Cracked JIC manifold

[GraySilvia]

Hello all,

Perhaps some of you read my thread at some point in the last two months about how I bought the stupid expensive JIC exhaust manifold for its quality and peace of mind knowing the fact that such a quality part would never crack. I should have kept my mouth shut. I've got about 4500 miles on it and there's a huge crack on the #4 runner on the back side of is after the sharper bend is completed. That's right, it did NOT crack at a weld.

The manifold was professionally ceramic coated shortly after I received it. Now, Phase2 said that this is unusual, that cast iron parts are usually coated. This seems like BS to me. Whenever you see a SS manifold on an SR in japan, it's wrapeed with header wrap, no? The ceramic coating is superior for two reasons. A) It doesn't hold moisture like the fiberglass wrap, so corrosion isn't an issue. B) The header is coated on the inside too, which means more heat stays in the exhaust, NOT trapped inside the exhaust which heats up the header more, like is the case with the exhaust wrap.

Well, I bought the header at Phase2, so I emailed them, and their response was basically to brush me off and blame it on the ceramic coating I had done, or, if that didn't work, talk to JIC directly. They also said that they didn't think that JIC would replace it outright. I'm rather disappointed in Phase2, about the only way they could have been less helpful is if they had not responded to my email at all....what do ya'll think of this situation?

[the_invisible]

The ceramic coat works like heat wrap. It keeps exhaust gas at high temperature so it retains high velocity and exits the manifold faster.

If too much heat is being held inside the exhaust manifold, the pressure increases. As far as I know, ceramic holds heat better than fiberglass, so therefore, exhaust gas temperature should be much higher in a manifold with ceramic coating than heat wrap. Thus, even greater pressure is trapped inside the manifold.

Also, your sig says that you have a T25 turbo. But do you know that those expensive Jic manifolds are made for better flowing turbo. The poorer flow of the T25 probably forced pressure inside the manifold.

The excess of heat and pressure were likely the culprits for your cracked manifold.

[GraySilvia]

Well, my turbo is a GT25/T04B hybrid rated at 475hp, so it's not choking up the manifold too bad

Did I mention my JWT ECU sucks and it's running rather retarded timing, which certainly isn't helping the EGT

[nissan_s14]

Pics? What does the JIC manifold look like?

[GraySilvia]

http://cgi.ebay.com/ebaymotors...#BID1 looks like this, just 3X the price :angryfire

[Phax]

I'm rather disappointed in Phase2, about the only way they could have been less helpful is if they had not responded to my email at all....what do ya'll think of this situation?

I think that your situation is an unfortunate one. It sucks to have parts break. Especially when you spent more for the part in the first place, hoping that by paying more, you'd be getting a piece of sufficiently higher quality. I don't know enough about ceramic coating to go into how it might, or might not have contributed to the cracking. I do know that I am getting my stock manifold ceramic coated, and that nearly all of the twin-turbo Diablo's have ceramic coated manifolds.

As far as Phase2's response to it, there's not much they can do. They're probably telling you exactly what they'd be hearing from JIC, if they tried to get a replacement part. "Oh, you modified the part after you purchased it? And post modification it broke? So sorry."

[SJN]

Here are some pictures on my JIC bullet exhaust.

http://200sx.timekiller.net/fo...?c=25

I haven't installed it yet so I don't know so much about it. Is it exactly like yours? I got it cheep so I wounder if there might be copy (fakes) out?

Not good to hear. And I fell sorry for you

[lessthanjakejohn]

SJN: If I were you I would cut between the inlets to the manifold where it mounts agaisnt the motor. This allows for thermal expansion and will help it keep from cracking.

[GraySilvia]

SJN, the JIC manifold has mandrel bend runners, not cut and welded like the one in that link. Looks like that might be a copy, but, i'm not sure. That damn JIC manifold still cracked regardless of the fact that the runners are one piece.

[240Z TwinTurbo]

GraySilvia, excessive EGT's will affect the ability of the header to survive, even SS. Although alot of headers sold are 304SS, it is not the ideal choice in turbo apps. Its ability to withstand the heat is limited to temperatures lower to what is seen in a decent street car. That is why I chose to use 321SS on the SR20DET'd RX7 and my twinturbo 240Z. If you would like to send your manifold to me I will fix it for free, but want to use it to make a JIG so I can duplicate them out of 321SS. Please let me know by resonding to this post. BTW, here are the pics of the manifolds I am referring to. I did not polish my header before welding which is why it looks greyish.

