Cracked Manifold

[sccrAdidas15]

Well, i did the seafoam the other day and smoke was coming out of the manifold, i figured it would be cracked with the retarted 1g manifold, i was just wondering what does a cracked manifold hurt in performance? like lose of air flow through the exhaust or what? Thanks! Oh and i'm trying to look for a new 2g manifold ported or an evo manifold..which is better?

 

[ielaser]

I had the same problem, my car was dropping boost, running rich and also had lots of knock. After I replaced it most problems went away. If you want a new one you should go with the gt manifolds which seem to flow better then the 2g and evo 3.

 

[sccrAdidas15]

where can u get these gt manifolds at?

 

[sccrAdidas15]

This one is better flowing? http://www.turbochargers.com/store/...d=121&osCsid=429a2437e5982bbe34dd6db0e9be24d8

 

[ielaser]

This one is better flowing? http://www.turbochargers.com/store/...d=121&osCsid=429a2437e5982bbe34dd6db0e9be24d8

^^Yeah, that's the one I'm talking about.^^

 

[No_Skillz]

Lets take it easy with the questionable info before we figure out what's really going on here. How do you know your manifold is cracked other than smoke? Have you checked gaskets? You will have dirty scorch marks in areas where you are leaking exhaust.

Leaking exhaust will result in a dirty engine bay and reduced spool on your turbo. It will not cause knock or make you run rich.

If indeed you determine that you have a cracked manifold, you still have more options before you spend money. One of which is JB Weld, which really wouldn't hurt to give a shot. Apparently 2G manifolds are popular replacements for you 1G guys, this is probably your next cheapest option, and honestly a ported 2G manifold will probably outflow whatever power needs you have.

The GT manifold listed is a ported version of the EvoIII manifold. I am NOT making assumptions of quality, just keep in mind that it is not an MHI unit.

 

[ielaser]

You are right NO SKILLZ, I should of mention that I changed other things such as the o2 sensor and plugs. I mentioned the gt manifold because he said new manifold and usually the 2g and evo 3 manifolds are a bit more expensive. Anyways, most 1g manifolds are usually cracked, so try taking off the heat shield and see if there are any cracks on it first and if there is try going to the junkyard.

 

[No_Skillz]

Thanks for capitalizing my name, I feel more important that way. You're right, you should have mentioned important things such as changing sensors and plugs, otherwise you would probably be reported for misinformation. And a GT manifold will not cost more than a 2G manifold from the classifieds.

 

[andymoraitis]

Leaking exhaust will result in a dirty engine bay and reduced spool on your turbo. It will not cause knock or make you run rich.

If indeed you determine that you have a cracked manifold, you still have more options before you spend money. One of which is JB Weld, which really wouldn't hurt to give a shot.

That's not exactly correct. A leak BEFORE the O2 housing (i.e. a cracked manifold) will cause the motor to run rich since metered air is esacping. After the O2 it has no effect on performance.

JB Weld won't hold for squat on something that heats up to 1600 degrees. If the manifold is cracked, which as mentioned needs to be verified, replace it with a 2G. For what it's worth, you could buy a used 2G manifold for dirt and it would do the job just fine. In the meantime, check the gaskets and make sure all four turbo to manifold bolts are tight as these have a tendency to loosen up from time to time. Just make sure to torque them when hot so that they shrink as they cool and stay tight when heat cycled.

Cheers,

Andy

 

[No_Skillz]

That's not exactly correct. A leak BEFORE the O2 housing (i.e. a cracked manifold) will cause the motor to run rich since metered air is esacping. After the O2 it has no effect on performance.

Hmm I didn't think of that. However, doesn't the O2 only detect the contents of the air passing it? If that's the case, escaping air shouldn't have an affect. I was thinking more along the lines of the leak being after the combustion, therefore having no affect on the tune.

 

[sccrAdidas15]

I'm just assuming it's the manifold since they suck on 1st gens, when i was putting the seafoam through my vaccum line, the smoke was coming out from under the heat shield so i'm guessing that would be the manifold unless it's a leak somewhere else around the 02 housing.