Stock WRX TD04 turbo on a Legacy Turbo

beatersubi · Post by **beatersubi** » Tue Dec 04, 2007 4:41 am

If you reconnect the stock sensors/solenoid to the appropriate vacuum sources/wastegate actuator, yes, you can run stock boost. I currently have mine set up that way and it has been running fine for ~5k mi.

Curiously, I normally see ~10psi (from td04) under load. I thought the stock boost was supposed to be 7-8psi. I'm not complaining, but I don't know why its doing this. Maybe its the top mount.

vrg3 · Post by **vrg3** » Tue Dec 04, 2007 4:52 am

beatersubi, you're probably confusing the ECU. You can't run the stock boost control with the TD04's wastegate actuator, because the TD04's actuator is calibrated to 9-10 psi (yes, higher than our stock maximum boost level) whereas the stock turbo's actuator is calibrated to 6 psi.

An intercooler will actually reduce the boost pressure reading at the manifold if all else is kept equal, because it represents a pressure drop.

It sounds like your ECU hasn't given up on trying to control boost and so is bleeding some pressure off the wastegate signal.

What I would recommend to anyone running a TD04 is to do what Arctic Assassian suggests if you want to run wastegate boost (which is close to the boost level of a stock Legacy turbo), or use an aftermarket boost controller if you want to run more boost.

dirtyhandssubaru555 · Post by **dirtyhandssubaru555** » Wed Dec 05, 2007 2:43 am

so the blue coupler isnt working out so well. i cant really run any amount of boost. the coupler just pops out. i can tighten the piss out of the hose clamp and nothing. i think i need to put a metal sleve in side the pastic intake tube.

vrg3 · Post by **vrg3** » Wed Dec 05, 2007 7:03 am

Pops out of what?

I was assuming you stuck a piece of steel pipe or something in that flexible elbow -- that would simulate the stock elbow.

dirtyhandssubaru555 · Post by **dirtyhandssubaru555** » Wed Dec 05, 2007 9:48 pm

the big end of the inlet tube blows off of the blue coupler. i called in sick to work so i could work on my car but i ended up being to sick to do any thing.

Arctic Assassian · Post by **Arctic Assassian** » Wed Dec 05, 2007 11:13 pm

At the throttle body? What your going to have to do is get a steel band that you can slip into the inlet tube, then put the coupler around the inlet so that when you clamp it down, it has the band to clamp against. I'm fairly sure I know what your problem is, can you post any pics so I can draw on them to show you what I mean.

dirtyhandssubaru555 · Thu Dec 06, 2007 12:18 am

the black tube is what blows off and my thought was just to put like 1/2 or 3/4in wide piece of piep inside so it has some rigity. i can get another pic of them apart if you need

vrg3 · Post by **vrg3** » Thu Dec 06, 2007 5:58 am

Oh, yeah, you definitely need a piece of pipe in there. The black pipe is meant to act like a hose, not like a pipe, if that makes any sense.

dirtyhandssubaru555 · Post by **dirtyhandssubaru555** » Thu Dec 06, 2007 6:43 am

heres what i did, but now the coupler slips off the tb. f-ing mother*ing cheap autozone crap!

dirtyhandssubaru555 · Fri Dec 07, 2007 12:28 am

i'm running waste gate pressure and im seeing almost stock psi. like high 7s low 8s and thats just on flat ground. i can feel a big diffence over the old vf11, i want to see what 10 or 12psi would feel like.

vrg3 · Post by **vrg3** » Fri Dec 07, 2007 12:46 am

Hm, your plumbing must be fairly restrictive... You should be seeing closer to 9 psi.

dirtyhandssubaru555 · Fri Dec 07, 2007 12:53 am

on waste gate pressure? i thought it would about 5psi, no?

vrg3 · Post by **vrg3** » Fri Dec 07, 2007 1:04 am

The TD04's wastegate actuator's calibrated to about 9 psi.

dirtyhandssubaru555 · Post by **dirtyhandssubaru555** » Fri Dec 07, 2007 1:10 am

well i did disconnect the waste gate actuator, maybe i didn't get it tighten enough and its not staying closed all the was. i do see a few pounds differnce time to time like around 3 to 4 psi diff. sometimes it looks like im almost makeing ten. how could i free up my intake?

vrg3 · Post by **vrg3** » Fri Dec 07, 2007 1:31 am

Do you still have the stock boost control solenoid hooked up? That'll make things weird and unpredictable.

