ON-BOARD-DYNO Pictures
 

Here are some pictures of the setup from my cheapy digital camera (can't wait for Santa).

GUAGES 0-1000 HP and TQ. 270 degree sweep custom faced by Nordskod. Has a tattle tale feature with just wiring up a switch.

Control Module
 

This is the brain box. Dyno cable in, 12V in, guage output, reset zero button, bounce/delay adj knob. Mounts on transom. All the automotive weatherproof connectors. Also does the math to convert Tq into Hp.

Dyno Strain Guage
 

One view. This is the Stellings piece found in the extension box. Normally there is a 1 1/4" gap between the backside of the flange and the bearing carrier. An universal bolts to one side with a shaft which bolts to the engine and the other side is where the bravo shaft goes into. Stock there is the flange and shaft going into the bearing carrier. It is on this shaft that I mount the strain guage in that 1 1/4" gap.

Dyno Strain Guage
 

Side view. The strain guage and a few electronics are then sealed in the liguid black to harden and form the 'rotor' which is the donut like piece on the backside of the flange. It is fixed to the flange and rotates. It is the transmission of TQ thru the flange and shaft which is measures. Any shaft with TQ applied to it will twist slightly and this twist is what I measure and is propotional to TQ applied.

Dyno Strain Guage
 

Another view. Right next to the rotor is the 'stator' which is attached to the bearing carrier. It is stationary and it provides power to the rotor and them picks up the TQ signal from the rotor. A cable comes out of it and runs to the control box.

Bravo back side view
 

Where the drive shaft will go into.

Looks good! Now just to get one installed. To bad I don't run a stand off box and too far away. :(

digital gauges an option down the road?

Digital gauges sure. But I wanted to have white on white to match most every one's gauges out there. The resolution on my gauges is to about 10. Digital would have resolution to 0.01!

Way to go Marty! Since you are putting this on a Stellings piece have you spoken to them about this product?

Marty, that is a 10. Is the connection inductive?

I will want to talk to you about making one to put on the back of our transmissions.

I grew up in So. Calif. and Fresno was a small town of nothing. Today it is a real city and now I have reason to visit there and home. I have talked with them and bought a used box for display and some of these internal pieces. Thanks.

I was not thinking so much of the look but of trying to split hairs. Reading those smaller changes is all. It looks great!!

Marc, Yes, sort-of there is an inductive coupling. It's wireless anyway between the shaft and the pick-up stator.

Yes, my next project/application is for a trans. like yours. I have yet to see a trans. What is the output shaft and flange like. Does the flange unbolt? Is there room between the trans housing and the backside of the flange? I looked at your site and the pictures are not clear. It would measure the TQ on the shaft/flange coming out of the trans. not quite engine/crank TQ but but would only be less the TQ requirement of the trans.

Oh yea, the calibration doesn't have to stop at 1000 TQ/HP. How about up to 10,000 TQ as in Top Fuel.

Marty.

Marty;

This is one incredible idea you had. I am glad that it finally materialized. My hat's off to you. Good luck with this project and of course keep us posted.:D :D

:eek: :eek:
pls keep us posted Mr zweitein.

:D :D

eins=1,zwei=2 in german.

I understand the "mechanics" of this setup. I don't understand why you can't make it work for the long shaft on the Imco box.

If the pickup to the sensor is an inductive or wireless connection, then couldn't you do the same thing on the torsion shaft?

Maybe a braket or something that needs to be bonded in place thru the access plates in the side after assembly or something...

I'm still thinking that Imco boxes are my choice, but am reeeeally liking your dyno setup...

VERY COOL :D:D

How do you know the "twist" amount of the drive shaft to get your start numbers?

Jon

The problem is assembly. The ROTOR piece which has the strain gauge housed in it needs to be bonded to the shaft. If this is done then the IMCO long shaft won't go thru the gimble and it's bearing. If it was bonded after assembly then the drive could not be removed and calibration would be too difficult.

Right now the assembly is bolted to a jig and an extension arm is attached with the shaft fixed in place, and a known amount of force is applied and the output is calibrated. The flange and shaft is very linear in how it distorts with TQ applied. 100 pounds hanging at 2' is 200 foot-pounds of TQ, etc.

