New exhaust manifold advice

Z

zaayer

Seaman Apprentice
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Jul 24, 2022
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I have a 2012 Volvo Penta 8.1 GiC-Q 400HP catalyzed engine. My manifolds are coming to the end of their life. The parts for the manifolds alone is over $4000 per side. That doesn't account for the elbow or anything else on exaust side. The manifolds are impossible to find so I am looking for a substitute. Does anyone have any advice on a replacement maniford that may not be catalyzed? I know the computer will look for the O2 sensors, but I believe there are devices to convince the computer that the nonexistent O2 sensors are running correctly. I am also willing to do aftermarket stainless exaust if that makes more sense. I just don't know where to start. Any advice would be much appreciated.
https://www.volvopenta.com/shop/0/part-sections/54160227 is what my exhaust systems looks like.
 
Z

zaayer

Seaman Apprentice
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Jul 24, 2022
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37
Scott Danforth said:
Contact Raylar engineering as they are the 8.1 experts

Your ECM will need to be reprogrammed to go non-cat


There is a set of VP manifolds on ebay

*OEM* Volvo Penta Port & STBD V8 Exhaust Manifold | eBay

Good Condition, Ready To Install.
www.ebay.com
Click to expand...
Those manifolds seem to be for a smaller V8 than the 8.1. The part numbers don't match up. Would you try to stick with the catalyzed exaust or would you try to change to non catalyzed? I am finding the manifold for sale, but out of stock. The price for the manifolds only is about $4300 per side. That is only the manifold. The elbows seem to run about $1400 per side. The cats will be about $1500 per side if they need replaced.
The one manifold seems to be weak near the O2 sensor. These are Aluminum so I am told welding probably won't work.
 
Scott Danforth

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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I personally would never have bought a cat motor. And if I was in your shoes, I would go with the full Raylar package and be pushing about 500hp
 
Lou C

Lou C

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Agreed on never buying a cat converter motor. A relative of mine had one, here in the salt pond and I convinced him to trade it before it had problems and buy an outboard powered version of the same boat. He'll be far happier with it.
For a simple comparison you can buy a complete exhaust for Volvo inboard gas engines from Barr Marine (good aftermarket) for approx $1000.
Cat engines in boats are plagued with check engine lights, fault codes and astronomical repair costs.
Now tell me EPA folks, just how much does this improve air quality? You don't know? and you have cost the consumer thousands for that? Let's go Lee Zeldin.
 
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