Homebuilt Dyno? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> General Rodding Tech
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 01-20-2006, 02:09 PM
ckucia's Avatar
Member
 
Last photo:
Join Date: Dec 2004
Location: cleveland
Age: 47
Posts: 555
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Homebuilt Dyno?

This is probably a dumb question, but is there any practical way to build an engine dyno for home use?

The "inexpensive" ones are about $10k.

I don't think it would have to be nearly as accurate as a good shop dyno. As long as it gave relative numbers and could identify the torque peak, that would go a long way towards tuning and evaluating different combos on a mild street engine. You could calibrate it by paying for some dyno time, getting figures, and then adjusting to match.

I did some web research and couldn't find anything besides what's being used by go-kart builders, and most of that won't scale up.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 01-20-2006, 04:17 PM
Member
 
Join Date: Dec 2004
Location: Madison, WI
Posts: 1,885
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
There is no "cheap" way to build a dyno. The dyno itself is not that expensive, around $6000 just for the "dyno core". Then you need a storage tank for the water, we use a 1000 gallon used milk tank, a pump, we use a 10 HP, lot's of copper piping and a control valve, we use a VFD controlled water valve. Now your close to $9000 to $10,000 and it's not installed yet. You need an enclosed explosion proof fire proof room, you need a data aquisition system, that's AT LEAST $5000 for junk and $15,000 for something decent with sensors. You need a computer, printer, a high volume exhaust fan, a fire suppression system, a filtered air intake box with ducting to outside air, and about 1000 other things you don't think of until your into the project.

I don't know of any "cheap" way to get into a dyno. I have tens of thousand in mine and we started out with a good base used system.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 01-20-2006, 06:05 PM
NAIRB's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Sep 2002
Location: cimarron, ks
Posts: 1,658
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
The cheapest home built dyno I can think of is an old car chassis, and a G force meter.

You'll look like Mad Max, but it ought to do the job.


Brian
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 01-20-2006, 07:27 PM
NXS's Avatar
NXS NXS is offline
wind & fire = guides to power
 
Last photo:
Join Date: Nov 2004
Location: Oklahoma
Posts: 1,534
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
I saw an old chassis dyno that simply had large steel rollers with disc brakes at each end. It also had sensors that measured how fast they accelerated and that looked like all it was. I'm not sure how accurate it was but the concept seems firm, XXX Hp will accelerate XXX mass in xxx time.

To do it at home you could design something like a standard transmission linked to the rollers by way of chain, the engine would be reved to the start of the power band, for example 2500 rpm and held steady...then max throttle would be applied until the engine reached max rpm, say 6500 rpm and that time would be measured.
Carb settings or timing could then be changed and the test re-ran. If the time increased or decreased you would know if average power increased or decreased.
A real savvy person could run some formulas and also end up with average Hp...if they knew the exact weight and diameter of the roller.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 01-20-2006, 07:29 PM
Member
 
Last photo:
Join Date: Sep 2003
Location: Buffalo, NY
Posts: 173
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I as well have always thought about building a engine dyno. If I am not mistaken most engine dynos use a water type brake, which I doubt I could build myself.

My idea was more along the lines of a intertia dyno. You could have some kind of real heavy metal drum (about the size of a 50gal drum) with a clutch mechanism to engage it to the motor and a disk brake to slow it down. It would have to be balanced perfectly and have a sufficent weight (I don't know what that would be? couple houndred pounds?)

Building such a setup I feel is very doable, now the trick is the computer part and measuring the output.

I would love to just have some junk engine in my garage on my own dyno and just make pulls for the hell of it!!

anyone else have any ideas?
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 01-20-2006, 07:39 PM
NXS's Avatar
NXS NXS is offline
wind & fire = guides to power
 
Last photo:
Join Date: Nov 2004
Location: Oklahoma
Posts: 1,534
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by Blob

anyone else have any ideas?
Great minds think alike?!!
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 01-20-2006, 11:14 PM
Registered User
 
Last photo:
Join Date: Jan 2006
Location: cornelius
Posts: 698
Wiki Edits: 0

Thanks: 46
Thanked 12 Times in 12 Posts
I don't think a homebuilt dyno would be very practical but their may be an alternative… Have you herd of the G-Tech? They plug into the cigarette lighter and attach to the windshield. They measure the G-Forces and with some electronic wizardry they will measure ¼ mile times and HP and Torque. I bought the first generation one off ebay for something like $40 to play around with. The new ones have alot of bells and whistles and even make hp and torque graphs. These run someting like $275

They are by no means perfect but if set up right they are normally really close. What they are really great for is to measure before and after times, HP and Torque. For someting like testing diffrent setups this may be perfect.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 01-20-2006, 11:47 PM
74Ventura's Avatar
Good,Cheap,Fast.Pick Two
 
Last photo:
Join Date: Aug 2003
Location: 70 Mile House B.C. Canada
Age: 33
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I was thinking about this too.Was thinking chassis dyno though,using an old packer/steamroller drum.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 01-21-2006, 07:02 AM
jim..'s Avatar
That 6 Cylinder Guy
 
Last photo:
Join Date: Jan 2006
Location: yes
Posts: 273
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
So if weight,mass,and accelleration rate somehow equals horsepower(I don't know the actual equation)can't you figure hp pretty close if you know the weight/mass of the vehicle as well as accelleration rate?