Placed inside the ROTOR assembly is a magnet and a magnetic switch to count the RPM of the shaft which is also the engine rpm(this way no connection to the engine is needed) and then thru electronics the TQ reading is multiplied by 5252 and divided by rpm and HP is derived and outputed.

At first I was only going to measure the TQ and output it but everyone doesn't seem to understand TQ and allways want HP for some reason, so there it is. To me, TQ makes the world go around not HP, so to speak.

I wish I was at SEMA this last week. Next year.

Marty:

Everything looks really good. Do you have it set up so you can store date to plot out onto a printer or computer ? I think it could be very valuable to see the whole tq & hp curve so you could see how it varies from the engine dyno. This could help the engine builder determine what components to use based on how the curves change in the actual boats they are being put into. Are you going to the PRI show in Indy ?

Doug

Doug, The output can go to a data logger and stored that way. That's exactally it- what works in the boat vs. on the engine dyno.

What and when is PRI?

PRI = Performance Racing Industry Trade show. It's in Indianapolis December 5-7. It has pretty much anything hi-tech hi-perf. you could think of. Last time I looked there should be abot 20 to 25 data aquistion companies there. It's mostly auto racing, but people like Eickert & Nordskog are coming. Pretty much think of any hardcore engine part, or driveline part, and it's there along with warehouses and tooling. They are based out of CA you have to have a business license to attend (or get in from a company that does) (949) 499-5413

Thanks for the reply Cobra. Simple solution to my question :D I can not waite to see how it all works. :D

Jon

Very good idea! Do you have a dash mounted switch for doubling the readings when bragging to friends??

That is really cool Cobra Marty!! What kind of resolution are you shooting for? Are you using two strain gages and comparing them or one and measuring cantilevered load?

Your idea has opened up many ways in my mind that this could be done with simple electronics. Maybe another way would be to mount a load cell under one of the front engine mounts to generate an analog signal, then pass through an a to d converter to a digital readout on the dash... possibilities seem endless.

Good luck bro... let us know how it turns out. If you need anything let me know, seems like we may be neihbors.

BT :cool:

Marty

When can I have one?

Way COOL! ;)
Great job Cobra Marty!!! I read your post about this several months ago. Glad to see it came together. The possibilities hmmmmmm.
blue thunder, I like your idea about the load cell. You got me thinking now, as i'm in the electronics industry. Then it could be used on all kinds of IO boats and it could probably be sold for a reasonable price. I don't know if it would be quit as accurate, but would make an interesting project.
Keep us updated!

:cool:

A load cell under the motor mount would measure the TQ indirectly and I have seen it somewhere, maybe even on a dyno.
That is like measuring HP by accelerometers. I measure the actual TQ applied to the drive shaft.

JimV- are you still boating in MI? My boat is still apart and won't be done till spring. Is your's ready to go? You have PM.

Understood on the Imco shaft. Makes sense now.
... maybe a modified 2-piece Imco shaft with a way to uncouple the section with the strain gauge (I know, I know, stop harping on the Imco thing)...

Some idea using/replacing the Bravo rubber donut coupler on the flywheel would be a cool variation...

Marty, Sounds like you might have something there. I also have the Stellings Bravo One extension boxes on my 32'A/T. I would be interested in trying one or two myself. Let me know please.

Mark/KAAMA

cobra marty,
That's Awesome! Great idea.

Good ole phi = TL/JG put to good use.;)

phi = TL/JG ?

phi=Torsional deflection(degrees)
T=Torque(in-#)
L=Length(in)
J=Polar Moment of Inertia(in^4)
G=Modulus of Rigidity(#/in^2)

You're measuring deflection of the shaft, right? Solve the equation to gain internal torque(T). Once torque is known and rpm is measured, you can solve for horsepower.

Is that how the device works? :)

Sort of. I can skip all that because with a known TQ applied = proportional measurable change in deflection. This way I don't care about J, G, or L.

Very cool...Love the idea. :cool:
Just curious, where did you obtain the torque vs deflection data for that particular shaft? Was it through measured testing? How will this apply to other such application(other drive systems)?
Just curious. :cool: