Figured a way to get COMPLETELY equal header tubes

[89onaquest]

Yes boys and girls...

 

I did find a way to get completely EQUAL LENGTH header tubes to not only fit, but leave room to spare! And all without a CAD program. Yes, I did this all out on a drawing board.

 

The runner legths are 7 5/8" long and the top of the flange is lined up with the center line of the exhaust ports. So not only are they equal length, the turbo sits roughly 3/4-1" LOWER!

Why lower? well I am installing remote filters, and I want to get the turbo heat as low in the engine bay as possible to increase air flow and suck the excess heat out of the bay as quickly as possible. I am hoping to be starting construction in the next month or so. Money is tight, however I am getting hell of a good deal on the tubes, all 10 bends for $150 shipped and yes .049 304 SS. All Madrel bent, and on a 3" CLR.

 

 

Right now this is all laid out on paper only. I am still tring to D/L a good CAD, looking for 02/04 mechanical. Right now I only have 04 architect.

Though I have done the 3 angle and looks like everything will have room with the routing I came up with.

 

If any have questions, post 'em. I will do best to answer

[Yellow_quest]

304 stainless has a history of cracking....it'll work but it's not the best suited for the 1600ish F temps that our exhaust manifolds see on a hard drive.

 

 

Might look into weld'els as they seem to be the standard in the race world....

 

 

 

 

Yellow_quest

[89onaquest]

then what SS do I need to use? 314?

 

or same guage mild steel?

[heefner]

Mild steel is easier to work with and repair if you do get a crack.  A performance manifold will see temps in excess of 1900 degrees.  Are the number of bends per runner also eaqual?  Equal length is nice but eaqual bends is evern better. Will you be using Mig or Tig to weld it together?

[ALANFROMPDX]

321 stainless and it really pays to have a qualified TIG welder do the work if you cannot TIG it yourself.

Steel is nice to work with but lets face it Stainless is the way to go.

Ideally you want good to great penetration as the welds can retain heat and cause cracking.

[ALANFROMPDX]

Both 321 and 347 are good for exhaust headers, especially turbo engines.

321 is more available than 347.

 

316L is an extra low carbon  grade of stainless that has only .03% carbon,it is used alot in the dairy and brewing fields. or beverage fields.

My father is a chemist  for a Major beverage company in portland and i have noticed alot of the equipment in 316l. and i am sure it is due to the changes in PH.

 

304 is the most inexpensive and available stainless in the 300 series.  It does not have the high temperature fatigue resistance that 321 does, but is considerably less costly and much more available. Most 304 tubing these days has the dual designation of 304//304L.

Most beer kegs are made of this grade. this i am sure of.

All my homebrewing equipment is made of this, mostly from converted kegs.

They are stamped in the top 304L.

I wont rant to long on my background but working in the aerospace field for 13 years gave me the opportunity to make some nice things.

I had my 15 gallon home brewery made in a day.

All Tig'd

All stainless.

 

I can go on all day about alloys but won't, drop me a PM

 

PDX

[89onaquest]

Mild steel is easier to work with and repair if you do get a crack.  A performance manifold will see temps in excess of 1900 degrees.  Are the number of bends per runner also eaqual?  Equal length is nice but eaqual bends is evern better. Will you be using Mig or Tig to weld it together?

 

the bends are not equal, 2 Vs 3 90*s but it is as close as I could get it without have a series of snakes, and a welding nightmare.

 

I will make the jig(an old head), and spot the pieces togeather, then take it to a shop to have them tig'd togeather. I already asked about bringing loose parts Vs spotted togeather, and he said spotted would be better, as they will not have to figure out how the parts go togeather, and screw it up and have to make me another one out of their pocket.

 

I am talking to tubing source to see if I cannot get 1 7/8" tubing with the 1 3/4" ID, so it would be thicker. I asked him about the 304 and turbo header and he said, it "should" hold up fine with some braces to prevent heat fatique bending. So I now have to either find the thicker metal, or add braces, which would be no prob...

 

I appriciate the input. If I can get 1/8" thick mild steel, should I just take that and call it a day? then have it coated later?

[importwarrior]

how about somthing like tyhis?

 

http://members.cox.net/starquest/Chad/MANIFOLD.jpg

 

all tubes are with in 1/8th of an inch.

[89onaquest]

how about somthing like tyhis?

 

 

 

all tubes are with in 1/8th of an inch.

kinda, but not really. Basically yes. To get to the point.

 

That looks good, do not get me wrong, but I am focusing more on tube length, then equality. I am looking for length that will hold 1 exhaust charge per tube.  If that makes sense. It will help cut down on turbulance and "fighting among the gasses" in the header.

