Chinacharger GT2870 vs Garrett GT2554 with Dynochart
 

Well, after searching through the forum, I decided that a chinacharger cannot be that bad afterall. Oh well :vash:.... Running on the same boost, I lost about 40bhp across my mid range, that's goodbye to drivability.
The only consolation is, the chinacharger cost me 1/3 of a Garrett GT28 but 80% of the performance.
Attachment 192257

I should have mentioned that car is a 1.6NA miata

Has anyone compared the wheels directly from the china parts to the real deal like I have with the T3 series?


I assume you're running a tiny exhaust? full boost on the 2554 at what looks like 4500RPM?

Specs of the chinacharger
Comp H/W(ind) : A/R.60- Ф54.13
Turboine H/W(exd) : A/R.64- Ф46.2
Cooled : Oil/WATER COOLED
Thrust bearing : 360°
Yes, you are right, I am running a 2.5inch exhaust.

This is interesting. And confirms savs theory.
I still want to figure out exactly WHAT is contributing to the power difference in the midrange.
So far we're guessing wheel DESIGN.
Do you have or can you get close up pictures of the compressor wheels on both units?
(and if you posted them already, I apologise cause I can't see pics at work lol)

Well according to your chart your boost is taking way longer to come on compared to your garret setup, which is directly affecting the power band in that section. Fix your boost down low and get the same power or more.

How do you fix the boost down low? its an inherent behavior of the churbo. I played around with ignition but not much difference either.
Sorry I dont have a side by side picture of the turbo, one is on the car, the other is off for a rebuild.

While the china turbo may have less lower end you can still up the boost on that thing to 20-25 psi and make a lot more power than that 2554 could ever dream of. Will it ever perform the same as a Garrett 2871? No, but we all know that already.

I would get a 3" exhaust and up the boost.
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What are you using for boost control? mbc?

A free'er flowing exhaust system will help spool. Also some like to richen up the fueling right before spool up to generate more exhaust gasses and help spool.

There's more to a wheel than the inducer and exducer measurements.

For example look at this wheel:

http://www.boostedmiata.com/gallery2...2/DSC_0017.JPG

and then this:

http://www.boostedmiata.com/gallery2...2/DSC_0015.JPG


you'd be hard pressed to see a difference...



now look at them from the top:

http://www.boostedmiata.com/gallery2...2/DSC_0016.JPG

pretty obvious they are different. yet they measure within 1mm of each other. The top blade of the ebay wheel extender further than the garrett and sits even with the lower blade. I couldn't tell you if it's better or worse.






same with the turbine here:

http://www.boostedmiata.com/gallery2...2/DSC_0012.JPG

http://www.boostedmiata.com/gallery2...2/DSC_0013.JPG

the profile, curve, fin spacing and exducer diameter are identical...I really tried hard to find a difference, but what you will notice is the china wheel has an inducer that's 5mm longer than the garrett. Is that better or worse?


Casting of the CHRA was identical, same AiReasearch "A" stamped on it. thrust bearing looked like it could be swapped with genuine garret parts. Butt dyno told me all was better, dyno proved me right.

So again, has anyone REALLY compared the wheels from the Garrett 2871 to the china?

How does that work? Still ain't going to fix everything past 5000RPM.

i am running the blitz EBC. Tried richen the fuel and also tweaking the timing, it makes a bit of difference but it doesnt make up the 0.2bar boost I needed across the mids.
25psi on my stock 1.6? I am a bit skeptical about it.
But thanks guys, meanwhile i am planning to get the exhaust done.

Here is that turbo at 16 psi with an old style begi cast mani and a 2.5" dp on a Mustang dyno.

Attachment 192256
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braineack, if i get the chance,i will do the comparison. I am guessing buying a chinacharger is a matter of hit and run. Some are terrific with others have shitty results like what I got.
I am guessing that if I want guranteed performance, I should just take the Garrett route.

I took some caliper measurment of mine in my build thread. I didn't really know what I was measuring, so it may not be enough data for comparison. I did not compare the measurment to a Garrett.

Compressor
Ind53.1mm
Exd 69.7mm

exhaust
Ind 51.7mm
Exd 45.7mm

I apologize for this worthless post if this isn't what you were looking for.

The dyno plot of my churbo follows the red curve int eh first post. Slow to start then takes off like a rocket. Very exponential vs the nice linear curve.

What a worthless post! j/k

I'm just saying; I bought it to do just what the OP did. Wanted to see what difference it would make. For my T3 application, seems that I benefited.

Nope. Which is why we're all just guessing shit.

You are the only person so far that has done any sort of real comparison between a china and a genuine (though not 2871) and your research so far points to wheel design being the biggest contributor to the power difference.

Replace exhaust and up the boost. What mani/dp are you using?
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I was going to go as far as putting the garrett compressor wheel on the ebay turbine and vise versa, but I'm HELLAlazy.

Custom made equal length manifold and downpipe. Free up the exhaust and upping the boost will see more improvement at the top and possibly slight difference in the mid range?

You should see gains everywhere.
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