jackal8788 Posted January 5, 2016 Author Share Posted January 5, 2016 Pretty sure he has a rescaled MAF and a 3bar MAP sensor which will get him 30psi + without throwing a code like you do on the stock 2bar MAP at around 21psi. ^Truth VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
fahr_side Posted January 6, 2016 Share Posted January 6, 2016 My other thought is that I could remove the current 3" pass-through resonator and neck down to a 2". That will certainly add some resistance and will be significantly cheaper than porting or pursuing a custom downpipe (and of course, any EWG options). Any thoughts on this? Yes, this is a good approach to increasing post-turbine EGBP without overdoing it or introducing too much turbulence. In fact a lot of aftermarket exhausts do this, even though the tubing in and out is quite large diameter. A 2" core resonator would flow much more smoothly than your test washer setup, though I would think 2.5" or possibly 2.25" would be more suitable. I have cars here running at 335whp on a 63mm midpipe and 52mm cans. Just as an example of how much difference EGBP makes, I have one customer with an 'active' exhaust... mufflers with twin inlets, one of which is valved. With these valves closed we can hold the car at 14psi boost at redline no problem at around 30% WGDC. With them open we get around 17psi at redline from zero WGDC. Since the car has meth injection and Si Drive we took advantage of this to tune for 1bar in S mode and 1.35bar in S#. Meth is triggered at 1bar, so running in S mode with the muffler valves closed is quite safe even with the meth tank empty. The downside with this setup is that his exhaust fab guys only provided a remote control key fob to activate the valves on the mufflers. The funny part is that there's almost no difference in sound level between the two settings, even though boost control is basically defeated by opening the valves. 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...
rebourne Posted January 6, 2016 Share Posted January 6, 2016 Like i said I'm way out of practice, but with air flow through a tube the length x diameter ratio greatly affects the flow numbers. Easy analogy, blow through a drinking straw and a 1"x11" diameter tube rolled from 8x11 paper. 1" tube is easier. Now cut a 1/4" section off the drinking straw and blow through that. 1/4" of straw is as easy as the 1"x11" tube (if not easier). Where it really gets fun is for same diameter of pipe as you go longer in length, same velocity, the airflow touching the walls is slower,than the middle. and as length goes up, this slower air actually starts to behave like a wall effectively narrowing the pipe even further. With a small enough diameter, and long enough pipe, you can get it to behave as essentially closed at higher velocities. So, yes, if you can swap in a section of smaller diameter pipe of substantial length, you'll generate far more back pressure than a short ring. (This is also why crushed bent piping isn't nearly as bad as people think, as a half inch bigger piping negates the potential gain you might see with mandrel bends... But I digress... And no longer have the data.) pic thread build thread Link to comment Share on other sites More sharing options...
fahr_side Posted January 6, 2016 Share Posted January 6, 2016 Resonators don't quite follow the rules for straight pipes, because the perforations make for turbulence (like the dimples on a golf ball), and that breaks up this boundary layer you mention to some extent. 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...
rebourne Posted January 6, 2016 Share Posted January 6, 2016 My other thought is that I could remove the current 3" pass-through resonator and neck down to a 2". That will certainly add some resistance and will be significantly cheaper than porting or pursuing a custom downpipe (and of course, any EWG options). Any thoughts on this? Resonators don't quite follow the rules for straight pipes, because the perforations make for turbulence (like the dimples on a golf ball), and that breaks up this boundary layer you mention to some extent. Ah, I ass-umed the "neck down to a 2" would be a straight pipe for testing... Resonators are way outside of any text book I read. pic thread build thread Link to comment Share on other sites More sharing options...
jackal8788 Posted January 7, 2016 Author Share Posted January 7, 2016 I'll be putting the plate in shortly but my confidence in it completely solving the issue has dropped a bit. I agree with the statements about a longer section at reduced diameter. The plate will still create a pressure drop / backpressure, but maybe not quite enough as would be needed. I know cww15 made a half-joke about a potato in the exhaust but I may actually try plugging a tip, even with snow, as a temporary means of creating further restriction since my exhaust drops to 2.25" diameter pipes at the 'Y'. Should know more in a couple hours. VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
GTEASER Posted January 7, 2016 Share Posted January 7, 2016 Take off one of the cans and bolt a plate over one branch of the y. GTEASER's 2012 Legacy GT - Sold GTEASER's 2009 XTeaser - Sold GTEASER's 1992 Legacy SS - Sold Link to comment Share on other sites More sharing options...
FLlegacy Posted January 7, 2016 Share Posted January 7, 2016 I don't think it would matter after the Y since the flow of one muffler is probably equal to the flow of the mid pipe. Sent from my SAMSUNG-SGH-I337 using Tapatalk Link to comment Share on other sites More sharing options...
jackal8788 Posted January 7, 2016 Author Share Posted January 7, 2016 Well the plate helped but it wasn't enough. There were not any abnormal noises that I noticed with it and it has decreased the severity of the overboosting but I was still able to get to 25+ PSI, though this time it was at closer to 70% throttle than the previous ~40%. VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
rebourne Posted January 7, 2016 Share Posted January 7, 2016 Doesn't that basically point the finger at the downpipe? Need a catted DP and/or better designed bell mouth? pic thread build thread Link to comment Share on other sites More sharing options...
