3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.
Sponsored by:

how bad can the exauhst manifold be cracked without affecting performance?

Thread Tools
 
Search this Thread
 
Old 02-20-05, 04:55 PM
  #1  
Senior Member

Thread Starter
 
viper_u27's Avatar
 
Join Date: May 2004
Location: chicago
Posts: 386
Likes: 0
Received 0 Likes on 0 Posts
how bad can the exauhst manifold be cracked without affecting performance?

just wanted to know when cracks in the manifold start to affect the performance of the stock twins. is some minor cracking still ok? i know eventually it will lead to disaster, but how long? anybody's experience would be nice...
Old 02-20-05, 06:58 PM
  #2  
Trying not to be stock

 
RevZempoe's Avatar
 
Join Date: Jan 2005
Location: Richmond, VA
Posts: 374
Likes: 0
Received 0 Likes on 0 Posts
don't go into boost and get a new manifold.
Old 02-20-05, 07:13 PM
  #3  
Moderator

iTrader: (7)
 
dgeesaman's Avatar
 
Join Date: May 2002
Location: Fort Kickass
Posts: 12,302
Received 16 Likes on 15 Posts
It's normal and not a big deal. I don't know what ^ is talking about.

When the cracks extend past the edges of the metal gaskets, or your boost pattern is affected, then replace them.

Dave
Old 02-20-05, 07:18 PM
  #4  
Trying not to be stock

 
RevZempoe's Avatar
 
Join Date: Jan 2005
Location: Richmond, VA
Posts: 374
Likes: 0
Received 0 Likes on 0 Posts
sorry, i just wouldn't run it hard at all if there was any crack in mine. I'd find a way to patch it up...then we'd talk. I just get the feeling that if he's asking, he's still running it hard.
Old 02-20-05, 07:29 PM
  #5  
Mr. Links

iTrader: (1)
 
Mahjik's Avatar
 
Join Date: Aug 2001
Location: Kansas City, MO
Posts: 27,595
Received 40 Likes on 26 Posts
Originally Posted by RevZempoe
sorry, i just wouldn't run it hard at all if there was any crack in mine. I'd find a way to patch it up...then we'd talk. I just get the feeling that if he's asking, he's still running it hard.
Due to the amount of heat the stock twins product, cracks are inevitable. Small cracks are expected and are not a problem as dgeesaman pointed out.
Old 02-20-05, 07:29 PM
  #6  
Moderator

iTrader: (7)
 
dgeesaman's Avatar
 
Join Date: May 2002
Location: Fort Kickass
Posts: 12,302
Received 16 Likes on 15 Posts
https://www.rx7club.com/showthread.p...manifold+crack
https://www.rx7club.com/showthread.p...43#post2450643
https://www.rx7club.com/showthread.p...manifold+crack

It won't hurt anything to run them until you have the budget for the new ones.

Dave
Old 02-20-05, 07:43 PM
  #7  
Trying not to be stock

 
RevZempoe's Avatar
 
Join Date: Jan 2005
Location: Richmond, VA
Posts: 374
Likes: 0
Received 0 Likes on 0 Posts
guess you learn new things every day. Just know I won't keep mine cracked :-D
Old 02-20-05, 07:45 PM
  #8  
RX-7 Bad Ass

iTrader: (55)
 
DaleClark's Avatar
 
Join Date: Jan 2002
Location: Pensacola, FL
Posts: 15,399
Received 2,438 Likes on 1,509 Posts
Exhaust gasses don't care in the least how the manifold *looks* - remember, we're talking about something we're seeing. You have to look at "will this keep the part from working like it should".

Cracks that creep into gasket mating surfaces are bad - they can blow out the gasket over time, causing an annoying exhaust leak. Cracking around the wastegate ports are OK as long as it's not causing too big of a leak around the wastegate flap for you to lose exhaust pressure going into the turbo, as it's being bled off by the crack.

The worst-case would be cracks that cause a chunk of the manifold to break off. I have NEVER heard of this happening, though - somebody would have likely documented it if that was a possibility.

Again, remember that exhaust gasses don't care what something *looks* like. You can have a helluva lot of cracking and not lose any performance of the part. We see something that's broken and ugly, and assume it to be a bad, failed part, when it might be working just fine.

Dale
Old 02-21-05, 01:37 AM
  #9  
Rotary Enthusiast

iTrader: (5)
 
Trout2's Avatar
 
Join Date: Dec 2002
Location: New Orleans
Posts: 1,082
Received 10 Likes on 9 Posts
They have to be pretty big and extend out towards the end of the gasket to affect performance. Manifold and wastegate cracks are very common, even on low milage turbos/manifolds.

Jack
Old 02-21-05, 02:25 AM
  #10  
Senior Member

Thread Starter
 
viper_u27's Avatar
 
Join Date: May 2004
Location: chicago
Posts: 386
Likes: 0
Received 0 Likes on 0 Posts
cool guys, thanks a lot




All times are GMT -5. The time now is 12:42 PM.