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Thread: dyno tests & exhaust

  1. #1
    Badburn
    Anyone ever seen dyno tests of mercruiser exhaust manifolds? Or maybe comparisons of stock to aftermarket headers? Just curious what kind of HP gains in buying a $4000 aftermarket exhaust.

  2. #2
    Decided Advantage
    Anyone ever seen dyno tests of mercruiser exhaust manifolds? Or maybe comparisons of stock to aftermarket headers? Just curious what kind of HP gains in buying a $4000 aftermarket exhaust.
    Wouldn't that be a great tech article in a perfomance boat mag!
    What engine are you talking about?
    You'll be able to hear the difference, but from what we have seen any performance advantage is lost in all the other variables(temp, weight, etc.), so you won't have to worry about buying a high pitch prop or anything.
    Exhaust upgrades seem to work best as part of a balanced performance upgrade.
    Like I said it would be great to see a product comparision!

  3. #3
    badbug
    on the same day i ran mercruisers stock cast iron pig exhausts and then installed a new set of big id tubes lightning water jacketed exhausts and there was 7 miles an hour difference without any tuning or jetting change. Alsoi a big difference in weight loss also. Well worth it and even more so for future up grades. Test done on a 22 ft inboard outboard stryker (red) with radar and gps.

  4. #4
    Badburn
    on the same day i ran mercruisers stock cast iron pig exhausts and then installed a new set of big id tubes lightning water jacketed exhausts and there was 7 miles an hour difference without any tuning or jetting change. Alsoi a big difference in weight loss also. Well worth it and even more so for future up grades. Test done on a 22 ft inboard outboard stryker (red) with radar and gps.
    No $hit? Thats huge..Could the stock manifolds really flow that bad? they have a 4 inch outlet and are only a foot or so from inlet to outlet.

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