Recommendations on manifold?

I used and
No issues appart from steering rod clearance.

I would have gone MSP but funds played a part.

 

I really don't wanna argue here... But this is engineering field and if you are not aware of tensile strengths of the steel welds "which btw can support few TON's over just few surface millimetres... Not just few KILO?s of Turbo's weight? Then? Weld strength calculation can prove this any day of the week?

Other exhaust manifold components that are subject to failure or (vibration if you will) include the exhaust system hangers, which are designed to hold up the entire system. These can break off, leaving the whole weight of the exhaust system to be carried by the manifold, and eventually causing it to fail/crack.

Talking about VG30 and support brackets ?. My support is simple cut-out/slightly bent metal plate that bolts on exhaust studs after dump pipe flange, on the turbo side. And in to the block holes that are meant for engine lifting bracket. (Engine?s left hand side).

Right hand side bit more difficult to explain ? I will post the pic?s anyway ?

All that effort is to support the ?weight of the whole exhaust system? before manifold in case there are some issues down the line, and equalization of the manifold stress loading ?
There was a good point about blowing holes through the welds, however according to Garret:
?The exhaust gas temperature can reach over 1600F/871°C under high load operating conditions; i.e. towing, extended uphill driving, or extended high rpm/boost conditions.?

Hypothetically speaking we can give the Garret?s approximate value of 871°C a new and more accurate value of 1050°C as a maximum heat dissipation at any load!!!

At that point we are short of 460°C, of the Stainless Steel melting point. Which is around 1510°C

Hypothetically speaking at that point we are ?glowing red? but not there yet to puncture any holes. Welds or SS?

With extra ?unburnt? oxygen left in the exhaust system at the maximum ?boosting? pressure over 43.51PSI/3Bar we might be able to archive that, but there shouldn?t be much oxygen left in there anyway? Not in the range of 10-20psi/0.68-1.37Bar ? Or we have some major tuning issues to worry about

All this hypothetical stuff on the side ?.

As for the story telling:
I happen to know one unfortunate WRX owner that had his SS manifold cracked one day after installation!!! ? Mind you that was second hand manifold and it was running for how knows how many click?s before he installed it, and it was running with no issues!!! ? Do you wander why is cracked??? - I have no answer on that ? I can only assign that to poor installation job? He also claims that he have heard a bang and felt instant loss of power ?so I can?t say that it was cracked before that point either??

 

There are some extra question marks appearing in stead of quote's for some unknown reasons ....

 

Its not the weld - its next to the weld thats the issue

It can happen when you copy from a paste sheet/ word sheet directly to the post.

I cannot argue with anything you said, because its all correct, there is a myriad of welding ways to weld anything well and most often than not, the weld is actually stronger than the metal. Just basic metal work nothing fancy.

The problem is the metal closest to the weld.

When welding is taking place the hot metal arcing actually strips away metal to support the weld and this means the metal closest to the weld becomes thin as well as sometimes brittle or weak (from the heating depending on technique used). This is why nearly all cracks in welds run along the edge of one side of the weld and hardly ever cross through it. There are types of welds/ welding to overcome this, but its not common to find this outside aviation welding.

The temps/ pressures and vibration all sound about right, it's just missing metal fatigue in the calculations, as you know a small amount of force over time can change the direction of a river

What I mean is that if you have an existing hole in the weld (which is right next to the weak section), then the area will not suddenly blow through in most cases but rather degrade over time by high pressure/ vibration and heat (metal fatigue will be concentrated on the hole by friction / metal fatigue and weakening structure) and this induces the cracking as well.


My only point I was making was that many SS systems have stood the time and shown the HP but there is a certain amount of gambling when its comes to nearly any SS welds and the only way you can do it with any guarantee, is to have an X- Ray of the welds just as aviation standards would require for certification. I wasn't suggesting that what you had done was incorrectly setup or wrong, I was just saying you cannot still guarantee the weld regardless without X-Ray (even though the probability of a good weld is still very high).

Bracing can improve its stability as you point out long as it has gaskets to prevent the induction of additional frequencies/ vibration. It would be good to see the pics of your system, because it would assist other SS owners (it's not a bad idea for SS owners!)

Sometimes I can sound abrasive but that's never my intent, just a different context intended.

Newer industrial machines often do both now in the one go (weld and x-ray)

Cheers for the input


JC

P.S. Coz replied and I am all good now!
Would love to share but it would be rude without his permission - he has me on the right track...............cheers


:zlove::zlove::zlove::zlove:

 

The problem with SS isn't heat tolerance, it's heat cycling. Every time the manifold gets hot and expands it creates stress points because bent tube welded to the plate flange can't expand evenly, enough cycles and the stress becomes a crack. Supporting the turbo to take the weight off the manifold will help a fair bit by not bouncing up and down on the back of the manifold, NA SS manifolds survive way longer than turbo ones, but ideally you should be using rubber or sprung brackets to accommodate expansion and movement of the manifold.

The proof of the pudding is in the eating, go talk to some SR20 guys about how successful their stainless manifolds were, none of the guys I know will touch them either.

 

I have only ONE question/concern,
"Do you buy/obtain your Question Marks at a discount rate?" If not, why do you throw them around with such Gay Abandon?:br:

 

I understand that you guys don't think that SS is best idea, and I already agreed with you on that too.

However I needed valuable space to install my oversized set of turbos and from what I could of find on the market that was only thing that would of done the job for me!
All other cast stuff was in the wrong shape for my purposes... Or insane markups which I wouldn't support...

I made sure that I did all I can to prevent any unwanted end result.

On the end of the day If bloody thing cracks and if the crack can be seen from the top.
I can jam my torch down and patch weld it... If crack is beyond my reach point than tough luck ... Engine out and Mid steel manifold custom fabrication will occur

But again my expectations are good few years of abuse to come out them manifolds

 

My turbos are not "bolt on kit thingy jig"
Seriously I couldn't be bothered with all the extra fiddling if I could salvage stock manifolds...

I had an issue with stock manifold as that S shape bent would reach down touching the silicone hose on the turbine output. Melting would be an outcome ...

In your garage there is a image of two manifolds that first one silver looking thingy... That would probably do a trick as it doesn't have that bent down...

 

Yes it is clocked properly... All hard lines used too "nightmare to get it all in and tucked them in to the position"

Thanks on the suggestion I can see your point with MSP manifolds.
But all hard work has been completed now and yeah it will take it's chances as it is.