Anybody Ever Made Their Own Dyno??

[Instigator]

Don't really have the facilities for one now, but been thinking about one for a while.
Probably needs to be a power head dyno to have any kind of usefull accuracy and probably want 400+ HP capacity.
Used to sell torque measuring equiptment with rotary transducers capable of handling that mutch torque that got me to thinking about building one.
Anybody ever done it, or any of you computer or electronic experts know what it would take to do this??
Curious if it is possible and or affordable to do it this way??
Keep seeing a used prop shaft dyno in the boat trader for $500.
but I heard they're good for loading the motor but not for measuring HP's for testing modifications.

[Unloaded Racing]

Instigator,
If you are going to Jasper maybe we can hook up and discuss building a dyno. I was involved in building 3 for the company I work for.
Tim

[Greg Moss]

I have a prop shaft dyno. your right about all it's good for is trouble shooting. Land and Sea has one that could be addapted to powerhead easier than building your own. the thing about power head dynos is all the different addapters you would have to have. Not to bad if all you are going to do is Merc V-6 2.0, 2.4, 2.5s but if you want to do any other motors there will have to be an other addapter. Then if you want to do OMCs and Yammaha's more yet. A prop shaft dyno will get you close for tuning for max power you just have to remember you will loose approx. 15% through the gear reduction and Water pump.

[B.Leonard]

Seems to me a prop shaft dyno is plenty. What good is it to know the exact power output of the powerhead?

Are you going to run without the lower unit?

I don't think so.

Do water pumps and lower units vary that much in how much power they consume?

I don't think so. (unless one doesn't have the pump in the lower like a Mercruiser Bravo drive)

You'll still see changes made to the powerhead at the propshaft. I'm assuming the adapter that you're thinking of would replace the lower unit? That makes no sense... to me. That's like trying to measure the power of a 4cycle without the oil pump running.

-BL

[Instigator]

Love to hook up at Jasper.
I'm staying at the Days Inn in Kimball.
How and where can I find you??

[Unloaded Racing]

We are going to be down early Saturday. We are staying at the Acuff. I will be in and out of Craig's (ZZ graphics)Big yellow EZ up. I won't be hard to find.

Tim

[fyremanbil]

Hey instigator, pretty much any old water brake dyno will do. There are lots of companies out there selling computor software that'll do everything you need. They can be adapted to most electric servo valve controled water brakes. Software usually has multiple anolog and digital inputs for sensors ie. EGT, fuel flow, etc. Dont know about running a water break with the input shaft vertical instead of horizontal. Dont think it would hurt to run through the lower unit though. I met a guy from Mercury at the " Superflow Dynos Technology Conference" years ago and asked for pictures of theirs. They ran a fairly conventional dyno, engines installed in standard configuration w/ lower unit.
Just thought of something. Wouldn,t total tuneup change without exaust adapter/tuner/towerhousing in place?
Good luck.

[BenKeith]

Hey Instigator,

I made my prop shaft dino but I happened to work where I was able to get a large pump and we had a test set with a good flow meter/regulator and guages. This saved me about $1,500 and is good for about 300 hp. I gives me a pretty good indication of how much power the motor is making and is fairly accurate as long as I maintain 180 degrees on the hydraulic oil. To do this I had to go to a 55 drum of of oil and add a cooling system. All it will do is load the motor to a given RPM and then you can calculate HP by the GPM and pressure at that flow rate. Will do nothing for torque. It does save me a lot of trips to the water, one hour away.

[LaveyT]

Gary,There is a shop mascot of sorts that hangs out at our shop for the JrDrag stuff.He builds Dynos for Clark deseil.He is bringing all kinds of crap in the shop on a regular basis that they were throwing away.HuuuuMMMM