ByteVenom

I unfortunately destroyed my first chinacharger through turbo noob negligence, but now I am wiser.
I'm curious as to people's thoughts on this turbo here (T25 T28 GT25 GT28 GT2871 GT2871R GT2860 SR20 CA18DET Turbo Turbocharger turbine | eBay)
My previous turbo would almost immediately hit 7psi+ at 3k rpms. (Unfortunately the listing has been deleted, so I can't pull the size data from that).
Now my new turbo, I know from memory is a bit bigger (we're talking an extra 10mm on the compressor imo), and has a .2 higher AR ratio.
I'm only looking for 200ish WHP, is this turbo overkill? Will I be waiting till 5 grand till I feel any boost?

P.S (Yeah I know chinachargers are iffy)

yossi126

iTrader: (6)

If you know it sucks then why get it? A real used, good example T25 will out spool this and be far more reliable than that POS out of the box.

ByteVenom

They're iffy, and they do suck, but in the way that produces horsepower.
I'm not racing my car, or anything like that. The maybe 500-800 rpm spool gap that a name brand turbo and my turbo share is fine by me when I can get a turbo for 150$ while I'm just learning.

Also, doesn't really answer my question at all. I'm asking for how much slower this turbo will spool, and basically how well matched it is to a miata 1.8 engine.

bjorno

buy it and let us know

patsmx5

iTrader: (16)

I ran that turbo before. If you push it past 350whp or so it will overspin and tear up the bearings. For 300whp it should last for years. Mine had full boost around 3600 or so with ebay manifold on my setup. For 200whp it's overkill but would last forever at that power level since you wouldn't be pushing it much. If you really only want 200whp I'd put a smaller turbo.

ByteVenom

Ah darn okay. Would you be able to give a guesstimate at what PSI it made 200ish?
I have a 7psi wastegate, I'm thinking that should get me to 180-200 based off of what I've seen around here.

I mean obviously car to car its different, and PSI doesn't mean everything. I'm also running stock exhaust (sort of), till further notice. That will kill some power.

chicksdigmiatas

iTrader: (11)

That is pretty much the turbo I started life with. The thing is still in my garage. It started blowing some oil after a few years, but it worked. I want to see someone experiment with one of the ball bearing churbos. If you feel like taking one for the team, try it and let us know.

http://www.ebay.com/itm/GTX2860R-Dua...FYzOl-&vxp=mtr

patsmx5

iTrader: (16)

I never ran it at less than 15 PSI. At 15 it was probably making 250whp or so? At 25-28 psi it was a lot stronger. For 200, probably 10 psi or less I would guess.

ByteVenom

So, its a solid turbo then I can presume?
I've been thinking the exact same thing about those new china ball bearings. They probably haven't caught on yet because people don't feel like dropping that much money on a churbo.

patsmx5

iTrader: (16)

The one I ran, when I ran it at 18-20 PSI, up to 8500-9000 RPM, it never showed any shaft play, wear, oiling, nothing. When I tried to run it at 25-30 PSI and rev that high, it started destroying the bearings. After thinking about it, I did some rough math, and I was soooooo far off the compressor map on my setup that it's a wonder the turbo didn't just explode from over-revving it. I was on the next page of the compressor map. I posted pics of it here in a turbo thread. My opinion is it's solid, especially for the money.

ByteVenom

Haha that is awesome. Did you have to run any oil restrictors on the turbo?

patsmx5

iTrader: (16)

I have never run a restrictor on a journal bearing turbo. Just a 4AN feed, and a 3/4" drain with a clean shot to the pan, above the oil level.

ByteVenom

Ah okay, so the stock oil pressure wouldn't blow out the seals? I'm running 4AN feed and 3/4" (something around there) drain as well.

I'm just asking because on my last turbo, Cxracing recommended to run a restrictor otherwise the turbo would not be happy apparently.
As it turned out my turbo still burned out, but that's because of other reasons haha.

CamH

I'm running the chinacharger linked in the OP on my 2000 LS. Works great. I get positive pressure before 2k rpm's if I mat it, full 15psi by 3500-4000rpms. I'm running an oil feed a restrictor at the turbocharger fwiw. Works good. I think this is a very good turbo for a stock bottom end build

MotoCARR

Great timing on this thread lol. Is the outlet a "true" T25 outlet? I plan on using the Flyin Miata cast downpipe for my build but have held off on getting a churbo because of posts like below.

https://www.miataturbo.net/diy-turbo...03/#post840195

CamH

I don't think the outlet is a "true" T25 outlet. The bolt spacing is weird. You'll probably be able to get 3 or 4 bolts in your flyin miata downpipe.

MotoCARR

What downpipe are you using?

CamH

I used one of these. I have 4 bolts in it: Mild Steel Flange 3" I.D.V-band Flange to TB25/TB28 and T25/T28 5 bolt Adapter

I ended up having to cut the vband off and weld directly to the flange to make a hard enough angle to get past the body of the car behind my turbocharger.

shuiend

iTrader: (24)

Yep with the standard FM/Begi/Ebay cast manifolds the v-band outlet adapter make the turbo to long to fit a down pipe without major surgery on the shelf.

ByteVenom

Did the turbo come with the outlet flange?
Was the flange just a standard T25 5 bolt outlet?