internet ay

heres pics of evans cracked meng manifold. it cracked the first time after 3 months about an inch from the head all the way around the weld. he got that re-tigged, and a week after he put it back on the same runner cracked right at the head flange on the weld, the funny thing is that he wasnt beating on the car at all the second time it cracked because he doesnt have the dump tube on the car so he wasnt really hitting boost.




in this pic below you can see where the manifold was re-welded and you can see the new crack at the head flange.



[Modified by internet izzay, 2:43 PM 2/24/2003]

boostin b16

hmmmm... i bet the reason why the manifold is cracking is because the head flange is slightly warped on both the 1st and fourth runners!! have him reweld the manifold and take it to a machine shop that has a lathe that can mill the manifold untill it is perfectly true(ie. head milling). i am willing to bet that solves the problem!
just my 2c!

TriK

did you support your turbo with a braket?...

SIXTYdashONE

wow, thats a first? meng manifolds cracking? , you should get a $100 welding gift certificate when you purchase one...

paulzy

iTrader: (1)

lol, just look at them, you know their gonna crack right when you fire it up. Imagine that thing trying to hold up a 30lb turbo without a flex joint or bracing

boostin b16

personally guys, i have one and it does just fine holding up my 25lb turbo ... maybe i just got lucky! To tell you the truth thought i have seen many purchased from NuImage hold up pretty well going on a year now daily driven. Whenever you see a "meng" mani crack its always on the 1st and 4th runner right? correct me if i am wrong because i am almost positive there is a few exceptions. in most cases when the meng mani is fabricated the makers weld the runners to the flang so tightly on the end two, that it bends the flange just a bit in on the two sides. now the weight of the turbo is one thing that will deffintly cause a crack or two , but with the flange being slightly bent in the fashion that i just described it stands to reason that when pressure is added to the flange by the exaust manifold bolts that it will crack either or both or the outside runners. need proof? just look at how perfect the crack around the number four runner is in the pic above. anyone who has a meng mani uninstalled right now? put it the head flange of the mani on a flat surface and wobble it back and forth!! then take it to ur local machine shop and have it milled, you will be a lot happer one you install it.

boosted hybrid

I just bought one. I am going to cut expansion slots in the flange, mill the flange and weld a brace to the block. This should cure the cracking problem. They will crack if you dont take the neccessary precautions.

accordfreak

did u have a brace on yours?

internet ay

no it wasnt braced.

SIXTYdashONE

It wont...so dont hold your breath... actually, nevermind, hold your breath

SIXTYdashONE

Im sorry, you must be under the impression that your opinion is worth more then a turd in the toilet. And dont break out any hammers for me boy. This is also beside the topic, bottom line is is that meng manifolds crack. are you going to argue? i dont think so..

AGen2integra

Yes i should have brace it from the point of when I got it.....I really wanted to but I was too damn excited to drive my first boosted car

SIXTYdashONE

Well its not good to rush, you know what they say, IF you Fail to Prepare, Prepare to Fail..

DIRep972

iTrader: (1)

damn, i like that. that is so damn true.

I learned that lesson a few weeks ago actually, thats why i decided to give my turbo set up a make over. basically im taking out all the little weak links, it will be perfect when i get it back together. only weak links left will be the stock motor and stock axles. hopefully

as for the meng manifolds, you get what u pay for. Theres a reason u can get an equal length tubular mani for the same price as a cast log style mani and its not a good one. maybe one day they will get all the weak links worked out of it. by then the reputation will prolly be ruined though. sucks for them

SIXTYdashONE

Why thank you Chris, i give you permission to use it now

Thats all there is to say about them, you get what you pay for. which is basically an OBX manifold, whats that say?

SuperT

The Reason these and most other manfolds out there are cracking is NOT due to the welding process, turbo not be supported, expansion joints not being present, not being braced etc etc..None of those is the reason...
The reason is due to the Material being used. 90% of the manfolds out there are using either 304 stainless steel or worse yet mild steel.
321 Stainless steel is the ONLY acceptable material for use in turbo headers. 321 stainless steel is alloyed with titanium in it and is the only material(besides iconel which costs thousands of dollars) that should be used in turbo header manufacturing.
304 stainless steel and mild steel break down under heat(in technical terms at 800 to 1590 degrees f. they begin a process called carbide precipitation and begin intergranular corrosion and CRACKING.

