patsmx5

iTrader: (16)

My front turbo, an ebay GT28, used to be very quiet and I couldn't hear it. That was at 18-19 PSI, several thousands miles, no issues. I recent pushed it up to 25 PSI, and after making about 20-30 runs it's now whistling on spoolup, starting at 1-2 PSI you can hear it begin to spool/whistle very loud.

Is my ebay turbo sad? bearings bad? Boost leak? Something else?

EDIT: still makes 25 PSI on front turbo to 8,500 no problem, just hearing a lot of noise as described.

18psi

iTrader: (76)

Buddy of mine would rebuild his every 6mo-1year afterhe started running them past 20psi.
Probably on it's way out. Rebuilds are cheap and easy. Make sure you don't wait until it eats itself.

patsmx5

iTrader: (16)

I'm gonna check the shaft play tomorrow when it's cooled off, I would guess it's the bearings unless I was blessed with just a boost leak.

Where do you get rebuild kits for ebay turbos? Ebay? g-pop shop? I got one for my GT3271 from g-pop shop, dunno if they sell them for ebay turbos.

patsmx5

iTrader: (16)

An ebay search shows two interesting things. Rebuild kits are 30-40 bucks, you can find rebuild kits with 360 degree thrust bearings too. I suspect that is what failed if it's the turbo, I doubt it has 360 thrust bearings.

Second, new turbo is.... 179 shipped!

And actually a 3rd thing, it turns out this turbo has a 1 year warranty. Hmm.... Gonna email seller if the shaft play is out and see what happens. Would be hilarious if they warranty it!

dc2696

iTrader: (2)

My GT35R made supercharger like noises just before it failed on me (bent shaft), not so much whistling though. I'd be checking shaft play asap.

18psi

iTrader: (76)

lol if they're that cheap I'd just keep replacing them with new ones

patsmx5

iTrader: (16)

Well the thing has zero axial play, but a lot more radial play. Pulled the compressor housing and it has barely hit the housing. Haven't inspected the exhaust side yet so can't comment on that. But radial play is pretty bad.

I emailed the guy I bough it from, told him I raced it and ran the crap out of it, and asked if he'd sell me a new one and a rebuild kit for a discounted price. We'll see.

Right now the plan is to just order a new one, and a rebuild this one for a spare. I think I just overspun this turbo. Maybe the balance is crap and that's why it eats itself at 25 PSI but was fine at 18-19 PSI.

Gonna pull this one apart and see what it looks like for fun.

18psi

iTrader: (76)

It might be lack of precise balancing. Or just cheap components that wear our too fast. Or loose tolerances. Who knows.

patsmx5

iTrader: (16)

I'm betting balance. I can't believe you would suggest my fancy ebay turbo might have "cheap components"!

18psi

iTrader: (76)

Nothing but top notch quality parts is what i meant

patsmx5

iTrader: (16)

Pulled the chra out of the turbine housing, that end looks clean/dry and almost no play at all. Looks like all the wear is on the compressor end.

18psi

iTrader: (76)

I wouldn't be surprised if g-pop or garrett rebuild parts dropped right in to these. I've heard of it before a few times. After all, it's likely a knockoff of garrett in the first place. they're not gonna design anything new or much different.

patsmx5

iTrader: (16)

Cool, thanks for the heads up. You're probably right too, I'm sure it's a knockoff of a garrett as you say.

I'm actually looking and this front turbo is tiny, I think I'm gonna put a bigger ebay turbo up front. I didn't really do much research before buying this last one, apparently there are better ebay turbos than the one I bought, it spooled like crap for being a T2 GT28 ebay knockoff. And I really want the small turbo to run 25-30 pounds without dying. I ran it at 30 and the midrange was nice (never went over 5K, this was months ago) , but quickly put it back to 25 but it died even doing that.

deezums

iTrader: (3)

Ebay turbos have weird excavator like turbine and compressor wheels, they don't always exactly match easily available Garrett stuff.

I think all these china turbos we love so much are chunks of turbos meant for industrial equipment, not that there's anything wrong with that.

You couldn't ever buy a 45/50 trim t3 from Garrett, but they shoved that compressor combo on a lot of OEM stuff.

The China t04es are especially bad about all this, think the majority are actually closer to to4bs.

Pretty sure the rebuilds and chras are interchangeable though.

18psi

iTrader: (76)

Ya We're talking specifically about the bearings. The wheels they copied from drawings likely lol

Looks kinda like it.....good enough.....jerb done

deezums

iTrader: (3)

That's mostly what I meant.

The turbos aren't made off spec that bad, they are sold off spec. China doesn't make turbos to sell to race car drivers, they make turbos to sell to people with shitty turbo diesels in heavy equipment. Ebay "vendors" slap bold words and HP numbers on slapped together turbos to sell to ricebros using closest available nomenclature. It's why it's impossible to find a true china garrett 60 trim t3, no excavator ever used a 60 trim compressor.

