3" Exhaust Install + Broken Manifold Stud = Less power?

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awolo

New member
Whats up guys.

As many of you know, I spent my weekend outside under my car installing my full 3" inch turbo back exhaust. Well I finally got it all installed. I also did some maintenance and changed plugs/wires (NGK-6RE or something like that)

During this process, I broke a manifold bolt of the stud on the head.

So the car sounds great, spools fine, and makes a solid 15psi...but she just doesn't "go" like she used too.

Would that broken exhaust manifold stud, being pre-turbo, really cause that much power loss?
 
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celigts

New member
Do you have an exhaust leak? Cuz I to have that issue cuz of my shitty gasket and mildly stripped stud. Doesn't spool as well as it should and from what the wideband says its running richer!

Oh and I can get my full boost psi but pulls worth shit. Might be getting like 5-8 psi total
 
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awolo

New member
I'm assuming I have an exhaust leak.

I mean, there is literally no bolt on the driver side lower Exhaust manifold stud. You cant exactly start the car and reach in to see if air is coming out either.

This is the only reason I think the car doesn't pull like its supposed to.

Going from a restrictive stock down pipe - cat - cat back TO a full 3" turbo back, you'd think she would have a bit more pull than stock.
 
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toayoztan

Moderator
The car should have more pull with the exhaust, more noticeably up top, and more spool.

A broken stud can cause a bad enough leak (whether acutely now or later after significant warping) to cause loss of power.

I remember when I first bought my '92, I raced it at the track...ran 17's lol. Turns out, had an exhaust leak, warped manifold, and somewhat apparent after a while from a airplane prop sound coming from the area.

That leak essentially acts like a WG left open.

Bryan
 
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awolo

New member
toayoztan":3tkry4y1 said:
The car should have more pull with the exhaust, more noticeably up top, and more spool.

Bryan
Click to expand...

Agreed. Only when I give her full throttle, its like she is revving for really not taking off like she used to.

This sucks. I have a race this weekend and little time to completely tare her apart.


I think i'm going to try removing the stud using a Left Handed drill bit. Another member had good luck with this method. on his AllTrac.
 
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toayoztan

Moderator
Did it snap off clean/flush or do you have a bit of stud left to grab onto or weld onto to make it easier?

If you attempt to do easy-out or lefthand drill, etc. to extract it, heat up the head around the stud to expand the thread, shoot some seafoam deepkreep or pbblaster, let it soak, reheat, and attempt very carefully.

Which stud is it?

Bryan
 
A

awolo

New member
toayoztan":3qsklb8u said:
Did it snap off clean/flush or do you have a bit of stud left to grab onto or weld onto to make it easier?

If you attempt to do easy-out or lefthand drill, etc. to extract it, heat up the head around the stud to expand the thread, shoot some seafoam deepkreep or pbblaster, let it soak, reheat, and attempt very carefully.

Which stud is it?

Bryan
Click to expand...

My superior strength, twisted it off flush with the exhaust manifold.

I'm going to run to the hardware store on my lunch break, buy a left handed drill set, PB Blaster, and a torch.

The stud that broke would be the first one on the right side, when looking at the engine.

NOTE: Im not going to be removing the exhaust manifold. Not sure if I was clear on that.
 
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toayoztan

Moderator
awolo":2nr8qh7z said:
toayoztan":2nr8qh7z said:
Did it snap off clean/flush or do you have a bit of stud left to grab onto or weld onto to make it easier?

If you attempt to do easy-out or lefthand drill, etc. to extract it, heat up the head around the stud to expand the thread, shoot some seafoam deepkreep or pbblaster, let it soak, reheat, and attempt very carefully.

Which stud is it?

Bryan
Click to expand...

My superior strength, twisted it off flush with the exhaust manifold.

I'm going to run to the hardware store on my lunch break, buy a left handed drill set, PB Blaster, and a torch.

The stud that broke would be the first one on the right side, when looking at the engine.

NOTE: Im not going to be removing the exhaust manifold. Not sure if I was clear on that.
Click to expand...

Yeah, if you don't need to remove the manifold at this point, and can get an extractor/easy out in there, then that should be fine. Just make sure you spend a good amount of time heating up the head. On that note...what manifold gasket do you have? If it's the stock metal one, you'll be fine with the torch. If it's like felpro or something...i can't be too sure on that.

Bryan
 
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awolo

New member
All stock as far as I know. When I was doing the Down Pipe install I did notice that the gasket was metal.

I'm def going to take my time. Remove what I can to make it easier to get in there and just be easy. Worse case it doesn't work and I have to tear everything off, which will most likely create more problems, but you'll have that.

I should have known it was going to break...stupid me.
 
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celigts

New member
Could each stud be removed without removing the exhaust manifold? I'd like to replace each stud and grease them up before reinstalling them. Re thread them to be safe and get and crud and whatever out.

I to have the metal sheeted gasket. So it's ok to heat the head enough to remove the studs easier?
 
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awolo

New member
If you where going to remove them, without removing your manifold, you'd almost have to drill them out, or see if you have enough surface area to grab them with some channel locks. Either way, you'd want to replace them with new studs.
 
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awolo

New member
celigts":3jtvci8g said:
Yea for sure. Can the manifold be removed without removing the turbo? Or just easier all at once?
Click to expand...

From everything i've read, it cannot be removed without taking off the turbo.

Which is why i'm going to try the LH drill method.
 
A

awolo

New member
Today is the day.

After work, im dedicating my evening to getting this stud out and replacing it.

I need to drive my car and i wanna hear that turbo scream!
 
underscore

underscore

Well-known member
After taking everything off several times I'd said it's probably easier to just remove the manifold and grab the remains of the bolt with some vicegrips after heating the crap out of it. I've also found filing off the threads on part of the bolt so that you're grabbing two flat surfaces can help. When I got my car it had the far left stud broken and that gave it a huge leak and lost the car a lot of power.
 
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awolo

New member
I do agree, it would be easier to remove the stud if the manifold was removed. I'm going to try this. Best case it works, worst case it doesn't, and I have to remove everything anyway.

But unfortunately, I dont have the time/tools to remove the manifold/turbo/lines/down pipe. :(
 
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toayoztan

Moderator
For future reference, if you can grab a piece of the manifold stud that snapped off, just use a small plumber's pipe wrench. That thing has never failed me. You will tear up the stud in an epic manner (not that you planned on reusing the stud), but it's a great tool - after heating and PB blaster, it was a cinch.

exhaustmanifoldstuds003.jpg


exhaustmanifoldstuds002.jpg


Bryan
 
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toayoztan

Moderator
Nicely done!

What's your method of installing new exhaust mani studs? I've read conflicting info.

Loctite or no loctite?

Hand tight or torque down?

Bryan
 
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