What wall thickness would work with the 321? .035 do the job?

 

I'd use .065 if you could, its easier to work with and a bit heavier, but the noise difference will be dramatic.ie thinwalled stainless tends to "ring" more, and with my level of welding skill I tend to chew up thinwall.. A good compromise would be the .049 I imagine. I have always wanted to build out of inconel but never had the ***** .. heh you screw up a weld and $$$ . I would think with 3 u bends you could build 2 manifolds easily.. 6" legs, so you could do the angle cut/weld/angle cut/weld/angle cut/weld tiger stripe thing (wtf is the proper term for that?) to get a tighter bend if you need.. The make some gussets out of the leftover =D heh like I said I like to do things once..

Unless you happen to have a mandrel bender? then Im coming over with some straightpipes!

 

Does anyone know how long the main runners should be? If I remember right Riceracing said to try to make them close to 13". Also remember someone saying to make them short for high RPM power and long for low RPM power. Does anyone have any input on this? By judging where my turbo has to sit and the pieces I already have cut out it looks like I can only get them ~9" long.

BicuspiD- I'll have to try the 321 next time. The 304 that I have here is .125 wall thickness

 

I am thinking of using the newly aquired water jet here at work to cut out a bunch of manifold plates out of stainless 304 or 321 ......and 4'x8'x1/2" stainless 304 sheet is around $600. I wonder how many plates I could get out of one sheet. I might be offering these shortly for sale. I will need to make patterns off of anything but FC's though. I am assuming they are a little different between series of engines.

-Morbius

 

at burns stainless the sell whats called inconel I beleave and that is supposed to hold up to heat much better than stainless and they even specified for rotary engines.

 

Inconel Is great stuff.I don't think Burns can bend past 120 degrees because it is very hard and will break. That doesn't mean that you can't cut / weld many times to get your bends. It is also more difficult to weld than 304 or 321 ss. Inconel will pollish t a very nice shine and can withstand alot more heat than 304 /321

 

Time for another update! I made it come out of the engine straight for 3", straight into the turbo and 13" runners like recomended.

 

like my welding process?

 

wheres the wastegate going to go??

 

It's ~3/4" from the frame rail



The wastegate?...Bahh we don't need no stinkin wastegate! But for real not sure yet.

 

Speaking of wastegates where would be the best place to plumb it in? I was thinking of taping into the first 3"s of the manifold?

 

Looks great! Tape the 2 flanges closed also and then poke a couple of small holes in the tape on one end to make purging the oxygen out easier. That should make your welds look purty inside and out.

 

Looks very nice. Is there a way you can weld a prop/support from the turbo inlet flange Engine flange, to the motor? Perhaps take a little stress off of the tubes/welds holding the weight of the turbo.

Wherever you can fit the wastegate, and minimize turbulence/welding will work well. A lot of tuners "siamese" the WG inlet, right off the turbo inlet area. Do you want to toue the WG back into the downpipe or goto atmosphere?

Excellent work so far ! keep us posted..

Richard

 

Thanks guys

I was also thinking I should make a brace somewhere to prevent the manifold from cracking at the engine flange. I saw a pic of rice racing's engine compartment once and he has a brace going from the middle of the intake manifold to the turbo (think thats how it went), seems intresting. I was thinking of welding triangles on the tops of the main runners at the engine flange, think that would be good enough?

I'd like to be able to do that siamese thing to the wg runners right before the turbo but there isn't any room Do you think it would be better to "Y" the WG runners out of the main runners or to "T" them? I also plan on runing the WG back into the dp, why do you ask?

 

When I had my manifold made we had one brace going from the engine flange to the turbo flange and another from the turbo flange to the intake manifold.

 

I'd probably y-them.. smoother flow.. where the runners come straight out from the engine, right at the point they turn up, Id prolly put a short turn down and go there, mountin the WG as close as I could to the runners. You dont want a long stretch to the WG in that location, may cause reversion as the gases "decide" where the path of least resistance is by fighting themselves, and it seems you wouldnt disrupt flow too bad by making a short run.

I asked about atmosphere and piping it in simply to facilitate mounting. If you know you are going to atmosphere, you can just vent it straight down.. If going back into dp, you must make sure the w/g outlet clears the rest of the manifold, and will be convenient to mate to the DP smoothly.

Next you can make me one

Richard

 

haha, make you one...lol It's taken me over 3 months to get this far! Of course it doesn't help that I'm kind of a slacker lately

 

Setzero,

Looks very nice so far, your patience is paying off. I think I understand why some folks have added the braces, such a long exh mani would seem to put quite a bit of load on the rotor housing/studs due to the cantilever length. Best suggestion hear is to make the mani flange at the motor as tall as the machined mating surface on the motor allows, this would help to counteract the cantilever effect of the large mani.

With the heavier wall tubing and full pen welds at the 1/2" flanges I doubt you will have issues with the mani itself. The only suggestion I could make is to bump up in thickness on the 3" pipe section that welds to the motor exhaust flange. The rest of the mani tubing should not be an issue.

For the wastegate tubing you seem to have many options. I would be tempted to use the space above the mani between the flanges, it would make access to the wg easy but may heat up the LIM a bit. Nothing that a heat shield wouldn't fix.

Nice work!

 

What about the difference in expansin rates of the headers and any braces? Is it possible for the hot pipes to expand against the brace and tear the manifold apart? Just wondering. Oh, and good work. I'm going to do the same thing.
Don.

 

I still think you would want to get the weight of the turbo off of the manifold itself as much as you can. Thats just undue stress on the welds, and with heat and vibration, It doesnt seem wise. You should be abl to fashion a stay, if anything, from the turbo flange to the engine flange. This way you dont really have to deal with the tubes expansion.

 

haha, never herd that one before


I'm not really sure yet where I should run the bracing and the waste gate piping, there are too many options it seems. Seems that every way I think of doing it there is a drawback. Just need to figure out which way is the "best" way of doing it.

If all goes well tonight I'll get to fire up my buds tig welder and try welding together some scrap pieces and se how it turns out.

Oh yeah, one more question. When I (or my buddy) weld the pipes into the engine flange should I weld both sides or just weld the inside?

Thanks

 

Yet another update on project manifold

Well I got off my *** and started working on it again this week and here's where I'm at now

 

pic 2

 

pic 3

 

call me crazy but are you sure you are going to be able to get the header on the car w/o lifting the engine to put it in? it looks like it goes out way too far. remember the studs stick out around 1.5" and that has to be accounted for