IwannaSportSedan Posted May 13, 2007 Share Posted May 13, 2007 red krinkle-kote from the auto-parts store, FTW Just remember to either sand it, or use plastic bonding primer, plastic adhesion promoter, or something. Link to comment Share on other sites More sharing options...
kiyanichenko Posted May 13, 2007 Author Share Posted May 13, 2007 so i cant just paint it red with normal paint? Link to comment Share on other sites More sharing options...
wukindada Posted May 13, 2007 Share Posted May 13, 2007 Our plastic manifolds have been tested @ 30psi & have had no issues;) Toyota 6EATS .........SUCK!!!!!! Link to comment Share on other sites More sharing options...
kiyanichenko Posted May 13, 2007 Author Share Posted May 13, 2007 i don't think anyone is going to be boosting their gt to 30 psi anytime soon. Link to comment Share on other sites More sharing options...
mikeyan Posted May 13, 2007 Share Posted May 13, 2007 oh, i wouldn't be so sure... we've got someone down in the retirement state with some tricks up his sleeve, as gathered from other threads. I don't believe 30PSI will be out of the realm. I do know of several LGTs running 24+ of boost with the (gasp) plastic manifolds. I do 22-23 with no issues. Mike SoCal Duck Hunters Club - Unit 52 Link to comment Share on other sites More sharing options...
john_knoxville Posted May 13, 2007 Share Posted May 13, 2007 I highly doubt that a well made thermoplastic intake manifold is the weak link when upping boost pressure. Our plastic manifolds have been tested @ 30psi & have had no issues;) fair enough. here is what i meant to post: We talked to some of the top Subaru and Legacy 2.5 GT tuners like Crawford Performance, Cobb Tuning, Easy Street and Squid Auto (formerly Kingpin) to get their take. Here's what we found: The Legacy's EJ25 uses the same block and similar heads as found on STIs and '06 WRXs. The main difference is the intake manifold and associated plumbing. In order to reduce manufacturing costs, the Legacy motor uses an ABS plastic intake manifold and end-tanks on its top mount intercooler. This is good for weight reduction and lowering intake temperature, but comes at a cost for high-boost turbo cars. Unlike conventional aluminum intake manifolds and runners, plastic manifolds typically use a recessed rubber O-ring to seal against the cylinder head instead of a flat gasket. Under stock boost, this is fine, but for anyone who wants to upgrade turbos or just increase the stock boost levels past 17psi, the O-rings just might do a Challenger. The plastic intercooler end-tanks will have similar issues with high boost or prolonged beatings at stock boost. While bolting up an aluminum STI manifold to the heads in order to hold more boost is a relatively easy task, getting the rest of the Legacy fuel, vacuum and boost plumbing to fit is not. Changing manifolds requires almost a complete engine bay fuel system swap since OE-quality fuel lines and connectors are near impossible to modify. That means the intercooler and throttle body will have to get changed out too. http://www.sportcompactcarweb.com/features/0706_sccp_2008_subaru_wrx/future_sti_plans.html Link to comment Share on other sites More sharing options...
mikeyan Posted May 13, 2007 Share Posted May 13, 2007 ummmm...having seen my manifold pulled off as well as tgvs, we have gaskets for both junctions between intake manifold and tgv and tgv to engine block. no problems and i think sport compact did as much research as they could have. crawfords own lgt with a twinscroll turbo has the stock intake manifold. Mike SoCal Duck Hunters Club - Unit 52 Link to comment Share on other sites More sharing options...
kiyanichenko Posted May 13, 2007 Author Share Posted May 13, 2007 i highly doubt anything will happen to the rubber seal if you boost it past 17 psi. Link to comment Share on other sites More sharing options...
kiyanichenko Posted May 13, 2007 Author Share Posted May 13, 2007 whats the stock psi for a lgt? Link to comment Share on other sites More sharing options...
mikeyan Posted May 13, 2007 Share Posted May 13, 2007 was it 13.5ish? or less? Mike SoCal Duck Hunters Club - Unit 52 Link to comment Share on other sites More sharing options...
mccorry Posted May 13, 2007 Share Posted May 13, 2007 13.5 psi is stock. At around 17-18 psi... you'll blow your TMIC side tanks off (the metal tabs fail). The manifold is plenty strong. Link to comment Share on other sites More sharing options...
kiyanichenko Posted May 13, 2007 Author Share Posted May 13, 2007 13.5 psi is stock. At around 17-18 psi... you'll blow your TMIC side tanks off (the metal tabs fail). The manifold is plenty strong. so will a perrin tmic do the trick? Link to comment Share on other sites More sharing options...
mccorry Posted May 13, 2007 Share Posted May 13, 2007 Yep... that's what I'm running. Either a Perrin or AVO all metal (welded) TMIC is what you'll need. Link to comment Share on other sites More sharing options...
