scoobydoobie Posted December 10, 2008 Share Posted December 10, 2008 Is there a difference between the STi exhaust manifold and the stock LGT manifold? If so, what are there differences? Thanks Link to comment Share on other sites More sharing options...
underpowerd Posted December 10, 2008 Share Posted December 10, 2008 same. Link to comment Share on other sites More sharing options...
addison Posted December 10, 2008 Share Posted December 10, 2008 looks. slightly different set up but as long as you dont do a wrx/sti style turbo swap they perform the same. Link to comment Share on other sites More sharing options...
praedet Posted December 10, 2008 Share Posted December 10, 2008 No differences in the exhaust manifolds... STis have a catless uppipe. 05-06 LGTs have a cat in the uppipe Link to comment Share on other sites More sharing options...
BoozeRS05 Posted December 10, 2008 Share Posted December 10, 2008 looks. slightly different set up but as long as you dont do a wrx/sti style turbo swap they perform the same. I was thinking intake manifold too.. EB's Subaru journal - 2005 LegacyGT Wagon & 2014 Forester FB25 (2008 specB - RIP) IG@legacygtliving Link to comment Share on other sites More sharing options...
scoobydoobie Posted December 11, 2008 Author Share Posted December 11, 2008 Cool, thanks for the info everyone. I figured that was the case, thought I'd check with the experts first. Link to comment Share on other sites More sharing options...
legacy95 Posted February 6, 2012 Share Posted February 6, 2012 looks. slightly different set up but as long as you dont do a wrx/sti style turbo swap they perform the same. bump an old thread How will a turbo swap hurt the performance with an sti exhuast manifold vs a lgt? If they are the same. Link to comment Share on other sites More sharing options...
thisisthenewsic Posted February 6, 2012 Share Posted February 6, 2012 the sti and lgt exhaust manifolds are the same. the sti uppipe has no cat. lgt does. "addison" was quoting about the wrong manifold. he was talking about the intake manifold being different then the sti manifold which is true. but like i said above. sti and lgt have the same exhaust manifold. just different upppipe. Link to comment Share on other sites More sharing options...
ArtiChoak Posted February 7, 2012 Share Posted February 7, 2012 I've heard the plastic manifold will actually flow slightly better due to not having welds interrupting flow. Not sure how true this is, though. Link to comment Share on other sites More sharing options...
trackhore Posted March 25, 2012 Share Posted March 25, 2012 Drivers side STi manifold has a tapped bung for some OEM sensor that the legacy does not have. The casting mark is there on the legacy manifold, but filled, or welded shut. Sorry for bumping an old thread, but I found this while searching for the purpose and thread pitch of the sti bung because I have to get it plugged. Link to comment Share on other sites More sharing options...
ama0787 Posted March 26, 2012 Share Posted March 26, 2012 Did you find out what is needed to plug it? Is it a ait sensor or possibly a map sensor (I would think we have both as back up but never checked) what sensor doe they use that we don't TIA, Anthony Link to comment Share on other sites More sharing options...
BAC5.2 Posted March 26, 2012 Share Posted March 26, 2012 Drivers side STi manifold has a tapped bung for some OEM sensor that the legacy does not have. The casting mark is there on the legacy manifold, but filled, or welded shut. Sorry for bumping an old thread, but I found this while searching for the purpose and thread pitch of the sti bung because I have to get it plugged. That must be aftermarket... That flat spot is empty on every car I've ever seen. Most people drill and tap 1/8" NPT to install an EGT gauge. [URL="http://legacygt.com/forums/showthread.php/proper-flip-key-interesti-159894.html"]Flip Key Development Thread[/URL] "Genius may have its limitations, but stupidity is not thus handicapped." - E. Hubbard Link to comment Share on other sites More sharing options...
fahr_side Posted March 26, 2012 Share Posted March 26, 2012 That must be aftermarket... That flat spot is empty on every car I've ever seen. The only USDM cars I can recall having a pre-drilled manifold were the bugeye WRX models. EGT sensor goes there. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
BAC5.2 Posted March 26, 2012 Share Posted March 26, 2012 "EGT sensor", which isn't actually a real EGT sensor, goes in the uppipe on the USDM cars. The spot on the drivers manifold is blank. http://i267.photobucket.com/albums/ii287/bac52/For%20Sale/371494944002.png http://i267.photobucket.com/albums/ii287/bac52/For%20Sale/371494944005.png 28 in fig.1 is the EGT sensor (which is an idiot sensor). 3 in fig.2 is the front 02 sensor on the pass. side. If there is a tapped hole on the drivers side manifold, it's not OEM. I'd bet dollars to donuts it's a pipe thread, and I'd be surprised if it wasn't 1/8" NPT. To solve it, just drill and tap a new hole, insert a bolt, then use a dremel and grind the inside smooth. [URL="http://legacygt.com/forums/showthread.php/proper-flip-key-interesti-159894.html"]Flip Key Development Thread[/URL] "Genius may have its limitations, but stupidity is not thus handicapped." - E. Hubbard Link to comment Share on other sites More sharing options...
fahr_side Posted March 26, 2012 Share Posted March 26, 2012 Oops, my bad. I have seen a factory EGT sensor in that location though... I just can't remember now on which model at the moment. Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs. Link to comment Share on other sites More sharing options...
BAC5.2 Posted March 26, 2012 Share Posted March 26, 2012 Oops, my bad. I have seen a factory EGT sensor in that location though... I just can't remember now on which model at the moment. It could have been on an older twin scroll with the tubular manifold. I think that's where Subaru taps for actual EGT during test analysis, since #4 is the hottest (because of that bump, actually). [URL="http://legacygt.com/forums/showthread.php/proper-flip-key-interesti-159894.html"]Flip Key Development Thread[/URL] "Genius may have its limitations, but stupidity is not thus handicapped." - E. Hubbard Link to comment Share on other sites More sharing options...
trackhore Posted March 26, 2012 Share Posted March 26, 2012 Having tapped various cast manifolds in the past for aftermarket sensors, this hole sure didn't look DIY. The threads were perfect and consistent, the flange around the outer surface was square and true. Anyway, I agree, I wasn't able to find any evidence of an OEM sensor in that location in my research, but this bung was as OEM looking as they come. Weird. FWIW, the thread size appeared to be M10x0.75. I say appeared, because my M10x1.0 thread chaser would only thread in a few turns. I didn't have anything that size at 11:00PM so I retapped to M10x1.0 and used a bolt I had in the drawer. I picked up a steel drain plug with about 9mm worth of threads that will fill the hole perfectly and won't protrude into the manifold runner. I'll try and take a picture of the manifold when I jack the car up to swap out the old bolt. Link to comment Share on other sites More sharing options...
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