UA-65274002-1 Jump to content
jman093

Help identifying Turbo

Recommended Posts

Hey all.

 

I'm trying to figure out what aftermarket turbo I've got here. Only marking on it is a .86 AR identification on the turbine housing. It sure as hell makes more boost than the stock T25. The car's a rocket compared to my stock one while wheezing through a factory airbox. Anyone know what this is?

 

IMG_0306_zps880daba5.jpg

IMG_0305_zps992ee0e0.jpg

IMG_0304_zps2a38b06b.jpg

Share this post


Link to post
Share on other sites

That thing is clocked way off. I'd be surprised if it wasn't needing a serious rebuild. It may be a hybrid of some sort. I don't recall a whole lot of them with the O2 bung in the turbine like that. Is there any type of tag on it? It may be on the bottom the way it's clocked on there.

Share this post


Link to post
Share on other sites
looks like it has nissan style comp inlet flange , t28 journal bearing is my guess

 

That's one of the main things I would like to know: whether it is journal bearing T28 or ball-bearing like a GT28rs or GT2860 or something. The o2 sensor in the turbine makes me assume T28 as well, but I don't know. My other main concern is who made it, since Garrett is not stamped on it. I'd hate for it to be a cheap ebay turbo that comes apart with its chunks taking out the intercooler and/or LG5.

 

That thing is clocked way off. I'd be surprised if it wasn't needing a serious rebuild. It may be a hybrid of some sort. I don't recall a whole lot of them with the O2 bung in the turbine like that. Is there any type of tag on it? It may be on the bottom the way it's clocked on there.

 

No tag. I checked with a mirror. The compressor has absolutely nothing on it whatsoever. The turbine has markings of AR .86, M3, and 2J. Clocking doesn't seem much off. The turbine is clocked identically to the stock T25 on my black one and the compressor is clocked about 30-45 degrees more counter-clockwise than stock.

 

Whatever this is it sure as hell makes boost. I'll need to get a chip burner to run the thing. Without much trouble, it causes the ECM to pretty violently cut the engine off for a couple seconds and then set the check engine light on for 10 seconds and store code 31 "TURBO OVERBOOST."

Share this post


Link to post
Share on other sites

overboost usually happens from a leak, but did you try adjusting the wastegate rod? I had to figure all that out when I switched to adjustable rod. once you figure out which turbo it is, looks kind of like a Merkur turbo or a modified one, I am not sure, but then also try and find whats the boost range of that adjustable WG.

Share this post


Link to post
Share on other sites
overboost usually happens from a leak, but did you try adjusting the wastegate rod? I had to figure all that out when I switched to adjustable rod. once you figure out which turbo it is, looks kind of like a Merkur turbo or a modified one, I am not sure, but then also try and find whats the boost range of that adjustable WG.

 

According to the factory service manual. Overboost sets at only 9.5 psi. It seems a bigger turbo would easily hit that since it's not much more than the stock T25's output. Are these actually able to get more than the 9.5 manual says?

 

From what I can tell it's definitely a T28-style of turbo (at least on the turbine side) because it has this bolt pattern on the back:

GT28RS_turbine.jpg

Share this post


Link to post
Share on other sites

That bolt pattern covers a wide variety of turbos. My GT3071RS has the same style housing, too, but without the O2 bung in it.

 

I am pretty sure over-boost is triggered at 20 psi. But I'm sure that would be adjusted by the tune.

 

I don't think the adjustable rod doe anything for adjusting boost. The wastegate range is determined by the spring inside.

 

I have no idea how far you can turn up the boost before things start to blow apart. Jarek can tell you that.

Share this post


Link to post
Share on other sites
That bolt pattern covers a wide variety of turbos. My GT3071RS has the same style housing, too, but without the O2 bung in it.

 

I am pretty sure over-boost is triggered at 20 psi. But I'm sure that would be adjusted by the tune.

 

I don't think the adjustable rod doe anything for adjusting boost. The wastegate range is determined by the spring inside.

 

I have no idea how far you can turn up the boost before things start to blow apart. Jarek can tell you that.

 

Great, so the turbo could be anything, lol. Oh well. Do you have a tune that changes overboost shut-off to 20 psi, or is the service manual just not correct?

Share this post


Link to post
Share on other sites

a 2-bar map has a hard limit of 208kpa(30.1psi absolute). if you consider boost to be any pressure above barometric pressure at your current altitude(and large parts of the TGP code does just that), then it will depend on your elevation. Denver is currently at 85kpa baro, which is a solid 10-15kpa lower than most of the US. the turbo would need to provide 123kpa(17.8psi) to max out the sensor there while somewhere closer to sea level would run into the same limit at 15.7psi.

Share this post


Link to post
Share on other sites
I don't think the adjustable rod doe anything for adjusting boost. The wastegate range is determined by the spring inside.

