[Supras] 57 trim CT26 alteration

[berniek at technicaldevelop.com]

 From what I understand, the customary way to allow more exhaust flow 
through a CT26 is to clip the turbine wheel.  I discussed this with 
Performance Techniques when I had one modified for 57 trim.  To cut to 
the chase, I decided on boring out the wastegate passage instead, as the 
cross sectional area can almost be doubled while still leaving at least 
.080" at the circumference for sealing by the disk.  The area is still 
far less than the area of the diaphragm in the actuator, so cracking 
open early from disk force did not appear as if it would be a problem.


Waste gate passage boring is one aspect of the modifications I forgot to 
mention in previous postings about mods.  The 15-17 PSI boost comes on 
explosively at 3000 RPM and it pulls strongly to redline with stock cams 
and a cleaned up head (valve bowls and intake passages cleaned up with a 
die grinder and carbine burr) with the other mods.  Caught it once at 
6500 RPM at the top of second gear, it was so quick.  Maybe the former 
owner installed an earlier ECU (from before full crankshaft 
counterweighting), also indicated by idle speedup when turning lights on 
(90-up does not have the circuit board parts stuffed for that 
function).  Just curious if anyone else has done waste gate boring.


    Bernie