who has welded on larger flapper???
 

i have an s4 to begin with, and real soon im going to port my wastegate, which means im goin to need to make my wastegate flapper bigger. So i got a honda intake valve thats pretty big, little bigger than the diameter of my tumb, now who has gotten one of these(or any other substitute) welded on there? Is there anything i should know? Im going to have a mazda shop guy do it for me but he needs to know as much info on it as possible. He said something about a floating wastegate door for the s4?
The honda valve is suggested i guess, i did a search. Basically you chop off the stem and you get a lilttle circle hunk of metal.

my wastegate is ported like crazy.. i can fit my thumb down in there and wiggle it around.

about the floating thing... the guy i got the turbo from sait it was supposed to wobble around... but when we got the door welded onto the flapper i just made it lay flat and welded it on. Now i seem to have more lag than i should. wonder if this is related. hmmmmmmm

Take the turbo to a turbo shop and ask them to replace the flap with a bigger one. They'll replace the flap, arm and shaft as a unit, so the flap will still float as it should. It's pretty cheap.

I did this to an S5 Turbo, which took some significant machining, as the flap on the twin feeds does not sit flat.

would the lack of "float" cause it to leak and cause boost lag? man i really dont feel like pulling that turbo off again...

As long as the flap sat perfectly flat against the housing when it was welded, it should seal fine. I guess it's possible the welding heat warped the flap a bit. Any wastegate leak will slow boost response. Were any other mods performed on the turbo at the same time?

for a s4 i ported my wastegate as big as i could. i measured how big i could go and it was only 27mm, so i ported to 26mm and get a 27mm flapper welded on. my boost went form 14psi to 6psi. no more creep at all.

I am about to have this done also. I got a bank loan to get my car stable and on the road as I needed two new rear tires and clutch work. The tires and clutch only came to about 350 bucks, so I have 650 to spend on some stuff. I need to get a walboro, get the wastegate ported, and possibly a Rtek7 chip or safcII. Is this a job for a garage or a professional welder? Will 27mm completely destroy my top end boost? I want to stick to 9-10psi not 6. Any comments from anyone who has done this would be appreciated.

im getting ready to port my wastegate today, so if i port the wastegate then i cant boost to 13 psi?

thanx in advance for any info

You can boost to whatever you want if you have a boost controller. The increased wastegate flow prevents the boost from creeping over the set level that the wastegate spring accuates at.

I ported my stock S4 wastegate pretty big and had a stainless steel washer welded onto the face of the stock flapper. It still "wobbles" like it's supposed to, if it didn't then it wouldn't seal right.
http://68.201.92.155/fc/wastegate.html

wow great! i think ill go with the stainless steel washer idea, seems to be a good way to go, thanks for the input. More is always welcome :)