DIY exhaust header

[Dutch_RsBlueS2]

Originally posted by Tylerb929
Sorry, but those aren't right if your making a flange out of them. I've drawn the flange in AutoCad based off the stock 3B exhaust manifold and there is a little bit of difference.

Maybe if you want you can share those autocad files with us, it would be very good for me so i can use it for a school assignment

[Pisobiker]

Originally posted by Tylerb929
Nevermind, I just checked them, there pretty much good except the size of the holes because obviously due to heat expansion the manifold is going to have a larger diameter hole so that it doesn't strip the studs. And of course the stock manifold is cast iron so its not too exact.

Yeah, I did check as well on the manifold (right now).
Stud holes are 11 mm diameter instead of 8.5 mm of the gasket, except for two of them (4th from left on top side and 5th from left on bottom side of manifold gasket drawing) which are 8mm diameter.

Anyway gasket fits the head studs like a glove (unlikely the manifold that has some little play). So, in my opinion, gasket mesurements are by far the best for precision.
It comes by itself, of course, that after having manufactured the header (some distortion by welding and machining) area of contact between flange and head must be machined flat, and holes would probably require some very small adapting by file.

Best way to work matching between head exhaust ports and header ports, then, is:

1)Evantual porting and polishing of head exhaust ducts;
2)Cut the metal gasket main holes down to match precisely head ducts shape and position;
3)Using the above mentioned gasket as a dime, machining the header ducts shape and position to precisely match the gasket.

This way flow will go through smoothly without finding any sharp edge or step on its way.


Marco

[Dutch_RsBlueS2]

Thnx again marco for the drawings but do you also have them in cad format ? thats easier or some other measures can be taken out of it witch arent in the .jpeg

The reason why i`m also involved in this thread is because i`m going to make a "fast" exhaust manifold for my future rs2 engine project. And i`m also doing this because of my school, i`m doing the HTS in holland wich is a high technical education for cartechnics. And i`m getting points for this so its good in 2 ways

And i also have a good source for wich material to use it will be SS but i`m sorting out wich one. It has to be one with more Ni. in it and less Cr. for high temps and it needs to be not the stiffest type of SS. Also the pipes between the head and turbo flange need to be thin, like 1 to 1.5mm.
The head flange has to be around 8mm if you want to play it safe because of heat. So the rough material should be 10 so you can machine it after welding to about 8mm.

Well come back to this later when i have some drawings and some more info on the SS. i`m gonna use. I guess the turbo flange will be a bit different but that doesn`t matter.

Greetingz Cees

[Pisobiker]

I'm sorry m8.
My laptop is actually broken so I'm not able to create nor view .dwg files (I use a Machintosh at work on which I have installed a Mac version of AutoCad. Those files are actually done with it then converted to a jpg format) but they are not readable by PC.
If you wish, send me an e-mail to me (pisobiker@katamail.com). I'll send the original file anyway. You may try to open it some way (I wouldn't know how).

Following is the latter flange needed, manifold to WG.
Main hole on manifold (and flange itself) isn't wery precise (hole has quite a big offset compared to center of WG seat). My drowing, instead, should be perfectly symmetrical (dotted circle is where exactly WG seat contacts to flange).


Marco

[Pisobiker]

Forgot to say:

latter flange have threaded holes to accomodate 8mm diameter WG studs. Didn't have the possibility to mesure thread size anyway (if standard, they shoud be 8x1, though).

[Jeffer]

Hi guys,

You've been busy while i was gone

I did some research on the net about ss variaties. I came to the conclusion that ss #321 is best suited for the job. You can also see that in the burnsstainless.com site.

Now i'm searching for a steelsupplier in Holland that has #321. I've heard that it comes from the steelplants in germany, and that in holland #304 and #314 are made. So i've not succeeded in that.

Dutch_bleu:
mail me your Phonenumber, then we can make an appointment.

Pisobiker:
I've had in mind to mill all the exhaust flanges one by one in stead of all linking the thogether like on your drawing. With separate flanges you generate less stress on the cylinderhead. Eventually one of the two different metals will give. What's your vision on this?

