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who has welded on larger flapper???

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Old 05-17-04, 01:17 AM
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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.
Old 05-17-04, 01:38 AM
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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
Old 05-17-04, 01:58 AM
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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.
Old 05-17-04, 02:01 AM
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I did this to an S5 Turbo, which took some significant machining, as the flap on the twin feeds does not sit flat.
Old 05-17-04, 02:35 AM
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Originally posted by NZConvertible
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.
would the lack of "float" cause it to leak and cause boost lag? man i really dont feel like pulling that turbo off again...
Old 05-17-04, 03:50 AM
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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?
Old 05-17-04, 07:56 AM
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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.
Old 05-17-04, 08:32 AM
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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.
Old 05-17-04, 09:11 AM
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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
Old 05-17-04, 09:13 AM
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Originally posted by calio64
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.
Old 05-17-04, 10:23 AM
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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
Old 05-17-04, 05:33 PM
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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
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