Also I've seen hp rated in kilowatts or megawatts,so how about a drum connected to an old power generator(big one),by putting a load on it and monitoring the current output ?

Or how about this:
http://www.charm.net/~mchaney/homedyno/homedyno.htm

Last edited by jim..; 01-21-2006 at 07:10 AM.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 01-21-2006, 07:18 AM
T buckets rule
 
Join Date: Oct 2005
Location: Hills of TN
Age: 64
Posts: 134
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have a home made engine dyno that we use for Jr Dragster engines. It has a solid steel wheel 30" in diam and 1" thick a 30 hp eng can spin this wheel really quick. I can't imagine how big a wheel you would need to do a perfomance type car engine.

Here is a link to the hardware and software package we use.

http://www.performancetrends.com/dtm-hdwe.htm
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 01-21-2006, 10:29 AM
ckucia's Avatar
Member
 
Last photo:
Join Date: Dec 2004
Location: cleveland
Age: 47
Posts: 555
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thanks for all the suggestions.

I was specifically thinking of an engine dyno as opposed to a chassis dyno.

I was hoping to build and tune and engine and then get an idea of where the HP and torque numbers were, so I could then use that info to make better final ratio choices rather than building the whole car and then having to keep swapping gears.

It would also help in determining if a 4 speed, 5 speed or 6 speed trans was the best fit for the torque band.

I know it wouldn't be a perfect predicter, but I thought it might be cheaper in the long run than experimenting after the engine was in the chassis.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 01-21-2006, 12:35 PM
Member
 
Last photo:
Join Date: Sep 2003
Location: Buffalo, NY
Posts: 173
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
If the flywheel on that Jr. drag dyno is that big, you would need a huge wheel weighing alot more then I thought.

Since most engine dynos use a water brake, maybe you could find some old industrial water brake(If there even is such a thing) or build your own. All the brake really is, is an impeller of sorts inside a housing and the water creates the resistance.
I guess you could also make something using air resistance like on some exersize bikes. Maybe build some kind of "fan" about 4 foot in diameter with the blades pitched at 90 degrees. with the blades pitched this way it would not pull itself in any direction and should create more resistance. It would have to perfectly balanced to handle the rpm. Hay with something like this it would engage alot easier than a gaint flywheel. I would also build a gaint super thick encloser for it in case a blade let go. I can picture it now, I just cant imagine what kind of sound it would make! A huge fan with paddle wheel like blades spining at 5000+ rpm!!!

This has got my going now, I do some research on air resistance dynos!!
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 01-21-2006, 12:40 PM
NAIRB's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Sep 2002
Location: cimarron, ks
Posts: 1,658
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by Blob
If the flywheel on that Jr. drag dyno is that big, you would need a huge wheel weighing alot more then I thought.

Since most engine dynos use a water brake, maybe you could find some old industrial water brake(If there even is such a thing) or build your own. All the brake really is, is an impeller of sorts inside a housing and the water creates the resistance.
I guess you could also make something using air resistance like on some exersize bikes. Maybe build some kind of "fan" about 4 foot in diameter with the blades pitched at 90 degrees. with the blades pitched this way it would not pull itself in any direction and should create more resistance. It would have to perfectly balanced to handle the rpm. Hay with something like this it would engage alot easier than a gaint flywheel. I would also build a gaint super thick encloser for it in case a blade let go. I can picture it now, I just cant imagine what kind of sound it would make! A huge fan with paddle wheel like blades spining at 5000+ rpm!!!

This has got my going now, I do some research on air resistance dynos!!


Dateline Anytown USA: Man Decapitated and Friends Maimed During Home-Built Dyno Testing.


You know, the idea of a home built wind resistance machine connected to a 400-500 horsepower engine doesn't sound like the safest thing I've ever heard of. Neither does very large, heavy spinning rollers or flywheels.

Nice ideas but read and try at your own risk.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 01-21-2006, 01:00 PM
T buckets rule
 
Join Date: Oct 2005
Location: Hills of TN
Age: 64
Posts: 134
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The people that built my wheel also make major parts for the internaional space station. Yes it has to be perfectley true and balanced, not to mention a good weld on the hub. That wheel will spin almost 2000 rpm at full power. I would hate for it to come apart or come out of the bearings.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 01-21-2006, 01:03 PM
NAIRB's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Sep 2002
Location: cimarron, ks
Posts: 1,658
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
My dad had an old Johnny Pop two lung John Deere, you know the ones with the great big flywheel on it. He was tooling around the corner on it one day and that big flywheel decided to make a break for it. Right through the bank's fron window.


I'm glad there were no fatalaties.
Reply With Quote Quick reply to this message

Recent General Rodding Tech posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Long Awaited 400 SBC Dyno Results Mad Maggot Engine 19 10-14-2011 07:29 PM
Drive shaft broke apart on chassis dyno Steam Roller Engine 6 03-08-2006 02:32 PM
dyno predictions zap60 Engine 26 02-16-2006 02:46 PM
Dyno disaster lust4speed Transmission - Rearend 5 03-01-2005 06:55 PM
Car missing while on Dyno? FBody Engine 11 09-07-2004 10:17 AM


All times are GMT -6. The time now is 11:22 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.