any fellow engine builders who dyno marine engines on here running full wet exhaust? Im building a new dyno room and trying to figure out HOW?? or, has anyone here dynoed at a facility that ran full wet exhaust, Im not talking water jacketed headers with dry tails ending water down drain or back to the tank, thats easy, Im talking stock manifolds, stainless marine ones, imcos etc with wet tails, Ive done it in past with my old dyno, blowing water all over but was not easy and was a giant , wet, mess!

This would be awesome as it seems all dyno numbers are a bit skewed by dry numbers.

Yup. Just a couple times. We opened the garage door, ran larger pipes for exhaust to go into. The boat exhaust was exactly how was going into boat. Bravo seawater pump and everything. Boy does that pump move some water.

Talk to Dave at MDG Performance marine in Maryland. Its been a long time since I had him do dyno an engine for me but i am pretty sure his dyno is set up this way. He might even see this. I think he is on here.

And added parasitic drag as well!

I'll second that!! Damn boat guys.

We were using a Mercruiser 383 as a mule for some of our transmission testing. I built a collector out of pvc pipe. Was big pipe, maybe even 12" - can't remember for sure. It might be in our pvc forest outside the shop. I'll take a look.

It was horizontal, about 4' long. Caps on the ends. Inlets on a tangent near the top, 2" water outlet on the bottom, 6" pvc pipe pointing straight up for outlet - then a 90 to get the exhaust out of the shop.

We never really ran at full throttle but it pretty much did the job. A little mist in the exhaust but it did capture most of the water.

Years back in Brads dyno room ( Smith Power ) he had a pair of 8" pvc pipes running trough the outside wall to a 250 gallon stock tank and would recycle it back with a pump that would feed the sea pump on the engine while doing a pull.

I like that better

We do run our dyno in full marine trim as it would be in the boat. Full wet exhaust, sea water pump, etc. We have numerous different header/manifold/tail pipes on hand from CMI and stainless marine with air fuel bungs in them, or we can run the customers supplied exhaust from the boat if need be. We feed the engine and dyno brake from a 1500 gallon reserve tank outside. With a garden hose refilling the tank we can run the dyno for about 30-40 minutes (give or take depending on engine load) while breaking in a engine at 3-4k rpm. Doing back to back pulls while dialing in a engine we will never run the tank dry. The exhaust shoots through the wall to outside. Because of our location noise could be an issue so we built a 5X8’ “room” outside that the exhaust dumps in to. The room has baffles in it and really suppresses the noise without adding any back pressure to the exhaust system