dynos

[Danhercules]

What is your thoughts on putting a motor on a dyno?
I have a chance to run my motor on a dyno after I change some things. Would you put it on the dyno for tuning?

[victorfb]

how well built is the motor? stock bottom end?

[flat broke]

Having never dyno'd a motor before and now opting to go that route in the future, let me give you my take.
The telemetry on the dyno is going to be able to tell you a lot about your motor. Oil temps/Pressures at different loads, water temps and pressures, exhaust gas temps, a/f mixtures, and a ton of airflow information. Having all of this on hand will let you stup the motor up for a pretty good baseline and be able to see what's going on. Yes all of this information costs money, but here's the sell. If you bolt a motor together, and take it out to the river, you have a 50/50 chance of everything working out alright. The best possible outcome is that you got a trouble free trip to the river and save the dyno $$ for second trip to the river. The worst possible outcome is that your brand new motor goes south because of a condition that you may have seen on the dyno telemetry. Not only will this probably ruin your fun, it might cost you in parts that you just bought. Granted it's an extreme example, but it is possible, and has happened to others. This year I wasted more money in gas and more time than I want to admit to, towing out to the lake to test something on the engine. I missed outings and did not enjoy the ones I did make as much because the boat was not running on top of it's game. For me, any new mill that goes in my boat is going on the dyno first. Not only to see HP/TQ numbers, but also to get a comprehensive picture as to what the motor will be doing in the boat. Much easier to wrench small problems on the engine stand, than in 120* weather in the confines of the bilge.
Chris

[Infomaniac]

Do not use the dyno for fine tuning unless it is EFI. It will be different when you put it in the boat.
Use the dyno to see exactly where the engine makes power and what ignition timing, cam timing, valve lash etc. changes make to the power.
Get the tune up close on the dyno and fine tune at the lake
[ October 07, 2003, 03:00 PM: Message edited by: Infomaniac ]

[Danhercules]

If I know where the motor makes power, and how much, will that help with pump set up?

[Infomaniac]

Yep. That should be the main objective.

[Danhercules]

victorfb:
how well built is the motor? stock bottom end? Stock bottom end. I am not going for high RPMS here. Just looking in the 5 to 5.5 K range.
I hear dynos are hard on a motor, I am not gonna have a high horsepower plant. I am gonna have a chance to have some cheep dyno time. Should I do it?
I was also told that it is one heck of an experiance. You kinda have to do it once in you life kinda deal and its well worth the $ in freeing up HP and tuning.
Any more comments?

[burbanite]

No reason not to...get a baseline and go.

[RandyH]

Danhercules:
victorfb:
how well built is the motor? stock bottom end? Stock bottom end. I am not going for high RPMS here. Just looking in the 5 to 5.5 K range.
I hear dynos are hard on a motor, I am not gonna have a high horsepower plant. I am gonna have a chance to have some cheep dyno time. Should I do it?
I was also told that it is one heck of an experiance. You kinda have to do it once in you life kinda deal and its well worth the $ in freeing up HP and tuning.
Any more comments? Great place to find out how your new Cam is doing and also easy to cut filters in the dyno room.
My 2 cents.
RandyH

[cyclone]

Danhercules:
victorfb:
how well built is the motor? stock bottom end? Stock bottom end. I am not going for high RPMS here. Just looking in the 5 to 5.5 K range.
I hear dynos are hard on a motor, I am not gonna have a high horsepower plant. I am gonna have a chance to have some cheep dyno time. Should I do it?
I was also told that it is one heck of an experiance. You kinda have to do it once in you life kinda deal and its well worth the $ in freeing up HP and tuning.
Any more comments? This comes from viewing about 20 different dyno sessions 3 of which were on my own personal motors. The dyno is no harder on your engine than running it in your boat.
The dyno will give you a great indication of where the motor makes power and how different states of tune affect its running condition. You can then take this info to your pump builder and he/she can set up your pump accordingly. You can also take this info to the lake to fine-tune the engine once its in the boat, allowing for altitude and air density.
The dyno will also allow you to easily break-in a brand new motor.
Its an invaluable resource no matter which dyno you take the engine to. And like Flat Broke said, you can spot problems with the engine right away on the dyno vs. dragging the boat to the lake and wasting time there.

[MandDPerformance]

Dyno's don't hurt engines. The operators of certain types of Dyno's is what hurts engines. Newer dyno with experienced operator and you wont harm your engine. Of course I'm assuming it was assembled and blueprinted properly. It's a lot easier to get close to a baseline or starting tuneup on the Dyno when the engines going into a jet boat versus a Flatty or Hydro. A good jet pump almost perfectly mimics the load that the dyno puts out.