Cannonball89 Posted March 22, 2011 Share Posted March 22, 2011 Well my turbo swap for my 71 is taking longer than I planned, mostly because I can't resist the urge to go overkill and fabricate stuff like this. Uses an exducer purchased from D&W Diesel Performance to expand the diameter from the 2.5" turbo (T3/T04E) outlet to 3" for the downpipe. Wastegate is a copy of a Tial 38MM from SSAutochrome. It was cheap and don't know if it will be reliable but I can always just bolt a Tial on later. Piping is 3" mandrel bent mild steel. Screamer pipe will be 1.5" mandrel bent steel. I haven't ported the turbine housing so 38MM is WAY bigger than I need but if I get creep it will be relatively easy to port the turbine, no modification to the downpipe and flange will be needed. You don't see a lot of divorced port wastegate set-ups, probably because they are more prone to creep than the external wastegates mounted to the manifold, but we will see how this works for me soon. If nothing else it looks cool. Quote Link to comment Share on other sites More sharing options...
Oddmanout84 Posted March 22, 2011 Share Posted March 22, 2011 I think it looks pretty nice. I do share the worries of possible boost creep issues though. If I had two of the 7 bolt blockoff flanges instead of the one I have, I might have tried this. Quote Link to comment Share on other sites More sharing options...
CamH Posted March 22, 2011 Share Posted March 22, 2011 I guess that probably won't perform any better than a normal internally gated turbo, but it looks pretty cool. Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted March 22, 2011 Author Share Posted March 22, 2011 (edited) I guess that probably won't perform any better than a normal internally gated turbo, but it looks pretty cool. I think it will perform in between a stock internal gate and a wastegate mounted directly to the manifold. The stock gate creates turbulence right after the turbine that robs power under boost. This set up will vent wasted exhaust gases either directly to the atmosphere or into the main exhaust pipe further downstream where turbulence is not as harmful (I haven't decided yet). So it will produce more horsepower than the stock internal gate. I also believe it will be less prone to boost creep than stock internal gate due to the less restrictive path that the wasted gases travel, but I don't believe it will be as effecient at controlling boost as the wastegates that are welded onto the manifold because I am using the small hole that internal gates use. Basically it's a trade-off. Once the car is back on the road we will find out for sure how effective it is. Edited March 22, 2011 by Cannonball89 Quote Link to comment Share on other sites More sharing options...
Noddle Posted March 23, 2011 Share Posted March 23, 2011 (edited) I also believe it will be less prone to boost creep than stock internal gate due to the less restrictive path that the wasted gases travel, but I don't believe it will be as effecient at controlling boost as the wastegates that are welded onto the manifold because I am using the small hole that internal gates use. Basically it's a trade-off. Once the car is back on the road we will find out for sure how effective it is. I had to go with a external gate because the internal gate could not handle the exhaust flow that was needed ( on a L24 engine ) even after I enlarged the hole on the turbo housing. Edited March 23, 2011 by Noddle Quote Link to comment Share on other sites More sharing options...
junglist Posted March 23, 2011 Share Posted March 23, 2011 Looks cool, I plan on running something nearly identical with the divorced port 2.5" to 3" exducer, 3" exhaust. I bought the flange, just haven't gotten to plumbing the car yet. I have a brand new Garrett T3/T04E 0.63 A/R turbo. I also have a knockoff Tial wastegate, mine has a Tial spring and I smoothed out all the casting and rough edges inside of it. I didn't have a ton of money at the time when I bought it, I figure I'll buy a Tial in the future. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted July 7, 2011 Share Posted July 7, 2011 The one I fabbed for my car is very similar but I angled the wastegate pipe/mount outward to help prevent possible boost creep. Works great! Quote Link to comment Share on other sites More sharing options...
260DET Posted July 8, 2011 Share Posted July 8, 2011 Doesn't look like overkill to me, should work well. You may need some welding lessons but the idea and concept is good. Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted July 9, 2011 Author Share Posted July 9, 2011 It has been performing pretty well. I have a spring rated at 0.7BAR which is roughly 10PSI. The boost seems to hold pretty steady at aroun 12PSI. So it could just be that the spring is really a 12PSI spring. I don't notice the boost creeping up like I've seen some people's cars, where it will stay at 10PSI then climb rapidly to around 20PSI. I plan on porting the wastegate hole on the turbine housing the next time it is off the car and it should be even better. And yea my welding isn't perfect, I should take some lessons or something. Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted July 9, 2011 Author Share Posted July 9, 2011 The one I fabbed for my car is very similar but I angled the wastegate pipe/mount outward to help prevent possible boost creep. Works great! I'm not sure what you mean by "angled the wastegate pipe/mount outward". Got any pictures? Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted July 9, 2011 Author Share Posted July 9, 2011 Here are a couple pics of it with the screamer pipe attached. It gets REALLY loud under boost lol. I sprayed it with some DEI high-temp paint, it has since flaked off of the pipe that the wastegate mounts to, but has held up everywhere else on the exhaust system. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted July 9, 2011 Share Posted July 9, 2011 (edited) It's a little hard to see but it's mounted at about a 45 degree angle. wow what a tiny pic! how do I make it smaller? Edited July 9, 2011 by skirkland1980 Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted July 11, 2011 Author Share Posted July 11, 2011 I see what you mean. I suppose that might be a slight improvement if you have ported the hole such as that it directs the exhaust gasses in that direction. On my turbine housing the hole is just drilled in at a 90* angle, so the exhaust gasses have to turn 90* anyway. Quote Link to comment Share on other sites More sharing options...
bthomp Posted August 7, 2011 Share Posted August 7, 2011 cannon, are we stalking each other now? that was the design i was going to use at first for my 3" downpipe with 38mm waste gate... Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 17, 2011 Share Posted August 17, 2011 I did about the same, but used 2.5 inch pipe and plumbed the wastegate exhaust back into the exhaust system for a quieter boost application. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted August 17, 2011 Share Posted August 17, 2011 Anybody have results for this type of setup? Preferably with datalog? Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted August 18, 2011 Author Share Posted August 18, 2011 Anybody have results for this type of setup? Preferably with datalog? I have a datalog from my Dyno session: The light blue line on the top chart is Boost/Vac. It seems pretty steady at around 12PSI, the wastegate spring is rated for 10PSI, so I suppose that indicates a little bit of creep, but not dangerous amounts. Unfortunately I was having a spark blowout issue that day due to incorrect dwell settings that didn't allow us to go beyond 5000RPM. It still made 250HP and 280lb/ft of torque though. I have since resolved the spark blowout issue and advanced the timing, and done a little more work on the fuel curves so I expect it is making closer to 300lb/ft of torque now. I have been trying to get to a dragstrip for the past several weeks but it seems to rain every damn saturday this time of year in Maryland Once I am finally able to get down a quarter mile I will post up a datalog of the full 1/4 mile pass to see if there is any creep in a real world situation, and of course post my timeslip. The online calculators say that my car should go mid 12's, but I don't think I will have the traction for that with my open R180 and 205/60-14 Sumitomo radials lol. I'm hoping for 13's at a MPH of around 100. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted August 18, 2011 Share Posted August 18, 2011 You should do 100 with NO problem, I'd expect 105ish. I did 98 on 9psi with the stock t3 and massive cylinder leakdown(previous owner put turbo rings on non turbo pistons), car weighed 2740 w/ me in it, open r180 with 225 kumho street tires. Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted December 15, 2011 Author Share Posted December 15, 2011 I've been meaning to update this thread for a while now, got busy with school and forgot about it for a while though. Anyway I was able to get out to the dragstrip in early October. The car was fast, a 13.4 @ 112 MPH and a 13.5 @ 114 MPH were my best times for the day. Obviously at those MPH's my E.T. should be well into the 12's but traction simply doesn't exist with my current rear end set-up of open differential and old hard Sumitomo radials. I will cure that over the winter with a Torsen LSD and Nitto 555R drag radials on all four corners. Here are my two best time slips (left lane both passes) Unfortunately that day also revealed that my divorced port set-up in it's current configuration is not effectively controlling boost. I saw over 20 PSI of boost with the 10 PSI spring in the wastegate. On my dyno run it held to 12 PSI, but for some reason it is seeing creep in real world conditions. Here is the datalog of the 13.4 pass: I am not giving up on the divorced port design though. I have too much time invested in making this to give up on it that easily. I found this great article by Corky Bell about how to port the wastegate hole to make it flow more, basically you dig a channel out in front of the wastegate hole leading up to the mouth of the turbine housing to kind of channel exhaust gases into the wastegate. Here is a link to that article: http://www.bellengineering.net/article_info.php?articles_id=273 I am also going to enlarge the hole quite a bit. People always say that you cannot enlarge the internal wastegate hole, but that is because they are running the flapper style wastegate, and having too big of a hole won't allow it to seal properly. However in my divorced port set-up I can enlarge it safely as long as I don't weaken the turbine housing. So that's the next step in Divorced Port Evolution, porting! Unfortunately we won't find out if my porting is effective for a litte while. I most likely won't be driving the car until my new differential is in, and that requires me having the side axles that John Coffey sells to let you run an STI diff with stock propeller shafts. It's cold outside anyway.I have just pulled the turbo out today (man what a PITA that was) and will update with some pictures of my porting before I start reassembling. Quote Link to comment Share on other sites More sharing options...
jgkurz Posted December 15, 2011 Share Posted December 15, 2011 (edited) Cannonball89, you are a man after my own heart. Here's my setup. I can't say enough good things about how much of an improvement I got from going to the divorced wastegate setup vs the internal gate. Here's a bit more info on my car. http://www.fstrnu.net/ Everything is pretty much the same except I'm in the middle of swapping in a GT35R. Edited December 15, 2011 by jgkurz Quote Link to comment Share on other sites More sharing options...
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