Dom_C

Well just finished porting my wastegate and welding on a new flapper. You guys think this is gonna be big enough?! haha It's pretty huge I'm expecting to see like 9psi or so with this I think. Now I know the welds are reaaaalllllly ugly but bare with me it's a tiny little flux core machine and it's really tough to get a bead going on such a small area. . oh well. I just started a basic welding class in school so hopefully I can look back at this weld and laugh . .haha What do you guys think I'll see for boost with this? I have a racing beat 3 inch turbo back, stock TID with cone filter. Rtek and walbro take car of fuel. I have a 3inch TID but took it off because I was getting like 14-15 psi with my smaller wastegate. Hopefully with the 3 inch i'll be able to get 10psi or so out of her. Oh the reason for the bigger wastegate is that I just switched turbo's and the one I got hadn't been ported yet so I figured I'd port the **** out of it.

Dom_C

here's a shot of the SSAC mani, seems to be holding up pretty well. Oh just to clarify, the new washer measures 35mmand fits inside the hole. . hopefully this will control boost

Carzy Driver

get you some flate plate steel and practice welding, other than that it looks good. That's my next project after it stops raining.

Dom_C

Yea, that's what we do in the welding corse at school. We cut a 1/4x3x6 inch peice of flat steel and that's what we do our tests on. I just started class last week so we havn't even struck an arc yet. Soon enough i'm sure. I'm going into maching, cnc and such for a major right now and maybe will minor in welding. Well see, but thanks for the coment

TonyD89

iTrader: (10)

Just wondering and trying to gain knowledge. But is mild steel tough enough for the heat? Seams such a thin piece of steel like a washer might disintegrate after time. Just wondering.

rx7legend

thats a ''zenki'' housing right 86-88 turbo II, im going to port mine but mine is a ''kouki'' 89-91 TII, and i don't really know what do i have to do, cansome one explain to me, i did search but didn't understand that well.

thanks

Carzy Driver

Yeah, back in high school I did that for metal shop, kept using the same piece all year, I arc weld for 3 hours straight and go through almost a 50 lb can each time. If you didn't get it by now I love to weld. I think my piece of flat stock was just about 1 1/4" thick when I graduated. Give it some more time and practice, you'll get better at it.

Carzy Driver

http://fc3spro.com/TECH/HOWTO/KWG/kwg.html

rx7legend

just a question, can i port as much as i can of the two holwa 89-91 housing or is there a limit?????

Dom_C

hahah yea that's actually my first atempt ever at welding. . and I couldn't even really get it, my buddy who actually owns the welder had to get most of it for me. By the end of the semsester I should be doing pretty good. And for all the wastegate poritng questions . .I did this with a stone grinding bit and a hand drill. . oh and a rotory file as well for cleaning it up a bit. Takes some time but it's well worth it. I actually ported my first wastegate with a milling machine. Any local machine shop should be able to help you out.
Dom

RotaryEvolution

iTrader: (30)

you will have no problem with creeping but you may see that washer disappear over a short periof of time, not because the welds won't hold up but depending on the material it is made out of. someone suggested an exhaust valve for a door flapper previously and i think that is a better alternative to the washer method. as far as size, it all is reliant on how you ported it, people still don't believe me that i can port the stock flapper to bypass enough even for a stage 2 hybrid but i can keep it at 7psi or jump it up to 15 all on the stock flapper.

Dom_C

That's crazy, i'm in no position to say that you can't but it does sound a little far fetched. I think it's possible with a dremle and alot of patients and time. You'd have to rally get it flowing smooth. Now you can do this with a open exhaust and open intake? I could see it not being a problem if you neglect one of the two, but not with both. An exhaust valve is a damn good idea, but we'll see how this works for me. . What do the people at BNR use for a flapper when they port the wastegate? Don't they port the wastegate to be pretty big as well?

NZConvertible

Shoulda used TIG like I did.




https://www.rx7club.com/2nd-generation-specific-1986-1992-17/serious-s4-wastegate-porting%85-343788/ (the pics are reposted near the end)

I did exactly the same thing and also used a mild steel washer. I had the DP off the other day and it still looks exactly like it did when I put it on 18 months ago. I wouldn't go circuit racing with it but for a street car it's fine.

