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Computer tuning SU's?
https://www.ausmini.com/forums/viewtopic.php?f=2&t=58527		 Page 1 of 5
Author:  MG Rocket [ Thu Nov 05, 2009 7:20 pm ]
Post subject:  Computer tuning SU's?
This one is for superdooper Mick and all the other electronic/computer smarts out there.
To electronically measure the height that the SU piston rises...Could you place
a light weight magnet on the outer rim of the piston skirt and then fixed to the outside of the bell a device
that detects the magnet and it's movement?
This could be recorded on a computer along with the readings from a wide band oxy sensor.
Drive the car around in all sorts of terrain and the computer could tell
exactly what was required to get perfect tuning and could give precise custom specs for the needle, theoretically in infinite steps.
Surely this would not be too hard to do?
Author:  GT mowog [ Thu Nov 05, 2009 7:28 pm ]
Post subject: 
Hi MG, hope you don't mind a response from me, but I would equally like to hear what others may suggest.

It would be fairly easy to connect a transducer, to the SU piston, but the method with a magnet is not one I have considered. Funny you raise this because I am developing just such a tool complete with EGO and logger. I think the Doc has tried the EGO and logger bit...

Matt was saying a little while back (here somewhere) that he had a SU bell top that he sacraficed, drilled a hole in it and put a coulored stick in to it, went for a drive and observed said stick, not elaborate but really got the job done.....
Author:  Asphalt [ Thu Nov 05, 2009 8:36 pm ]
Post subject: 
There was someone on turbo-minis who build something like this:
http://www.turbominis.co.uk/forums/inde ... tid=196857

But I guess a coloured stick is all you need, realy (look at the "high-tech stick" on page 2) :)
Author:  74snail [ Thu Nov 05, 2009 9:06 pm ]
Post subject: 
It might be better to think about a sensor to measure fuel to air ratio.


And as far measuring SU piston movement , it might better to look at air displacement by the piston.




.
Author:  MG Rocket [ Fri Nov 06, 2009 9:11 am ]
Post subject: 
Asphalt wrote:
There was someone on turbo-minis who build something like this:
http://www.turbominis.co.uk/forums/inde ... tid=196857

But I guess a coloured stick is all you need, realy (look at the "high-tech stick" on page 2) :)

Thanks for the link Asphalt, that guys idea is really a electronic version of
Mad Matts coloured stick. And of course you have to take the bonnet off to
tune it.
What I was thinking was something that could be installed for an indefinite period and be logged on a computer.

74 snail wrote:
It might be better to think about a sensor to measure fuel to air ratio.
That's why you would also fit a O2 sensor and it would be logged to the computer....to determine exactly at what heights the needle needed modifying to get the correct mixture.
A computer smart guy could create a little program that would draw up a profile of the exact needle your motor needs and then you take this profile to someone with a computer controlled lathe or whatever and presto you have the exact tuning for your motor and driving style...... almost as good as fuel injection.
Author:  sgc [ Fri Nov 06, 2009 9:45 am ]
Post subject: 
You know, funnily enough you could do this with Lego :shock:

All you'd need is a shaft attached to the carb piston with a rack gear, then run a pinion with a shaft encoder. I think you can get a computer interface for this with Lego Mindstorms..
Author:  MG Rocket [ Fri Nov 06, 2009 10:12 am ]
Post subject: 
sgc wrote:
You know, funnily enough you could do this with Lego :shock:

Yeh I reckon it would be quite easy.....for some people...not for me but it would be great for professional tuners and home tuners.
And you gadget guys and ricers at heart, you could have two extra gauges,
one to give you your fuel air ratio and one to give you the needle height....of course entirely pointless....but it gives you something that no one else will have.
Author:  Mick [ Fri Nov 06, 2009 2:54 pm ]
Post subject: 
Its a tricky application because for the heat, vibration and enclosed space inside the bowl..also you don't want to put a friction force on the piston to upset its operation or dampen its natural oscillations...and you have to keep the bowl sealed as well....but with some thought and a decently modified bowl I think it might be able to be done with one of these:
http://www.robot-electronics.co.uk/acat ... ngers.html

It works between 3-6cm, and for the application of 5 volts, it will give you DC voltage back relative to distance. Its still a tricky question however, the operating environment isn't very sympathetic with vibration, heat and a tight working area being the main issue.

But couple the output to a voltmeter for simplicity, create a series of lights or go a little more in depth and attach it to a PIC 12F675 and LCD...its up to you if you think the application is valid.
Author:  mini-dunger [ Fri Nov 06, 2009 3:29 pm ]
Post subject: 
at holdens we use these things called proximity sensors/ reed switches they detect the position of a pneumatic cylinder thats attached to clamps of our jigs .... could be an option?
Author:  mini-dunger [ Fri Nov 06, 2009 3:31 pm ]
Post subject: 
Image

Like this
Author:  mini-dunger [ Fri Nov 06, 2009 3:34 pm ]
Post subject: 
Image

bit better
Author:  Mick [ Fri Nov 06, 2009 3:36 pm ]
Post subject: 
Those proximity switches are just switches. They're a simple 1 or 0 device, the ram is either at one end or its not...

I was trying to think of a sensor I knew of that would do it with a magnet, but its hard because magnets are really all or nothing devices depending on distance from the the sensor. They're either doing nothing, or they're wiping your credit cards.
Author:  MG Rocket [ Fri Nov 06, 2009 4:49 pm ]
Post subject: 
Thanks SooperDooper.
As I said, I know nothin. Those infra red rangers would require installing at the top of a modified bell...as you said. They would then shoot a beam at the piston to read the height. Am I understanding it right? If so...the big plus is no weight on the piston.
I was thinking that with a magnet on the piston and some sort of strip reading device that is the full length of the bell attached to the outside of the bell that could detect the position of the magnet. Or it could be the other way round...
a little ball bearing glued to the piston and some sort of magnetic strip detector attached to the outside of the bell.
The extra weight on the bell could pose a problem especially as it is off centre but given the pistons were once made out of brass ( I think it was the Doc that said this) this should not be too much of a problem.
Author:  Mick [ Fri Nov 06, 2009 5:41 pm ]
Post subject: 
I'm a little worried there might be a little too much interference, if you can find the component locally, I would be willing to give it a shot. I could hook it up to an LCD as well via a 4 dollar micro.
Author:  DOZ [ Fri Nov 06, 2009 6:05 pm ]
Post subject: 
I have used LVDT's for this sort of application in the past although they are quite expensive. They don't have any friction, just the weight of the pin might be an issue...http://en.wikipedia.org/wiki/Linear_var ... ransformer

This could be added to an Innovate Motorsports data logger and fuel ratio meter.

Daniel
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