There is company after company making these 304 SS, Mild steel, or plumbing store weld el manifolds for cheap to make a very quick and handsome buck, but they are doing it at your expense...If they just say in there ad that its made of "stainless steel" you can bet your bottom dollar its 304, not 321. 321 costs twice as much as 304 and about 6 times as much as mild steel or weld els. If its made of 321, it will say so!

There is nothing you can do to combat this carbide precipitation...it is the nature of the material. You can see in the photos that his is starting this process and hence the cracking.

They crack at the welds because that is where the two pieces are flowed together during the tigging process with 308 and 309 wire. Since that area has already had the temperature raised during the welding process, carbide precipitation has already begun!!

The solution(and yes, this is a sales plug) is use manifolds made of 321 stainless steel...yes, they cost more, but it is well worth it! A 400.00 dollar manifold that is useless after less than a year is just a waste of money...spend twice that and it will last for years! Super T Motorsports produces all of its B and D series honda headers out of 321 stainless at a very reasonable price...it really is cheap insurance...

Regards
Dave



[Modified by SuperT, 2:29 AM 2/26/2003]


[Modified by SuperT, 2:37 AM 2/26/2003]


[Modified by SuperT, 2:40 AM 2/26/2003]

AGen2integra

Hey I like your sales pitch......
j/k

Full-Race Geoff

321 cracks too, dont kid yourself. I know another turbo manifold fabricator that has had 321 crack on him on numerous occasions, so now he is going to thickwall for street manifold fabrication. 321 isnt all that. I have quite a bit laying around my shop, and i also choose to use it quite rarely. Mostly for dumptube duties.

if you want, ill get you some solid data on material strengths, i pulled them off CES (cambridge engineering selectors) at school last week. I also highly recommend http://www.matweb.com (materials web). very interesting stuff.

out of curiosity, are you purging (backgassing) your manifolds?


[Modified by FFgeoff, 9:47 PM 2/25/2003]

SuperT

Geoff,

321 is better than the 304 and 316 used in your headers, the extra thickness of your headers does not compensate for the material properties themselves, it only delays the cracking process for awhile, you can not stop carbide precipitation and intergranular corrosion that is inherit in cheaper grades of stainless steel. Only 321 and 347 are stabilized grades of stainless steel, not 304 or 316. I assume you use those materials due to cost? Becasue they are not the best choice in material, you can not argue that point(but you will try, no doubt you must be an engineering major)


Can 321 Crack, yes...but so can and have the 2 foot thick girders of steel on bridges and the 5 inch thick wheels on trains, you point is baseless...

The truth still remains, 321 IS THE best readily available material for turbo headers, period.. Not 304, not forged weld el 304, not 316...

321...

People on this board have emailed me and IM'd me actually saying that you would probably start making some sort of negative type posts on my or any other turbo header manfacturer out there because you see us as competition. My manifolds are unquestionably made of better material then yours and for a cheaper price, thats the way captilism works...

Besides,

My above post is still true and you did nothing to address the real point being made...That is why his, all other manifolds made of cheaper materials are cracking...

That is the point...

Regards,

Dave


[Modified by SuperT, 3:10 AM 2/26/2003]

B17AGSR

If I bought a manifold it would be the inlinepro stainless cast manifold.....excellent contruction plus it has warranty from cracking, if it does...

Full-Race Geoff

very sorry to hear that you are getting that excited. i was just trying to discuss the materials, its a very important topic to me, being a mechanical engineer. I simply wanted to get into a technical discussion on manifold materials, not a pissing match. If others have said that i would get all bent out of shape, im sory to hear this but that is not the intention whatsoever.

we dont use 304, we use 304L. There is a huge difference, look it up if you have an opportunity.

you are comparing apples to oranges here. I wont respond to any more of your posts, i apologize that you are so upset, and its a shame you dont understand more about basic stress analysis.