[GraySilvia]

Yeah, i'd be up for that. Just send me a PM or IM me, my AIM name is in my info if you have it. I'm gonna need this manifold for my next SR powered vehicle . I bought one of the $285 manifolds off ebay last night, at least it comes with a 5 year warrantee against cracking! I'll give it a shot, perhaps cut between the runners on the flange and see if it helps prevent cracking at all. Thanks for the help.

[drumma022]

IMO--It also comes down to the fact that many of SS manifolds will eventually crack, its just a matter of time. There are many factors attributed to this and cannot always be just one single answer. It can even come down to the water used to cool the manifold after welding... just a thought.

[SJN]

Well. Check out this link :

http://www.jic-magic.com/Exhau...d.htm

The manifold there looks more like mine than that on ebay.

[GraySilvia]

Interesting. I don't know what to believe anymore. The only reasons I have to believe that my manifold is JIC is A) that's what phase2 sold me (they didn't have the correct picture on their site either) and B) it said JIC bullet exhaust on the box...maybe they changed the design because the one piece runners were prone to cracking, like in my case.

[240Z TwinTurbo]

perhaps cut between the runners on the flange and see if it helps prevent cracking at all.

Cutting the flange between ports is not going to prevent your header from cracking. It prevents the warpage of the flange from causing leaks and also from breaking off the studs holding the manifold onto the head. I would not be too concerned, but it is something you can do if it makes you happy. BTW, $285 seems very cheap for the manifold shown????

[GraySilvia]

Yeah, $285 does seem cheap, but I guess they've got a sweatshop full of 12 years old chugging them out somewhere (j/k). Who knows, I figure i'll give one a shot for that price. It comes with a 5 year warrantee, so, why not.

[pampadori]

Well, my turbo is a GT25/T04B hybrid rated at 475hp, so it's not choking up the manifold too bad

Did I mention my JWT ECU sucks and it's running rather retarded timing, which certainly isn't helping the EGT

where is your ecu pulling out timing? up top? down low? mine added 3-10 degrees downlow and pulled out about the same up top. i actually had a friend pull the code out of the eproms. this showed the same as what my multichecker was showing.

retarding the timing up top actually makes power. my sard turbo manifold cracked. after welding it heavily when first getting it (as it came cracked) about 2 months later it cracked again. i again welded it heavily. no new cracks in 6 months. we put about 10 stainless rods into that bastard.shaun

[C-Kwik]

I'm not an expert on ceramics coatings, but are you sure the crack goes all the way through? Stainless steel expands from heat more than cast iron or steel. It's always possible the coating only cracked.

As far as one piece runners, they don't make a manifold any less prone to cracking. With the ceramic coating the Stainless steel is probably subject to a little more expansion. It could cause it to expand beyond the scope of JIC's design and testing.

I'd still look into the possibility of seperating the head flange so that there is one flange for each runner. Also make sure the holes for the studs in the head flange are larger at the outer runners. This will prevent manifold studs from shearing off and undue stress. Also you may want to consider using a bellow or flex joint in the downpipe.. A manifold can crack from the exhaust system tugging on the whole system.

Lastly, why anyone would ceramic coat a stainless steel header is beyond me. Why cover up such beauty? Especially when stainless steel already has good heat rejection properties...I guess that's just me though...

[GraySilvia]

where is your ecu pulling out timing? up top? down low? mine added 3-10 degrees downlow and pulled out about the same up top.

I don't know where it is actually pulling timing and how much, I just know that my car isn't making the HP it should for the mods that it has, and the blame has fallen to the ECU after countless hours of prodding, experimenting, etc. That's one reason I just bought a power FC, so I can actually look at timing and knock and ADJUST things, not send my ECU back to JWT so I can wait another 3 months for them to reprogram it.

Quote »I'm not an expert on ceramics coatings, but are you sure the crack goes all the way through? Stainless steel expands from heat more than cast iron or steel. It's always possible the coating only cracked[/quote]

It's cracked bad. Not only can you hear it and smell it from inside, but you can put your hand behind it at idle and puff puff puff puff goes the exhaust pulses. Oh, and for the ceramic coated, the SS will just turn blue and weird colors after 10 miles anyway :shocked2

[C-Kwik]

It's cracked bad. Not only can you hear it and smell it from inside, but you can put your hand behind it at idle and puff puff puff puff goes the exhaust pulses. Oh, and for the ceramic coated, the SS will just turn blue and weird colors after 10 miles anyway :shocked2

Ouch.

The blue and wierd colors are just beautiful....

[ItzGenX]

Many metals turn blue/purple after being over heated.