Barrel_Ball Posted July 9, 2016 Share Posted July 9, 2016 (edited) After about 5 years of tossing around the idea, asking people, doing research, I decided to finally tackle making my own exhaust manifold for the L28ET since I was rebuilding it, anyway. My goal was an exhaust manifold that was as equal-length as I could get it, with space being the main compromising hurdle. This is purely experimental, and I have no idea if there will be major gains with this setup. I'm not after huge power numbers, but I would like better turbo spool time, and not have a cummins exhaust note. Two of my friends helped with the manifold, one made me some flanges, and the other did the final TIG welding after I tacked it together with the MIG. Flanges made, using a beat-up N42 head as my template Also used a sawed-off efi manifold, and later, a spare, complete intake for clearance checks I started by angling runners 1 and 6 in a similar fashion as it would go with a low-hanging log manifold. Then, I ran runner 3 towards 1 at as close to a right angle as I could get, with the intention of joining them with a 90 degree bend, in the direction of exhaust flow. But not before joining it with runner 2, first. Like so. Then mirrored for the other side. Seen from above, I used a wider radius bend for runners 3 and 4, so they traveled a shorter distance from their respective ports to where they collected with 1-2 and 5-6. The runners are made using the Vibrant 1.5" stainless mandrel bends, and are joined in the main collector, which is comprised of 1.75" of the same material. Note how it loops around to exit at the turbo flange, which is close to the stock turbo location. A Subaru turbo flange was used, as that was the only turbo I had at the time. There is now an adapter bolted to it for a T3 flange, as I had found an RB25 series 1 turbo (not shown). The finished product is quite nice. A video of the sound and operation test is here. Any opinions/feedback from folks on here who have experience with this stuff is welcome. Edited July 9, 2016 by Barrel_Ball Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 9, 2016 Share Posted July 9, 2016 After about 5 years of tossing around the idea, asking people, doing research, I decided to finally tackle making my own exhaust manifold for the L28ET since I was rebuilding it, anyway. My goal was an exhaust manifold that was as equal-length as I could get it, with space being the main compromising hurdle. This is purely experimental, and I have no idea if there will be major gains with this setup. I'm not after huge power numbers, but I would like better turbo spool time, and not have a cummins exhaust note. Two of my friends helped with the manifold, one made me some flanges, and the other did the final TIG welding after I tacked it together with the MIG. Flanges made, using a beat-up N42 head as my template DSC_0449.JPG DSC_0450.JPG Also used a sawed-off efi manifold, and later, a spare, complete intake for clearance checks DSC_0569.JPG I started by angling runners 1 and 6 in a similar fashion as it would go with a low-hanging log manifold. DSC_0570.JPG Then, I ran runner 3 towards 1 at as close to a right angle as I could get, with the intention of joining them with a 90 degree bend, in the direction of exhaust flow. DSC_0580.JPG But not before joining it with runner 2, first. DSC_0583.JPG Like so. DSC_0590.JPG Then mirrored for the other side. DSC_0592.JPG Seen from above, I used a wider radius bend for runners 3 and 4, so they traveled a shorter distance from their respective ports to where they collected with 1-2 and 5-6. DSC_0596.JPG The runners are made using the Vibrant 1.5" stainless mandrel bends, and are joined in the main collector, which is comprised of 1.75" of the same material. Note how it loops around to exit at the turbo flange, which is close to the stock turbo location. DSC_0598.JPG A Subaru turbo flange was used, as that was the only turbo I had at the time. There is now an adapter bolted to it for a T3 flange, as I had found an RB25 series 1 turbo (not shown). DSC_0599.JPG The finished product is quite nice. DSC_0625.JPG A video of the sound and operation test is here. Any opinions/feedback from folks on here who have experience with this stuff is welcome. Two words: Expansion Joints. You need expansion joints. Quote Link to comment Share on other sites More sharing options...
TimO Posted July 9, 2016 Share Posted July 9, 2016 I agree. You absolutely need to install expansion joints or some of your welds will crack. Ask me how I know?? Quote Link to comment Share on other sites More sharing options...
rturbo 930 Posted July 9, 2016 Share Posted July 9, 2016 Hey! I saw your video on youtube a while back, pretty much the only video I could find on the subject. Good to see you here. Do you think you could get us a driving video with a good microphone? Your video only gives us a glimpse of the difference in sound. Quote Link to comment Share on other sites More sharing options...
Barrel_Ball Posted July 10, 2016 Author Share Posted July 10, 2016 Never, have I seen expansion joints (you mean those accordian-like sections, right?) on a stainless, tubular, turbo manifold. I can understand, with Mild steel, and occasionally, cast iron, due to different expansion rates with those materials. Could you point out where I would need them, and why? This is purely in the experimental phase, so if it does crack, I can figure out where it cracked, why, and rectify the problem to prevent it happening again. It will have to come out again, anyway for ceramic coating once I've determined it a success. The demo video I posted shows not only the difference in sound, but at-rest turbo response, as well. That may not say much at this time, but I'm being optimistic, here. As for a road test video, that will still be a ways away, since at the time of the test runs, the car wasn't tuned yet, and now it's in pieces, getting re-wiring and bodywork, as well as other improvements and repairs. Might see the car on the road for August, but no promises, there. I will assure you, though, that further updates on the development will appear as they unfold. For the time being, though, let's discuss. Quote Link to comment Share on other sites More sharing options...