You're right, I still don't believe you, or at least don't believe we're getting the full story. When I asked you what you were doing different to everyone else you couldn't or wouldn't answer me...

Dom_C

haha we don't get to use the tig till the end of the semester . .haha But that's a damn nice looking wastegate you go there. .lol I would also love to see how you can port the stocker to handle any significant flow . .

RotaryEvolution

iTrader: (30)

3" TID, 3" turboback exhaust, large streetport and S5 upper with a S4 lower intake. i ported out the wastegate as large as the stock flapper will allow diameter wise and flared it out as much as possible into the exhaust runner to smooth the flow going through the wastegate. i also ported the S4 turbine side inlet runners to more match the S5 style and increase flow characteristics.

do i care whether you believe me? i could give a **** less.

the point about the washer on the wastegate is people need to be choosy about the materials they use for the washer, especially if they still have a catalytic converter. if you have tested different materials and know of one that works and can give info on where to source those for people then do it rather than just saying "i haven't had an issue with mine". the exhaust valve method was the best one i've heard.


and as i said before, i have used the same porting method on several wastegates with similar mods and none of them have more than 1-2psi boost creep past the stock boost level. i will post up some pics later.

InMyWhiteTII

Wouldn't it be...i couldn't give a **** less? O_o

Yeah I like the exhaust valve idea, it makes much more sense. Exhaust valves are put through hell in piston engines, so it makes sense that they can stand up to hellish abuse. I can definately see that washer disintegrating over time.

KeloidJonesJr.

iTrader: (8)

The weld job looks like it was done by a soldering iron. Good stuff though. Keep us updated!

Dom_C

Just got it all back together bout to go test her out. I'll let you know what I can hit for boost.

88rxn/a

iTrader: (6)

you shouldnt creep a bit.. that is about the size of mine and im runnin 3inch TID, 3 inch cat back, 2 1/2 DP, and 3 inch tesat pipe with barely any creep if any at all!!!

TonyD89

iTrader: (10)

Exaust valves are Stainless. Even stock valves. They can take alot more heat.

Dom_C

still get pretty good creep . .lol I still hit about 10psi in second, it falls to like 7 or so. Then third I can hit 12 still, but it falls off to like 8 or so. This is alot better, I have the fuel mods to handle it so this is a good level. I'll have to get an ebc soon so I can pull a solid 10 or 11psi all the way through.

RotaryEvolution

iTrader: (30)

what kind of boost controller are you using? it sounds like that is the cause of the boost creep not the wastegate. also test the lines for the wastegate actuator, you could have a pinhole leak in one.

NZConvertible

So how is that different to everyone else's? You don't really think you're doing anything special here do you? I just want to know why you think your little wastegate port can control boost so well when others can't.

To put your results in perspective, my wastegate port is considerably bigger than yours (more than double the area) and has been extensively back-cut and smoothed, and my divided 2.5" DP improves wastegate flow compared to the standard backplate. Without a boost controller it makes 8psi. So my wastegate outflows yours and you have less backpressure from the 3" DP, yet we make the same boost. Why? You should be making more.

Somebody else reading this because they want to port their wastegate might give a ****. The experience of many others shows that following your example may lead to disappointment...

What difference does a cat make?

Well, after 18 months (~18,000 miles) the washer I used is still completely intact, so I do know of a material that works. Simple as that. I'm certainly not the first to do this and I've yet to see anyone report failure. Like I said, I wouldn't recommend it for racing, where sustained high exhaust temps are normal.

RotaryEvolution

iTrader: (30)

if the washer fails it will destroy the cat and you still offered no suggestion on a type of washer so basically you are the one who is giving little help here aside from just being an ***. i posted my experiences and i have done 3 similar ports all with acceptable boost creep below fuel cut levels on free flowing exhaust systems so maybe YOU are the one doing something wrong..


i won't even comment on this thread anymore as you can never be wrong, it's getting old.

NZConvertible

What part of mild steel did you not understand? I mentioned this several times, and described it in detail in the link I posted to my wastegate porting thread. What else do you need?

Remember, I have no boost creep, so I'm obviously not doing anything wrong. I want you to explain what everyone else is doing wrong, since your experience is not typical. If you can't answer this very simple question, why should anyone follow your advice?