Greets,
Jeffer

[Dutch_RsBlueS2]

Originally posted by Jeffer
Hi guys,

You've been busy while i was gone

I did some research on the net about ss variaties. I came to the conclusion that ss #321 is best suited for the job. You can also see that in the burnsstainless.com site.

Now i'm searching for a steelsupplier in Holland that has #321. I've heard that it comes from the steelplants in germany, and that in holland #304 and #314 are made. So i've not succeeded in that.

Dutch_bleu:
mail me your Phonenumber, then we can make an appointment.

Pisobiker:
I've had in mind to mill all the exhaust flanges one by one in stead of all linking the thogether like on your drawing. With separate flanges you generate less stress on the cylinderhead. Eventually one of the two different metals will give. What's your vision on this?

Greets,
Jeffer

I think if you like i can supply all sorts types of S.S also all sorts of Tubes/Pipes. I`will mail you when i`m at home But we can talk it out if we meet in the near future

[Pisobiker]

Originally posted by Jeffer

.......
Pisobiker:
I've had in mind to mill all the exhaust flanges one by one in stead of all linking the thogether like on your drawing. With separate flanges you generate less stress on the cylinderhead. Eventually one of the two different metals will give. What's your vision on this?

Greets,
Jeffer

Jeffer, I honestly don't have a big experience with SS.
It maight be fine to do the way you suggest. But I don't think linking the 5 single flanges will cause significantly higher distortion or more stress on the head,giving instead to the assembly some higher overall rigidity.
What I'm concerned about is that on a complex SS header like the one needed for our 5 cyl engines, in which duct shapes and lenghts would never be the same among each other, thermical expansion and distortion may be a rilevant problem which, apart form cracks,may cause the whole weight stress of header+turbine+downpipe to be taken only from few single flanges and studs instead of being (more or less) evenly distributed to all of them.
Since on a tubular SS exhaust header issues with distortion and cracks are a rilevant problem, it maight be wise to ask someone who has already experimented different designs for feedback.

While manufacturing and welding, moreover, its very likely to happen that a lot of internal stresses are created among the elements, which could further increase weakness of the assembly (SS resistance drops quite a lot with increasing of temperatures). As said I don't have the data and enaugh experience with SS to tell, but might also be good to figure out if a termical treatment for "stress reliefing" would be needed and the exact way to do it (how high the temperature, for how long, and way of cooling everything down).

Just some thoughts.

Marco

[porkkis]

Originally posted by Pisobiker
Forgot to say:

latter flange have threaded holes to accomodate 8mm diameter WG studs. Didn't have the possibility to mesure thread size anyway (if standard, they shoud be 8x1, though).

M8x1,25 is the standard size.

[Pisobiker]

yeah, that's right.

M6 and M7 are 1.0

[Dutch_RsBlueS2]

quote: ---> Jeffer


I've had in mind to mill all the exhaust flanges one by one in stead of all linking the thogether like on your drawing. With separate flanges you generate less stress on the cylinderhead. Eventually one of the two different metals will give. What's your vision on this?

Well i actually talked this over with a real genius from the HTS(Autotechniek)(the school wich i visit everyday ) and he had some interesting things to say. But its very much to type here, i will if i have some spare time. But what i`m looking for in the catalog at our company is a SS sort wich has less Cr. and a higher percentage of Ni. So it stands up against high temps and also it is a mistake to use thicker tubes. At least thats what this material (god) said. Its more usefull to use like 30mm tubes wich are only 1-1.5mm in thickness. This will not generate that much stress and also let you make a head-flange out of one part. He said that if you use a little bit thicker flange it won`t bring any trouble.

Btw i will mail you my phone nr so we can talk dutch its much easier

Also with all the knowledge i am gaining here on the forum and with some help from school i will make a 3d model within a few weeks and will post it here to here from you. Appart from the material there are several things we have to think of but that will come in a later stadium.

[Jeffer]

I'm now gathering pics of homemade headers.
Will post some later.

Greets

[Jeffer]

Here's an example

[Dutch_RsBlueS2]

Damn, this peace looks sweet, but i guess this is also meant for a 20V Turbo?

But you have to make a custom downpipe with a new pipe for the wastegate.

Where does this manifold come from? or who built it?


Greetz Cees