dynoing with FULL wet exhaust??
 

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

The guy I use always has all accessories on wet exhaust, water pumps, alternator etc.

I never looked real close but there is a Huge tank outside, pretty sure they recirculate the water.

Seems to me to be the way to get a true number, seen a pull the other day. The only thing the motor had on it was the recirculating water pump, dyno long tube dry headers no flame arrestor.

Would love to see the same motor ran both ways just to see how much the seawater pump, alternator, power steering pump makes a difference.


Long time ago Fountain did a comparison with a bunch of different exhaust. Was interesting.

So WHERE did the water go, into the 5 x 8 room then down a drain? Thats my real question, diverting the water out in a way to catch it and not just blow it everywhere. I have dynoed with wet exhaust out the door with my old dyno, extended tails with 4 x 6 couplers into 6" pvc directed over barrels with sump pumps in them that sent water back to manifolds BUT this was a VERY rinky dink, messy m watery deal. So Im looking at PHYSICALLY how to direct water into something besides just blowing all over or on the ground as this will be in a new building with walls, etc, Thanks

I understand, doesn’t sound like the way we do it is what you are looking to accomplish. The “room” is made of cinder block with openings in the base. All the water drains out the bottom. 5x8 building is on top of a concrete hill so it all naturally drains away from the main shop and eventually ends up in our gravel parking lot. All of it is our property so where the water ends up is not a major concern. Might not work in everyone’s situation, especially if containing the water is an issue. Maybe if said structure was water tight on the bottom with pumps to pump the water back in to the water supply tank

I have in the past but forgot how we rigged it up.

I use a 50 gallon drum and recirculate water when I idle engines out of the boat it`s amazing how quickly that 50 gallons turns steaming hot.

This is how I did it in past but going to engineer a better way, too temporary, too messy!​​​​​​

We ran a 250 gal tank setup at dyno shop for one of my engines and recirculated water. Like ICEDEDPPL said, the water heated up very quickly and it threw off setup/ HP #s due to warmer than running conditions water through intercooler. We ran hose water through cooler and picked up major HP and needed to jet accordingly.

Where I dyno at has 2 huge simi truck mufflers on the opposite side of the wall at the back of the dyno. The mufflers are outside of the building with 5" stacks that go up past the roof. Every engine that they dyno are hooked to these mufflers with flex pipe of the same size as the header collector. The mufflers have a valve a ball valve at the bottom that are opened when doing wet exhaust to just let the water drain out of them onto the ground. The exhaust water is not recirculated. Works great, but it will deplete the storage tank eventually if you don't keep an eye on it. I will draw a quick picture and post it

https://cimg3.ibsrv.net/gimg/www.off...9b5d833ed5.jpg

That would be great to airbrush a SEMI on the side of the dyno building,,,,,, just saying.:drink:

It is pretty cool to stand outside and listen to 1000hp being pulled.

My thought is as big of a tank as you can fit behind the dyno, then run flex pipe or softwall rubber exhaust hose through the upper portion of the tank above the water line, then install a large "squirrelcage" fan/blower in the top of the tank and vent outside. This should take all the fumes out and keep the water in. Then simply run a valve/ fitting at the top of the tank that will run up and feed the sea pump. I would be concerned with the water heating up quickly that's why I would say build the tank as large as possible. I would also run a large line with as much pressure and volume from your water supply to the building into the tank and run a drain off the tank to the outside right above the stagnant water line. This will allow fresh water to run in the tank while you are running with the hot water hopefully running out of the drain. Obviously you probably won't move enough through it to keep it cool for hours but I would think it would be enough to cool it for a few good pulls? I'll draw something up to illustrate what I'm trying to explain lol.

Smitty, I have heard that Tyler Crockett runs wet exhaust on his dyno. Maybe you can run over and check his setup out.

https://cimg4.ibsrv.net/gimg/www.off...c650a35ea7.png


Obviously pretty crude but a quick paint project to help explain what I'm talking about hahaha

I'd run the exhaust water across and under the st into a shallow pool and watch all the fine ladies in the winter get into Smitty's Hot Springs.
Just a thought. (.) (.) I mean :)

SB,

I like you more and more every day. :ernaehrung004:

Thanks. Brad.
(937)545-8991

Smitty's Titties! Adults only Heated Pool!

Not to sound ignorant but how would you get at AFR or EGT wet?

Laz Mesa dyno’s with full wet exhaust. Mesa Balancing.

Prior to the point where the water mixes in with the exhaust gas stream.

So that makes sense with dry exhaust, I still don't know how you read in a full wet scenario.

There is no full wet scenario, the exhaust is dry when it leaves the exhaust port of the cylinder head, water is not introduced inside the manifold (or header), but rather after it, in the riser or tailpipe sections.

Prior to the point where water is introduced to the exhaust gas, it's only in the cooling jacket of the manifold or header.

No, he has water jacketed dry headers, Ive dynoed there before I had my own dyno. So his water leaves header jacket then goes into return w a hose, exhaust stream has no water in it, Smitty

It's the same situation that allows a lot of people on this board to have A/F monitors (O2 sensors) in their boat even with wet exhaust.

https://cimg7.ibsrv.net/gimg/www.off...7340a036e9.jpg
https://cimg1.ibsrv.net/gimg/www.off...6c21b16118.jpg
We dyno all boat engines wet. Once the water is mixed you can use schedule 40 to route it outside. In pic you can see one of our adapters we made to go from 5 inch down to 4 inch. Also you can use your o2 sensor in adapters or we also have bungs in tail pipes.

[QUOTE=DrFeelgood;4858129]There is no full wet scenario, the exhaust is dry when it leaves the exhaust port of the cylinder head, water is not introduced inside the manifold (or header), but rather after it, in the riser or tailpipe sections.

Prior to the point where water is introduced to the exhaust gas, it's only in the cooling jacket of the manifold or header.[/QUOTE


Thank you

Tyler has always done my Dyno work.

What kind of headers are those? And are you ready to sell the PR at fire sale recession prices yet? I could even trade you a 32 for it! LOL
firesale

Lol keeping the PR for now. They are CMI big tube, 2 1/4 inch primary. We took the boat to CMI and they custom built the pipes for it.

Hey put me at the front of the line!

Yep, thats how Im NOT going to do it, having done it that way in the past and trying to get away from the mess not to mention that I often dyno in winter time too. I DO have a good idea now after thinking about it for a week though!