mobythevan Posted March 22, 2005 Share Posted March 22, 2005 Any ideas how this would work on the L28ET, how this clipping may affect spool? The clip is 10 degrees from original blade position. I know everyone will say just get a stage 3 turbine, but I am curious anyway. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted March 22, 2005 Share Posted March 22, 2005 It can't be that bad since Garrett cuts their turbine wheel 9 degrees I think on some turbos. Quote Link to comment Share on other sites More sharing options...
Clifton Posted March 22, 2005 Share Posted March 22, 2005 From Garrett's web site. Clipped Turbine Wheels When an angle is machined on the turbine wheel exducer (outlet side), the wheel is said to be ‘clipped’. Clipping causes a minor increase in the wheel’s flow capability, however, it dramatically lowers the turbo efficiency. This reduction causes the turbo to come up on boost at a later engine speed (increased turbo lag). High performance applications should never use a clipped turbine wheel. All Garrett GT turbos use modern unclipped turbine wheels. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted March 23, 2005 Author Share Posted March 23, 2005 Yeah, I saw that in some of their info. Hmmm.... Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted March 25, 2005 Share Posted March 25, 2005 I have a clipped turbine wheel. No issues with spoolup or anything like that. Maybe I just don't know what I'm missing????? Quote Link to comment Share on other sites More sharing options...
yo2001 Posted March 25, 2005 Share Posted March 25, 2005 Garrett will say just about anything to sell their GT series. They need the money . I'm actually running clipped wheel now but I've not really notices any downside to it. Quote Link to comment Share on other sites More sharing options...
Clifton Posted March 25, 2005 Share Posted March 25, 2005 Clipping a wheel reduces it's effiency and creates lag. Doesn't take an ingenier to figure it out. You still have a 1.9" exducer. If you compared the lag to a stage 3 wheel with about a 2.25" exducer the lag will be similar but now it will flow a little more as the bore is larger. If clipping was all of that there would be 600 rwhp 2JZ Supras running small clipped wheels instead of P and Q trim wheels. Anyone with an N/A motor knows increasing the pipe diameter helps HP and adding a cam with more duration gives more top end with a little sacrifice in bottom end. It's similar to that. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted March 25, 2005 Share Posted March 25, 2005 But clipping the wheel will open up the close end of the turbine wheel which also increase the airflow. Unlike the redesigned stage V, stage 3 or standard T3 turbine wheel, the design is same, it's got real closed profiles. by open it up it would hurt much. IMO. Less back pressure. I would choose stage III or larger wheel on a 2.8L I-6 though. The stage I isn't going to be enough flow even clipped. The lag isn't much, IMO overrated. Mostly what you feel is the slower transition from a larger heavier wheel. All comes down to the combination though. Larger compressor, larger turbine. Clipping is things in the past I guess since you do have more option than just simple stage I and stage III wheels. My turbo now, I ran Clipped 11 degree what they called GEN3 Ptrim with 50 trim T04E. from comparing to stage III/50trim, the spool is about same may be slower by 100rpm. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted March 25, 2005 Author Share Posted March 25, 2005 Like I said in the other thread I went ahead and got the turbo with the clipped turbine, so I'll just see how it works. Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted March 27, 2005 Share Posted March 27, 2005 In '94 whenI had to replace my turbo, Turbonetics set me up with a To4B S3 Trim Compressor section, a watercooled center and clipped stock turbine. I have noticed no difference in WHEN it starts to build boost, but it does build faster and harder, with more power on top. When I go UMS and bigger injectors, I will get a To4E/T3 Stage 3 or 5 exhaust, since I will be putting in an external wastegate and 3" downpipe. I don't want to choke off the upper end. Quote Link to comment Share on other sites More sharing options...
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