Just seen a post on WSCC asking if anyone knows how to make a diy home rolling road so thought id ask the same Q here.

Calibration wouldnt be an issue as such if you only used it as a comparitor for mods.

There's some software called Home Dyno (which I've probably still got at home somehere). I used it with some success - of course it can only be used for before/after comparisons for modifications but it is useful.

Basically the software takes a .wav sound file which contains "blips" for every spark. The sound file is recorded whilst accelerating in gear (2nd generally) on flat road. The software then works out how your rpm increases over time, and given weight, gear ratios etc it creates an rpm/bhp/torque curve.

The software is designed to be used with an induction pickup on the HT circuit plugged into a line-in recording device (laptop, tape recorder or whatever). However when I used it I hooked up a tap from crank angle sensor to line-in (with resistors to attenuate).

Basically any way you can get a sound file that "clicks" in time with RPM, so even a feed to a digital tacho etc may work.

Very ingenious! I like to have a look at that myself

Their website doesn't appear to exist anymore, but here's an archive of it to see how it all works: -

http://web.archive.org/web/20070701215201/http://ww w.charm.net/~mchaney/homedyno/homedyno.htm

Found this - might be worth a look

Link


[Edited on 25-10-07 by RazMan]

Oops, and the software appears to have landed HERE

Wonder how that happened?

http://www.kaichia.com/forum/forum_posts.asp?TID=1400&PN=2

This comes up every now and again if you're talking about a traditional rolling road then, no, is the sensible answer....... think about it......would you realy want to accelerate your car up to 90mph in your 20x 10ft garage on a set of rollers you made yourself......?

There is a dynometer you bolt to the wheel hubs which 'might' (and I stress the word 'might' ) be a more sensible option but if you REALY want one second hand ones come up quite often and they're not stupidly expensive - not locost either mind you

Or make one youself see:

http://members.fortunecity.com/jasoncuadra/id47.htm

Probably have a go at this once the car is on the road..

Very simple physics and maths and data processing required.. Not to difficult..

Cheers

Dan

"Burgerman"[1] posts on a usenet group I frequent. He runs a few websites incuding this one that has info on dynos.

[1] John Williamson, called burgerman 'cos of his trailer/dyno for bikes, looked like a burger van

Just a thought - You might be able to get an add-on to strap onto your ECU mapping software. This will probably already have datalogging facilities so you don't have to install another sensor for the revs input.

Plonk a laptop on the passenger seat and go out for a blat - a few 2nd gear blasts up and down will really annoy the neighbours though


[Edited on 25-10-07 by RazMan]

I don't see why you would need to record the sound. A pick up from the HT lead would be enough to measure the engine revs over time. Accelerating from 1000 RPM to the red line in, say, second would give a good before and after graph for any changes you'd made.

You record the sound to get it into the computer so your software can graph it. To get ANY data into a computer would need analog-digital converter (ADC). The soundcard is just the easiest way of doing this without buying specialist hardware.

Found another solution: -

http://forums.audiworld.com/vag/msgs/457.phtml

The Butt Dyno.

Designed for VAGCOM, but basically it's a spreadsheet that will be useful if you have any form of datalogger, such as Digidash 1 (digidash 2 software already does dyno plots I believe).

Basically feed it rpm/time etc and it generates a graph in excel.

Also you can record a simple wav file in car and analyse the frequncies (by Goldwave)
The lastet option is to use the Nintendo WII controller since it has a G-sensor.

The Butt Dyno looks quite useful - you might even be able to knock up a simple circuit to take the output from the ecu and convert it to feed the Vagcom proggy.

[Edited on 25-10-07 by RazMan]

quote:

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Originally posted by D Beddows
This comes up every now and again if you're talking about a traditional rolling road then, no, is the sensible answer....... think about it......would you realy want to accelerate your car up to 90mph in your 20x 10ft garage on a set of rollers you made yourself......?

There is a dynometer you bolt to the wheel hubs which 'might' (and I stress the word 'might' ) be a more sensible option but if you REALY want one second hand ones come up quite often and they're not stupidly expensive - not locost either mind you

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The Veypor VR2 digital dash has a BHP / dyno function. Not used it myself yet, but could be used for comparisions of before / after mods.

http://www.veypor.com/

Mike