Performance Exhaust

[SUPRA_ALLEGRO_LANE]

Has anybody upgraded there Exhaust Manifolds to a performance style? Anything like what I'm showing here?


cmi_big_tube_sport.jpg

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[SUPRA_ALLEGRO_LANE]

Nobody has done this or thought about it?

[SquamInboards]

Maybe THIS would solve my exhaust hose overheating issue, or Jetlink's similar issue!!

How much?

I think for me personally, I don't long for more power in the boat - especially since upgrading the engine to the GT-40 - and I spend very little time looking at the engine these days, thankfully!

[crystal waters]

Nobody has done this or thought about it?

Why, other than supposed power increase would you want to do this?
You have a rare supra classic.
IMHO to make such change would take away from that.

[cadunkle]

I have considered it. The factory manifolds are fairly restrictive, though nowhere near as restrictive as older log and snail manifolds. There are also potential weight savings. Stainless is available and will last far longer if boating in salt or brackish water. This does not detract from the value of the boat, it's a bolt on part that replaces a wear item.

Critical consideration is width. Most performance exhausts will be wider than factory. You don't have much room to work with. Measure the factory exhaust width (about 31" IIRC) and measure the doghouse width. Go from there. Personally for the significant cost ($2500-ish typically) I would only upgrade if my manifolds were rusted bad or already failed. $2500 will get you a lot more power if you put it into the engine, but putting it in the exhaust will only give a marginal performance improvement on an otherwise stock low output marine engine.

[War wagon]

I have been thinking about doing this. My reasoning is I want to weld a bung in so I can really dial in my carb with a wide band o2. Stainless would be much easier to work with than the cast iron