Yes, if you disassembled it and stuff, maybe you put it together with a different amount of tension. I suppose even the different mounting holes might make some difference.

You could free up the intake by reducing the sharpness and number of bends and reducing the number of transitions between pipes and hoses. So your current setup isn't actually that good, but at this low boost and airflow it's probably not a huge restriction. You could check by comparing the boost reading you have in the manifold to the reading you get if you hook the gauge to the compressor outlet nipple.

Arctic Assassian · Post by **Arctic Assassian** » Fri Dec 07, 2007 1:37 am

Glad you got it hooked up right.

BXSS · Post by **BXSS** » Mon Dec 10, 2007 3:59 pm

Not sure if they have the same actuator, but my JDM 90* inlet TD04 boosted 8psi of actuator boost.

Glad to see the TD04 worked for you DHS555 (try double clamping the part that is blowing off).

FuJi K · Post by **FuJi K** » Thu Dec 13, 2007 7:40 pm

you can get good power out of the TD04L for daily driving.
I did this swap into my Impreza and had full headerback exhaust, WRX TD04L/TMIC, TXS FCD, TXS MBC, boosting avg 15psi and at 15psi I made 178whp 244wtrq on a mustang dyno.

The torque drops off after its peak at 3600rpms. HP holds above 150whp from 3600-redline.

dirtyhandssubaru555 · Post by **dirtyhandssubaru555** » Wed Jan 02, 2008 6:03 pm

well things seem to be holding up fine after a 3 or 4k miles. seeing a good 9 psi. i think i did have a minor leak, but since im waiting a week for my new flywheel(9.5pounds) i took the intake tube apart and got it to fit better and i think leak free!

tmarcel · Post by **tmarcel** » Sat Jan 05, 2008 5:27 am

vrg3 wrote:beatersubi, you're probably confusing the ECU. You can't run the stock boost control with the TD04's wastegate actuator, because the TD04's actuator is calibrated to 9-10 psi (yes, higher than our stock maximum boost level) whereas the stock turbo's actuator is calibrated to 6 psi.

Well that's not correct. There's been a variation in WGs on the Subaru TD04L since the inception of 2002. Remember, that same turbo has graced various motors from '02-07 model turbo Subarus. The TD04 that I had purchased last year was sprung to 6-7 psi only. Cobb also confirms this as well.

Arctic Assassian · Post by **Arctic Assassian** » Sat Jan 05, 2008 11:06 pm

I think Vikash was generalizing the 03-07 wrx td04, which has a wastegate boost of 9-10 psi.
BTW I got to crawl around in an 08 STI at the dealership I work at. I'll try to steal my dads camera to take some pics. It's got a vf-48.

New92 · Post by **New92** » Sun Jan 13, 2008 6:16 am

tmarcel wrote:
vrg3 wrote:beatersubi, you're probably confusing the ECU. You can't run the stock boost control with the TD04's wastegate actuator, because the TD04's actuator is calibrated to 9-10 psi (yes, higher than our stock maximum boost level) whereas the stock turbo's actuator is calibrated to 6 psi.
Well that's not correct. There's been a variation in WGs on the Subaru TD04L since the inception of 2002. Remember, that same turbo has graced various motors from '02-07 model turbo Subarus. The TD04 that I had purchased last year was sprung to 6-7 psi only. Cobb also confirms this as well.

So your saying that pre-'02 is sure to be 9psi?

91legacyawdturbo · Post by **91legacyawdturbo** » Sat Jan 26, 2008 9:07 am

Thats not a bad way to do it. With my SS I have a 90 degree elbow on the compressor intake, with a 2 inch metal pipe then it goes to the black boot, black boot to a custom adapter with the breather connections and pcv valve connections. for the compressor outlet I have a samco tmic hose kit that has been cut after the 90 degree, extended by two inches again by a metal pipe then goes into the 02 wrx tmic. I'm about to install a fcd and kick up to 15psi currently spiking at 15psi. I've been running it for 7 months and still pulling strong. About 200whp

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Stock WRX TD04 turbo on a Legacy Turbo