S4 wastegate porting
#6
This is my social media.
iTrader: (22)
Join Date: Jan 2006
Location: WA
Posts: 2,744
Likes: 0
Received 0 Likes
on
0 Posts
Yes. The bigger... the better. When the turbo is already out and you have the opportunity to port the **** out of it, why not?
Here's some motivation:
(These images have been used for reference purposes from Aaron Cake's Homepage and BNR Supercars)
Here's some motivation:
(These images have been used for reference purposes from Aaron Cake's Homepage and BNR Supercars)
#7
Lives on the Forum
iTrader: (8)
But that only permits you to port maybe the size of your index finger.
IF you want to actually do an all-out port job to the max size allowed by the turbine housing, you'll have to weld on a larger flapper cover. Then you can make the WG about the size of your thumb, which should flow about twice as much as the first version.
Trending Topics
#8
Lives on the Forum
iTrader: (8)
Here's some pics of the last WG I ported, series 4.
Stock:
After porting:
As you can see I've gone from about 14mm in stock form to about 24mm which is pretty much the limit of the turbine housing casting itself. It's hard to tell but I've made an angled "backcut" to angle the wastegate hole in the direction of incoming exhaust air, so it only has to make maybe an 80 degree turn instead of a full 90 degree turn. That's why the port looks...uneven. I also cut a little relief into the turbine back plate and back of the flapper door to allow a little more opening angle for the gate...with the back plate installed in stock form the flapper can only open maybe 1/4 of an inch.
Stock:
After porting:
As you can see I've gone from about 14mm in stock form to about 24mm which is pretty much the limit of the turbine housing casting itself. It's hard to tell but I've made an angled "backcut" to angle the wastegate hole in the direction of incoming exhaust air, so it only has to make maybe an 80 degree turn instead of a full 90 degree turn. That's why the port looks...uneven. I also cut a little relief into the turbine back plate and back of the flapper door to allow a little more opening angle for the gate...with the back plate installed in stock form the flapper can only open maybe 1/4 of an inch.
Last edited by RotaryResurrection; 01-11-13 at 12:13 PM.
#11
rotors excite me
iTrader: (16)
Your port is looking decent so far, but don't waste your time with a washer. I've done it, other guys have done it, only to have them melt away. It may last longer if it's grade 8, but I wouldn't chance it for all the trouble it is to replace it again. Go to a local machine shop and ask if they'd give or sell you one or two old exhaust valves. They frequently have bent valves come in that can't be reused so you're likely to get them cheap or free. They're often stainless, but can be welded on with standard rod and they hold up to the abuse MUCH better.
#16
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,816
Received 2,586 Likes
on
1,837 Posts
you are right that power is going to be the same though
Thread
Thread Starter
Forum
Replies
Last Post
Shainiac
Single Turbo RX-7's
12
07-17-19 02:20 PM