Turbo retiring

[optional187]

My turbo's been screeching for a while now until the car warms up, so i've been expecting it to go out. Now its making a whirring noise a lot like a supercharger, which from what i understand is the next step toward it totally giving up. I took off the intake hose today to take a look at the wheel and see how much shaft play i had, which doesnt seem like a huge amount...but it was moving more than i think is regular. also, there were spots of oil hanging around, which i dont really understand? its also losing a lot of psi in the higher rpm's...i run 14psi and it will fall all he way down to about 6 by the time i get up to 6000rpm. whats up with that? i put the stock bov back on and did a test run...i can hear what sounds like a boost leak but cant find one anywhere.

its a stock t25 with about 142k on it...just put on a ebay bov about a month ago that doesnt recirculate, figured it wouldnt be to much of a problem since i've been running the stock bov flipped so it doesnt work (which is how i'm running 14psi, the limit of the stock turbo.) other than that all i have is a intake cone to replace the stock airbox and a greddy licp.

 

[Rayek]

I would definately try a boost leak test first off.

When the turbo starts making that sound, it is almost at it's last breath . Most likely fixing the boost leak will put a bit more strain on the turbo. Given its current state it might not be able to handle much more .

-Edit
Also, please recirculate the BOV. You are just asking for problems if you vent to the atmosphere. Alot of info can be found on these forums. I started out with something similar to your problems, which with a little reading here I could have totally avoided. Live and learn right?

 

[optional187]

yeah, i know all the problems with venting. honestly, my car has run fine...only problem was letting off between shift or pulling up to a stop light i'd have to keep the car from shutting off cause of it running too rich. venting cant really cause the turbo to give up can it?

i've checked all the obvious spots (to me) for a boost leak, any abnormal spots to check? i was thinking about taking off the heat shields and seeing if maybe somethings cracked on the actual turbo. if i had a boost leak wouldnt it keep me from boosting in the first place? it spools up fine to 14psi then gradually drops off as the rev's climb.

 

[JusMX141]

Turbo's junk, for sure. I'm quite impressed it lasted this long for a T25!

Time to upgrade. A 14B or Small 16G makes a nice, inexpensive transition and can still be run on the stock fuel system at low boost.

venting cant really cause the turbo to give up can it?

No, venting cannot hurt the turbo....but too stiff of a blow off valve will cause compressor surge which puts force on the turbine shaft and causes the journal bearings to contact the housing instead of riding on a thin film of oil.

Your blow off valve didn't flutter at all before this turbo died, did it?

 

[optional187]

so lets say i get a ebay small 16g and fmic...as long as i keep it under say 15 psi or so i shouldnt have to upgrade anything else right? i'm doing a bit of reading around on here and i'm just trying to figure out how i can maybe upgrade the turbo a tad but nothing major, without having to do much else. i've got the money to do a little bit to the car, but ultimately i'm saving up for a new car to drive daily. thats when the gst can have some money dumped into it to play.

actually...i ran on a flipped stock bov for about 3 years. it did nothing BUT flutter. the ebay bov was a turbo xs type which uses a spring and washer system to adjust it. i had to cram a bunch of washers in it to even get the car to run as good as it did, but everything seemed fine. i would occasionally get a flutter still though.

 

[spooling 1g]

I would at least do a fuel pump to.

 

[optional187]

on a side note...anyone know if engine oil restorer is bad for turbo's? i've thrown a can of that stuff in the last few times i've changed my oil cause my car sat for a while before i started driving it again.

 

[JusMX141]

so lets say i get a ebay small 16g and fmic...as long as i keep it under say 15 psi or so i shouldnt have to upgrade anything else right?

eBay doesn't offer Small 16G's....just the Evo III 16G which flows a good bit more air and will be a little more laggy than a Small 16G.

Every car is different, I can't just say "you'll be fine at 15psi." I just installed a Small 16G on a customer's 1G....the car's totally stock aside from a K&N air filter and a 3" turbo-back exhaust. The safe zone on this particular car is 14psi. The Small 16G responds identically to the 14B it replaced (full boost around 2700 rpms), and offers a good bit more pull on top.

 

[optional187]

thanks for all your feedback jusmx141, its really helping me out here.

i was hoping i could find a small 16g on ebay, but i guess you're right...there's nothing but evo III 16g's. how would you say this turbo would generally act on a mostly stock car? i really dont want to have to get an exhaust cause i dont like all the noise...but i also dont want to have to wait forever for a turbo to spool.

 

[kenamond]

If possible, replace the turbo before it grenades. When it goes, you can pump a quart of oil into your intercooler in a minute and a bit of that will make it into the intake manifold and through the cylinders. And the destroyed thrust bearing will be flushed out of the center section, down the oil return tube, and end up in your oil pan.

If you want to play it safe, disconnect the WGA arm from the lever on the turbine housing. The car won't boost anymore which you'll certainly notice in your 1/4 mile times but it won't put much demand on the worn-out T25. If the turbo won't spool, it's less likely to come apart catastrophically.

