mike tkach

iTrader: (3)

i would think the same.we know the dyno measures the power but we have no real way to measure the power in the boat except mph vs a known past setup.

stimleck

Mike when you finish a dyno session and you have the motor dialed in, do you assume there will be some additionaly tuning once its in the boat?
If so is it carb, timing or both?

looks like I have found a skilled and trustworthy guy that will tune my motor on the dyno, it wont be cheap but it will be cheaper than pulling it out afterwards if its not running right. US friggin rookies think its so simple to buy a motor and drop it in, we are pretty clueless.
Years ago I had 2 supercharged 454's built by Tommy from Chief, it was so straightforward that we did nothing, he handed the boat over running perfectly

stimleck

I guess I should have searched "dyno" first lol

http://www.offshoreonly.com/forums/g...dyno-test.html

Bawana

Around here you will not touch dyno time for $500.00. Also most of the shops around here build stock car, sprint car etc. motors..... They don't and wont dyno big CI blower motors on the little dynos they have. So the couple of shops equipped to do bigger marine supercharged, or for that matter big torque at low RPM motors, charge per hour thats its on the dyno set up & tear down is on the clock too. so you looking at a minimum of $1000.00.

mike tkach

iTrader: (3)

usually the tune will be a little richer in the boat depending on the application but being a little on the rich side wont burn an engine down.

FIXX

iTrader: (2)

i know a guy that will spin anything on his dyno..close to me to boot..

Budman II

iTrader: (1)

Pay attention to the type of fuel they will run during the dyno session. For example, there is a local guy who is just around the corner from where I work with a dyno, so it would be super convenient for me, but unfortunately he will only run racing fuel on his dyno. He is concerned that the ethanol in pump gas will cause problems with his system. That won't work for me, so I am going to have to go somewhere else.

Probably also a good idea to ask up front exactly how they run the engine on the dyno. Do they break it in on the dyno in a controlled manner and make sure everything is good to go before they start flogging it?

That's another reason that it is a great idea to do both - start it up and run it on a cart, and then dial it in on the dyno, as SB suggested. That's my plan, and I'm building a startup cart just for this purpose. The cart will come in handy down the road for any future builds, and also to help your buddies out with their builds.

CDShack

Dyno time is priceless! It is crazy what different cam, head, intake and carb combinations like and don't like. It produces real numbers for your exact set-up. Timing, spacers, header tube sizes, jets, fuel pressures, a good dyno shop will have a bunch of "variables" to try. And it generally is an all day affair! You can see where you're HP/torque is, where it falls off, which can help in things like propping the boat. If you know it falls off at 5500, you can prop up to 5500 instead of going down in pitch to just to get to 5800 because motor App on your computer told you 5800 was magic.

We always bust them off on a stand, first to make sure they run (so we don't get embarrassed at the Dyno shop--I have had one lock up wrist pins on the stand---but that's a long story) Break in the cam etc. That way you don't waste dyno time on that stuff.

Now having said all that, you can "tune" a motor in a boat, making runs, reading spark plugs, and I've done plenty of that as well. But for total comprehension of what you've built and what it does, dyno all the way!

ICDEDPPL

iTrader: (1)

Where we dyno we were told that the dyno operator no longer has any control over the correction factor.. don`t know if its the new software or hardware they had

cig92

Stimleck- bring it across the boarder to the buffalo area, 1 1/2 hours from Toronto. There are many dyno's in the area. One is $80 per hour and he's fairly quick (4hours or less) and the other is jan-cen and they range from $350-500. They are a big machine shop building motors upwards of 4,000 hp and have a very nice Dyno. There are lots of good engine guys over here and I have yet to pay 500 for a single Dyno run. It's worth the trip and every penny. Btw, isn't double r reasonable? They are in your back yard