I've had about all the fun I can have with my RX6 wastegate vented to the atmosphere and now I need to get it silenced. I stopped by the local custom muffler shop and they had no idea how to best route the wastegate back to the downpipe. He thought he could weld it, but wasn't sure if the vibration/heat would crack it again. I want to get this done right the first time, so...

Could you guys please post pictures of your pipes??? I already have the pictures from here
http://www.geocities.com/valspeed/engine.html
but they didn't do anything other than a straight weld, the best I can tell. In order to prevent cracking, I've heard I need to use a "slip joint" or a "bellows type fitting," but I don't know what those are and neither did the muffler man.

Any help tremendously appreciated!!!

 

I think these pics are at bad angles to gleem any good info from for your purposes, but here is what the DP looks like from the ASPEC GT35/40 kit with wastegate returning to DP.

http://flathat.woodstream.net/RX7/GT3540/

K

 

Hrm...I just had my wastegate dump routed back into the midpipe WITHOUT a flex pipe. I guess we'll see what happens! It's out being jet hot coated so I'll post pictures when it returns.
Michel

 

here is a pic of the downpipe i made.

my first time with welding stuff and it was a bit of a pain to get everything to work right since i have no flex pipe. so far 3 months on the street of daily driving its been ok.




James
93 mb

 

You guys are great! I really needed to have all this done by this Friday, but it looks like both my welders have decided to take the same week off........

Good to see a pic of the flex joint. I'd never seen one and didn't know how to describe to them what I was needing. Picture's worth a thousand words!

If anyone has other pics, feel free to post them. The more I can hand the guy, the more likely it will be done right the FIRST time!

Thanks again

 

on a side note, i will be making a new downpipe for my car soon. changing manifolds and wastegates. does anyone know where to buy the little flex sections?

thanks,
james

 

If you haven't found it already... check out www.roadraceengineering.com. They have different sized flex sections FS there...

-Manolis

 

TailHappy:
yes a "flex-joint" is needed to help prevent cracking due to some heat expansion that occurs..it also helps in removing/installing your downpipe!

good luck!

 

will you be able to here the wastegate at all?? Mine is vented to the atmospher, and it seems that all I here is the wastegate.

 

You will not hear it at all.....It is well worth the effort and cost - my local Midas shop hooked me and a friend both up for $80 each. It isnt show quality work but it certainly gets the job done. I would have to say this is one of the favorite mods I did. The wastegate sound was fun the first time or 2 but I certainly have never missed it.

Shawn
www.3rdgenrx7.com

 

APEX'i RX6 W/ Tial 46mm wastegate - 2300 miles no prob. so far (Very quiet.) Down pipe had JetHot 2000 coating before welding. ( Changed my mind ) It was very difficult to prep the downpipe for welding with the ceramic finish. The ceramic actually penetrated deep into the pores and seeped out when welding. I can't figure out how to post the pic directly s here is the link.

https://www.rx7club.com/forum/attach...postid=1290972

 

[ img ] https://www.rx7club.com/forum/attach...postid=1290972 [/ img ] but without the spaces

 

OH YA - I don't know how long I have spent trying to figure that out.

THANKS -

 

A buddy of mine has a grand national and he doesnt have a bov just a turbonetcis wastegate, and when He lets off the throttle it goes whoo she she she!! Its the only way I know how to type it.. I have also heared a single turbo fd make the same noise with a greddy type R bov. Does anybody know if its aparticular wastegate??

 

Haha yes, that noise is compressor surge/stall. It's bad for the turbo, it makes lag between shifts worse, and you could bend a turbine blade.

 

The link in the first post was to Mark's setup. It has a slip joint to handle the expansion. SS pipe expands a lot, and the dump tube only gets hot when you are on boost, versus the downpipe which always gets hot. Since they expand somewhat independently of each other, a bellows, slip joint, or flex section helps to avoid stressing the pipes. They might crack without it, but it sounds like it works okay without such devices in some instances. I'd rather just do it once and avoid cracking anything, so some type of flexible connection seems like a good idea.

I don't see them on the web site, but I think Burns Stainless (http://www.burnsstainless.com/) has little SS bellows sections that you can weld into the dump tube. This seems like the most durable solution, but slip joints and flex sections probably work fine, too.

And holy crap, check out the Quad-turbo Mercedes 500SL on the Burns home page: http://www.burnsstainless.com/

-Max

 

I was thinking of doing this also. The venting to the atmosphere is cool but it gets a little too loud sometimes. All I have read is just make sure to route it far enough back into the downpipe so it doesn't cause backpressure on your turbo.

 

I checked out that link and that Mercedes is absolutly amazing.

 

Thanks for the new posts. As time has gone on, I've started leaning toward leaving the wastegate the way it is and maybe trying to fit a small (maybe motorcycle) muffler to it. Some people had reported some fairly large (on the order of 50-100hp) decreases from routing the wastegate back into the exhaust, and claimed that's why the setup is like it is in the first place. I've had some fun with the loudness in the meantime, but it's certainly not good if you're trying to get away with anything!

Shawnk reported having this done for $80. Any other rough estimates of how much it cost, especially once the downpipe was already on the car? I was quoted $500, with the stipulation that it could cost more if there were any complications. They said in order to do it right and get a good weld, they would have to remove everything and test-fit several times, which would ultimately make it a day-long job.

Thanks again