Turbo sizing question

Chello

New Member
Jun 8, 2011
104
0
0
Victoria, Australia
Hi people, I bought a t4 with these specs, can annyone break it down for me as I don't know how to read compressor maps. One reputable workshop said basically a hi-flow of a standard ct-26.

.70 cold side housing
51.99mm ind on cold side
81.74mm exd on cold side
.68 rear housing
73.42mm ind hot side
57.97mm exd hot side

Just looking to see what it's the equivelent of? i.e 57 trim etc.

Anyone used one around this size on their 7m?

What sort of rpm do you guys think it come on boost at?

I had a search, nothing that I could find I may have been searching the wrong thing.
 

arknotts

formerly ark86
Jan 9, 2008
461
1
0
Ohio
Wheel trim is calculated like so (referenced from Garrett):

trim = (inducer^2/exducer^2)*100 for the compressor
trim = (exducer^2/inducer^2)*100 for the turbine

This means your compressor trim is (51.99^2/81.74^2)*100 = 40
Your turbine trim is (57.97^2/73.42^2)*100 = 62

According to MDC, a stock CT26 is:

Compressor 1.70"/2.550", 5 blades
Turbine 2.650"/2.045", 10 blades

Therefore stock compressor trim is (1.7^2/2.55^2)*100 = 44
Stock turbine trim is (2.045^2/2.650^2)*100 = 60

If my math is right, it seems about equivalent to a OEM CT-26 to me, if not flowing less because of the lower compressor trim.
 

arknotts

formerly ark86
Jan 9, 2008
461
1
0
Ohio
laotionracer101;1759998 said:
Lol @ the math and then the words Referenced,According,Therefore,Equivalent. :icon_cool

no mockery just funnies.

LOL, yeah graduate school will do that to you. I did that (technical writing) for so many years, it's hard for me not to write that way when it comes to some things :p.

Chello;1760011 said:
Wow, ok. The front housing is physically bigger to the eye and rear housing is slightly bigger

Sounds like the housings have a different A/R than OEM. Do you have a CT-26 you can compare it to? You could always take the compressor housing off and compare the wheel sizes yourself to make sure.
 

Chello

New Member
Jun 8, 2011
104
0
0
Victoria, Australia
Yeah I had the ct-26 sitting next to it, the rear's look around the same size the t4 was a little larger but the front's were a fair bit different, there is another on ebay exactly same specs, am I allowed to post it here? But that one says it's 650hp, but it is on ebay that's why I thought I would ask here.
I'm picking the turbo up soon it's and a friends place I will try and get a few happy snaps for comparison
 

IJ.

Grumpy Old Man
Mar 30, 2005
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I come from a land down under
Chello;1760202 said:
Yeah I had the ct-26 sitting next to it, the rear's look around the same size the t4 was a little larger but the front's were a fair bit different, there is another on ebay exactly same specs, am I allowed to post it here? But that one says it's 650hp, but it is on ebay that's why I thought I would ask here.
I'm picking the turbo up soon it's and a friends place I will try and get a few happy snaps for comparison

Of course ;)