trwebb26 Posted July 11, 2007 Share Posted July 11, 2007 I'm getting ambitious so I want to work on building a mild steel tubular turbo exhaust manifold. My first question is - on a Z head - how do you get from rectangular exhaust ports to a circular tube? Does somebody sell the transition piece I need or am I going to have to make my own? Quote Link to comment Share on other sites More sharing options...
tfreer85 Posted July 12, 2007 Share Posted July 12, 2007 Just subscribing.... Quote Link to comment Share on other sites More sharing options...
Challenger Posted July 12, 2007 Share Posted July 12, 2007 Go to a header or exhaust shop and have them use one of there fancy schpancy machines to do it. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted July 12, 2007 Administrators Share Posted July 12, 2007 Just subscribing.... tfreer, You’re not in trouble, just a heads up. That little button at the top of the thread titled “Thread Tools” has the option to subscribe without actually having to post in that/this thread. HTH. I'm getting ambitious so I want to work on building a mild steel tubular turbo exhaust manifold. My first question is - on a Z head - how do you get from rectangular exhaust ports to a circular tube? Does somebody sell the transition piece I need or am I going to have to make my own? Ok, so you need what is called a “square to round”. You might be able to “beat” the round pipe into submission, er, a square at the entrance with a bucking bar. Being as you are planning to use mild steel, any reason why you couldn’t just use the flange of an existing square port header for its “square to round”, cut the pipes off where you need them or just use the first 2-3 inches for your project? Might be able to find someone’s old rusty square port header cheap or free if it is dented or trashed. All you really need is a good THICK flange with approx 2-3” of the pipe coming off the flange.. Just a thought. Quote Link to comment Share on other sites More sharing options...
tfreer85 Posted July 12, 2007 Share Posted July 12, 2007 tfreer,You’re not in trouble, just a heads up. That little button at the top of the thread titled “Thread Tools” has the option to subscribe without actually having to post in that/this thread. HTH. Copy that Mr. BRAAP, learn two things in one day... Question though, don't want to thread-jack but say one's building a sheetmetal intake for an LS1 with the cathedral style intakes, how do you replicate the "submission" process with quality assurance in mind? Tyson Quote Link to comment Share on other sites More sharing options...
blueovalz Posted July 12, 2007 Share Posted July 12, 2007 This is what I've had to do several times. What I did was determine the outer circumference (not area) of the tube, and then match that to the sum of the square port's inside dimensions. Then I take the end of the tube that must now be made square and place it in a vise and start to flatten it out slightly. BUT before it do this I place a large C-clamp onto the same end of the pipe, except that it this is oriented 90º to the vise jaws. This way, as I squeeze the tube with the vise, the C-clamp prevents the tube from being squeezed outward and becoming ovate. This then causes the tubing to take a square shape. Do this a small amount, then remove, turn 90º in the vise and C-clamp, and repeat by squeezing and deforming the tube end a little more. You may need to repeat these "cycles" several times, each time rotating the tubing another 90º to keep it forming the way you want. Depending on the port configuration you may need to open (or close) the C-clamp between cycles to perfect the shape. The size of the tubing is important. If the circumference of the tube is larger than the sum of the square port's inside dimensions, no amount of squaring up will allow the tube to fit. In my case my exhaust port header flange had 1.4" X 1.4" ports, thus the sum of these sides are 5.6". The tubing I'm using is 1.6", which has a circumference of 5.0". This is slightly smaller than the port's size and once the tubing is squared up a bit, will fit nicely. The more round the corners are, the smaller the tubing diameter you'll want to use (as it compares to the square port's dimensions). Be sure to get a few test pieces of pipe to verify what will fit before commiting to purchasing a lot of tubing. Lastly the square part usually transitions to the fully round portion within about 1.7". If there is a bend immediately out of the port, the square portion will have a shorter transition, and will be more difficult to square up (will require smaller and more numerous cycles of "squeeze-and-turn". Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted July 12, 2007 Administrators Share Posted July 12, 2007 Copy that Mr. BRAAP, learn two things in one day... Question though, don't want to thread-jack but say one's building a sheetmetal intake for an LS1 with the cathedral style intakes, how do you replicate the "submission" process with quality assurance in mind? Tyson MR BRAAP?.. Now I feel like the mean step Dad... Just plain ole BRAAP or even Paul is fine, really... BTW what was the other thing you learned today? Mr... Quote Link to comment Share on other sites More sharing options...
