Getting my car back together; the last real hurdle is porting the wastegate. With regards to the side in which the flapper opens into, is this adequate? It seems to let the door open a slight bit more, but this is my first wastegate porting and I don't want to tear into it again Please excuse my dremel work, I am a novice... (note the OH $#&% mark on the gasket mating surface... )




Another Angle




Other Side, which was performed by a machine shop btw

 

Have you checked this thread out?

https://www.rx7club.com/3rd-generati...tegate-426526/

 

Yes, however in another thread on wastegate porting (https://www.rx7club.com/3rd-generati...ations-726267/) it shows removing material on the center housing side. Clearly I have not removed nearly as much as he but I do not know if his was excessive (3" turbo back and RB exhaust with mine, stock boost levels; his goals may be different)

I guess I'm wondering if people got away with just porting the wastegate and doing little to nothing to where the flapper contacts the housing.

 

I remember the key area being where the flapper seats. That is the only thing I enlarged to get 15psi dead nuts with no creep. 3" to 3.75 cat back. I did not waste my time with the rest of the casting, just made the seat as large as possible with out the flapper falling through.

 

He's right.....difference on mine between where the flapper shut and casting left was a little less than 1/2 a mm. Don't go crazy, you still what the flapper to seal off....

 

Thanks for the replies,

The overlap for the flapper to housing is likely 0.75 +/- 0.25 mm, as far as I can tell.

Machine shop worked by the roughly same instructions: measured diameter of flapper door, located center of flapper door when in closed position, then went to town. There is the smallest hint of light coming through the port nearby the hinge, but not enough to worry me.

 

Looks good from the pics. I like to use either paint or machinist die and apply it with the wastegate closed. Then port just short of the edge of the die. You don't want to go too big or it may leak boost when closed.

 

On a side note there appears to be a crack in the port of the wastegate, is this normal with these turbos? I bought another set for my car cause of the crack I found when I ported mine, which was cracked as well........

 

My previous turbo housing had a crack in the exact same spot, near the hinge going toward the turbine. Must be a thermal fatigue zone or a weakness inherent to the casting process (improper use of risers, etc); I'm not a casting engineer (it's almost an art) so I can't accurately speculate.

 

The twins all crack over time. They retain too much heat. The crack shown in the picture above isn't significant enough to cause any issues.