 

I have to look up the math I used again, but from what I recall, this would be optimum for 16-18 PSI. Just as one charge is finishing its push, another comes in. This was set for a 4 Cyl 2 cycles at a time at off ends of the header. 1/3 2/4

 

EDIT: do you mind telling me if those are 304? or what they are?

[eeaston]

Here's mine.  11" equal length runners, used 5x 16GA(.065) 304 SS u-bends 2.5" CLR @ $20 each.  If I do another one, it'll be 321ss, I'll see how long this one lasts.

 

 

You can see it sits nice and low and leaves plenty of room to access the spark plugs.

[89onaquest]

Here's mine.  11" equal length runners, used 5x 16GA(.065) 304 SS u-bends 2.5" CLR @ $20 each.  If I do another one, it'll be 321ss, I'll see how long this one lasts.

 

 

You can see it sits nice and low and leaves plenty of room to access the spark plugs.

thats exactly how I did mine, just shorter runners.

 

I am getting my bends 2@25 on a 3" CLR from a guy on ebay. Do you mind telling me where your getting yours from?

[heefner]

Easton from that pic it looks like the down pipe will hit the ABS bucket?  I'm assuming that you will scrap the ABS but would it work if you kept the ABS?

[rjf]

Well it looks pretty.  I hope you do something about

all the heat you are going to have.  The turbo is very close to

the brake lines and they will fail if they get too hot

(happens to the best, for those who remember

Parnelli Jones lost a brake line that way at Indy one year).

Also you should wrap all the runners in insulation, as you have about

10+ times more surface area than the stock manifold.

 

Question for all of the folks who have built or are building

one of these exhaust manifolds.  All of the designs I have seen

start with a thick base plate that bolts to the head.  But one of the

problems with the stock manifold is that it was so rigid it was causing

mounting stud failures.  That is why folks cut the webbing on the stock units.

What keeps these custom units from causing the same stud failures?????

[89onaquest]

Well it looks pretty.  I hope you do something about

all the heat you are going to have.  The turbo is very close to

the brake lines and they will fail if they get too hot

(happens to the best, for those who remember

Parnelli Jones lost a brake line that way at Indy one year).

Also you should wrap all the runners in insulation, as you have about

10+ times more surface area than the stock manifold.

 

Question for all of the folks who have built or are building

one of these exhaust manifolds.  All of the designs I have seen

start with a thick base plate that bolts to the head.  But one of the

problems with the stock manifold is that it was so rigid it was causing

mounting stud failures.  That is why folks cut the webbing on the stock units.

What keeps these custom units from causing the same stud failures?????

with the thickness of the stock manifold, the heat/cool cycle can move the studs alot, with the relatively thin mounting plate, this is not as promenant.

[ALANFROMPDX]

I always thought it was due to the rate of change due to heat.

Thermal expansion is the reason.

Aluminum expands more than anything at high heat.

it is the expansion of the head that rips the studs out , that and over torqueing.

 

Don't want to geek anyone out with thermal expansion info but things expand differently to the same amount of heat.

 

And the closer the coeficient the better.

Aluminum is 24 and cast iron is 12 but stainless is around 16 and 321 is 18.

the difference is less using 321 stainless and an aluminum head.

Again we have 24 and 12with iron

or 24 and 18 with 321

stainless will still expand but at a closer range than the cast iron.

 

thermal expansion is not only linear or in a line but area and volume.

Area is like it swells and volume would be like a pot having more volume when it is heated.

that is why labs use pyrex glass over normal glass.

ordinary glass coefficient is 9 and pyrex is at 4.

so it is safe to say hot and cold the volume is the same .

 

coefficient is a constant number that serves as a measure of some property or characteristic.

[heefner]

having said that, wouldn't you want to use iron so that it swells less and puts less pressure on the studs.  If anything use stainless studs so that they will swell equally with the manifold.  I can't see where having the mani expand as much as the head would be benificial.

[89onaquest]

having said that, wouldn't you want to use iron so that it swells less and puts less pressure on the studs.  If anything use stainless studs so that they will swell equally with the manifold.  I can't see where having the mani expand as much as the head would be benificial.

what allan said is true, just very technical.

 

Iron expands at twice the rate of aluminum. Aluminum sheads heat 2X faster.

 

When you have a metal that holds heat that much, it stresses the threads in the aluminum head to a point they can be ripped free, by the iron manifold. Simply changing the studs, or bolts do you no good. It is the base tapped metal that is being ripped apart.

 

Stainless steel can lose heat at 1.5X that of aluminum. IE aluminum is 12, SS 18.

