, but...

...by what you said, you took it very easy after the 740's where fitted and mapped in, then once you had swapped the turbo and had that mapped in, you gave it some beans and then noticed the problem?

If so, then the issue 'could' lay with the 740's. Where they new or flowed/checked?
Or, don't get me wrong, no offence to your mapper, it could be a mapping issue. (remember my Apexi knowledge lol.) But the man is only human.

prodriverules

iTrader: (52)

As Steve above has mentioned it could lye with the mapper but I have to ask why did you change from the vf34 to 18g?

wrathchild_78

iTrader: (3)

ok one at a time:

the turbo will be inspected for sure (if not rebuilt). Just for peace of mind.

that is exactly what happened. That is the reason why previously I hadn't noticed anything wrong with the VF34. The VF34 was changed with the TD05 because the shaft was playing and I thought that if I am to remap my car then why not make it more powerful?

The injectors is something I haven't thought before. The 740's were bought new from the previous owner, sold to some other guy then bought back from me and installed again to the same car (!! lol). So, they may be used but I had them flow checked and cleaned 5 months ago iirc.

I too was suspecting that it might be a mapping issue but after all those tests we did, I don't believe it anymore.

thx for answering

wrathchild_78

iTrader: (3)

any other suggestions/ideas?

what do you think of the turbo? Does it look like a copy or is it a genuine TD05?

Japorter

Get a twin scroll or an evo!!!

wrathchild_78

iTrader: (3)

never a traitor!!


Twin scroll is a good choice if I had a few thousand euro to spend (but I don't! )

Japorter

To be honest 18g on a classic 2lt is about right tho...

dunx

iTrader: (3)

What boost does it make if you remove the hose to the actuator ?

Ideally being careful as you will achieve huge boost levels if the turbo / up-pipe aren't leaking.

Mine makes 2.1 bar at 3500 rpm on a GT30.

dunx

wrathchild_78

iTrader: (3)

this is something i haven't tried at all.

Can you please explain what this will prove? Lets say that I do this test and I see 1.8bar @ 4000rpm. What this tells me?

I will do it anyway tonight

dunx

iTrader: (3)

Any increase in boost tells you the actuator is leaking or isn't closing fully...

dunx

P.S. You could feed pressurised air to the actuator and check the diaphragm isn't leaking that way.

wrathchild_78

iTrader: (3)

Just for your info...after many tests, the problem of late full boost was caused by:

1. 10% from a much bigger up pipe than it was needed (almost 60mm!!). When I changed this to a new one, I saw around 100rpm decrease in full boost.
2. 30% from a too restrictive and small cat at the down pipe. The decrease was around 300 rpm.
3. 60% from the turbo itself. The mechanic that actually did the flow tests told me that this TD05 was in a complete mess!! At this very moment, it is being rebuild!

Glowplug

iTrader: (8)

New up pipe, new down pipe and a rebuilt turbo. Should see you happy again.
I was going to say you should of had the td05 checked before you fitted it, but then you probably wouldn't of spotted the up and down pipe issues. Good result.

wrathchild_78

iTrader: (3)

you are right! I should have checked the turbo but the previous owner told me that it was in perfect condition with a rebuilt done and a total of 4000km
so why bother check it if it was in such a good condition? In fact, when it came to my hands, i saw with my own eyes that it was indeed in perfect condition.

well, now i know better and next time i will check everything