HuD 91gt Posted July 11, 2016 Share Posted July 11, 2016 They probably mean slip joints on the collector pipes. Quote Link to comment Share on other sites More sharing options...
Barrel_Ball Posted July 11, 2016 Author Share Posted July 11, 2016 Not sure I'd trust slip-joints to not leak on a turbo manifold. I am thinking, though about adding a support bracket, from the turbo compressor housing, to the intake manifold. I have read that supporting the turbo with just the header isn't a good idea, since as the header heat-cycles, the weight of the turbo could cause the whole thing to sag. I'm not too worried about it, right now, as I still have much work to do, before the car runs again, what with no front wiring harness, and all. You can make anything work - Where there's a will, there's a way. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 12, 2016 Share Posted July 12, 2016 Expansion joint on runner to #1 & 6. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted July 12, 2016 Share Posted July 12, 2016 I ran all my pipes to one collector. There was enough room there and the turbo isn't far from the original location. Quote Link to comment Share on other sites More sharing options...
Barrel_Ball Posted July 12, 2016 Author Share Posted July 12, 2016 Expansion joint on runner to #1 & 6. Dumb question: Before, or after where the others collect into them? There's plenty of room after the 3-1 joints, but before them, I'm not so sure, yet. I'll see what my local performance shops have, and measure from there. Quote Link to comment Share on other sites More sharing options...
Wizzurp Posted July 12, 2016 Share Posted July 12, 2016 Wtf flange/turbo will be on this? That doesn't look real familiar to me. Quote Link to comment Share on other sites More sharing options...
Barrel_Ball Posted July 12, 2016 Author Share Posted July 12, 2016 (edited) I originally made this with a Subaru turbo flange, since I had an IHI VF52 That I was gonna use, but I had come across a Nissan T3 from an RB25, after it was completed, so I made an adapter to go in between. It spaced the turbo out about 2 inches, but that turned out good in the end to make room for my intercooler setup. Edited July 12, 2016 by Barrel_Ball Quote Link to comment Share on other sites More sharing options...
Wizzurp Posted July 12, 2016 Share Posted July 12, 2016 I was more confused about the spare two bolts on the flange haha Quote Link to comment Share on other sites More sharing options...
Barrel_Ball Posted July 13, 2016 Author Share Posted July 13, 2016 I was more confused about the spare two bolts on the flange haha Ah, those were the studs for the mounting bracket from the Subaru, who's up-pipe I butchered for that flange. Ha! Quote Link to comment Share on other sites More sharing options...
Wizzurp Posted July 13, 2016 Share Posted July 13, 2016 Gooootcha, my company manufactures turbos and I was going to say I'd never seen anything other than the standard three bolt flange. That is funny. Quote Link to comment Share on other sites More sharing options...
StanleySlater Posted July 16, 2016 Share Posted July 16, 2016 That's great, that you finally decided to tackle making your own exhaust manifold @Barrel_Ball. I also think that you need to install expansion joint, otherwise some welds will crack.My friend had completed a similar kind of a project of exhaust manifold few months ago. He found some helpful information over here and did all the welding work with the help of the professionals. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 16, 2016 Share Posted July 16, 2016 Thermal expansion along the longest straight run to the ends will cause the problem. The rest of the welds should be fine as there is a loop for expansion. The #1 & #6 runners though, are long enough to cause an issue. Normally the expansion joint is placed where the secondary pipes enter it on this manifold, so maybe that will be where there is a strain...but it will still walk on the #1 & #6, the addition of the pipe at the normal expansion point may just make the ends pull "up" in an arc around where the pipe is welded to it on the top. Once those welds break, then it will expand axially towards each end of the head, and sometimes away from the face... Quote Link to comment Share on other sites More sharing options...
Barrel_Ball Posted July 17, 2016 Author Share Posted July 17, 2016 Thermal expansion along the longest straight run to the ends will cause the problem. The rest of the welds should be fine as there is a loop for expansion. The #1 & #6 runners though, are long enough to cause an issue. Normally the expansion joint is placed where the secondary pipes enter it on this manifold, so maybe that will be where there is a strain...but it will still walk on the #1 & #6, the addition of the pipe at the normal expansion point may just make the ends pull "up" in an arc around where the pipe is welded to it on the top. Once those welds break, then it will expand axially towards each end of the head, and sometimes away from the face... I can kind of see where you're getting at, now. Almost sounds like I would be back at square one if where 2/3, and 4/5 join 1 & 6 are where the expansion joints should be. I measured the straight parts of 1 & 6, and they're shorter than the length of the available expansion joints I'm aware that exist (2.5" available room as opposed to the 3" or so of the joint). I have seen/heard of countless aftermarket and custom manifolds, made from the same material, and welded the same way, with longer, more complex runner sets, and the only ones I have heard of cracking, are the cheap ones that were welded poorly. Is there a reason why they don't break, shortly after installation? Quote Link to comment Share on other sites More sharing options...
Canadianz Posted July 17, 2016 Share Posted July 17, 2016 Looks great, see what happens, if it cracks modify it. Quote Link to comment Share on other sites More sharing options...
Barrel_Ball Posted July 18, 2016 Author Share Posted July 18, 2016 Looks great, see what happens, if it cracks modify it. I think I'll do just that for now. I'm more curious to see what kind of, if any, performance gains I can get with this particular design. Quote Link to comment Share on other sites More sharing options...
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