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Discussion Starter #1
Are there any options at all, other than stock?

The specific thing I'm taking issue with, on the stocker, is the small passage which links all 3 cylinders. see image, below.

tmp_1524-2014-05-14 20.46.1033188040.jpg

Is this a feature to promote better cylinder breathing, or simply provide a more musical exhaust note? The exhaust runner length for each cylinder is a different length on the stock manifolds.

You builders of race cars, what do you use?
Fabspeed, any thoughts?
 

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I believe LN Engineering sells an exhaust gasket, most likely their own creation.
 

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That passage is for the secondary air injection system that helps with catalytic converter 'light off' during cold starts. It is fed by the secondary air pump under the right intake manifold. The factory multi layer gaskets work fine.
 

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don't fix it if it ain't broken :hilarious:
 

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Discussion Starter #5
don't fix it if it ain't broken :hilarious:
So funny. Ding! Thanks for playing. And please note the image, below.

OK people, we've had our one dimwitted reply, that's all for this thread.

Some of you will remember I'm really interested in reducing exhaust noise, hence the question, and I'd better spell it out: with each exhaust valve open, I'm guessing that three different length pipes will be singing, at three different frequencies.

3 fundamentals to deal with, not one.

The note about SAI, above, was really helpful, as a reason to use the stock gaskets.

And NHP includes their gasket w/ their catted headers, apparently without the SAI passages. They also report infrequent but possible cat-related CELs. ... maybe this is why?

mmmv,
-PM.
 
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if you're after less exhaust noise - aren't there other areas in the exhaust system to start from that have greater effect on the noise comparing to manifold gasket?
or do you want not to change anything else and hoping to achieve results by just playing with the gasket?
 

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Discussion Starter #7 (Edited)
My goal has been to reduce the drone of my Borland exhaust, making it more liveable. seeing the interconnect between the exhaust runners, for me, complicated the issue. If I want SAI to work as intended, I keep the stock gasket, and the more complex exhaust note.

I've built two replacement tip assemblies to combine the exhaust streams, the latest effort may be found by searching for "porcine rhinoplasty".

It was a relevant question as I'm going to put on a stock set of exhaust manifolds which I've had ceramic coated, an easy thing to try, since the gaskets are coming off anyway.

I actually think the exhaust side is about as good as I can get it. I'm going to try and reduce any drone from the intake plumbing, and dynamic the floor, if I can find an article describing carpet removal.

Thanks for the thoughts, all.

-PM.
 

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Discussion Starter #9
As far as the gasket goes, I just went with pelicanparts oem/supplier gasket; I didn't want to screw up the secondary air injection.

Overall the ceramic coating I used was a mixed bag. It has remained near perfect on the stainless parts of the exhaust, and flaked badly on the non-stainless.

I suspect the surface prep allowed tiny pockets of rust to remain ... The manifolds look great, as do the unmodified parts of the borla itself.

When I returned to my X-pipe tip assembly I buffed/sanded/dremeled the surface rust as best as I could, painted it with rustoleum extreme barbeque paint in gloss black covered with a couple of coats of clear VHT engine enamel.

The paint on the tips took some knocks going back on the car - so I rotated the tips down, masked and re-shot them. After curing on the car it has hardened nicely. Not ceramic coating but not expensive either.

mmmv,
-PM.


Did you ever find a better gasket? How is the ceramic coating holding up?
 

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Would you do the ceramic coating again? I have the entire exhaust off right now and want to do what "should" be done while its off. Is the ceramic a DIY job?
 

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Discussion Starter #11
Yes - definitely the headers if nothing else to reduce engine compartment heat.

There are diy ceramic coatings but my issue was with the process done at my local coater -- I would contact jet-hot for my next job. They have multiple coatings and some cool colors too. Their bright silver stays that way, rather than browning, as stainless does.

I did the whole exhaust to keep the underside of the car as cool as I could get; do it for that and desired appearance ...

mmmv,
-PM.
 

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I just took a closer look at the OEM manifold. The flange holes where the studs go into are split. I even found a piece of weld stick attached to manifold still. Rubbish really. I think I will look for or make a custom set and have them coated. Thanks for the
 
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