 

The boost pressure is controlled by the sping inside, however, the spring pulls on the rod holding the puck wastegate valve) shut, shortening the rod should tighten up the spring creating higher tension on the wastegate, thus requiring more boost pressure to overcome the higher tension, opening the puck at a higher boost level.

On my Grand National, shortening the rod 1 turn makes 1 more PSI boost.

Share this post


Link to post
Share on other sites

Well, I have a new turbo question, so I'll go ahead and just update this thread instead of making another.

 

First just a little update on the turbo/car if anyone cares.

 

I never did figure out what this turbo is. Whatever it is, I've put a few thousand miles on it and it still boosts strong. I did finally look into the wastegate issue recently and found it and the vacuum hosing wasn't hooked up right at all, which is why it hit ECM overboost fuel cutoff so easily. It isn't quite as powerful under part throttle now, but I can now go WOT. Before it would hit overboost with about half-throttle. I think it would be beneficial to ditch the ECM controlled wastegate for a manual one. Should get that little extra part throttle boost back. Anyways I can now romp around on it all day without hitting overboost on the street.

 

Excited about this, I took it to the drag strip a couple weeks ago to see what it would run, but even though I've never hit overboost on the street, I was hitting it on the drag strip towards the latter third of the track. Could only run a 15.4 with the car cutting off fuel slowing down the last third of the track. 1000 ft MPH was faster than the 1/4 mile MPH. I gotta figure out this damn tunerpro $8F stuff and raise the boost limit a couple psi. If it ran mid 15s cutting fuel out half the track in summer heat, I think this turbo should be good for mid 14s with the limit raised.

 

On to my current dilemma. The car has been developing an exhaust leak that's been getting really bad. I figured "F%$k, there goes the crossover," but it was actually the turbo.That white turbo outlet flange gasket in the first picture? Those are a bunch of paper gaskets with a metal gasket sandwiched between them. Some people's kids, man. I can't believe that lasted as long as it did before blowing out. I put a new cometic gasket on there tonite and all that paper gasket came crumbling out in pieces. The only reason I can see why this was used is that instead of stock bolts attaching the exhaust to the turbo, there are studs. They aren't fully threaded studs and the nut runs out of thread before it tightens, so instead of just putting a washer on like a sane person, these paper gaskets were piled up to make the flange thicker and take up the gap. I chose washers on reinstallation. Leak fixed and only needed one metal gasket!:willy_nilly: I'd like to eventually find some proper bolts like stock and ditch those studs.

 

The question: When changing the gasket, I found the lower bolt hole on the right side did not have a bolt/stud in it. There are only 4 studs attaching it together. I assumed this was due to laziness and that bolt was the hardest to access, so it did without. But I tried to put a bolt in there couldn't get one in. Looking with a mirror, the hole for the exhaust flange and the one for the turbine output flange don't seem line up. They aren't even close. The other 4 are all perfectly matched up. Are there multiple Garrett 5-bolt flange designs out there, particularly one would match only those 4 bolts with the stock t25? I tried searching, but can't find much.

Edited by jman093

Share this post


Link to post
Share on other sites
I think it would be beneficial to ditch the ECM controlled wastegate for a manual one. Should get that little extra part throttle boost back.

 

alternatively, changed the desired boost table to allow for more pressure at lower throttle and keep ECM control.

Share this post


Link to post
Share on other sites

you can drill out the holes in the DP a little I would think. what spark gap are you running? 

 

 

yeah I was thinking it was a combination of maybe wrong gap or grounding broken plug, boost leak, and/or needed rod adjustment.  

Share this post


Link to post
Share on other sites

if you really want to know what compressor it is, pull the housing and measure the minimum and maximum size of the compressor blades. I had to do that to find out what I had in-hand as well, what I was told was a T70(and it clearly wasn't, way too small) measured out to be a T04E 46 trim with a T4 O-trim turbine.

 

your compressor housing doesn't look nearly as simple as mine was to separate though.... I only had 6 bolts to deal with and plenty of space to get a wrench in to.

Share this post


Link to post
Share on other sites

you can drill out the holes in the DP a little I would think. what spark gap are you running? 

 

 

yeah I was thinking it was a combination of maybe wrong gap or grounding broken plug, boost leak, and/or needed rod adjustment.  

 

It would have to be a lot of drilling. It does hold-no-leaks with the new gasket, so I'll leave it be. I'm just asking because I'm curious as to why it doesn't fit and curious as to what turbo I have.

 

 

if you really want to know what compressor it is, pull the housing and measure the minimum and maximum size of the compressor blades. I had to do that to find out what I had in-hand as well, what I was told was a T70(and it clearly wasn't, way too small) measured out to be a T04E 46 trim with a T4 O-trim turbine.

 

your compressor housing doesn't look nearly as simple as mine was to separate though.... I only had 6 bolts to deal with and plenty of space to get a wrench in to.

 

I'm not that curious though, lol. That thing is staying put unless completely necessary.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...