johnc Posted June 29, 2011 Share Posted June 29, 2011 What Leon said... The cone or megaphone is after (really part of) the final merge collector. A final collector with a straight extension off the minor throat is leaving a little on the table. Cone shape and length are used to tune for a specific rpm band. For most of the L6 street installs a 2.5" minor throat (assuming each of the two collectors off the header are 2.5") with a 7 degree cone to 3" will help mid-range power. For high rpm power (as on my old race engine) I went with a 2.75" minor throat and a 7 degree cone merge to 3". That moved everything up about 1,000 rpm. The cone also makes the exhaust louder. Keep that in mind when building for a street car. I measured a 3db increase with no other change on a customer's autocross E36. Quote Link to comment Share on other sites More sharing options...
Xnke Posted June 30, 2011 Author Share Posted June 30, 2011 Nope. Not even close, gotta come in a LOT more at the bottom. From what I have been able to work out, the #5 tube only clears the block by about a half inch. Johnc, do you have a set of these on a car that you can see how far off the block the #5 primary sits? Quote Link to comment Share on other sites More sharing options...
josh817 Posted June 30, 2011 Share Posted June 30, 2011 I'm curious how that is going to work but otherwise looks great... The part that is getting me is the two different angles and locations of the collectors. I'm guessing the secondary tubes don't have to be equal length like the primaries. If they do then I don't see how that works... Quote Link to comment Share on other sites More sharing options...
240zip Posted June 30, 2011 Share Posted June 30, 2011 It would have been nice if Stahl had plans, drawings or other information to assist in this DIY approach. I know they have the jig. Quote Link to comment Share on other sites More sharing options...
johnc Posted June 30, 2011 Share Posted June 30, 2011 I don't have a set of the headers or an engine to put them on right now. EDIT: Keep in mind bellhousing and trans clearance. Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 1, 2011 Author Share Posted July 1, 2011 Yeah, that's why they are out as far as they are now. I'm trying to avoid pulling down the Z any longer than I have to, but this weekend It's getting a new intake/exhaust gasket, and I'm going to get the primaries fitted into the car. Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 1, 2011 Author Share Posted July 1, 2011 Yeah, that's why they are out as far as they are now. I'm trying to avoid pulling down the Z any longer than I have to, but this weekend It's getting a new intake/exhaust gasket, and I'm going to get the primaries fitted into the car. Josh, the secondary length is just as important. What you don't see is that the primary tubes are about 10" too long...so you can adjust the total length of the primary/secondary to match bank-to-bank. Quote Link to comment Share on other sites More sharing options...
josh817 Posted July 1, 2011 Share Posted July 1, 2011 Oh ok. I was wondering why it didn't look like my pictures. By the way this is all I have as far as engine bay... Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 2, 2011 Author Share Posted July 2, 2011 Oh, so the Death Metal Datsun is yours? Those are the photos I've been working from. Quote Link to comment Share on other sites More sharing options...
josh817 Posted July 2, 2011 Share Posted July 2, 2011 No I saved it from somewhere. I wish I remembered where. I remember that plate bolted on the block for a trigger wheel pick up... Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 5, 2011 Author Share Posted July 5, 2011 I'm pretty sure his handle here on HBZ is FP280Z, but he's a member here. Anyway, I'm fitting up the collectors probably next weekend; but am at an impasse. Do I buy a pair of merge collectors that are 1.625" x3 to 2" x1, or use the 1.625" x3 to 2.5" x1 that stahl sent with the header? I am running a 2.5" exhaust already; and don't want to move up to a 3" pipe yet...this one is only a few months old. I can't seem to find any 2 into 1 collectors that go from 2.5" in to 2.5" out, let alone any that are 2.5" to 2.25" that I could cone up to 2.5". I'm leaning toward the dreaded y-pipe...although if I could find the right bends I'd make a 12 or 15 degree merge. Quote Link to comment Share on other sites More sharing options...
johnc Posted July 5, 2011 Share Posted July 5, 2011 SPD custom makes collectors to whatever specs you want. Run the Stahl collectors as supplied and then add the final merge collector. IMHO, assuming you're going with a 3" exhaust at some point, I would just run a "Y" pipe until you finally make the jump. Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 6, 2011 Author Share Posted July 6, 2011 If that's the case, then I can make a y-pipe, not a problem. I have read all over that a y-pipe is what I don't want to use with a header; but in this case I guess it'll work fine. Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 7, 2011 Author Share Posted July 7, 2011 Had another guy come to me needing a 2" mandrel exhaust for his V6 mustang, so went ahead and ordered some exhaust parts. Found a 2.5 to 2.5 merge collector; it necks down to 2.375 and I'll cone that back up to 2.5 for now. Later I can cut it back to 2.5" and cone up to 3" when I move to that point. Hopefully the tubes all fit where I want them (they measure out to that point right now!) and this will go in the car next weekend(or maybe the weekend after that, we'll see) Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 31, 2011 Author Share Posted July 31, 2011 (edited) Ok, so I finally got the header put together and fitted up in the car. Fitment isn't perfect...If I cut the secondary collector off and moved it forward about an inch and a half, I'd have better transmission clearance, but I'd be getting awful close to the firewall. Nothing hits, nothing rubs, throughout the full range of motion of the engine. Getting it in the bay, however.... It takes practice. That's RedZedTurbo holding the header up after I finished welding the flange on the back. Tomorrow the welds get cleaned up, the header will get blasted and VHT'd for now, I need to get it on the car and make sure it doesn't have any issues before I send it off to be ceramic coated. As it is, I need the car up at least 14 inches off the ground to get the header into the bay, and I have to pull all the head studs to get it installed. John wasn't kidding about it being tight on the steering shaft, but morso it's tight on the TC rod box. Edited July 31, 2011 by Xnke Quote Link to comment Share on other sites More sharing options...
Xnke Posted August 1, 2011 Author Share Posted August 1, 2011 And for the bad news...The damn flange needs to move to the back of the car by an inch. Just one inch further back and I wouldn't be hearing the sound of the exhaust ting, ting, ting'ing against the transmission case...tappy tappy on one of the case bolt heads. Time to order another manifold gasket...at least it doesn't take me long to get things apart and back together. Quote Link to comment Share on other sites More sharing options...
johnc Posted August 1, 2011 Share Posted August 1, 2011 Now people are starting to understand why that particular header cost so much. Getting the equal length primaries to fit is a real pain and the secondary merge makes it even more difficult. Quote Link to comment Share on other sites More sharing options...
Xnke Posted August 1, 2011 Author Share Posted August 1, 2011 It is an awesome header though...I drove it around today and it's like a whole new car. Had to almost completely rework the fuel map...what was rich before is now a little lean. I'm going to take the car on a road trip this weekend, assuming everything goes well this week. Quote Link to comment Share on other sites More sharing options...
ollie Posted August 4, 2011 Share Posted August 4, 2011 I finally received my Stahl header today and it is a work of art, well worth the wait. Really looking forward to installing this on the car, probably won't be until the winter though. Quote Link to comment Share on other sites More sharing options...
240zip Posted August 9, 2011 Share Posted August 9, 2011 did you get the DIY kit or has something changed ... meaning they're selling completed headers again. Quote Link to comment Share on other sites More sharing options...
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