I couldnt care less if youre making manifolds. I can barely keep up with the orders we have now. I just like the science behind them. This is not a real job to me, im a college student, and i have a year left. This is something im doing for fun, which pays the bills and allows us to push the envelope in manifold fabrication a bit.

If nothing else, id love to see quality manifolds on the market. By my trying to share with you, the experience that another fabricator had after building many manifolds comes off as my being an ***, then my apologies. giving yourself props is never a good way to make yourself look great, either.




[Modified by FFgeoff, 11:39 PM 2/25/2003]

SuperT

I think you should be a pyschology major...You in a very subtle way try to subvert the issue...
Your posts are pointed and have a bit of condescending subtle jab to them..

Very clever...

And by the way 321 always has and always will be a better material the 304 or 316, nothing is going to change that...

And BACK to the topic of the thread...

This is why this manifold cracked most likely, as well as many more like it made of lower grade stainless...that is the point...

To the owner of this manfiold, sorry about your unfortunate experiences with the manifold, I didn't intend the post as a jab on you.

Regards,

Dave



[Modified by SuperT, 4:50 AM 2/26/2003]

SuperT

[This is what I mean by subtle pointed jabs...very condescending.

At least I know enough to use the best material available(321) and not use cheaper 304 or 316 just to lower production costs...

You know why this heats me up so much? Because Im a Import Drag Racer First, shop owner second. Mis information abounds on the internet and can be at times very unfounded....You challenged some of my posts...I responded...

Lets move on...

Regards,
Dave



[Modified by SuperT, 4:45 AM 2/26/2003]

Full-Race Javier

By carbide precipitation and intergranular corrosion, i assume u mean the localized corrosion “attack” at or on the grain boundaries of an alloy. Under most conditions, a metal corrodes uniformly and evenly and the grain boundaries only become slightly more reactive than the rest of the material/matrix. There is always the possibility of other conditions in which the grain boundaries become very reactive. This results in the intergranular corrosion, and the material/parts overall loss of strength and or weakness. In our case, this leads to a crack or cracking in the mani.

Yes, I agree that most austenitic stainless steels like 304 stainless will undergo this intergranular corrosion. It occurs when the material is heated into or slowly cooled in the 500 -800degC or 950-1450degF temp range. In this range, chromium carbides can and usually precipitate at the grain boundaries. The alloy is in a sensitized condition when the Cr carbides precipitate along these boundaries. When a 304 stainless mani is in a sensitized condition and exposed to a corrosive environment (IC engine exhaust gas and it related byproducts) the material near the grain boundaries is attacked and weakened.

Failure of 304 filler rod weld can also occur in a similar manner. Its known as weld decay.

There are 3 ways to combat weld decay, intergranular corrosion, and carbide precipitation. They are:

1) heat treat and quench
2) add Ti or Cb…..forming 321 and 347 respectively
3)lower the carbon content of the material near 0.03 wt % or less

Full-Race manifolds are made out of 304L! the carbon content of this material is low enough (0.03%), that cracking due to the above mentioned methods is not a problem.
If 304L didn’t “work”, then real engineers wouldn’t use it in industry

also, poor welding skill and or incorrect filler rod material can cause even a so called superior mani made out of a superior material to crack. poor design and or incorrectly stress mani's will crack too....its known as a stress corrosion. when combined with a corrosive environment, it accelerates the "attack" on the material being used.

pics are easier to understand than my rambling



phew, thats enough for now.

[Modified by javierb14, 9:23 PM 2/25/2003]


[Modified by javierb14, 9:47 PM 2/25/2003]

SuperT

Well said...

304 and 316 are both available in L(low carbon content)

But that is still not a better stianless then 321, indeed it is better then regular 304, but still not as good as 321.

Yes, anything can crack and for a variety of reasons, weld quality, filler rod used, etc etc..its just in the case of most of these manifolds around, its due to the lower grade of material used.

Thanks for the input

Dave