jackal8788 Posted January 8, 2016 Author Share Posted January 8, 2016 (edited) Well, I made a new plate today with 1.375" diameter hole because as noted, the other plate helped but wasn't enough. Annnnnnnnnnnnnnd....................IT WORKED!! I maxed out at about 10.5 PSI which is just what I was seeing the wastegate actuator move at last weekend when I tested it. This was the happiest I've ever been to only see 10 PSI on my boost gauge I don't see this as being my final solution but it does get the car back to a safe and fun status and I can finally stop spending money on chasing ghosts. Long term I am leaning most toward getting an EWG at which point I simply drop out my restrictor plate and enjoy. What a ride this one has been! Edit: I should point out (in case it is not clear to some) that I was running a 0 WGDC map when I did this pull - that's why only seeing ~10 PSI was a good thing Edited January 8, 2016 by jackal8788 VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
BBPeik Posted January 9, 2016 Share Posted January 9, 2016 Congrats Jackal, Great to hear you finally made some progress. Now to get it back to 21 PSI and all will be well. My someday I will be done with it thread. Link to comment Share on other sites More sharing options...
jackal8788 Posted January 24, 2016 Author Share Posted January 24, 2016 So I've been talking with a local guy who does a lot of custom exhaust fabrication and we are looking at options for a custom EWG header. I wondered if the flanges for the header (the two which connect to the engine exhaust ports and the one which the turbo connects to) can be purchased anywhere? My gut feel was no and that those who have had custom headers made also had the flanges cut by their fabricators. Is this correct? He has a laser table so I know we can cut the flanges. Just don't want to do it if they can be purchased. Second question - does anyone know the tubing sizes that are have been successfully used? I'm talking for individual runners and size once the runners merge. Thanks in advance all! Sent from my iPhone using Tapatalk VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
jackal8788 Posted January 25, 2016 Author Share Posted January 25, 2016 Also wondering about tubing wall thickness since this has to support the turbo as well. Does anyone know what wall thicknesses have been used? VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
FLlegacy Posted January 26, 2016 Share Posted January 26, 2016 So through all of this would you say that running an aftermarket downpipe with stock catback be a good idea, or in your opinion would it not make much difference? Link to comment Share on other sites More sharing options...
jackal8788 Posted January 26, 2016 Author Share Posted January 26, 2016 From my experience, turbo spool and response was significantly improved with the aftermarket downpipe and my stock catback. Of course there is (obviously) more on the table with the pass-through aftermarket exhausts, but as you know so very well, that was my undoing. I would definitely say the downpipe is a worthwhile upgrade. When I had my DP and stock CBE, I was still able to get 332/381 at the wheels with the 20G and e85. VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
jackal8788 Posted January 27, 2016 Author Share Posted January 27, 2016 A small update - I'm still evaluating options on the EWG header. I've been in contact with Six Star and it sounds like they have revised their original design for better flow characteristics. Unfortunately, they have no pictures of the new design. I'm weighing this against what my fabricator might be able to come up with so no final decision has been made. However, thanks to a certain someone, there will be a billet TD05/18G travelling to southeast Wisconsin from fahr, fahr away.... VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
Ellesedil Posted January 27, 2016 Share Posted January 27, 2016 However, thanks to a certain someone, there will be a billet TD05/18G travelling to southeast Wisconsin from fahr, fahr away.... Is it coming off the Millennium Falcon? Link to comment Share on other sites More sharing options...
Apexofthevortex Posted January 27, 2016 Share Posted January 27, 2016 Is it coming off the Millennium Falcon? Should most definitely be able to make the kessel run in less than 12 parsecs with that new turbo. Link to comment Share on other sites More sharing options...
jackal8788 Posted January 29, 2016 Author Share Posted January 29, 2016 This handsome little fella arrived today so I installed the black and red springs for a 1 bar opening pressure. Sounds like the turbo will be here by Wednesday and all my gaskets are in hand. I just need to make up my mind on the header.... VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
ebo03 Posted January 29, 2016 Share Posted January 29, 2016 Nice color choice. Mine are also blue! Link to comment Share on other sites More sharing options...
jackal8788 Posted January 29, 2016 Author Share Posted January 29, 2016 Nice color choice. Mine are also blue! You speak in the plural - are you running the ETS header? VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
jackal8788 Posted January 29, 2016 Author Share Posted January 29, 2016 Tangent - I wonder if I should change or generalize the name of this build thread since the '20G' really isn't applicable anymore.....oh GTEASER? VF54 to 20G to VF54 to 18G build thread Link to comment Share on other sites More sharing options...
GTEASER Posted January 29, 2016 Share Posted January 29, 2016 you rang? GTEASER's 2012 Legacy GT - Sold GTEASER's 2009 XTeaser - Sold GTEASER's 1992 Legacy SS - Sold Link to comment Share on other sites More sharing options...
Elegua Posted January 29, 2016 Share Posted January 29, 2016 A small update - I'm still evaluating options on the EWG header. I've been in contact with Six Star and it sounds like they have revised their original design for better flow characteristics. Unfortunately, they have no pictures of the new design. I'm weighing this against what my fabricator might be able to come up with so no final decision has been made. However, thanks to a certain someone, there will be a billet TD05/18G travelling to southeast Wisconsin from fahr, fahr away.... I had that very same kind of turbo installed for my stg3 set-up before I installed the EFR7163. With a decent meth set-up, won't be disappointed. I needed to upgrade my suspension to Konis and RCE blacks to keep the car from hobby horsing under power. Link to comment Share on other sites More sharing options...
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