Weird ct26 question upgraded ct or stock wheel?

marcmann982

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Alright i checking out a forum post on "thesupraforums" and saw this can anbody help us figure this out??


I made a strange discovery yesterday while pulling two spare ct-26 turbos out to look at them...

1st difference:
The stamping inside the housing. 1st turbo has the number "2" stamped in it, the second turbo has the number "4". (From here on out, the number 2 turbo is always on the left.)
"What are the difference in housing other than the housing to w/g nipple?"[/I
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2nd difference:
The nipple that leaves the housing and goes to the wg is in two different places, albeit, very close to each other. (I placed a small bolt where the nipple would normally be found in the first pic below.)
"I wonder, which one is better if there's a difference?"
(See pics below)

3rd difference (and most notable):
The intake (compressor) wheels are completely different. One is the 5fin design (with large gaps between 1st and secondary fins) and the other is an 8fin design with very little space between 1st and secondary fins.
"Of course this last difference really needs digging into."

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There are a few other minute differences. For example, there is a slight difference in size between the oil inlets and outlets, slight variations in w/g arm design, different wheel fastening nuts, and very small cosmetic difference on the exhaust housings. I have pics of these, as well, if need be.

Now, I know there are actually quite a few ct-26 housings and wheels. But both of these supposedly came off 100% stock 7m's. One an 89 and one a 90 that I owned. I'm not sure anymore which one came from which. Though, I think the 5fin (with the "2" stamp) is from my early '89. Are both these turbos truly stock? Is one a rebuilt ct-26 hybrids, different versions, what? I don't know. Maybe one of them has the ceramic wheels? I don't know yet. I've tried digging for info like crazy and have come up empty-handed. There doesn't appear to be any porting and the compressor wheels both appear to be the same diameter or at least the viewable portion.

And info would be great!
 

mkiiichip

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Just produced in different years. There are slight differences, as you have noticed. But when it comes down to it, they're the same (mechanically).
 

MDCmotorsports

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marcmann982;1694411 said:
And info would be great!

See below.

Nick M;1694464 said:
Both are factory stock.

Negative. The 8 fin comp wheel is from a small t04b garrett. Its almost nearly identical as the ct wheel, but has thicker fins due to its commercial diesel design. This would be an "upgrade" so to speak from the stock ct comp wheel.

mkiiichip;1694477 said:
Just produced in different years. There are slight differences, as you have noticed. But when it comes down to it, they're the same (mechanically).

#1, you're correct. The numbers are nothing more than the casting marks for the years they made the CT26. #2 comment, see above about the comp wheel.

Poodles;1694516 said:
Haven't seen that 8 fin compressor wheel before to be honest, but the rest is normal.

See above. You're correct sir... with your little eye you spy....
 

mkiiichip

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MDCmotorsports;1694537 said:
This would be an "upgrade" so to speak from the stock ct comp wheel.

Thanks for the clarification, but are you referring to an upgrade in strength, or flow?
 

MDCmotorsports

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mkiiichip;1694640 said:
Thanks for the clarification, but are you referring to an upgrade in strength, or flow?
More for strength but in terms of flow....there are no known compressor maps for a stock ct26 released from hitachi.
That said, we do have the compressor maps the the little to4b wheel.
Further, from a rebuilder point of view, have you ever tried to find a good used or new ct26 comp wheel?