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Premium Member
'91 MR2 Turbo
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19,832 Posts
Discussion Starter #1
I understand the concept of clipping the turbine fan(15 degrees) on the turbo for flowing more exhaust, but exactly what part of the blades are clipped? the ends or the side(s) of the blades ? If the side(s), which side(s). Must this be done by a machine shop or can you do it in your own garage ? I do understand this proceedure must be exact and balanced...
 

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89Supra, 92MR2
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54 Posts
Turbo clipping details-?

Can you elaborate a little on the turbo clipping (purpose and reported results)? These are designed with very high precision and the turbomachinery dynamics are pretty complex. I am not sure making changes would be beneficial.
If the application were different than the original turbo design criteria, then it would possibly get bettter results. Perhaps the pollution standards were a major design factor for mass production. If performance results were better I would think the OEM would have saved money (i.e. tighter clearance requirements) by making the blades shorter originally.
 

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Premium Member
'91 MR2 Turbo
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19,832 Posts
Discussion Starter #6
I had read this in the MR2 Primer and was curious. And was thinking of it as an option. But wanted more info.


There are very few options (at least in the USA) for changing the turbine housing or wheel. The single entry CT-26 turbine is easily available, but it does not bolt to the stock MR2 turbo elbow, so serious modifications are required to use it. The most widely available alternative is to clip the turbine wheel. Clipping the wheel does reduce its ability to extract energy from the exhaust, but since there is so much exhaust at the higher RPMs where the stock turbine wheel chokes the engine, clipping is a reasonable choice. Dyno runs with a 12 degree clip have shown ~15 rwhp improvements in peak horsepower and moved the choke point from around 5.5K to 6K RPMs. There is a slight increase in turbo lag, but this can be kept to a minimum if the compressor wheel is kept to a modest size (since there is really no need to go with a large compressor wheel as we determined in the 3S-GTE turbo sizing primer).
 

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jdm 2nd gen ftw!
mr2 turbo
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265 Posts
i had my ct-26 clipped after i got it rebuilt with a 50 trim upgrade seems to run very nice, car spools at 3k rpm usually depending on weather never felt the upgrade without the clipping inside it so i dont know how much i got out of it :( but it did not cost that much since i was getting in rebuilt anyway, they told me it will help with low end spool up and high end output, i dont want to imagine it without it) does anyone have there ct-26 like this without the clipping?
 
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