auxilary Posted March 4, 2005 Share Posted March 4, 2005 ok, so I have a dillema: I am fabbing up a downpipe for my Z, and the problem is that since the turbo's ont he wrong side, I have minimal spacing for my external wastegate. It's a tial 44mm unit, so it's not exactly small... The easiest way to do it is to run it from the wastegate runners (i'll have to cut a portion off to angle it the other way and weld on a vband included with the wg) and dump it straight into the downpipe, because of small clearance. Here you can see the wastegate runner (the part that's pointing towards the bottom of the screen will be cut and rerouted to be straight), no downpipe mockup downpipe mockup, no wastegate. you can see that I have very little clearance Here's the world's dirtiest ms paint diagram of how it's supposed to run. So my question is.... Can I just have everything welded straight up, or do I need to put some sort of a tiny flex pipe where the 3" mark is for the wastegate dump pipe into the downpipe? Will there be significant heat expansion to cause cracks and make something break down the road, or can everything be solid stainless steel? (304) Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted March 4, 2005 Share Posted March 4, 2005 If you weld everything up solid, after a couple heat cycles, everything will be out of alignment and you won't be able to get your vbands to line up if you take the WG off. Ask me how I know. The thermal stress will eventually crack the weakest point. I have a similar WG dump length on my L-series, I ended up making a double-overlap slip joint and it works well. The outlet on the WG has two concentric pipe sections, welded together at the WG flange. The downpipe has a single pipe welded to it, that is sized to slip between the two pipes on the WG flange. It was easy to make, all you need is access to a pipe-stretcher at the exhaust shop. There is enough clearance to allow some expansion, but it doesn't seem to leak at all. A short section of SS flex section will also work, kind of pricey and hard to find though. Or, you could just run a screamer pipe. Not my idea of cool though. Good luck Doug Quote Link to comment Share on other sites More sharing options...
Drax240z Posted March 4, 2005 Share Posted March 4, 2005 Yup follow Doug's advice there. 304 has a very high coefficient of thermal expansion, so you certainly will need something! I'd go for the SS flex section myself. Quote Link to comment Share on other sites More sharing options...
auxilary Posted March 4, 2005 Author Share Posted March 4, 2005 my concern is that there's very little room to fit anything flexible in the space... it's 2-3" between the wg and downpipe at most.. who'd carry a flexpipe that small anyway? Quote Link to comment Share on other sites More sharing options...
Tim240z Posted March 4, 2005 Share Posted March 4, 2005 How about a slip joint? Maybe a 2" piece on the downpipe and a 2" piece off the WG, with one side sliding inside the other. It may leak a bit when cold, but I doubt that would too big a problem, since I doubt you will boost it much when cold.... Maybe some of the smarter guys can chime in....seems logical though, no? Quote Link to comment Share on other sites More sharing options...
auxilary Posted March 4, 2005 Author Share Posted March 4, 2005 slipjoint sounds like an easy cost effective idea... i just don't want to dump excess gas to the atmosphere, because it's very loud, and will attract more attention than i want Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted March 5, 2005 Share Posted March 5, 2005 A single slip joint will work fine, but if you want no leakage, a double would be better. Especially if the joint is only going to be overlapped about an inch. http://www.burnsstainless.com/MergeCollectors/TurboCollectors/turbocollectors.html Have a look at how Burns does their slipjoints. That is what I did for my downpipe and it works well. I have about an inch of overlap in the slipjoint. The double pipe should be the inlet side, IE for your case, the outlet pipe from the WG. Doug Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 20, 2006 Share Posted April 20, 2006 Whats a good source for slipjoints? Quote Link to comment Share on other sites More sharing options...
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