miataspeed1point6

iTrader: (1)

My exhaust manifold had a small pinhole leak near the dipstick when I installed my kit. Now after 2 weeks it has grown so large under acceleration it sounds like a misfire. I've been meaning to replace it, but I just haven't had the time. On to my questions.

1. My boost gauge only reads 2-3 psi. I'm pretty sure the cause is the air rushing out the leak instead of going threw the turbo. Am I correct?

2. How hard is it to replace the gasket now that I have my whole kit installed? I'm assuming it will be easy, just difficult to get to all the bolts. Anyone recommend a method?

3. My vacuum read a solid 20 on my gauge before I put on the turbo. After the turbo its around 18-19. Is this caused by the exhaust manifold leak or is it just a small leak i'm missing? I used soapy water to check EVERYTHING, but its always possible I missed one.

turbored

1. Probably. What's your car's vacuum level @ idle? It might be a combination of both.

2. You'll have to remove the obvious bits. Might want to soak the bolts in something like PB blaster so they come out easier. Which Gasket? The head/manifold gasket or the manifold/turbo gasket? You might try running without the gasket between the manifold and turbo. It probably won't leak, and you probably won't have a problem of blowing out the gasket

3. I had to remove a bunch of stuff on my turbo, and after I reassembled everything it went from about 20 to 16. I spent an evening tightening all my clamps, and zip tied and replaced all vaccum lines, and vacuum went to 21.

You're probably missing a small leak somewhere. The exhaust manifold leak won't cause less vaccum.

miataspeed1point6

iTrader: (1)

Cars vacuum at idle is 18-19. The gasket is head to manifold. And I will triple check for vacuum leaks. Thanks!

Braineack

iTrader: (62)

get a large hose that you can listen through. Say a length of gardening hose. hold it up to the edge of the manifold while the car is running and try to listening for the leak. It should sound like clicking, like you're low on oil or the lifters are ticking. If there is a leak at the manifold try tightening the manifold bolts at the problem area.

Did you install the heater hose bracket above or below the manifold?

miataspeed1point6

iTrader: (1)

I sprayed soapy water on the manifold and had splatter from all over the rear of it, so manifold gasket is for sure the culprit.

The heater bracket actually doesn't fit the greddy manifold, so I just used some wire wrapped around the manifold to hold it.

I will be fixing this on saturday, I'm hoping I can just remove the downpipe bolts and intake hoses and just unbolt the manifold.

Braineack

iTrader: (62)

I'd make sure you can't tighten it down first.

When it is off make sure you true the manifold surface. Did you make the relief cuts? If not do them and then true the surface.

you need to trim the bracket so it looks like this:

miataspeed1point6

iTrader: (1)

I had a machine shop true the manifold. Then I made relief cuts. Is it possible doing it that way let the manifold somehow untrue itself? And eventually I will trim the bracket, I have NO metal working tools at my house so things like that take me a while to get done. Thanks for the help.

jayc72

iTrader: (14)

Make sure the leak is at the head to manifold and not the turbo manifold flange. When I had a sizable leak at the turbo->manifold flange (caused by a broken stud) I swore it was at the head. Using a 2ft length of vacuum hose in my ear I could easily tell that the leak was coming from the turbo flange, in fact I could tell exactly where on the flange it was leaking. It'll sounds like a put-put-put sound, VERY obvious.

I'd be surprised if it was a leak at the head, unless you didn't use the gasket or didn't torque things down enough.

For what it's worth other than the noise coming from under the hood and the smell of exhaust I could barely boost over 5psi, where previously I was able to get to 9psi.

Braineack

iTrader: (62)

the manifold could have come untrue once the cuts were made. Just double check the torque on the studs before ripping the system out. I know the GReddy would kill my 15min. teardown record.