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What's a flex joint
Posted: Tue May 18, 2004 4:09 am
by georryan
And is it a good idea to use one with a larger exhaust? What is it sappose to do?
Posted: Tue May 18, 2004 4:22 am
by aspect
It's a section of pipe that is made of metal fibers instead of solid metal, so it can bend a bit and still hold exhaust. Looks like a really big braided hose.
For subaru engines it isn't really neccesary because what little engine vibration there is exerts force to the left and right, instead of forward and backward like most inline engines.
If a boxer engine really torques to the side, the exhaust will just twist on its hangers a bit, which isn't a big deal. If an inline engine that has the manifold mounted to the front really torques, it will apply a lot of force to the 90-degree bend at the bottom of the manifold.
If a powerful inline 4 like a dsm were to have a solid pipe, you can imagine the up and down vibration on the muffler due to all the leverage the engine has.
edit: DSM downpipe w/ flex

Posted: Tue May 18, 2004 4:32 am
by georryan
ah, thanks. I'm not totally sure how rsstiboy thought that would fix my problem of my exhaust banging around, though.
Posted: Tue May 18, 2004 8:43 am
by aspect
No clue...
Posted: Tue May 18, 2004 3:38 pm
by legacy92ej22t
Shouldn't this be in the exhaust forum?
Flex joints are still a good idea on pre-turbo exhaust components. IIRC the stock crosspipe has one. I think a flex joint is good in the cross-pipe and up-pipe, like our CES systems georryan.

Posted: Tue May 18, 2004 3:51 pm
by georryan
Yeah it should, I thought it was something else related to the car's frame though. Doh!
Yeah I'm trying to figure out how soon I can put those things on! I went to Home depot to find a bolt that I could fill that hole with were the egt goes, but couldn't find one that fit right. So I'll have to try an autoparts store or a different hardware store, or just go buy an egt.
Anyways, to stay on subject, if any admins want to move this that is way cool by me.
Posted: Tue May 18, 2004 4:22 pm
by vrg3
The EGT probe thread is most likely a pipe thread... Hopefully it's 1/8" or 1/4" NPT. At the hardware store or Home Depot go to the section with all the little brass fittings and hopefully you can find something made of steel with the right pipe threads on it. I wouldn't use brass in the exhaust.
Posted: Tue May 18, 2004 5:17 pm
by georryan
Thanks!
Posted: Wed May 19, 2004 2:59 am
by georryan
Well I think it is 1/8" but they didn't have anything in that size. 1/4" was too big.
Another question about the flex joint. It is sapposed to help flex, but its the back end of my dp that is hitting my frame, so it won't help with that. I guess I could see how it could be nice if you have lots of power, but won't the hanger bushings themselves just give you the room you need?
Posted: Wed May 19, 2004 3:28 am
by vrg3
Did you go to Home Depot? Maybe try an actual hardware store instead... Or just go ahead and buy an EGT probe since you're gonna have to at some point anyway. One of the most affordable is the Westach probe that Aircraft Spruce sells:
http://www.aircraftspruce.com/catalog/i ... enders.php
Posted: Wed May 19, 2004 3:49 am
by georryan
I didn't know it would be that cheap. I did go to home depot. I was surprised they didn't have anything that small either.
If I buy an autometer egt I think they come with a probe, so buying one may not be the most cost affective choice. What type of probe do you guys suggest.
(I can't believe I'm jacking my own thread.)
Posted: Wed May 19, 2004 4:02 am
by vrg3
Hehehee....
The Westach gauge is actually the most affordable gauge out there, too, so it still might make sense to get the Westach gauge and probe together.
You also might consider Team Rip's EGT probe:
http://www.teamrip.com/accessories.html
It's shorter-lived than most, but it has very good response.
Posted: Wed May 19, 2004 4:03 am
by BAC5.2
Unshielded will give the best results. Shielded will give slightly lagged temps, but it'll be cheaper and last longer.
Posted: Wed May 19, 2004 4:04 am
by legacy92ej22t
Ya, I got an Autometer Phantom series EGT that came with a probe. It seems pretty sweet. I can't wait to get it in.
I think it's 1/8" too. I've been meaning to make sure but I have the EGT in MD and the up-pipe in PA.