IwannaSportSedan Posted May 14, 2007 Share Posted May 14, 2007 so i cant just paint it red with normal paint? I would use high-heat capable paint, and a plastic-compatible primer. Or a high heat paint that bonds with plastics chemically. Sanding the plastic may be necessary, to give the paint a non-glossy surface to cling to. You want something that sticks well, and that withstands the heat under the hood. The red crinkle-coat stuff would probably approximate the color and texture of the STI's red aluminum manifold as closely as possible, if that is the direction you are wanting to go. Link to comment Share on other sites More sharing options...
red beast Posted May 16, 2007 Share Posted May 16, 2007 to keep the engineer in a job Link to comment Share on other sites More sharing options...
kiyanichenko Posted May 16, 2007 Author Share Posted May 16, 2007 can i replace the O-rings with something stronger? Link to comment Share on other sites More sharing options...
morrisok Posted May 17, 2007 Share Posted May 17, 2007 why did Subaru start making plastic intake manifold on the legacy and 08 wrx's? Kiyanichenko, I wondered the same thing after I noticed that my wifes 07 Impreza has a metal manifold. I asked the tuner when I was getting dynoed and he said that BMW and MB has been using plastic in their manifolds on the full range of US models for 3-4 years. Morrisok Link to comment Share on other sites More sharing options...
kiyanichenko Posted May 17, 2007 Author Share Posted May 17, 2007 Kiyanichenko, I wondered the same thing after I noticed that my wifes 07 Impreza has a metal manifold. I asked the tuner when I was getting dynoed and he said that BMW and MB has been using plastic in their manifolds on the full range of US models for 3-4 years. Morrisok ya but you see, they are not turbo charged and know one is planning on dropping a turbo into them. Link to comment Share on other sites More sharing options...
kiyanichenko Posted May 17, 2007 Author Share Posted May 17, 2007 can i replace the o-rings with gaskets? Link to comment Share on other sites More sharing options...
morrisok Posted May 17, 2007 Share Posted May 17, 2007 ya but you see, they are not turbo charged and know one is planning on dropping a turbo into them. Yes while most of the models of BMW and MB in the US are not turbo charged there is the BMW 335 (turbo petro) and MB E320 Blutec (turbo diesel) which are both turbo and many of the models of both BMW and MB outside of the US also have a turbo diesel or petro choice. Morrisok Link to comment Share on other sites More sharing options...
RobY Posted May 17, 2007 Share Posted May 17, 2007 to keep the engineer in a job They should have moved said engineer to the exterior styling department... Link to comment Share on other sites More sharing options...
mikeyan Posted May 18, 2007 Share Posted May 18, 2007 can i replace the O-rings with something stronger? it is already a gasket... if you want, i'll take pictures of the ones i have sitting here... Harman Motive reused my stock gaskets 23lbs of boost. Mike SoCal Duck Hunters Club - Unit 52 Link to comment Share on other sites More sharing options...
kiyanichenko Posted May 18, 2007 Author Share Posted May 18, 2007 damn Link to comment Share on other sites More sharing options...
mikeyan Posted May 18, 2007 Share Posted May 18, 2007 http://www.legacygt.com/forums/showthread.php?t=61976 Stock "plastic" manifold, who knows what kind of godly amount of boost... seems fine. The plastic manifold not holding up to boost is not necessarily a problem as reported by Sport Compact... There are plenty of us here running lots and lots of boost with the stock lgt plastic manifold. Mike SoCal Duck Hunters Club - Unit 52 Link to comment Share on other sites More sharing options...
robust Posted May 25, 2007 Share Posted May 25, 2007 generally engineers would design these things to contain a 'proof' and 'burst' pressure. each of those is determined by either a max normal operating pressure or a failure pressure and then a factor is used to determine a requirement for pressure containment. at proof, no yielding or damage can occur but at burst some yielding/leakage can occur as long as it's not a sudden release of pressure. for commercial aerospace, the federal aviation regulation specifies the factors. for automotive, im not sure it's regulated but im sure they use a similar approach. even still, automotive generally dont optimize until they have tiny margins on the requirements as weight isnt as big of an issue, especially in a passenger car. so you can assume this thing will take a good bit amount more pressure than the stock levels. i was surprised when the end tanks popped off of peoples ICs at such low levels for those reasons. Link to comment Share on other sites More sharing options...
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