Dyno Pull Video - 468 Chevy on my homebuilt dyno

[mecrez]

just wondering if anyone out there could possibly give an experienced opinion on what I would like to do for a dyno

here is what I was thinking:

I picked up a pair of large cessna hydrostat pumps, I thought these could be ok, because you could adjust the displacement by the swash plate, and you could also adjust the pressure, so it might be easier to control

Also instead of using pressure and flow to calculate the torque from, I thought it would be possible to place a lever arm on the body of the pump. The pump would be mounted so it could rotate on its axis; the only fault is that I'm not sure if the same torque from the engine is applied to the body of the pump, but that way you could directly measure the force multiplied by your lever arm gives you the torque.

Unfortunately I haven't found much information on the pumps, and do not know their original application.

Please let me know what you think, or if all of this has already been discussed please show me I must have missed it.
Thanks
Matt

[86rocco]

I'm not familiar with the Cessna pumps but what you propose sound very similar to my friend's dyno a commercial unit by Stuska pictured here it can be accurately calibrated by hanging weights on the load arm.

[mecrez]

rocco is right on with the arm, if anyone knows anything about cessna pumps or where I could find any information that would be appreciated
Thanks
Matt

[DaveMcLain]

Here is a video of a 468 Chevy running on my homebuilt dyno. We built this dyno setup about 6 years ago using components from Land and Sea, it's been a very good learning tool for our shop. It's nothing fancy but it works good. This engine is making 650 horsepower and running mufflers in the video.

[bruce]

Great video!! Bet your neighbors love you huh?

Any more pics of the dyno?

[DaveMcLain]

We have not had any complaints from the neighboors but our shop is out in the country about a mile from town. While I have not heard it because I've always been here working when it's running but some people have told me they have heard an engine running on the dyno at the golf course which is several miles away(900 horsepower 557 Ford engine). I ALWAYS wear ear protection and in that case I was wearing muffs, and earplugs, most people are absolutely astounded at how loud an engine can be, even one making 400 horsepower with a two barrel carburetor. We never run after about 8:30PM either and I think that helps. I'll post some more pictures because I have some of various engines I've tested.

[DaveMcLain]

A few more pictures of my dyno runing various engines over the last several years.

[Thomas Vaught]

Looks a lot like the old GO Power engine dynos.

Tom V.

[DaveMcLain]

It probably is similar, a water brake with a torque arm. Overall I'm very pleased with the setup it works well. The software is good too. There are some updates I've been meaning to do to the electronics, they have some new stuff with more channels. My dyno tends to be about 5% conservative when compared to a Superflow or DTS. It's certainly not fancy but at the time I put it all together I really needed a dyno and A dyno is very much better than no dyno. I was up and running, doing testing for around $10,000.

[bruce]

[DaveMcLain]

When I bought my dyno stuff from Land and Sea I bought their absorber, Dyno Mite data computer, load valve and software for my PC. This little computer is pretty cool and it just connects to my PC via a regular comm cable. I run at a data rate of 56K. They have a newer version than mine with many more channels and a faster data rate that I'll upgrade to in the future but it's always hard to change when something is working good. I changed to their Dyno Max 2000 software a couple of years ago and it's really nice and much better than their earlier software which I also was very satisfied with. This version can do so much more that it took me a while to get it figured out when compared to the older version I was used to. I needed the new version so that I could do an average torque and horsepower score for an entire run while doing development work for our Engine Masters' engine, worked great.

The little Dyno Mite computer can opperate completely self contained if you want it to, I did it like that when I first got it going. I would program it to do the pull and then I would download the data to my PC offline, worked ok but now everything's shown on the PC monitor in real time. I bought a 21 inch monitor just for this purpose and it's excellent.

[larrycavan]

Nice job Dave.

What do you seal the wooded cab spaces with?

Larry C

[DaveMcLain]

For data acq I'm using the Land and Sea Dyno Mite box and their DynoMax 2000 software on my PC. This setup works very good and I like the software. The little computer on the dyno is pretty neat, it's small and it can even opperate independently from the PC, you can program it to record data when certain rpm and torque thresholds are exceeded and then stop again when rpm and torque drop to a certain amount. I used to do it that way and then download the data to the PC offline. I abandoned that pretty quickly once I got my setup really going and now it opperates in real time showing live data on the computer monitor during a run, egt's etc. Needless to day, I bought a 21 inch monitor just for this purpose. I like the Dynomax software package even though it's rather expensive. The graphing, data smoothing and report printing are all nicely done. I had an older version when I first started that worked well but wasn't nearly as full featured as DynoMax 2000. DynoMax can be a bit intimidating at first because of it's versatility and features but once you figure out which options you need for your testing it flows and works really well.