speed sensor for boost control?
Turbo Mini Forums

I'm looking at picking up an Apexi AVCR electronic boost controller that will do rpm and gear based boost.

The main thing i'm struggling with though is how to provide a speed signal for it so that it knows what gear i'm in. I'm not too hot on electrical stuff so if anyones got any idea's it'd be very appreciated.

couple of links to the manual/wiring diag's for it just incase.
http://www.apexi-usa.com/content/pdf5483.pdf
http://www.apexi-usa.com/content/pdf6115.pdf

I'm hoping i can give it an rpm signal from my mjlj and a pressure signal from the inlet manifold.

Would rather see if it's do-able before blowing the cash on one.

Nick.

Edited by Nick on 25th Aug, 2009.

The speed signal could be interesting, I don't know how it's generated on modern cars but if I get a few quiet evenings I'll look into a way of recreating it on a Mini.

Two microswitches on the gear change rods - 1 for axial movement, 1 for linear movement.

Signal as follows:
00 first
10 second
01 third
11 fourth

Easy, no?

Could you not use a speed signal from the rear wheel then combined with the rpm surely it would be able to calculate it. If so then mount it in the rear brake backplate and count the smooth end of the wheel studs - this is what i have done for my launch control!

On 5th Sep, 2011 Vegard said:
I stand corrected. You should know

A lot of modern cars have the speed sensor at the "back end" of the gearbox using a hall switch or VR type pickup.

But even if you replicated this, it would defeat the point (assuming the intention is to minimise wheelspin) so you would need to rig something up on the back wheel(s).

Something like a Hall switch inside the drum assembly pointing at the back (dome ends) of the studs as they go by ???

EDIT - Scruffy (above) must have been posting while I was typing :)

Edited by Rod S on 25th Aug, 2009.

Schrödinger's cat - so which one am I ???

Can't you weld a small trigger type wheel to a driveshaft?

We are putting a speed sensor on a nut on the HS couplings on the driveshaft. This is for our digital speedo rather than boost control.

I did post a link for a circuit for an optical sensor some time ago. I'll see if I can find it.

Don't worry about wheelspin, the AVCR will still be able to work out which gear you are in as the rpm to driveshaft speed is fixed by the gear ratio.

EDIT: Link

Edited by Paul S on 25th Aug, 2009.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Schrödinger's cat - so which one am I ???

I was also thinking something like this would be better, surely its going to be much more reponsive!

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

Depending on how well the megasquirt boost control works I'm thinking about getting a Apex AVCR for the mig once its up and running for gear dependant boost. The megasquirt works on a tps and rev table but for the time being we'll be running whatever boost the actuator is set to in first and second and then trun on boost control once into 3rd.

Personally I think the future is in traction control, whether it be done by boost control, fuelling, timing or whatever.... (hence my mis-reading the thread earlier).

It should be especially useful for those of you who like the drag strip, and it must be worthwhile as they banned it in F1 a few years ago.

There is an interesting thread on the MS-Extra forum about it.

Schrödinger's cat - so which one am I ???

Yeah hopefully they are bringing back the "Anti-Rev" feature is MS3 :)

Im making a trigger wheel to fit on the pot joint for my speed sensor, mainly for my speedo.

I'll post some pics up, but it'll be a while before I can start it.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Team Racing

Well thats the thing I wasn't sure of. I was thinking of mounting a sensor towards the gearbox end of the pot joint where play would hopefully not be too bad. I can't remember what the fit is like on them TBH. Plan B was to fit a sensor on a modified speedo drive out the back of the box.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

you could aim the sensor at the crown wheel

Team Racing

ah but what about neutral?

No input surely?

because there is a neutral you would need 3 micro switches, one for axial, two for linear. unles somone has a cunning solution.

Just a thought, would it need a nuetral? its not got any boost to control?

ah,

just thought,

you could have both micro switches on in first (11), when you change to neutral or second one will turn off (01),

in third they would swap over (10), and if forth and reverse they give 00.

This all seems very complicated. If you are going to do it with switches then personally I would just rig it to shut a solenoid valve in 1st gear giving a reduced boost level, and then open this up in all the other gears. Once you are moving and into 2nd you should be able to use full shove.

If you wanted simplicity, you'd just lighten your right foot.

But that wasn't the question.

If you want simplicity you fit a boost controller or an ECU with the same facility, with a wheel speed sensor from a driven wheel and an rpm input. This will work every time unlike a load of microswitches crammed into the gearchange housing, linked to god knows what collection of relays and solenoids.

a 3 pin hall efect speedo sensor from any rover with a k-series up to 1.6 litres(r65 gearbox) will fit a mini speedo drive with some minimal bodging(infact, it may just screw straight on!), however you will obviously need to converto to an electronic speedo. the problem is if you fit the sensor on just one driveshaft rather than the diff casing /pinion it will throw the avcr out if one wheel slips more than the other. you could mibby fit a reed switch / hall effect swithc and some magnets on a disk into the mini speedo itself, similar to how early cable driven honda speedo's got a speed output to the ecu.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.