Dyno: built her own or just pay the time for tune it?

[honda_power]

Hi guys, I just curious about your opinion. Im in the engine team of U of Ottawa and I want know if its really benefit to have her own dyno or location is a better way. Consider we start from scratch and not necessary a lot of budget.
Tanks to reply me!

[honda_power]

Hi guys, I just curious about your opinion. Im in the engine team of U of Ottawa and I want know if its really benefit to have her own dyno or location is a better way. Consider we start from scratch and not necessary a lot of budget.
Tanks to reply me!

[Chuck Dean]

Build/buy your own dyno or face paying $100/hr to use a dyno. The last dyno session I had, we were working in the engine bay w/ the car on the dyno for 70 hours (over a span of two weeks). If you're new to this, you'll probably spend most of your time troubleshooting unexpected problems - and do little tuning.

Get your own dyno if it's a possiblity at all.

[Benjlv]

if you get your own dyno...spend some time in researching what kind of dyno you should get. It is important to be able to hold RPMs solidly as you are calibrating and also to have a accurate torque feedback. Ideally you would have a AC dyno but I doubt any FSAE team can afford one. Water brakes are cheap...but you may have problems holding load sites... This is just something to keep in mind. I reccomend before spending any money on a dyno to get in contact with people who have done all of this before with the small engines FSAE uses. Perhaps feedback from other teams here would be good or maybe this is a topic that can be searched for in the forums here.

[PedalOnTheRight]

We were recently contacted by a graduate student of the school who wanted to build us a dyno as a research project. Although it sounds like we might be his guinny pig, it's definately worth it. We were lucky enough last year to get time on a dyno for free, but it was a limited # of times and the place was far away. I've been looking into the resources that we have to build our own or purchase one, and in my opinion, it would be MUCH better to have one in house.

[Igor]

If you're going to build your own, look for a elctromagnetic retarder from a truck. It's an eddy current brake which will be very controllable as a dyno. So you can do very precise transient response tuning (or hold the engine comfortably at an RPM)
They look something like this http://www.kloft-retarder.de/

You will need a controls/EE guy to build the controller though.

Igor

[LSU Dave]

I'd recommend asking around for free dyno usage. I'm in Baton Rouge... not exactly the center of the automotive industry... and I was able to get access to two engine dynos here in town for free. My advice is to go find a shop that makes drag bikes or something of that nature, and ask them if anyone they know might let you use one.

The owners are usually crusty old men who are hard to deal with, but a case of beer goes a long way.

[Alexandre D.]

A dyno is nice for sure... But lot of money/ressources/risk goes into it. First ask yourself what kind of engine developpement you want. What kind of engine are we talking about? What ECU? There's probably a local shop with a dyno that would be really happy to help you with a few days of dyno testing, free of charge.
I wouldn't recommand doing it by yourself if you really want a dyno. Mod an old one. Building your own dyno won't give you more points. Dynos are worth a LOT of money. It's not because dyno maker are greedy but because it's not easy to make a good, reliable, SAFE, stable and accurate dyno.

[Chris Boyden]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">It's an eddy current brake which will be very controllable as a dyno. So you can do very precise transient response tuning (or hold the engine comfortably at an RPM) </div></BLOCKQUOTE>


Igor,

We used a local dyno service where the guy had a DynoJet chassis dyno for quads with the eddy current brake for load control. It was awesome for holding the rpm at a chosen set-point.

Any idea how much the Truck eddy current brakes (retarders) cost?

[Dan G]

Here's a 5 page thread about building a DIY dyno from an eddy brake on the megasquirt forums...

http://www.msefi.com/viewtopic.php?t=7294

This is another thread by a guy that built his own. His website is dead now, but if I remember the pictures, it looked pretty GHETTO. Still an interesting idea...

http://www.thirdgen.org/techbb2/showthread.php?s=&threadid=249330 (http://www.thirdgen.org/techbb2/showthread.php?s=&amp;threadid=249330)

[drivetrainUW-Platt]

neither of those links did much for me Dan

[honda_power]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">free dyno usage </div></BLOCKQUOTE>
Thanks you for all your suggestions, I take note of that! Thanks guys!

[Igor]

Chris:
It's too long ago to remember the price, we decided later it would be cheaper still to make our own retarder. When we were halfway building that, we got an entire eddy current dyno donated by a sponsor.
But in hindsight it would have been way better to buy the truck retarder rather than make one ourselves. It just costs too much time. (I did really enjoy designing it though, so from that point of view it was worth it)

Igor
the EE/controls guy

[Chris Boyden]

Igor,

I'm curious about electromagnetic stuff...so this got me thinking about eddy current brakes.

What did you use for the coil core materials?
soft iron, mild steel, transformer iron?

What kind of DC supplies did you want to use to power the coils?

Did you guys build or buy the big ass power amplifier for the controller coil drivers?

~How much power did each coil consume?

The eddy current brakes look like a big disc brake with coils mounted in a hex pattern. it seems like a 4wd truck disc with hub and the calipers removed/retrofitted with would make a decent brake rotor and provide cooling for the heat from the eddy currents.

How were you going to control it?

Sounds like a fun project..

[Igor]

We used mild steel for the coil core material. The setup would be simpler though than the 6 coil setup from the truck version, we used just one large square core with a gap in it for the disc. Winding that with lots of copper would produce enough braking force.

I planned on using car batteries as the power supply, it won't last very long (depending on the size) but it's cheap and simple with more than enough power. I build a microcontroller based control box, modern mosfets can switch these loads without breaking a sweat.

Now here comes the caveat; it has only worked in my computer simulations. We had build the core, disc and controller when we got a complete setup donated. This doesn't mean it won't work though http://fsae.com/groupee_common/emoticons/icon_smile.gif

Using a brake disc might be hard. The eddy current is related to the conductivity of the material, so aluminium works much better than steel. The disc might also get unstable because of the attraction between the core and disc. I forgot the formulas on gap energy in transformer cores, but one big gap might be energetically preferrable to two small gaps, leading to the disc wanting to crash into the core.
Bolting an aluminium plate to a disc brake might be a good idea though. This way you get the cooling from the brake disc and the complete bearing setup.

We eventually got a testbench based on a truck retarder, a bit of a hobby project from a small company. They controlled the coils directly from the 230V but that wouldn't be my preference.

Ok, this got a bit longwinded. If you want to spare the rest of the community more of this you can PM me at dorrestijn at spykercars dot com.

Igor

[Frank]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Build/buy your own dyno or face paying $100/hr to use a dyno. The last dyno session I had, we were working in the engine bay w/ the car on the dyno for 70 hours (over a span of two weeks). If you're new to this, you'll probably spend most of your time troubleshooting unexpected problems - and do little tuning. </div></BLOCKQUOTE>

Our record stands at:

2001 2 days (some average wiring by us)
2002 1 day (tuning) + 1 day (data logging manifold pressures)
2003 1 day
2004 no days
2005 no days

grand total for 5 years of dyno time $1500

you're nuts if you use a chassis dyno

UQ acceleration winners 2004 FS and 2004 FSAE-A