Porting the ct26 wastegate

1-2clutch-u

Member
Feb 18, 2006
379
0
16
chi town and ohio
I have a 7mgte with 3in exhaust and 60-1 ct26 and avcr. With the avcr off it makes 10is psi by 3k or a lil before. But by 4.5k boost creeps up to 1.2 bar (17 psi). I know this isn't a common problem with the ct26 so I am going to port the wastgate. Wondering if anybody has done this or has had luck with this problem. I dont want to go external wg. Thank you
 

mecevans

Supramania Contributor
Jan 18, 2009
1,295
0
0
M-bay, cali
I did it. Scribed the flapper door then made a second a few mm in. Got a carbide bit and went to town. I get no creep or spikes. Holds steady all the way to redline.
 

Bmettie

Member
Apr 27, 2010
188
0
16
Florida
^ just a hair smaller than the flapper. Scribe the outline of the flapper, then remove the WG actuator, open flap and grind out a circle just smaller then the scribe line. Also clean up the walls inside the turbine housing leading to the WG hole. I have the same setup as you and the same problem with a 60-1 CT, even at stock boost it would still creep up to FC at WOT. After the mod I've had no problems what so ever.