Blameless Posted June 16, 2012 Share Posted June 16, 2012 Anyone out there done this? Hey guys, Iv got after market stainless headers on my race car but I am thinking about match porting the headers on my LGT. I recently single turbo'd my mates old twin turb legacy and the ports were badly miss matched which got me wondering if the newer turbo castings were any better or not... I have read a bit of stuff on Nasioc about people doing this to their cars and claiming pretty good results but wanted to hear if anyone here has done it on their LGT? Grim speed sell ported stock manifolds but don't say anything scientific or measured about any power increases. I was also surprised at how many people were porting them out to the exact size of the gasket!? This won't help the life of the gasket surely! Anyway at this stage I am keen to hear from anyone else that has done this to their leggy's and there reflections on potential issues, cracking thin walled casts, gasket life if ported to gasket size ect... Thanks PS if there is no one here that has done a write up I'll do one for mine as I go along. (If I am convicted this is going to be a improvement and net some gains) Link to comment Share on other sites More sharing options...
m sprank Posted June 16, 2012 Share Posted June 16, 2012 No real power to be made. Even a Grimmspeed set up with the larger cross tube makes minimal gains. I have seen unmodified OEM manifolds crack (just threw out a set from an 05 LGT last week, cracked between 2 and 4 all the way through). Link to comment Share on other sites More sharing options...
Pete1122 Posted June 17, 2012 Share Posted June 17, 2012 There may not be a ton of power to be had but the biggest reason to have them ported with the x-pipe is faster spool. I bought a set from Grimspeed for my WRX and was impressed with the quick spool up time. Link to comment Share on other sites More sharing options...
Blameless Posted June 17, 2012 Author Share Posted June 17, 2012 Hmmmm thanks guys... Simply match porting them will surely net some flow gains even if small. Has anyone else got some feedback? Also keen to hear if anyone has ported their exhaust side on their heads to suit the manifold gaskets? Link to comment Share on other sites More sharing options...
bnguyenbb6 Posted June 17, 2012 Share Posted June 17, 2012 http://forums.nasioc.com/forums/showthread.php?t=2271466 Read post #15 from Maxwell Power. Just food for thought. Link to comment Share on other sites More sharing options...
m sprank Posted June 17, 2012 Share Posted June 17, 2012 I tend to agree with MP. The results we have seen tuning back this up. Link to comment Share on other sites More sharing options...
fahr_side Posted June 18, 2012 Share Posted June 18, 2012 I tend to agree with MP. The results we have seen tuning back this up. Don't worry. This member has never let little things like the laws of physics or anecdotal experience stand in his way before. This thread is a testament to that. I say let him pass some hours with a die grinder if he wants to. 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...
Blameless Posted June 18, 2012 Author Share Posted June 18, 2012 Don't worry. This member has never let little things like the laws of physics or anecdotal experience stand in his way before. This thread is a testament to that. Nice troll fahr... your posts sometimes make me curious of your age? As for my coolers linked above (I would be interested in how many intercoolers have you ever made fahr?) they are flowing much better than stock, not splitting at high boost and selling faster than Fahr can troll this forum Cheers to the rest for your input Link to comment Share on other sites More sharing options...
fahr_side Posted June 18, 2012 Share Posted June 18, 2012 Nice troll fahr... your posts sometimes make me curious of your age? Quite sure my age is higher than your IQ, but thanks for playing. 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...
turbodog Posted June 18, 2012 Share Posted June 18, 2012 Hmmmm thanks guys... Simply match porting them will surely net some flow gains even if small. Has anyone else got some feedback? Also keen to hear if anyone has ported their exhaust side on their heads to suit the manifold gaskets? I think that if you take everything apart and measure it, you'll find that everything is basicly port matched about as well as it can get on a modern subaru turbo motor, between the heads, manifold parts, uppipe and turbo. The exhaust velocity, temp and pressure is huge before the turbo, any step change in diameter (up or down) is a major flow restriction. I do not believe there are any diameter steps in the manifold on purpose, contrary to the nasioc thread above. If you're that curious, go ahead and pull the manifold and take some measurements, it's not that hard. Pay no attention to the gasket diameters, which make no difference. It's the head port diameter/location and manifold diameter/location that matter. While you're at it, feel free to polish it internally and wrap it with exhaust wrap, both of which will actually help, while actually reducing underhood temps. Link to comment Share on other sites More sharing options...
turbodog Posted June 18, 2012 Share Posted June 18, 2012 See below about port diameters: http://www.iwsti.com/forums/gd-exhaust/170919-oem-exhaust-manifold-porting.html DO NOT, I REPEAT DO NOT GASKET MATCH. Link to comment Share on other sites More sharing options...
