I'm planning to build a 16V Syncro exhaust manifold once I've gained more experience with my TIG welding. What I basically want to do is make a stainless copy of the VWM cast manifold as used in the 16V G60 Limited; i.e. it's a cast manifold that looks pretty much like the regular 16V KR / 9A manifold except the downpipe mating flange is offset and twisted so that it mates with a Rallye downpipe. VWM manifold: (These images were sent to me from a guy who was selling this very manifold on eBay.de some months back. How much did it go for in the end? Put it this way... it was only a few hundred quid more to buy a decent AC/DC TIG welder.) I plan to keep this thread updated as I make progress. The first question I have however is can anyone recommend a good fabricator to get the head and downpipe flanges cut please? I do happen to have a 16V head flange that I was given, but it's not stainless (as far as I can remember without digging it out) and I'd have thought I'd want the flanges to be in 304 stainless (presumably - I yet need to read up a lot more on different stainless types). Does anyone have design files for the 16V head flange, e.g. in DXF format? Also, are there any sources for mandrel bends that I should avoid? The sellers on eBay who are offering stainless mandrel bends - are they all pretty much the same thing and same sort of quality, or is there a lot of crap out there? Cheers, Trev
I looked at where these stainless supplies come from before the motorsport mark up was applied. Here are a couple of links to potential suppliers. http://www.allstainlessltd.co.uk/pr...lbow_10w.jpg&productpic=phot_nbfitt_elbow.gif http://www.lancs-fittings.co.uk/
Thanks Dan, much appreciated. At a very quick first glance, the prices for mandrel bends in the first link seem to be a lot cheaper than the ones I see for sale in most places (e.g. eBay). Presumably those are mandrel bends.
Are you thinking I could consider making a complete manifold and downpipe replacement? I'm thinking I'd possibly do that in future, but for the time being I'd keep it simpler by just copying the VWM part and retaining the downpipe, but maybe replace the whole lot as a kind of MK2 attempt. Are there any other aspects you'd look at improving on? I don't know how critical it is, but for starters those individual cast runners look to be very different lengths. So - in the ideal world - I'd make something with equal length runners. There's a picture of a VWM Limited manifold copy over on Dubforce where they've done exactly that, so that all four tubes look pretty much equal length. But the build complexity is much greater obviously. I need also to consider what diameter of tubes to go for. I measured the port diameters on a spare 16V head earlier and they're about 38mm. Downpipe port diameters about 44mm.
I bought a copy of this book Trev: A very interesting read, even if it is all in imperial units. It may not matter so much that the primaries are unequal lengths - the main point of the above manifold is to keep the cylinder pairs 1&4, 2&3 isolated from each other to prevent interference during valve overlap. After that, it gets very complicated, very quickly!
How thick is the metal on the flange? I have a mate who works with stainless and has huge sheets of it laser cut to make all sorts of stuff.
Didn't Sambo do something similar recently - maybe check his build thread for that old Honda with the 1.8T in it. EDIT: Found it - different thread, but here it is http://www.clubgti.com/forum/showthread.php?t=230446&highlight=flange
Some highly useful information and suggestions there. Much appreciated, thanks. Alexisblades99 - looks a good book, and probably one of the cheaper ones on the subject. Going to get that ordered. Ian - I'm not sure how thick the flanges should be. Any suggestions? I'm guessing around 8-10mm. Would it be possible for me to get in touch with your friend about this, and do you know what kind of data he'd need? DXF file? Mike_H - I was about to look for that thread. That's spot-on what I need for a reference, that is. I did phone up one of the suppliers that Danster mentioned and the guy on the phone reckoned that the schedule 40 pipes that Sambo used sound a bit heavy for an exhaust manifold, and that schedule 10 might be more suitable. On a 1 1/4" (42mm OD) 90-deg bend, we're talking about a wall thickness of 3.56mm vs. 2.77mm. Considering head ports are 38mm and downpipe ports are 44mm, I'm thinking of using 1 1/4" (42.16mm OD). The next size up would be 1 1/2" / 48.16mm OD.
Another option, according to chap at All Stainless Limited, is to use hygienic tube fittings: http://www.allstainlessltd.co.uk/products.asp?category=4&subcategory=1&productimage=draw_od_90degbend.jpg&productpic=phot_hyg_bend_p.gif These are of a much thinner wall (1.5mm) than the nominal bore fittings, and also have the advantage of being available with various bend radii. I'm still tempted to use the nominal bore fittings however (schedule 10, 2.77mm wall) because I'm probably more likely to be able to TIG weld them to each other, and also to the much thicker flange material, without royally f*cking them up! Other advantages of welding thicker walls: less likely to have heat distortion problems, less likely to have cracks, less noise?
Another nominal bore supplier for reference: http://www.completestainless.ltd.uk/page/nb_elbows (Grades 304 and 316)
Did you get my PM Trev? He says he can do it and I think he mentioned DXF while he was baffling me with science.
I got the nominal bore bends through today from All Stainless. Went for Schedule 10, 1.5", 316L. Well, I hope they're "L" -- the print on the side suggests they are. Bought a load of 90 bends together with a nice long straight length. So cheers to Danster for the tip. My mate Alan is now designing the flanges in Solidworks for me, which will be laser cut in stainless.
Spotted this which might be interest to some of you http://cgi.ebay.de/Hosenrohr-Passat-Golf-Syncro-16-V-G60-/110716136222?pt=DE_Autoteile&hash=item19c7322b1e Use that downpipe with a scirocco 16v manifold and job done? Certainly looks like it would work
Hi mate, Funnily enough I do have a Scirocco 16V cast manifold; I was actually going to do something pretty similar to that. Looks like the the way it's done is quite tidy as well. Thinking about it, I'm guessing that they've carefully pressed and twisted it so that the flange is no longer twisted at an angle like it is on the Rallye / G60 Syncro downpipe. Can't see any welding on it.
Or OE? But can't think what passat it would have come on, all the others I've seen are the same as rallye.
Definitely no OE Syncro downpipe other than the usual Rallye / G60 Syncro / carb Syncro types as far as I am aware.
If you look at the flanges where it pivots, the pivot points are side on instead of diagonal on like the g60 downpip