tfreer85 Posted July 12, 2007 Share Posted July 12, 2007 MR BRAAP?.. Now I feel like the mean step Dad... Just plain ole BRAAP or even Paul is fine, really... BTW what was the other thing you learned today? Mr... Umm sorry sir..... I mean Paul I learned not to stick your "thing" in holes where you can't seen where it goes... Thats off topic though...made my day more interesting to say the least. Tyson BTW I'm a 911/fire dispatcher.... Quote Link to comment Share on other sites More sharing options...
MONZTER Posted July 12, 2007 Share Posted July 12, 2007 Here is what I did. Simply make a form out of steel by grinding it to shape. Make it the size of the inside of the tube you want. Once the form is made, grease it up as well as the inside of the tube, then use a press or vise to press the tube over the form. The steel should be formed perfect. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted July 12, 2007 Share Posted July 12, 2007 Did you Jet-Hot (or similar process) the header flange and stubs then before adding the rest of the headers? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 12, 2007 Share Posted July 12, 2007 One word of warning about cutting the flange off an existing header... some of them are REALLY CRAPPY!!! Look in the tubes and see how pinched off they are. Mine were probably only about 60% open due to whatever process was used to make the round tubing into square. Quote Link to comment Share on other sites More sharing options...
buZy Posted July 13, 2007 Share Posted July 13, 2007 Here is what I did. Simply make a form out of steel by grinding it to shape. Make it the size of the inside of the tube you want. Once the form is made, grease it up as well as the inside of the tube, then use a press or vise to press the tube over the form. The steel should be formed perfect. Killer fab work! Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted July 14, 2007 Author Share Posted July 14, 2007 Great advice from everyone. Keep it coming. I was down measuring up my 280zx turbo head and I was shocked to see that the center two cylinders had bigger exhaust ports than the outside four. Anybody know why? Second question - what does everybody reccomend as far as tubing inside diameter goes? I imagine that as long as I kept the same cross sectional area as the exhaust port (or larger) - I should be good to go? It is complicated because the center two ports are bigger than the other four. I guess I should size the tubing for the center ports and use that ID on all the runners. Third - I've seen the SICK manifold that monzter has been putting together - and it says in there that ~30" runners are the ideal length. I was thinking I would just try to make them equal length and however long they ended up to get a good turbo position I would call it good. Any comments on this plan? Thanks! Quote Link to comment Share on other sites More sharing options...
MONZTER Posted July 14, 2007 Share Posted July 14, 2007 Great advice from everyone. Keep it coming. I was down measuring up my 280zx turbo head and I was shocked to see that the center two cylinders had bigger exhaust ports than the outside four. Anybody know why? Second question - what does everybody reccomend as far as tubing inside diameter goes? I imagine that as long as I kept the same cross sectional area as the exhaust port (or larger) - I should be good to go? It is complicated because the center two ports are bigger than the other four. I guess I should size the tubing for the center ports and use that ID on all the runners. Third - I've seen the SICK manifold that monzter has been putting together - and it says in there that ~30" runners are the ideal length. I was thinking I would just try to make them equal length and however long they ended up to get a good turbo position I would call it good. Any comments on this plan? Thanks! Hey, On mine I used 1 5/8 and the tubes are 26.5 long. It is a lot of tubing to fit it all in there. On my center two ports I simply made the form to go from square to round for that one first, and then ground it down more after making the center ones and used it to make the others. As a side note, I made the form in 3 pcs so that I could remove the center section of the form to let it collapse for easy removal. This may be necessary because the short side of the rectangular port is narrower than 1 5/8. The size and length of the tubes was all given to me by Burns Stainless. They have software to determine the correct details given a list of parameters I supplied. This service is free if you buy there merge collectors. I think a lot of people here will argue that long equal length turbo headers are unnecessary, but if you look at Corky Bells book on turbo charging, and check out the section on headers, you will see all of the Indy and professionally prepared cars with long tube merge collector designs. Now if this actually helps on a 2 valve Z engine, I guess we will see. Personally, I love the challenge and the look, so if that's all I get by doing it, then I am still happy. Quote Link to comment Share on other sites More sharing options...
