So I often thought about upgrading my SR20 T25, and there was so much debate about how expensive it is and all that. So to clarify things, here is my emails.
------------------------
Hello,

I had inquired previously about upgrading my current journal bearing stock sized SR20 T25 turbo. Correct me if I'm wrong, but I believe the specs are as follows:
Compressor: T-25, 60 trim 56mm
Turbine: T-25, 62 trim 53.8mm 0.64 A/R turbine housing.

I was wondering what my options are as far as upgrading the compressor side of this turbo. I have a spare CHRA and spare compressor and was thinking about having it bored out to accept a T-28, 60 trim 60 mm wheel.

The turbo is currently on a '99 Miata and it makes about 220whp at 12 psi. What could I expect at the same boost level running the upgrade that I mentioned?

If I sent you my CHRA and compressor, I can rebuild the CHRA myself. Could you just bore the compressor housing and sell me the upgraded wheel and the new shaft? What is pricing like to do exactly this?

Thanks,
-Todd
-------------------------

Hello Todd,

Thank you for your interest. You can usually expect a 10-15% increase in
power with this upgrade. These wheels are $95.00, machining is $100.00,
balancing is $65.00, the rebuild kit is $88.00 and return shipping is
$25.00. Is your turbine wheel/shaft bad? Or do you want it upgraded as
well. A new stock unit is $155.00, upgrade T28 turbine wheel is $175.00 +
$100.00 machining. Let us know if you have any other questions or if you
need anything else. Thank you,
-----------------------

So for $373 to take the compressor side from specs similar to a GT2554 to a GT2560, I'd say it's worth it.
Do I care enough to do it? I'm still not sure yet...

 

yawn

 

The answer on this forum seems to be Chinacharger

 

i'd keep your eye out for a s15 t28. they can be had cheap and it has your compressor wheel. IE: offer this guy $300 plus your t25 http://forums.nicoclub.com/gt28r-for...r-t510535.html.


S13 Red-Top T25:
Compressor: T-25, 60 trim 56mm 0.60 A/R BCI-1 compressor.
Turbine: T-25, 62 trim 53.8mm 0.64 A/R turbine housing.
Stock Boost: 7 psi
Safe Boost: > 13-15 psi After that The Turbo is past it's efficiency
Max Boost: 17 psi
HP Ratings: 240 - 250 RWHP
Type of Bearings: Journal Bearing


S13 Black-Top T25:
Compressor: T-25, 60 trim 56mm 0.60 A/R BCI-1 compressor.
Turbine: T-25, 62 trim 53.8mm 0.64 A/R turbine housing.
Stock Boost: 7 psi
Safe Boost: > 13-15 psi After that The Turbo is past it's efficiency
Max Boost: 17 psi
HP Ratings: 240 - 250 RWHP
Type of Bearings: Journal Bearing


S14 Zenki (1993-96) Black-Top T28:
Compressor: T-28, 60 trim 60 mm 0.60 A/R BCI-1 compressor in T-04B housing
Turbine: T-25, 62 trim 53.8mm 0.64 A/R turbine housing.
Stock Boost: 7 psi
Safe Boost: > 13-15 psi After that The Turbo is past it's efficiency
Max Boost: 17 psi
HP Ratings: 250 - 260 RWHP
Type of Bearings: Journal Bering


S14 Kouki (1996-98) Black-Top T28:
Compressor: T-28, 60 trim 60 mm 0.60 A/R BCI-1 compressor in T-04B housing
Turbine: T-25, 62 trim 53.8mm 0.64 A/R turbine housing.
Stock Boost: 7 psi
Safe Boost: > 13-15 psi After that The Turbo is past it's efficiency
Max Boost: 17 psi
HP Ratings: 255 - 265 RWHP
Type of Bearings: Ball Bearing


S15 Black-Top T28:
Compressor: T-28, 60 trim 60 mm 0.60 A/R BCI-1 compressor in T-04B housing
Turbine: T-25, 62 trim 53.8mm 0.64 A/R turbine housing, Inconel Turbine Wheel.
Stock Boost: 7 psi
Safe Boost: > 15 - 18 psi After that The Turbo is past it's efficiency
Max Boost: 20 psi
HP Ratings: Approx. 300 RWHP MAX
Type of Bearings: Ball Bearing

ref: http://www.240sxforums.com/forums/sr...rbo-specs.html

 

..............5 threads later

 

I had the same issue. Went with a T3 instead.

 

I'd take a look at my dyno thread before I bet on chinacharger. It appears that you may in fact sacrifice considerable HP for bargain price.

You may be able to hold out and buy a real 2871 or whatever for half price if you get a good used one.

Don't get me wrong, my car is fast. However if a "real 2871" could net me another 50-60 whp and it cost 300-400 more than my china turbo. I probably would have gone with a good used "real" 2871.

Keep in mind the 50-60hp number was pulled out of my ***, and there could be other factors with my setup that only allowed me 280hp at 19psi.

 

I HIGHLY doubt it would make 50-60 more. No way. not at same boost/afr/timing/etc. maybe 10-20. 30 tops.

 

I just wanna make 250whp and my stock sr20 won't do it. How much whp could 460's support?

 

True but for the price range and his powergoals he would probably be ok with a chinacharger. If you want I have a real 2871 for sale that you could compare with the chinacharger 2870

 

i say go for it, should give you what you are looking for. I was going to go the china turbo route, but i saved myself just short of fail and since then picked up a used garrett. i spent 300 dollars more but i feel it was worth it in the long run?

 

I think I may do this upgrade, but back to my other question. What is the max whp that 460cc injectors would support on my car?

 

china t28/t3

http://cgi.ebay.com/ebaymotors/GODSP...item255ddbba76

 

So, a relevant question would be.. are journal bearings the only reason for lower hp on a chinacharger vs ball-bearing garrett?

 

250rwhp max.