Max Capacity Posted June 18, 2012 Share Posted June 18, 2012 FWIW, my heads were just ported. I asked about matching and they said not with these engines. Just norrow the divider and do some work in the valve pocket. I said ok you guy's know what works better than I do. They charged me about $300. The Tuner could see a difference and added fuel and whatever he needed to keep the tune safe. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Blameless Posted June 18, 2012 Author Share Posted June 18, 2012 See below about port diameters: http://www.iwsti.com/forums/gd-exhaust/170919-oem-exhaust-manifold-porting.html DO NOT, I REPEAT DO NOT GASKET MATCH. Thanks, I have no intention of gasket matching and was SHOCKED myslef to see so many doing it. But rather making sure all the holes are matched. Thanks again for the input. Just a case of checking while they are off. Be interesting to see how they line up. Link to comment Share on other sites More sharing options...
Blameless Posted June 18, 2012 Author Share Posted June 18, 2012 FWIW, my heads were just ported. I asked about matching and they said not with these engines. Just norrow the divider and do some work in the valve pocket. I said ok you guy's know what works better than I do. They charged me about $300. The Tuner could see a difference and added fuel and whatever he needed to keep the tune safe. This is as I understand it. The real gains are to be found in flow work on the head and this gets into specialist territory. Thanks. Link to comment Share on other sites More sharing options...
turbodog Posted June 18, 2012 Share Posted June 18, 2012 Thanks, I have no intention of gasket matching and was SHOCKED myslef to see so many doing it. But rather making sure all the holes are matched. Thanks again for the input. Just a case of checking while they are off. Be interesting to see how they line up. I strongly suggest a good thick layer of exhaust wrap while you have them off, if you want. And you can smooth the cast finish or any sharp edges on the insides. Link to comment Share on other sites More sharing options...
Max Capacity Posted June 18, 2012 Share Posted June 18, 2012 This is as I understand it. The real gains are to be found in flow work on the head and this gets into specialist territory. Thanks. Correct from what I also understand. These guy's do a lot of high HP engines of all kinds in this area, so I feel confident in there work. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Zac88 Posted June 23, 2012 Share Posted June 23, 2012 I was just about to port mine but now im waiting. Is there anymore information to back up Maxwell Powers claims? Link to comment Share on other sites More sharing options...
mwiener2 Posted June 23, 2012 Share Posted June 23, 2012 I don't agree with Mr. Powers when it comes to turbo cars. NA, yes. Turbo, no. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
Zac88 Posted June 23, 2012 Share Posted June 23, 2012 I don't agree with Mr. Powers when it comes to turbo cars. NA, yes. Turbo, no. Whats your thoughts on the whole porting thing and EL headers? Link to comment Share on other sites More sharing options...
Blameless Posted June 24, 2012 Author Share Posted June 24, 2012 I don't agree with Mr. Powers when it comes to turbo cars. NA, yes. Turbo, no. Tell us about your thoughts and your experience on this? Link to comment Share on other sites More sharing options...
Zac88 Posted June 24, 2012 Share Posted June 24, 2012 http://forums.nasioc.com/forums/showpost.php?p=37361287&postcount=26 AWESOME post by KillerB Link to comment Share on other sites More sharing options...
m sprank Posted June 24, 2012 Share Posted June 24, 2012 EL headers deff make more power. Porting the stock manifolds makes little power. KillerB holy headers have shown great results on the dyno. Have yet to actually get to work with a set. Link to comment Share on other sites More sharing options...
mwiener2 Posted June 24, 2012 Share Posted June 24, 2012 Turbo plumbing needs to be sized correctly for the flow. That's about it. As long as the pipe size is correct for the amount of flow, porting and gasket matching don't add up to much. Now if your ports are too small for the flow you need, that's another problem. But then you'd up your pipe size to match. I agree with most of KillerB's linked post. Don't agree with him on thermal products. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
Zac88 Posted June 24, 2012 Share Posted June 24, 2012 So runner lentgh or EL vs UEL isnt really an issue? Link to comment Share on other sites More sharing options...
mwiener2 Posted June 25, 2012 Share Posted June 25, 2012 Not really. Only in a situation where 1hp could win or lose a race. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
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