katman Posted July 14, 2007 Share Posted July 14, 2007 "Simply make a form out of steel by grinding it to shape. Make it the size of the inside of the tube you want. Once the form is made, grease it up as well as the inside of the tube, then use a press or vise to press the tube over the form." +1 That's what I do. On a L head you'll need two of those mandrels because ports 3 and 4 are different shape. Now as to sizing a header, on a N/A motor you're trying to coax everything you can out of the cylinder during the exhaust stage so knowing the cam and application is everything. On a turbo, well it just ain't that important IMHO. Corky's book would for sure be a good starting point, although you can make silly horsepower even with the stock manifold. Quote Link to comment Share on other sites More sharing options...
Careless Posted July 15, 2007 Share Posted July 15, 2007 does anyone know of any books on header and intake design? like a really healthy book dedicated to the science... with theory, and results based on worth-while tests, rather than hearsay? I think most of the books I've come across generally have a small section related to naturally aspirated motors. Or what's even more common, is that when they do have a lot of info, they tend to contradict not only other books, but themselves too in a lot of cases. I'm particularly after header and intake / valvetrain setup for naturally aspirated motors. (inline 6 = better, if that's what the book is based on) Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted July 17, 2007 Author Share Posted July 17, 2007 Great tips on the header fab! I ordered my pipe today at a local plumbing supply place. I decided to go with the 1 and 1/2" schedule 40 pipe. I got 10 "short" 90 degree bends and 10 "long" 90 degree bends along with 4 sections of 12" long pipe (it was WAY cheaper than buying a 21 foot stick). The total came to around $160 Does anybody know where I can buy a good pre-made 1/2" thick header flange? A guy was selling them on ebay last week, but all of the ports were the same size so I didn't get one. I guess I can order some 1/2" stock and make one. Anybody? I started to make my die out of the head of a sledge hammer i had laying around the garage... boy that didn't last that long. That thing has a massive case harden on it. I dusted 2 brand new sawzall blades messing around on that thing. I guess I'm going to have to order some 2" mild square stock and start with that. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 17, 2007 Share Posted July 17, 2007 I'm in the Monzster and katman camp (with far less finesse, and more "Primitive Pete Tech"): Made a mandrel out of a chunk of steel, slightly tapered it like the end of a spike, then heated up Sch10 Piping and rammed it onto the mandrel while red hot. That kept falling out of the vice, so I welded it to a stake, and put it in the anvil. Then it was like any other blacksmithing operation: Ram it on, heat it, hammer it....one end ended up nicely matching the ports, the other was easily welded to round tubing. After making Six like that, the obvious conclusion that #3 & 4 were different dawned on me. Having the header flange nearby would probably have caught me before getting that far! All I can say is "Think Ahead"! LOL Quote Link to comment Share on other sites More sharing options...
340ZXTTAZ Posted July 18, 2007 Share Posted July 18, 2007 hey trwebb26 where did you buy your schedule 40 stock from? Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted July 18, 2007 Author Share Posted July 18, 2007 I bought it from a local place called Columbia Pipe and Supply (http://www.columbiapipe.com/). They have an office right down the street from where I work. The "long" radius pieces were between $5-6/per and the "short" radius pieces were between $8-9/per. (the long ones are cheaper because they are way more common - even though they are bigger and have more steel in them). That is a BARGAIN compared to what Mcmaster-Carr charges (~$10/per piece). Call one of your local plumbing / HVAC repair shops that would work with gas lines and ask who they buy their stuff from. Quote Link to comment Share on other sites More sharing options...
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