The oil in the compressor might be normal. There is a VC breather line from the passenger side of the VC to the intake pipe that will send a bit of oil upwind of the compressor. It builds up over time. Or it could be a leaking seal on the turbo.

Good luck!

 

[optional187]

thanks for the post

could you further explain the disconnecting of the wga arm? cause i have no idea what that is. its going to be at least two weeks before i have a chance to work on the car

 

[kenamond]

thanks for the post

could you further explain the disconnecting of the wga arm? cause i have no idea what that is. its going to be at least two weeks before i have a chance to work on the car

Good thing I don't post on this forum more than once a week at the moment

If you look at the passenger side/front of the motor, you'll see the turbo compressor housing (snail-shell-shaped silver aluminum housing). There will be a (corroded maybe) brass "can" bolted to it. The back side of this "can" has an arm (rod) sticking out of it (toward the driver's side) that is the actuator arm. That arm connects to a lever on the turbine-side of the turbocharger. You may have to remove the heat shield from the exhaust manifold (has a burning hand symbol pressed into it) and loosen the other, lower heat shield on the exhaust housing (called the O2 housing) to get at it...I forget. The second heat shield is difficult to completely remove, but you can take the bolts out and move it around...but only if you think you need to remove it to get at the lever. The arm is connected to the lever with a pin and a clip. You pop the clip off the pin (I *carefully* use pliers), and push the pin out. The arm will probably pop loose and "shrink" a bit back into that brass "can" (the arm is spring-loaded to pull into the "can"). Then put the clip and pin somewhere you won't forget/lose. Then the turbo will not boost. The reason for this is that the lever controls the wastegate. This is a "back door" that bypasses exhaust coming from the engine so that it can bypassa the turbine wheel. Normally, that brass "can" which is spring-loaded will hold the "back door" closed letting all of the exhaust to pass through the turbine which, in turn, drives the whole turbocharger. When the turbo generates a certain boost pressure on the intake air, that brass "can" will push out the arm and open the wastegate - but only a bit - so that your boost doesn't go any higher (that's how boost is controlled on our cars). When you disconnect the arm from the wastegate lever, the "back door" is free to open *all the way* (not just a bit) and at will (you should be able to turn that lever with your fingers with the arm disconnected, so the exhaust will easily open it up all the way), so lots of exhaust will "decide" to go out the "back door" rather than through the turbine wheel, and the turbo will not spin up much. You'll basically turn off the turbocharger.

So find that actuator arm and see where the other end goes and figure out how to disconnect that other end. Then just deal with the lower power.

The other option is to use your foot to not boost. If you have a manual transmission, shift at low rpm (under 3000rpm). That should keep the turbo from spooling up. A mix of using less gas pedal and shifting much sooner should give the dying turbo a break, too.

And when you finally go to deal with the real problem, enjoy wrenching on the car. If that's your cup of tea, you'll get a kick out of it and become a pro in no time (well, a couple of years). The death of my T25 was the start of me "getting into" my DSM.

Good luck!

 

[optional187]

thanks for the detailed reply, the car actually started smoking really bad so i just stopped driving it and put it up on jackstands. over the past two days i've been slowly taking the thing apart. so far: radiators out, intakes out, licp's off, stock turbo's out, stock manifold's off. the t25's got so much shaft play its hard not to laugh about it!

i've got a eIII b16g that i have to put the water lines on. it came with a new oil return line, nice stainless exhaust manifold and stainless o2 housing aswell as a stainless j-pipe...but it didnt come with a 90* pipe to hook up with the stock intercooler. is RRE the only place that sells a 90* pipe with a nipple to hook up for the boost source? and am i correct in thinking that i can hook a MBC between the 90's nipple and the stock vac. line?

other than finding a way to hook it up to the stock intercooler, finding a stainless oil supply line, and figuring out how to bend the water lines (and how the heck a banjo bolt works) this is going like a breeze! i figured it'd be harder than this but so far everythings just coming off so easily and putting the 16g on seems pretty straight forward.

said it before but i'll say it again....thank god for vfaq and you guys!

 

[Rayek]

on a side note...anyone know if engine oil restorer is bad for turbo's? i've thrown a can of that stuff in the last few times i've changed my oil cause my car sat for a while before i started driving it again.

I didn't see a response to this question so I'll pipe in here
If you are talking about the goop that you put in your engine to clean out the build up, then yes it is bad for your car. I remember looking at a bottle of it and it said "not recommended for turbo applications."

Also, the reason why your car was running too rich between shifts as you mentioned, is because the air is measured before the intake pipe, then when it goes back through your piping, it is blown off into the atmosphere instead of re-routing back through your intake pipe. In a nutshell, your ecu thinks X amount of air is being sucked in, but in reality there is less air than what was measured before since it is being discarded into the atmosphere. Our cars are a 'closed loop system' and are set up to re-route the air stock from the factory. There are ways around this but are expensive alternatives for just being able to vent to the atmosphere. I would recommend just going to autozone and get a radiator hose that will fit the openings, and chop her off for length. I did that on mine and it looks like kinda like a stock setup. (not ghetto rigged)