If you measure ebay turbos, then cross them with stuff like this here...

Compressor Wheels - Garrett Racing - Applications - TurboMaster

You can take that compressor wheel number and find a genuine garrett china turbo. The website above has a "where used" search option. You can use that to find specific turbo models, then you can use that to reference exact equipment models for super searching. Say you want a garrett 50 trim T3, I can probably find you a john deere that had that front side for you.

So if Pat likes ebay turbos, and the turbine holds up. Well, he can likely find a genuine larger garrett front side for less than the cost of a new china turbo. Send the CHRA out to balance for ~$50 and maybe it does high boost longer? Or just buy an ebay t3 and swap a garret cold side, then there's lots of cold sides to test from.

I like to ramble, sorry.

18psi

iTrader: (76)

Or just send to Gpop (if they do these too) and have them rebuild with proper parts and balance. But that would still cost more than a replacement. I mean, they're almost free lol

patsmx5

iTrader: (16)

Thanks for the info. Some googling shows this "GT28" is T2, 49.2mm inducer on the compressor, and 47mm on the turbine. Tiny! My old Garrett GT3271 was T3, 51.2mm compressor, but a 64mm turbine. Compressor was a tiny bit bigger, turbine was hugely bigger. I can't say power is all that different really, but the garrett lived at high boost for years.

I really don't know crap about any of this, but I want a cheap turbo that will run 400whp on its own without going off the map and dying from pushing it too hard. This ebay GT28 would do that at 300whp, but not 400whp.

If possible I'd like to keep my T2 manifold, but if I gotta go T3 then that's fine I'll do that.

deezums

iTrader: (3)

What's 400whp, something like 40lb/m? I don't think you can do that with a single fast spooling T frame turbo. I doubt any t2 is gonna be capable, turbine housing is just too small. No t3 compressor will flow 40lbs, a super 60 tops around 36IIRC. A true t04e 50 trim would be about perfect though, 75/55mm compressor, and I think they're pretty readily available. The problem is you'd be all over the surge line, 14 psi on 1.8 liters is ~16lb/min and 1.95pr. If you look that up on the comp map, it's on the surge line on the left. 16lb/min is at 4100 rpm, so it's pretty safe to say this thing ain't spooling till at least 4,000.




A 46 trim might be better though, I think you might be able to find one of those off an excavator pretty easy. 400 would be maxing this thing out, but leveraging all of the map available still.



Here's a nice billet wheel, to help get to 40+lb/min...

Billet Turbo Compressor Wheel Garrett T04E Trim 46 442293 0015 50 8 75mm 6 6 | eBay

And here's the turbomaser page for the corresponding "where used" search on that compressor wheel. Go through each to find the top thing, it actually says conch shell in italian or something, but it means compressor cover and it's a good searchable part number.
442293-0015 - Search Usage in TurboMaster

The first couple will pop up john deere sites selling the compressor cover for around $109. Sometimes you are lucky and find ebay ones. Here's a brand new one, just overseas. Pretty sure you can get one new here in the states for around $110.
443219-0104 Compressor housing TO4E08 | TM Sport & Racing

You can get a backing plate on ebay, usually pretty easily.
New Garrett T04E High Quality turbocharger Back Plate Seal Plate Very Best | eBay

A normal "stage 1" t3 turbine wheel off an ebay t3 would be perfect, and you could swap between .48 and .63 housings to suit pretty cheaply. Those go for around $130 at the lowest, $50 to get it balanced and you have a nice billet wheel turbo with a pretty decent map for ~$400. You don't have to get the billet wheel though, pretty sure the tractor house might be able to source you a normal cast one for around $40.

I don't really know enough about t2's, not sure it's worth your time saving those little turbines. All I know for sure is a huge AR t2 housing is the same as a small AR t3 housing.

patsmx5

iTrader: (16)

deezums, many thanks. Looks like you're right on a T2 ain't gonna cut it at all. I like that first map, T04E 50 trim looks like that could work. Is that something I can buy, or do I have to build it with parts as you described? I would like to just buy a 400whp cheap turbo that won't fail at 400whp and just use it as is if possible. A HX35 came up in my searching, it looks like that could be an option? Still searching around on that, looks like a 54 or 56mm compressor, which is about what I want. Something in the 55-59mm range would be about right I think.

Back on teh T04E 50 trim, I have a 1.9L that breathes well, so I might be ok on getting past the surge line. I would be fine with 4K full boost, hell I'd be fine with 4,500 it hits 25-30 by then that would be great. I spin it to 8,500 so that's still a 4K powerband which is plenty. Do you happen to have a link to the T04E 50 trim that would be close to the one you described building?