 

The thickness of the metals also comes into play.

even though SS sheads heat slower, it is only 1/2" thick. So the expansion may only be a couple thousandths of an inch, not much. Where are the Iron at 3+" thick may increase in size in the hunderedths of an inch, which anyone that builds engines, that is a big deal.

[rjf]

""allanfrompdx wrote -

And the closer the coefficient the better.

Aluminum is 24 and cast iron is 12 but stainless is around 16 and 321 is 18.

the difference is less using 321 stainless and an aluminum head.

Again we have 24 and 12with iron

or 24 and 18 with 321

stainless will still expand but at a closer range than the cast iron. ""

 

This is a reasonable explanation.  I did not realize that the coefficient of

expansion of SS was so much closer to AL.  Seems like a design consideration

for those folks trying to weld one up from steel pipe elbows.

 

A couple of comments on responses to my original question.  

The "cure" on the stock manifold was to cut the webbing.  This tells me that it was the difference in side to side expansion(shear) that was cracking the studs, not the expansion of the base flange (tension) pulling them out.  The cut webbing allows them to flex side to side a bit more.  The thickness of the flange is not changed  

 

The custom units being created have a thicker flange than the stock unit.  And if SS has a greater rate of expansion (to make it closer to AL) then there would be less shear load but greater tension load on the studs with the custom units.  I do not

know what the coefficient of expansion is of the metal used in the bolts, but

this rationale would lead me to believe that SS bolts may be called for.

[89onaquest]

Has anyone thought of doing a sticky on header design techniques, and overal design, and general good information like the metal expansion formulas and explainations and such?

 

If not, then this would make a good canidate.

[jinx]

quite a few of us locally make our own manifolds from sch 40 elbows and have no durability problems with em. One thing I include is a support bracket... thats alot of weight 'hanging' off there.

 

We normally make paired runner types, 2&3 1&4. Not worth it to sweat the details of having an equal length turbo manifold imo. Its mor important to 'merge' exhaust flow so u don't have air hitting deadends and having to 'find' their way outta the header - like the stock 2.6 manifold.

Look at a GN stock manifolds.. far from equal length, but they all 'blend' towards the collector. Spools like crazy, sustains a very broad torque curve.

[importwarrior]

steel flanges and 304 runners

[ALANFROMPDX]

Really cool having all these people doing different things too.

Theory is one thing but actually seeing how some hold up over others is the real information.

Kinda like giving our cars CPR.

all they really need is a better intake and exhaust and they would have had it had they continued the line. It is just a matter of time til one is featured.

everyone keep up the good work and thanx for sharing.

 

Alan

[eeaston]

If you're looking for 16GA 304, go to

http://www.ssheaders.com/JBends.htm

 

Heefner- There's more room than it looks in that pic(it would fit with a custom DP), but my ABS is bypassed anyhow and the can will be going away.

 

RJF- Don't worry, I'll do plenty of heat shielding.  Also, headers do have way more surface area(maybe 2-3 times),  but that is offset to a large extent by the much lower thermal conductivity of SS over cast.

 

As for thick flanges, you have to have them fairly thick to get a good seal since the studs aren't diametrically opposed across the port opening.  The runners aren't stiff enough(like thick cast ones) to hold the flanges flat if the flange were cut into 4 individual ones.

 

Aluminum has a COE of around 12 (in/in*F), cast iron is between 6 and 10, and the low-alloy steels most of us use for flanges are right around 8(stainlesses are around 9.5), so the head will expand more than the flange at a given temperature, however I'd expect the flange to be considerably hotter than the head.

 

The thickness of the flange doesn't increase the shear force on the studs or the tensile force (since the stud expansion length will always be the same as the flange thickness and they have very similar COE's anyhow)  If it's a problem, I'll try some ARP studs.

[steelwindmachine]

For our turbo headers and NA headers we usually use 1/4" steel flange with SS 321 tubing.

 

You DO NOT use stainless bolts on the header, turbo flanges or down-pipe flanges because stainless will gall from the heat. Use Grade 8 black-oxide coated bolts without Anti-seize. Instead use graphite lube.

 

You can use grade 8 header bolts or studes from ARP and they'll be fine.

 

A steel flange will be fine and won't really rust since any moisture its exposed to when the car is running will be burned off immeadiantly. You could spray paint it with a hi-temp paint if it irks you.

 

No need to reinvent the wheel here.

 

For more online info, check Stainless Works or Burns Stainless.

[89onaquest]

1/4" is a little thin for amounting flange IMO.

most N/A motors use 3/8 to prevent warpage. and they even have lower exhaust temps.